A self-cleaning, automated apparatus with a filter for fluids includes a nozzle unit assembly that has a first tube inside a second tube. Each of the tubes has a different pattern of one or more slots or holes. One tube rotates while the other is fixed, so that part of the pattern of one coincides with the other at times, resulting in a jet of cleaning fluid that removes debris from a filter. The filter is rotated so the jet can reach all parts to be cleaned. The pattern of the rotating tube may approximate a helix and the pattern of the fixed tube may approximate a line.

Two primary classes of water systems are aquatic water systems and filtered water systems.
People exercise, play, and relax in aquatic water systems such as pools, spas, and hot tubs. People and nature make the aquatic water in aquatic water systems dirty, necessitating cleaning. Modern aquatic water systems employ a pump that forces the aquatic water to move through pipes to a filter system to remove impurities. The filter system strains the aquatic water through a filter that traps contaminants such as particles and, in some cases, chemicals. The filtered water recirculates back to an aquatic water reservoir through pipes, in the example of a pool.
People depend on filtered water systems to make water clean enough for a particular purpose such as drinking, farming, raising livestock, or use in industry. A filtered water system takes in water from a source, filters the water through a filter system, and outputs filtered water. Whereas an aquatic water system recirculates the water in a loop, to and from a reservoir such as a pool, a filtered water system receives water from a source and outputs the filtered water to a destination that is not the source. A filtered water system may, for example, be installed in a dwelling to improve the quality or taste of the drinking water. In another example, a filtered water system may be provided in a remote area to give the nearby population access to clean water. In another example, a filtered water system may be transported to the site of a natural disaster to help victims, whose normal supply of clean water is interrupted, obtain drinkable water.
Aquatic water systems and filtered water systems both use filters to trap contaminants. The contaminants trapped in the filter, however, collect over time. As the trapped contaminant accumulate, they begin to fill the filter pores through which the water must pass. The thus-constricted filter pores cannot pass the same volume of water per unit of time, reducing the performance of the water system: less water passing through the filter system leads to fewer contaminants being removed from the water. In an extreme case, the accumulated contaminants restrict the flow of water so much that the pump cannot push water through the filter system, and thus no further contaminants can be removed. The pump and the water quality both suffer degradation or failure.
Conventional approaches teach periodic filter replacement or cleaning.
Filter replacement is expensive and inconvenient. The replaced filter, loaded with contaminants, must be accommodated in a landfill. Filter replacement also requires the attention of a caretaker who periodically checks the filter, exercises judgment as to the timing of replacement, and manually swaps the dirty filter for a new, clean one.
Periodic filter cleaning overcomes some of the disadvantages of filter replacement, but at a price. Filter cleaning, in water systems, takes place outside the filter system or with the filter in its normal place (in situ or inline filter cleaning).
Removing a filter for cleaning can be laborious. Larger water systems have large filter systems with large, heavy filters. Cleaning a filter manually requires significant space and additional equipment. The quality of the manual cleaning operation leaves much to be desired in many instances. Moreover, this process, like that of filter replacement, still requires a careful caretaker.
Inline filter cleaning, until this disclosure of the inventive concepts below, has involved backwashing, a process profusely wasteful of water resources and requiring substantial manual intervention. With conventional inline filter cleaning, the water circulates backwards through the filter system to loosen and flush away contaminants. This cleaning process cleans the filter, but the backwards-flowing water, heavily laden with contaminants, cannot be recirculated to the aquatic water reservoir; it must be shunted out of the system, perhaps into a nearby field, down the drain, into the sewage system, or elsewhere. The volume of water required for successful backwashing increases with the size and dirtiness of the filter.
Backwashing permits filter re-use, an advantage over filter replacement. Backwashing requires less labor than filter removal for cleaning. Nevertheless, the backwashing process requires the caretaker to perform several acts: the recirculating pump is deactivated; the flow of water from the aquatic water reservoir to the filter system is blocked; the water filter system inlet is connected to a hose or pipe that will direct the dirty, backward-flowing water toward its desired destination; the recirculating pump or another pump is activated to force the aquatic water to flow opposite its normal direction, toward the outlet of the filter system; a suitable volume of water is forced backwards through filter; aquatic water is added back to the aquatic water reservoir in the volume that was spent in the backwashing; and at last all of the foregoing steps are reversed to restore normal water flow.
Then, because a significant volume of new, untreated water has been added to the system, the aquatic water in the reservoir is tested and treated as required to achieve health and sanitary standards. The backwashing process is thus labor-intensive and wasteful and does not overcome the requirement for the caretaker perform periodic checks and to exercise judgment as to when the operation should be performed.
Various filter-cleaning technologies have been developed.
U.S. Pat. No. 3,236,249, issued Feb. 22, 1966 (D1, hereafter), teaches an air filter cleaner apparatus for the air filters used with heavy industrial engines. Air is a kind of fluid. These filters have accordion-pleated, folded paper that traps particles in air flowing to an engine. The cleaner apparatus is adapted to clean filters of various sizes and wall thicknesses without changing the cleaner. The filter cleaner design does "not require driving motors or other power devices" and "eliminates all hand labor." This design provides multiple, interior spray heads and multiple, exterior spray heads. The exterior spray heads force water only against the exterior pleats of the air filter, but are angled so that an air filter placed into the cleaner apparatus rotates on a freely-rotatable platform under the force of the water, allowing the entire surface of the air filter's interior to rotate in front of the interior spray heads. The exterior spray heads, however, due to their angle with the exterior of the air filter, spray water not directly into the pleats of the air filter but obliquely, resulting in less effective cleaning compared to a design where the cleaning fluid is sprayed directly into the pleats of the air filter. All of the spray heads, interior and exterior, spray at the same time. Operation of this cleaning system requires the filter be removed from its normal operating location to a separate filter cleaner device.
U.S. Pat. No. 3,297,163, issued Jan. 10, 1967 (D2, hereafter), teaches in FIG. 6 a swimming pool filter that may be cleaned by a stationary jet stream, without separating the filter from its housing. The swimming pool filter in this document is not accordion-pleated but, instead, a series of vertically stacked but spaced disks. Outside the filter is an elongate jet manifold that has multiple jet openings directed inwardly toward the center of the filter. Like the device in D1, the device in this document D2 does not use a driving motor or a power device. Instead, the device includes either a manually operated crank handle or an angled stream of water directed against an impeller that rotates the filter to bring each part of the filter in front of the openings of the stationary, elongate, jet manifold. The filter cleaning operation can be actuated by manually operating a control lever. Like the device in D1, all of the cleaning jet openings operate at the same time.
U.S. Pat. No. 3,363,771, issued Jan. 16, 1968 (D3, hereafter), teaches a filter for possible use in a swimming pool. The filter is not accordion-pleated, but a screen mounted on the outside of a support structure, made of rods, that defines a cylinder. A motor rotates the cylinder during normal operation. This document describes a "nozzle in the form of a slot." This slot is the inlet for the normally circulating water to enter the filter system. This inlet slot directs water to be filtered against the mesh of the screen, covering the rotating cylinder, at an angle in opposition to the direction of rotation of the cylinder. Multiple pipes feed the inlet slot so that the water entering the filter system has a uniform flow along the length of the cylinder. The document teaches that the positioning of the inlet slot, the positioning and use of a mesh, and the location of the rods inside the cylinder close to but not touching the mesh, combine to induce a continuous automatic backwashing operation. The filter in D3 may be suited to remove only large particles which, when jarred loose from the wire mesh, separate out due to gravity.
German patent publication DE3537138A1, published Oct. 18, 1985 (D4, hereafter), teaches a device for cleaning a filter bag used in the manufacture of wet glues. During manufacturing, material is undesirably caked on the outside of the filter bag. To remove the caked-on material, multiple water jets are used on the inside and outside of the filter, all simultaneously operating, to fragment the caked-on material for removal.
U.S. Pat. No. 4,790,942, issued Dec. 13, 1988 (D5, hereafter), teaches a filtration apparatus with a semi-permeable membrane for use in reverse osmosis, ultrafiltration, dialysis, electro-dialysis, water-spitting, pervaporation and microfiltration, where one or more substances are separated from each other. The semi-permeable membrane is made of filter media, which can become clogged by the accumulation of dissolved or suspended material. The cleaning method does not use any directed jets of fluid.
U.S. Pat. No. 5,074,999, issued Dec. 24, 1991 (D6, hereafter), teaches a backflushing assembly for a cylindrical stack of filter disks. The disks are cleaned by introducing a backflushing water supply that induces a fluid-driven rotation to the filter disk stack, and by raising and lowering a backflushing nozzle assembly along the length of the filter disk stack, from within the interior of the stack. The raising and lowering is performed by manually or by introducing pressurized fluid into a cylinder connected to the nozzle assembly.
U.S. Pat. No. 5,989,419, issued Nov. 23, 1999 (D7, hereafter), teaches ways to clean pleated filter cartridges used in swimming pools. The document teaches that the filter is removed from its operational location and rinsed with a garden hose, combing each longitudinal pleat fold with water. The filter is then soaked in a solution of muriatic acid and water to remove calcium or mineral buildup, and then rinsed, loading the cartridge on a spindle rod and then using a garden hose to spray the filter while inducing rotation with the water flow. The document also teaches an in-situ cleaning system that sprays water from either one of two alternative manifolds equipped with multiple nozzle jets. One set of nozzle jets, mounted on one of the two manifolds, is angled to induce a clockwise spin on the filter which is allowed to freely spin on an axle and bearings. Another set of nozzle jets, mounted on the other of the two manifolds, is angled to induce a counterclockwise spin. All of the nozzles of a given manifold operate at the same time.
U.S. Pat. No. 6,156,213, issued Dec. 5, 2000 (D8, hereafter), teaches a system similar to the in-situ cleaning system of D7 for cleaning pleated filter cartridges. This document teaches sets of manifolds either exterior to the filter cartridge or interior to the filter cartridge.
United States patent application publication 2004-0149318, published Aug. 5, 2004 (D9, hereafter), relates to cleaning pleated filter cartridges. This document teaches that such cartridges should be cleaned from the inside-out direction to avoid the further impression of small-sized debris particles into the pleats, which might occur when cleaning from outside-in. In this document, multiple, angled nozzles spray fluid within the cartridge and induce the cartridge to rotate around the spray nozzles. All of the nozzles operate contemporaneously.
U.S. Pat. No. 6,874,641, issued Apr. 5, 2005 (D10, hereafter), teaches a self-cleaning filter assembly for a pleated filter cartridge where the cartridge is mounted on a hydrodynamic bearing that uses a film of water as the load bearing component that enables rotation of the cartridge filter element. A longitudinal manifold sprays fluid from a set of inclined nozzles along the length of the exterior of the pleated filter cartridge to clean the cartridge and also induce the cartridge to rotate on the hydrodynamic bearing. All of the nozzles spray contemporaneously.
United States patent application publication 2006-0243309A1, published Nov. 2, 2006 (D11 hereafter), teaches a portable cleaning device for cleaning paint rollers or spa and pool filters. Cleaning the filter or roller requires removing it from its operational location and placing it in the portable cleaning device. The portable cleaning device connects to a fluid source such as a garden hose; a longitudinal pipe with nozzles sprays water on the filter or roller while a second longitudinal pipe sprays fluid from a single opening onto an impeller to rotate the item being cleaned. All of the nozzles operate at the same time.
France patent application publication FR2913348A1, published Sep. 12, 2008, in the French language (D12 hereafter), appears to show a cleaning device for a hollow, cylindrical element, where an internal, longitudinal manifold and an external, longitudinal manifold simultaneously spray fluid from multiple jets along the length of the element as a motorized gear rotates the element.
France patent application publication FR2944454A1, published Oct. 22, 2010, in the French language (D13 hereafter), appears to show a cleaning device for a cylindrical element, where an external, longitudinal manifold sprays fluid from multiple nozzles along the length of the element. The nozzles are inclined to induce the element to rotate. Some internal nozzles spray fluid over part of the interior of the element.
U.S. Pat. No. 9,422,738, issued Aug. 23, 2016 (D14 hereafter), teaches an elongate nozzle tube arranged outside a filter element made of pleated sheets. The nozzle tube has openings that direct water along the exterior of the filter element. The filter element is rotated. The housing that encloses the filter element and the nozzle tube also includes an ultrasonic transducer tube at one side of the filter to aid in loosening deposits from the filter element surface. In normal operation, the water inlet introduces water to be filtered in an area outside the filter element, and the water outlet removes filtered water from a position interior to the filter element. The top of the filter element is closed by a plug. In a cleaning operation, a drive motor drives the filter element and a pump forces water into the nozzle tube. The nozzle tube has multiple nozzles formed as slots. Water pumped into the nozzle tube by the pump exits all of the nozzles at the same time, all along the length of the nozzle tube.
The more nozzles in use at the same time, however, the lower the pressure of the fluid ejected at any given nozzle.


Genomic instability in T-antigen expressing cells can be overcome by modifying the gene expressing T-antigen so that it lacks Bub1 binding. Stable cell lines can be produced by incorporation of the modified T-antigen gene, preferably together with the catalytic sub-unit of the telomerase construct.

Stroke is the name given to sudden neurological deficits most commonly caused by obstruction or haemorrhage of an artery supplying a region of the brain. Any region of the brain can be affected.
There are an estimated twelve million survivors of stroke in the principal European, American and Japanese markets, with the number of new cases in these markets growing at 7 percent per annum. Approximately 30 percent of stroke patients require ongoing nursing care, estimated to cost between $25 billion to $30 billion per annum in the US alone.
The 20 percent of survivors with moderate or severe disability after stroke are potential candidates for neural stem cell transplantation therapy. Existing drug treatments serving these patients are limited and seek to address the effects rather than the cause of the condition.
Huntington's disease is an uncommon, inherited, progressive and fatal neurodegenerative disorder. In the US, approximately 35,000 patients show overt signs of the disease, with a further 75,000 carrying the abnormal gene. There are no existing treatments for the disease.
Dementia is the most devastating and costly age-related disorder. The most frequently encountered type is senile dementia of the Alzheimer's type (AD), although some (but not all) treatments for Alzheimer's may eventually prove applicable to other dementias. Currently, the cost of caring for Alzheimer's patients, who can no longer safely care for themselves, is estimated to approach $100 billion in the US. Age itself is a risk factor for Alzheimer's, the prevalence of Alzheimer's in the population doubles from age 65 to 75, and again from 75 to 85, at which point 35% show signs of AD. With the ageing of the population, over the next two decades the number of Alzheimer's patients in the US alone will increase from 4-5 million to ten million cases. The social and financial burdens will expand proportionally. Dementia is also seen following loss of blood supply to the brain, for example, following cardiac arrest or some forms of cardiac bypass surgery, also following suffocation or following multiple infarcts in the brain.
Creutzfeld-Jacob disease is a rare disorder, one of a number of transmissible spongiform encephalopathies involving progressive inflammatory neurodegeneration occurring due to the buildup of physicochemically abnormal prion protein. A variant form is seen in cases of variant CJD, a rapidly progressing fatal prion disease mirroring the bovine disorder, "mad cow" disease or bovine spongiform encephalopathy (BSE). The theoretical risk of an epidemic of this disorder in the UK and possibly elsewhere remains, due to the widespread consumption of meat products from BSE-infected cattle during the 1980s and early 1990s.
Traumatic Brain Injury significantly affects over 500,000 individuals annually in the United States alone with a variety of affects from mild concussion to coma and death. 80-85,000 patients annually suffer a head injury that leads to very significant neurological deficit or disability. The estimates of total economic cost place the price tag for TBI at almost $50 billion in the US alone.
Stem cell replacement therapy is seen as a viable treatment option for many diseases including, but not limited to, those described above for which significant cell loss and damage is a cause or consequence. Stem cells can be derived from human tissues at any stage of development, from the early embryo to the adult. Early embryonic stem cells are capable of forming cells from any tissues; however, the cells are likely to form tumours when transplanted. As the tissues develop through the fetal and adult stages, the resident stem cell populations reduce their developmental potential and lose their inherent tumourigenic capacity, becoming somatic stem cells, also known as tissue- or lineage-restricted stem cells. Somatic stem cells are multipotent, that is they are capable of becoming any differentiated cell type from their organ of origin.
Embryonic stem cells can be 'differentiated' or selected to form populations of somatic stem cells, which phenotypically resemble somatic stem cells from fetal or adult tissues and therefore lose their tumorigenic potential (for example, WO03-A-000868). Only somatic stem cells (derived from adult or fetal tissues or differentiated from embryonic stem cells) represent, at the current state of knowledge, safe stem cells for cell therapy. The cell lines described in this invention are examples of somatic neural stem cells.
Somatic stem cells from the brain have been proposed as treatments for intractable neurological disorders including Parkinson's diseases, stroke, Huntington's, and and spinal cord injury. Despite early success in anecdotal clinical reports, controlled transplant studies with primary human fetal brain tissue in Parkinson's disease have, however, failed to deliver any consistent benefits [Freed CR, et al., NEW ENGLAND JOURNAL OF MEDICINE 344 (10): 710-719 MAR. 8, 2001; Olanow et al., ANNALS OF NEUROLOGY 54 (3): 403-414 SEPTEMBER 2003] and widespread clinical application of such transplants is in any case constrained by practical and ethical problems.
The heterogeneity of primary human fetal tissues and cells in terms of both cell purity and quality makes the interpretation of such clinical trials difficult. Alternative products can be built on new knowledge of the potential of stem cells as a source of scalable purified cells and tissues for transplantation. For example, following the demonstration that neuroepithelial stem cells and, significantly, clonal cell lines derived from neroepithelial stem cell populations, can restore functional deficits in animal models of neurological diseases [Sinden et al., NEUROSCIENCE 81 (3): 599-608 DECEMBER 1997; WO-A-9710329; Gray et al., PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES 354 (1388): 1407-1421 AUG. 29, 1999], many groups have shown that fetal human neural cells can be expanded for several months in defined media with additional growth factors either as genetically immortalized (by means of the transduction of different immortalizing genes) or as expanded stem cells using specialised culture methods (sometimes referred to as 'epigenetic' methods) [Flax et al., NATURE BIOTECHNOLOGY 16 (11): 1033-1039 NOVEMBER 1998; Vescovi et al., EXPERIMENTAL NEUROLOGY 156 (1): 71-83 MARCH 1999]. Neural stem cells, as described in the prior art, have been transplanted into experimental animals and have shown evidence of survival. However, these cells and cell lines are not suitable for use in human patients due to their uncontrolled provenance and manufacture and have not as yet shown evidence of functional efficacy in validated animal models of human neurological disease.
Real clinical and industrial progress in human stem cell transplantation is dependent upon the availability of cell lines with controlled sources and manufacturing that are able to expand quickly and serve as a sustainable resource, available on demand to a broad population of patients. Cell lines could be specific to individual disorders or general across a class of disorders. In order to achieve this goal, cell lines must be generated with appropriate biological characteristics (tissue or cell specific phenotype) and must be sufficiently robust to survive a scaleable manufacturing process to make master and working cell banks of frozen vials of cells from which reproducible, GMP—compliant, clinical lots and commercially viable product batches can be derived. One approach to this problem is to use an immortalizing gene to safeguard the regenerative potential of a cell line and prevent it from entering early senescence. Examples of immortalising genes that have been used to generate neural stem cell lines include: (1) telomerase reverse transcriptase (hTERT) [Telomerase immortalization of neuronally restricted progenitor cells derived from the human fetal spinal cord Roy N S, Nakano T, Keyoung H M, Windrem M, Rashbaum W K, Alonso M L, Kang J, Peng W G, Carpenter M K, Lin J, Nedergaard M, Goldman S A NATURE BIOTECHNOLOGY 22 (3): 297-305 MARCH 2004], (2) SV40 T antigen [Sinden et al., op cit, WO9710329], (3) combinations of SV40 T and hTERT (WO0121790) and myc proteins [U.S. Pat. No. 5,580,777; Flax et al., op cif]. Genetic overexpression of c-myc, a naturally occurring protooncogene that is normally expressed during cell development, is demonstrated in this invention as a means of stably enhancing cell proliferation and preventing changes in cell karyotype, thereby avoiding transformation of the cell phenotype.
Following from considerable experience in developing stem cell lines as therapeutics, we believe the following represent the key features of a human stem cell line for application in the clinic:                Multipotent cells that can develop into specific cells typical of the tissues that are targeted for transplantation.        Cells that are derived from a single founder cell (clonal cells)        Genetically stable cells with normal chromosomes        Cells that have the ability to differentiate into appropriate cell types, in vitro and in vivo.        Cells that can be grown in large numbers and stored        Cells that are safe, particularly not showing tumourigenic potential        Cells whose migration, once implanted, is limited to areas of tissue damage        Cells that are efficacious in recognised animal models        Cells whose provenance is fully documented
While expansion of stem cells on surface or suspension culture is possible without genetic immortalisation ('epigentic' culture), expansion of human neural stem cells is slow and the resulting cultures contain a high proportion of differentiated progeny, which will not survive subculture manipulations [WO99-A-11758, Vescovi et al., op cit]. Further, long term culture of 'epigenetic' stem cells may induce chromosomal alterations that may prevent the clinical application of the cell lines. There are no reports of genetic stability of human epigenetic somatic cell lines, although recent reports have indicated chromosomal aberrations in embryonic stem cell lines at greater passage numbers [Draper et al., NATURE BIOTECHNOLOGY 22 (1): 53-54 JANUARY 2004; Inzunza et al., MOLECULAR HUMAN REPRODUCTION 10 (6): 461-466 JUN. 1 2004].
Therefore, the scalability of epigenetically expanded cell lines is limited from an industrial point of view and the product may vary from cell passage to cell passage. The use of an immortalising gene that will not generate a transformed cell phenotype or otherwise influence the stem cell's biological potency or safety but otherwise enhance the cell's industrial scalability and stabilise the karyotype is highly desirable.
Over the past 10 years increasing information has been emerging about the role of myc oncogenes in normal and cell proliferation, differentiation and apoptosis. To maintain cell proliferation Myc and Max proteins dimerise and translocate to the cell nucleus where they serve as transcription factors. Recently Coller et al., [PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, 2000; 97:3260-3265] identified 27 genes that were induced, and 9 genes that were repressed by activation of c-myc (cellular myc) in primary human blastocysts. Induced targets included cell cycle genes (e.g. G1 cyclin D2) required to maintain division, and pro-apoptotic genes (e.g. TRAP1) involved in cell death, while repressed targets included genes encoding extra cellular matrix and cytoskeletal proteins, indicating a role for myc in cell adhesion and structure. A recent report has shown that a v-myc (viral myc)-immortalised murine neural stem cell line is able to promote the regeneration of damaged neurons in a Parkinson's disease animal model and promote functional recovery [Ourednik et al., NATURE BIOTECHNOLOGY 20 (11): 1103-1110 NOVEMBER 2002].
The ability of c-myc to maintain cell proliferation makes it a prime candidate for stem cell immortalisation, provided that cell division can be regulated in vivo. For therapeutic use of myc-immortalised cells, a preferred embodiment would permit control over the function of the Myc protein, such that the immortalising protein was not functional after transplanting the cells. This would reduce the risk of overgrowth or tumour formation by the transplanted cells. A preferred conditional form of Myc is a fusion between Myc and the hormone-binding domain of a modified estrogen receptor [Littlewood, et al., NUCLEIC ACIDS RESEARCH, 1995; 23, 1686-1690].


A method and apparatus for reducing ingress noise (304) in the upstream frequency band and reducing power consumption in a cable communication system (200) by not allowing signals generated in the customer premise (104) to enter the upstream frequency band on the cable network (110) unless a customer premise device (102) is attempting to establish a communication link. An RF detector (206) monitors the signals on the coaxial cable for an RF signal. The comparator (208) indicates to the logic circuit (210) when the RF signal has exceeded a minimum threshold. The logic circuit (210) determines if the subscriber premise device (102) is attempting to establish a communication link. If the subscriber premise device (102) is transmitting the logic circuit (210) closes the ingress switch (212) to connect the subscriber premise device (102) to the network.

The present invention relates, in general, to cable communication systems, and more particularly to cable data communication systems.
Cable communication systems are being designed to handle a wide variety of services including telephony, video and data. One method of integrating these services is by using a system similar to cable television systems. The cable network consists of several cables, splitters, combiners and amplifiers. A plurality of customer premise devices such as televisions, computers, set top boxes and modems are typically connected to a cable network through a single coaxial cable routed throughout the customer premise. The connection is made to the cable network through a cable access unit which is typically mounted on the outside of the customer premise. Other customer premise equipment such as telephones and FAX machines may be connected to the cable access unit through other types of cabling such as twisted pair wiring.
Typically, a frequency band is chosen for upstream transmissions (transmissions from the customer premise to the network) which is different from the frequency band for downstream transmissions (transmissions from the network into the customer premise).
Poor connections, faulty cables, and noise from customer premise devices introduced in the upstream frequency band contribute to ingress noise in the cable network. Faulty connections and broken cables couple radio signals and noise into the cable network. In addition, customer premise devices may introduce noise generated in the customer premise device into the cable network. Local oscillators and phase lock loops, for example, may generate harmonics in the upstream frequency band and be a source of ingress noise.
Since the customer is responsible for the cabling inside the customer premise, the service provider typically cannot control or predict the quality and condition of the cabling and customer premise devices in the customer premise. Noise in the upstream frequency band cannot be eliminated by simple filtering since the frequency at which the noise occurs cannot be predicted and since the noise will likely occur in a channel that is being used for upstream communication and, therefore, cannot not be attenuated. Ingress noise becomes more problematic as the number of customers on the cable network increases.
Typical cable communication systems power the subscriber cable access units from the network through the cable. This allows for the system to operate when power is not available through the subscriber premise. Although the power consumption of each individual cable access unit may not be large, the combined power requirements on the network are significant. A slight reduction of power consumption of each cable access unit can greatly reduce the demand on the system.
Therefore, there exists a need for a method and device for reducing the level of ingress noise and reducing power consumption in a cable communication system.

Data communication apparatus and method thereof


A slew-limited output driver circuit facilitates finding a circuitry that allows a flexible setting of the slew-rate of an integrated circuit, with only a small footprint and latency, and which allows realizing different driver modes without additional components integrated protection against ESD. A short circuit will be solved by a slew-limited output driver circuit comprising a switchable current mirror providing an output current equal to an input current, wherein the current mirror is controlled by an additional switch, which is switched in response to control signals and/or an output current level of the output driver circuit, wherein adjustable operating modes of the slew-limited output driver circuit are realized by the control signals.

With output drivers, fast rise times can cause electromagnetic emissions and noise. Furthermore, high output currents due to electro-migration reduce the life of said circuits. It is therefore desirable that an adequate limitation of the signal rise times would eliminate the disturbing effects. The signal rise times are related to the slew-rate which is defined as the change of voltage or current, or any other signal quantity, per unit of time.
In the prior art, various possibilities for limiting the rise time are known, which can be subdivided essentially into two groups: According to U.S. Pat. No. 6,441,653, namely the limitation of the output current and according to U.S. Pat. No. 7,471,111, namely the detection and adjustment of the voltage profile at the output pad of the driver.
The limitation of the output current possesses the following disadvantages: Resistors in the output path require high layout space for the resistive components, as a high current carrying capacity and thermal stability must be ensured. Furthermore, the signal level at the resistive load will be disturbed by the resulting resistive voltage divider between the driver and the current limiting. Also a dynamic change of the resistance value is difficult to manage.
If a current source as an output driver, as in U.S. Pat. No. 7,471,111, is used no low-impedance driver will be feasible and the signal level at the resistive load will be disturbed as well.
Also the detection and adjustment of the voltage curve at the output pad of the driver according to the prior art has a few disadvantages. On the one hand, if the output driver is regulated based on the output level, for example if, like in U.S. Pat. No. 6,441,653 the output current of the preamplifier is reduced in accordance with the output voltage, whereby the driver transistor is turned on slowly, it is detrimental that the recharge current of the preamplifier is partially dissipated. Furthermore, the output voltage shows a non-linear characteristic due to the variable gate voltage of the output driver, and an ESD (electrostatic discharge) protection for the transistor gate of the feedback will be necessary. On the other hand, if a reference edge is used and its replication has to be generated at the output of the output driver a high circuitry complexity is necessary, the switching speed is limited and there is a high latency in the signal path.
It is therefore the purpose of the invention to find a circuitry that allows a flexible setting of the slew-rate of an integrated circuit, with only a small footprint and latency, and which allows realizing different driver modes without additional components integrated protection against ESD and short circuit.


A vehicle generator controller comprises a voltage detection circuit for outputting a voltage detection signal D to regulate a generated voltage VG in accordance with a battery voltage VB, a gradual increase control circuit for outputting a gradual increase control signal E in response to the voltage detection signal D and a switching element for intermittently controlling a field voltage in response to the gradual increase control signal E, the gradual increase control circuit includes a smoothing circuit for smoothing the voltage detection signal D by a charging time constant and a discharging time constant and a comparator for outputting the gradual increase control signal E by comparing the smoothing signal with a triangle voltage, both the charging time constant and the discharging time constant of the smoothing circuit are set to one second or more and the gradual increase control signal E moves to a waveform for gradually decreasing the field voltage when the battery voltage increases. With this arrangement, the vehicle generator controller suppresses a torque shock when an electric load is turned on as well as suppresses the drop of a battery voltage when the electric load is repeatedly turned on.

1. Field of the Invention
The present invention relates to a vehicle generator controller for gradually increasing the current generated by a generator by gradually increasing a field current by intermittently operating a switching element when a battery voltage is dropped by the turn-on of an electric load, and more specifically, to a vehicle generator controller by which the cyclic drop of the battery voltage is suppressed when the electric load is repeatedly turned on and off.
2. Description of the Related Art
Conventionally, in a vehicle generator controller, since a torque shock is caused when a generated current is increased in instant response to the drop of a battery voltage, the current generated by a generator is gradually increased by gradually increasing a field current by the gradual increase of a conducting ratio (duty) executed by the intermittent operation of a switching element.
FIG. 2 is a circuit diagram showing a conventional vehicle generator controller disclosed in, for example, Japanese Unexamined Utility Model Publication No. 64-34900.
In the drawing, a generator 1 driven by an internal combustion engine (not shown) includes an armature coil 101 and a field coil 102 and is mounted on a vehicle.
The rectifier 2 of the generator 1 for subjecting the ac output from the generator 1 to full wave rectification includes an output terminal 201 acting as the main output terminal of a generated voltage VG, an output terminal 202 for exciting the field coil 102 and an output terminal 203 for the ground.
A controller for controlling the field current IF (generated current IG) of the generator 1 is composed of a voltage regulator 4 for regulating the output voltage VG (battery voltage VB) from the generator 1 to a predetermined value, a smoothing circuit 5 for smoothing the voltage detecting signal D of the battery voltage, a comparison circuit 7 operating in response to the output signal level from the smoothing circuit 5 and a constant voltage power supply circuit 8 for creating a constant power source A.
The smoothing circuit 5 and the comparison circuit 7 constitute a gradual increase control circuit for gradually increasing the field current IF of the generator 1 when the battery voltage VB drops.
A battery 9 mounted on the vehicle is charged by the output created by the generator 1 through the rectifier 2. A key switch 10 is connected to an end of the battery 9. The electric load 11 of the vehicle such as head lights, an air conditioner and the like is connected between both the ends of the battery 9. A switch 12 for imposing the electric load 11 is inserted between an end of the electric load 11 and one of the ends the battery 9.
The voltage regulator 4 includes resistors 401, 402 for creating a detected voltage Vb by dividing the voltage VB of the battery 9, resistors 403, 404 for creating a reference voltage VR by dividing the constant power source A, a comparator 405 for outputting a voltage detection signal D by comparing the detected voltage Vb with the reference voltage VR, an emitter-grounded transistor 407 inserted to the field coil 102 in series therewith for intermittently controlling the field current IF, a diode 408 for absorbing the surge caused by the intermittent operation of the transistor 407 and a resistor 409 inserted between the base of the transistor 407 and the output terminal 202.
The voltage regulator 4 includes an emitter-grounded transistor 410 having a collector connected to the base of the transistor 407, a pair of diodes 411, 412 inserted in series between the output terminal of the comparator 405 and the base of the transistor 410 in inverted polarity and a resistor 413 inserted between the constant power source A and the point where diode 411 is connected to the diode 412.
The smoothing circuit 5 includes a pair of diodes 511, 512 connected in series to the output terminal of the comparator 405 in inverted polarity, a charging resistor 513 inserted between the constant power source A and the point where the diode 511 is connected to the diode 512, a capacitor 503 inserted between the cathode of the diode 512 and the ground and a discharging resistor 515 connected in parallel with the capacitor 503.
The comparison circuit 7 includes a comparator 702 for outputting a gradual increase control signal E by comparing a triangle voltage VT created from a triangle generator 701 with the capacitor voltage VC from the capacitor 503, an emitter-grounded transistor 712 inserted between the base of the transistor 407 and the ground and a resistor 713 inserted between the point where the base of the transistor 712 is connected to the output terminal of the comparator 702 and the constant power source A.
With this arrangement, the comparison circuit 7 creates an intermittent control signal based on the gradual increase control signal E to thereby create an intermittent control signal F to the field coil 102 by the intermittent operation of the transistor 407, so that the comparison circuit 7 gradually increases the field current IF and the current generated by the generator 1.
The gradual increase control signal E which is output from the comparator 702 gradually increases the conducting duty of the transistor 407 in response to the voltage which is output from the smoothing circuit 5, that is, to the capacitor voltage VC to thereby gradually increase the field current IF.
A series circuit composed of a diode 111 and an initially exciting resistor 112 is inserted between the key switch 10 and an end of the field coil 102.
The constant voltage power supply circuit 8 is composed of a series circuit inserted between the key switch 10 and the ground and including a pull-up resistor 801 and a Zener diode 802.
With this arrangement, when the key switch 10 is turned on, the constant power source A is created from the point where the pull-up resistor 801 is connected to the Zener diode 802 based on the battery voltage VB.
Next, operation of the conventional vehicle generator controller shown in FIG. 2 will be described with reference to the waveform views of FIG. 3 and FIG. 4.
FIG. 3 and FIG. 4 show the change in time of respective signals D-F and respective voltages VB and VC as well as the current which is output from the generator, that is, the current IG generated therefrom which corresponds to the turning on and off of the electric load 11, wherein FIG. 3 is an operation waveform view when the head lights, defoggers and the like which are usually in an on-state are turned on and FIG. 4 is an operation waveform view when a hazard indicator, a winker and the like which are intermittently imposed are turned on.
In this case, since the charging resistor 513 in the smoothing circuit 5 has a relatively small resistance value and the discharging resistor 515 therein has a relatively large resistance value, a charging time constant is set to a short time of about 100 milliseconds and a discharging time constant is set long of about a few seconds.
Further, it is assumed that the voltage detection signal D from the comparator 405 and the gradual increase control signal E from the comparator 702 exhibit an approximately equivalent operation waveform in the usual state that the electric load 11 is not turned on.
First, when the key switch 10 is turned on, the battery voltage VB of the battery 9 is imposed on the Zener diode 802 through the resistor 801 and the constant power source A which is clamped by the Zener diode 802 is created from the point where the resistor 801 is connected to the Zener diode 802.
With this operation, although the controller of the generator 1 is made to an operable state, since the generator 1 does not yet start power generation, the signal level on the non-inverting input terminal (+) side of the comparator 405 in the voltage regulator 4 is lower than the reference voltage VR on the inverting terminal (-) thereof and accordingly the comparator 405 outputs the voltage detection signal D of a level.
At the time, since the capacitor 503 in the smoothing circuit 5 is not charged, the capacitor voltage VC has a zero potential. Therefore, the signal level on the non-inverting input terminal (+) side of the comparator 702 in the comparison circuit 7 is lower than the triangle voltage VT and the gradual increase control signal E is fixed to a low level and the transistor 712 remains in an off-state.
Consequently, the transistor 407 is turned on and the field current IF flows to the field coil 102 to thereby put the generator 1 to a power generation possible state.
When the internal combustion engine starts operation and the generator 1 starts power generation by being driven by the internal combustion engine, the signal level on the non-inverting input terminal (+) side of the comparator 405 in the voltage regulator 4 is increased by the increase of the battery voltage VB. When the signal level on the non-inverting input terminal (+) side becomes higher than the reference voltage VR, the voltage detection signal D is switched from the low level to a high level and the transistor 407 is switched from a conducting state to a shut-off state.
As described above, the voltage regulator 4 detects the battery voltage VB at all times and when, for example, it detects the drop of the battery voltage VB, it increases the conducting ratio of the transistor 407 through the comparator 702.
Since the field current IF is increased by the increase of the conducting ratio of the transistor 407 and the battery 9 is charged by the increase of the output from the generator 1, the battery voltage VB is controlled to a constant rated voltage.
When, for example, the switch 12 is turned on and the electric load 11 is turned on, the comparator 702 is operated and the field current IF is increased by the drop of the battery voltage VB.
At the time, although the comparator 405 which responds to the battery voltage VB creates the voltage detection signal D of a low level by increasing the conducting duty of the field current IF, since the discharging time constant of the smoothing circuit 5 is set longer than the charging time constant thereof, the comparator 702 in the comparison circuit 7 increases the conducting ratio of the transistor 407 so as to gradually increase the duty.
Therefore, as the conducting ratio of the transistor 407 increases, the field current IF gradually increases so that the output from the generator 1 gradually increases while suppressing a response shock.
When, for example, the usually-turned-on electric load 11 (head lights, defoggers and the like) is turned on, the voltage detection signal D intends to increase the conducting duty by becoming to the low level when the electric load 11 is turned on as shown in FIG. 3. However, since the capacitor voltage VC is dropped by the long time constant and the duty of the low level section of the gradual increase control signal E is gradually increased, the generated current IG is gradually increased while being suppressed without reaching a value corresponding to the response at once.
At the time, the battery voltage VB temporarily drops by a drop amount VB when the electric load 11 is turned on.
Further, when the electric load 11 is turned off because the switch 12 is shut off, since the voltage detection signal D of the high level which is output from the comparator 405 is imposed on the transistor 407, the intermittent control signal F is made to an operation waveform equivalent to the voltage detection signal D which relatively promptly returns to the waveform before the electric load 11 is turned on.
At the time, since the charging time constant determined by the resistor 513 and the capacitor 503 in the smoothing circuit 5 is short and the capacitor voltage VC is promptly charged as shown in the drawing, the gradual increase control signal E from the comparator. 702 also relatively promptly returns to the waveform (waveform in the low level section having a small duty) before the electric load 11 is turned on.
Likewise, when the electric load 11 (hazard indicator, winker and the like) which is intermittently imposed is turned on, the battery voltage VB also temporarily drops by the drop amount VB when the electric load 11 is turned on as shown in FIG. 4.
Thereafter, when the electric load 11 is turned off in the cyclic turning on and off thereof, the gradual increase control signal E which is output from the comparator 702 returns to the waveform before the electric load 11 is turned on.
At the time, since the gradual increase control signal E promptly returns to the waveform before the electric load 11 is turned on as described above when the electric load 11 is turned off, the battery voltage VB also temporarily drops by the drop amount VB when the electric load is turned on next time likewise the time when it was turned on for the first time.
Therefore, since the battery voltage VB cyclically drops each time the electric load 11 is repeatedly turned on in the case of FIG. 4, the head lights which have been turned on lower their quantity of light cyclically, by which the driver is made uncomfortable.
As described above, although the conventional vehicle generator controller gradually increases the field current (generated current) by the gradual increase control circuit composed of the smoothing circuit 5 and the comparison circuit 7 so as to suppress the torque shock when the electric load 11 is turned on, since the charging time constant is set short, the capacitor 503 is the smoothing circuit 5 is charged in a short time when the electric load 11 is turned off. Thus, there is a problem that when, in particular, the electric load 11 is repeatedly turned on and off, the battery voltage VB greatly drops each time the electric load 11 is turned on, by which the driver is made uncomfortable.
An object of the present invention made to solve the above problem is to provide a vehicle generator controller for suppressing a torque shock which is caused in response to the turn-on of an electric load as well as suppressing the drop of a battery voltage when the electric load is repeatedly turned on.


The present inventions provide a controlling device for reducing external interrupts for a processor and the method thereof in a real time system. The controlling device decides whether it should trigger a real interrupt to the processor or combining as many interrupts as possible in one interrupt. The controlling device comprises a buffer, an interrupt controller, and an interrupt recording table. The interrupt controller receives interrupts, then saving information of interrupts to the buffer and reading out limitations of the interrupts, the limitations including interrupt deadlines and processing time of each interrupt. The interrupt recording table stores the limitations of each interrupt. The interrupt controller comprises a timer for counting timing references of the interrupt signals. After receiving an interrupt, the interrupt controller compares the limitations and selectively sends an interrupt signal, a real hardware interrupt, to the processor.

Referring to FIG. 1, in a general real time system, when a external device 100, such as I/O device or bus, send an external interrupt request to an processing unit 101, such as CPU, DSP, the processing unit 101 immediately processes the Inter Service Routine (hereafter ISR) corresponding to the interrupt after receiving it.
However, when the external device 100 sends too many interrupts to the processing unit 101 to be processed immediately by the processing unit 101. If the processing unit 101 processes every interrupt requests and processes the corresponding ISR, sometimes, it is easy to reduce the processing speed of a CPU or a DSP. Thus, the system efficiency is decreased and the difficulty of debugging is increased to cause unpredictable interrupt and may reduce the system efficiency.

Method and apparatus for multi-interrupt controller for reducing hardware interrupts to DSP


A new Portable Sound System for providing a sound system which is operable while mounted in a vehicle and also operable independent of any such mounting The inventive device includes a housing, a sound signal generating unit located in the housing a housing speaker mounted in the housing and electrically connected to the sound signal generating unit and a mounting frame permanently mountable in a vehicle wherein the housing is removably mountable in the mounting frame and wherein the housing and the mounting frame include mating connectors for connecting the sound signal (generating unit to the electrical power system of the vehicle and the vehicle speakers when the housing is mounted in the mounting frame. A power supply is provided in the housing for powering the sound signal generating unit when the housing is removed from the mounting frame. The power supply may be a rechargeable battery that can be recharged by the electrical power system of the vehicle when the housing is inserted in the mounting frame.

1. Field of the Invention
The present invention relates to sound systems and more particularly pertains to a new Portable Sound System for providing a sound system which is operable while mounted in a vehicle and also operable independent of any such mounting.
2. Description of the Prior Art
The use of sound systems is known in the prior art. More specifically, sound systems heretofore devised and utilized are known to consist basically of familiar., expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art sound systems include U.S. Pat. No. 4,784,361; U.S. Pat. No. 5,441,421; U.S. Pat. No. 5,381,684; U.S. Pat. No. D317,607; U.S. Pat. No. 4,450,495 and U.S. Pat. No. 5,341,434.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new Portable Sound System. The inventive device includes a housing, a sound signal generating unit located in the housing, a housing speaker mounted in the housing and electrically connected to the sound signal generating unit, and a mounting frame permanently mountable in a vehicle, wherein the housing is removably mountable in the mounting frame and wherein the housing and the mounting frame include mating connectors for connecting the sound signal generating unit to the electrical power system of the vehicle and the vehicle speakers when the housing is mounted in the mounting frame.
In these respects, the Portable Sound System according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of providing a sound system which is operable while mounted in a vehicle and also operable independent of any such mounting.


The siphoning device, with measuring indicators, is used for liquid--liquid separation. The body member has an outlet with an open tip; the outlet can have a peripheral rim with notches proximate the open tip. A two-way liquid valve contoured to approximate the contour of the interior of the outlet, controls liquid flow out of the body and permits flow into the body. A stem portion affixed to the liquid valve extends through and beyond the open tip of the outlet. Pressure on the stem places the valve in an open position and permits liquid to be discharged. An air pump interacts with the body to expel air and draw in the liquids. Generally the air pump is a flexible bulb with a one-way air valve to restrict air flow into the hollow body while permitting air flow out. The hollow body can be in two parts which are removably connected to one another. The travel of the liquid valve within the hollow body is limited by stops.

1. Field of the Invention
The invention relates to a siphoning device having particular utility as a "food baster," but also lending itself for use as a device for medical, scientific and industrial applications. The device can be used for the separation of immiscible liquids. The device can further be used for withdrawal of a measured or unmeasured amount of liquid from a container in one location, storage of the liquid during transportation and deposit of the liquid in a container at a remote location. The device uses a combination of an air valve and a liquid valve.
2. Brief Description of the Prior Art
The devices commonly known as basters do not effectively contain the liquid which has been drawn into the device. Typically these devices expel some of whatever liquid the user is attempting to move before the device has reached the final destination.
The term baste is used in the application consistent with the definition in the American Heritage Dictionary, Third Edition, Copyright 1994, InfoSoft International, as follows:
baste tr.v. basted, basting, bastes. To moisten (meat, for example) periodically with a liquid, such as melted butter or a sauce, especially while cooking. baster n. PA1 1. Fluid leaks due to flow under the force of gravity. PA1 2. When hot liquid is used, air above the liquid expands and pushes the liquid out, making the handling of liquids difficult and dangerous. PA1 3. The amount of liquid that can be drawn up is limited by the size of the bulb and the air trapped within the bulb. PA1 4. Making exact liquid measurements are difficult, because of leaking of the device and the inability to control the amount of liquid drawn into the device.
In its simplest form (hereinafter referred to as the `simple baster`) the simple baster consists of only two parts. The first part is the bulb, which is typically made of rubber or a rubber-like plastic. The bulb is generally thick and soft to allow for flexibility as the device is operated by squeezing and releasing the bulb by hand. The second part is a hollow round tube or cylinder, tapered at one end to a small opening. The bulb is attached to the tube at the wider end, with the small opening being used to collect and disperse liquids. While baking meat, to add flavoring and prevent dehydration, it is desirable to take broth or meat juices to baste the meat. The baster is employed in this endeavor by holding the device in one hand and ejecting some of the air from the bulb. The lower end of the tube is placed below the liquid surface, the bulb is released and the vacuum draws the liquid into the tube. The tube is then moved to the top of the meat being cooked, the bulb is squeezed and the liquid is ejected over the meat. In the simple baster, when the liquid is drawn into the tube, it is frequently hot. The hot liquid heats the air in the tube and the bulb, causing expansion of the air. The expansion of the air forces at least some of the liquid out the tube. It is often impossible to draw or retain enough liquid in the baster to adequately baste the meat. Attempts to contain the liquid by turning the tube over, bulb end down, can leak hot liquid in an uncontrollable and dangerous fashion. Turning the baster all the way places the bulb, filled with hot liquid, near the user's hand and may cause burns through the flexible bulb.
Another way the simple baster is often used is to separate the meat juices into their component lighter fat and heavier water-soluble parts. When separated from the fat, the heavier water-soluble material is frequently used as a component in gravies. The heavier materials will be referred to as `flavorings`. While it would be desirable to wait for a brief time for the fat and flavorings to separate, for distribution into different containers, this is not always feasible. The nature of the simple baster is not well suited for use as a separator because the contents begin to exit as soon as they have entered, often with outside air bubbling through and remixing the liquids to be separated. Any attempts to draw all the pan juices into the baster for separating in one operation results in mixing the pan juices, just the opposite of the desired separation.
Among the problems encountered in the simple baster is the inability to prevent the liquid from dripping out due to simple gravity. Further, the heat of the air trapped above the liquid, in both the tube and bulb, drives the liquid out of the baster in an uncontrolled manner.
Another shortcoming of the simple baster is the inability to measure or control the exact amount of liquid delivered by the baster. The only control over the volume entering the tube occurs when the bulb is squeezed a particular amount or the inlet pulled out of the liquid. The user must estimate how much to squeeze the bulb prior to insertion into the liquid, since squeezing the bulb after the tube has been partially filled drives the liquid out of the baster. Thus, the device cannot be operated in a cumulative manner.
The simple baster, or a similar device, can also be used for a multitude of tasks that involve moving liquids. These liquids can be hot or cold, acid or base, aqueous or not, highly fluid or partially viscous.
Small versions of the prior art simple baster, such as the medicine dropper, generally operate as intended. Volatile solutions, however can generate vapor pressure sufficient to force the liquid from the tube. Due to the small amount of liquid, the capillary action and/or surface tension, are sufficient to allow the dropper to retain the liquid until it is dispensed. As the medicine dropper is enlarged to the size of the simple baster, the flaws of the design appear.
Capillary action, as used herein, refers to the force that results from greater adhesion of a liquid to a solid surface than internal cohesion of the liquid itself. This action causes the liquid to be raised against a vertical surface, as water is in a clean glass tube. Surface tension, as used herein, refers to a property of liquids arising from unbalanced molecular cohesive forces at or near the surface. As a result, the surface tends to contract and has properties resembling those of a stretched elastic membrane.
In summary, the prior art simple basters are deficient in at least four ways:

Siphoning device for use in basting, measuring or immiscible liquid separation


A metal-enclosed, gas-insulated switchgear assembly having at least one active part (19) is mounted in an enclosure extended along an axis (18). The active part (19) is provided on at least one side with a contact-making assembly (25). The contact-making assembly (25a) is electrically conductively connected to a connecting part (26) which is provided with a shielding electrode (28). The shielding electrode (28) is connected to a supporting element (35) which bounds an intermediate area (40). The supporting element (35) is connected, on the side facing away from the shielding electrode (28), to a fitting (37) which has holes (39) which originate from the intermediate area (40) and are designed to hold fixing screws. The connecting part (26) is designed for advantageously simply assembly. The connecting part (26) dielectrically shields the heads of the fixing screws.

1. Field of the Invention
The invention is based on a metal-enclosed, gas-insulated switchgear assembly as claimed in the preamble of claim 1.
2. Discussion of Background
Patent Specification EP 0 382 323 B1 discloses a power breaker for a metal-enclosed, gas-insulated switchgear assembly, which has a connecting part for electrical connection on the side of a quenching chamber facing away from the drive. This connecting part is designed advantageously in dielectric terms and is electrically conductively connected to the active part of the bushing. The heads of the screws which rigidly connect the connecting part to the said active part of the bushing are covered by a metallic shield, which acts as dielectric shield. When the connecting part is being fitted and removed, this shroud must also always be fitted, and respectively, removed, which involves additional assembly complexity.

Metal-enclosed, gas-insulated switchgear assembly


A system, method and program product for implementing a dynamic programming platform. An embodiment is disclosed having: a system for generating code for a multithreaded runtime environment, wherein the system includes an infrastructure for sharing bulk data between different threads without data-level synchronization; and a bulk data processing system having a set of bulk data operators that can operate on slices of the bulk data during runtime while different threads process the bulk data.

1. Technical Field
The present invention relates generally to dynamic programming environments, and more particularly to a dynamic programming platform that supports bulk data operators designed to operate in a shared memory space in a multithreaded environment.
2. Related Art
In data-centric software development, it is typical to identify and lay out blocks of raw data (typically large volumes of floating point or integer data) that developers desire to access both (a) en masse (rather than at the element level) and (b) from multiple threads with as little synchronization overhead as possible.
As to (a), accessing data en masse rather than at the element level generally makes code more compact and maintainable, but also increases overall performance significantly because loops that had to previously make passes though data elements instead appear as primitive and compact operations within the language execute in efficient, native, "tight" loops with minimal overhead.
Regarding (b), developers also seek to access shared blocks of data from multiple worker threads in organized ways specifically designed to remove the need for thread synchronization. When worker threads can easily access and operate on sub-sections of the data in a parallel fashion, then the host platform's hardware can be fully loaded with negligible synchronization overhead (rather than, e.g. confining computation to a single thread or be impaired by costly use of OS-level heavyweight synchronization). For example, it's typical and effective for large buffers to be shared between worker threads where, by design, each worker thread only accesses predetermined sub-ranges of the input and output data buffers. This allows multiple worker threads to run simultaneously without synchronization overhead since their working range of data access has been designed so that each worker thread can read and write concurrently without any possibility of data loss or corruption due to race conditions.
These "developer knows best" design patterns are attractive because they require no synchronization overhead and crafted to be inherently safe and uncomplicated. However, if a dynamic language runtime imposes a synchronization specification for all data access, then even a multi-threaded design pattern without any need for synchronization will perform poorly as each data element access incurs the synchronization overhead imposed by the runtime environment.
There is a clear demand for software developers to access large blocks of raw data (a) en masse to reduce total overhead and (b) in sub-sections that multi-threaded worker design patterns can leverage to remove any need for data access synchronization. That is, as dynamic languages evolve, it's clear there's a contemporary demand for built-in, high performance, "element-wise" computation on large blocks of raw data that can be accessed outside the language's normal requirements of object safety and synchronization.
There are a number of third-party add-ons that deliver data computation tools that address some of these aspects (generally associated with efficient and parallelizable bulk data computation), but by nature of being third-party add-ons, they impose restrictions on the host platform and therefore the portability of code that uses these add-ons. Because they also add-on to the language environment, they require developers to invest time setting up the add-on and learning the details and nuances of the particular add-on. Host platform restrictions or a new learning curve may not impede some developers, but they do restrict a language's broader appeal since every developer interested in clean and efficient bulk data computation is immediately burdened with having to reinvent the computational wheel (or at least shop around for one and deal with installing it).

Dynamic programming platform for implementing bulk data operators in a multithreaded environment


A method of monitoring acoustic activity in a formation from a wellbore includes positioning a flow manipulation device into the wellbore, the flow manipulation device defining a flow path through which fluid may flow. Fluid is then pumped into the wellbore and through the manipulation device. A sensor disposed near the manipulation device is then coupled to the formation, the formation is fractured with fluid, and acoustic events in the formation are detected with the sensor.

Various types of acoustic sensing are used during hydrocarbon production. Generally speaking, acoustic sensing may be active or passive. Active acoustic sensing applications include vertical seismic profiling and hydrofracture monitoring, or any other application that includes source activation. In hydrofracture monitoring, for example, a fluid may be injected into the formation to stimulate microseismic activity. Passive applications do not use ancillary means to stimulate the well but instead simply monitor acoustic activity created during production, or monitoring. In each sensing application, the acoustic sensors are used to obtain information to help operators better understand the characteristics of the fracture, such as propagation direction, geometry, dip, and other parameters. In active monitoring applications, the information permits adjustment, in real time, of the injection process parameters in case of a mismatch between the planned and actual fracture. The "real-time" expression refers here to enabling a reaction in a time which is fast enough to have an impact on the economics of the fracturing job (for instance stopping the injection in case the fracture is in danger of extending into a water zone).
Many current microseismic fracture monitoring systems employ a wireline seismic array tool deployed in a monitoring well. A monitoring well, however, is not always available or suitable for microseismic monitoring (e.g., if located too far from the injection well). In addition, there is a high cost associated with running a seismic wireline tool in a monitoring well, mainly coming from the preparation of the monitoring well.
Other fracture monitoring systems have been proposed in which the sensors are deployed in the injection well, thereby eliminating the need for a monitoring well. These systems, however, are typically limited to use in applications where tubing is used to convey the fracture fluid.

Method and apparatus for detecting acoustic activity in a subsurface formation


A new Angelonia plant named ‘Cas Lavener’, articularly distinguished by the purple-violet flower color, slightly upright and semi-trailing habit with dense foliage and branching, exceptional heat tolerance, and good vigor.

The present invention comprises a new Angelonia, botanically known as Angelonia angustifolia, and hereinafter referred to by the variety name 'Cas Lavener'.
'Cas Lavener' is a product of a planned breeding program. The new cultivar 'Cas Lavener' has a purple-violet flower color, slightly upright and semi-trailing habit with dense foliage and branching, exceptional heat tolerance, and good vigor.
'Cas Lavener' originated from a hybridization in a controlled breeding program in Gilroy, Calif. USA. The female parent was an unpatented hybrid seedling identified as '432-1' with a lavender and white color. '432-1' has fewer branches and darker and larger foliage than 'Cas Lavener'.
The male parent of 'Cas Lavener' was an unpatented hybrid seedling identified as '421-3' with a deep lavender color. '421-3' has smaller flowers, fewer branches, and is more prostrate than 'Cas Lavener'.
'Cas Lavener' was selected as one flowering plant within the progeny of the stated cross in 2006 in a controlled environment in Gilroy, Calif. USA. The pollination took place in September 2003 and the seed sowing in March 2006 all in a controlled environment in Gilroy, Calif., USA.
The first act of asexual reproduction of 'Cas Lavener' was accomplished using vegetative cuttings from the initial selection in June 2006 in a controlled environment in Gilroy, Calif. USA.
Horticultural examination of plants grown from cuttings of the plant initiated in June 2006 in Gilroy, Calif. USA, and continuing thereafter, has demonstrated that the combination of characteristics as herein disclosed for 'Cas Lavener' are firmly fixed and are retained through successive generations of asexual reproduction.
'Cas Lavener' has not been observed under all possible environmental conditions. The phenotype may vary significantly with variations in environment such as temperature, light intensity and day length.
A Plant Breeder's Right for this cultivar was applied for in Canada on Dec. 24, 2007 (PBR 07-6080). 'Cas Lavener' has not been made publicly available more than one year prior to the filing of this application.


A high heat flux catalytic radiant burner of the present invention includes a housing with an inlet and an outlet end. A catalyst layer which has a coating disposed on a support is positioned between the two ends. The catalyst layer has a total specific surface area of 0.1 to 10 m.sup.2 /g. The support has a specific surface area of 1 m.sup.2 /g or less. The coating is a thin film of a nobel metal. A mixture of air and gas enters the housing though the inlet end and enters the catalyst layer where the gas is oxidized and releases heat such that the burner maintains operational firing rates of approximately 40 to 413 kBTU/hr ft.sup.2 and produces extremely low emissions.

The present invention relates generally to an industrial gas fired catalytic radiant burner for drying or heating an article or substance, and more particularly to an economical burner which has high radiant efficiency at a wide range of firing rates with low emissions.
Industrial burners are used to dry and cure products coated with paint, primers and other polymeric coatings; dry food or grain; perform plastic thermoforming; create steam; heat water; dry paper, ink or other liquid films; perform glass annealing, and other things. In addition, burners have many other potential applications including use for power generation in gas turbines and use as a short contact time, high temperature incinerator for pollutant containing air streams.
In radiant burners, oxygen from the air oxidizes a gas when a mixture of air and gas reaches a certain temperature. The mixture is heated by passing the mixture through openings of a heated substrate, which causes the oxidation of the gas and ideally produces only carbon dioxide, water and heat. Some of the heat released from the oxidation process is then used to heat the substrate for oxidation of more gas.
When oxidation is incomplete, unwanted high emissions and unburned hydrocarbons are produced. A known reticulated homogeneous burner operating with a composition of 10% excess air and a firing rate of 100 kBTU/hr ft.sup.2 was found to release relatively high emissions of 40 ppm of unburned hydrocarbons, 50 ppm carbon monoxide and 12 ppm nitrogen oxides.
Some heterogeneous gas burners are designed to lower the emissions and raise the efficiency of the burner with the use of a catalyst layer that includes a certain chemical coating or catalyst placed on a heated surface or support. Most of these catalytic combustors operate at cool temperatures (<500.degree. C.) which limits the surface reaction rates or mass transfer in the pores of the support. At high operating temperatures (up to 1500.degree. C.), current catalytic burners have high emissions and fall substantially short of the possible 38% efficiency using a simple energy balance because high surface temperatures associated with ignition causes dispersed catalyst and support particles to sinter and block the pores, which causes catalyst deactivation. These catalytic burners have catalyst layers with relatively large total specific surface areas (e.g. including wash coats).
In addition, nobel metal platinum has been used as the catalyst because of its thermal properties, but platinum can be very expensive when large amounts of the platinum are required for efficient heating. Finally, high radiant efficiency is difficult to maintain at high temperatures because of the large amount of oxygen required for complete oxidation.
Accordingly, it is an object of the present invention to provide an improved catalytic radiant burner with a high radiant efficiency and low emissions operating at a wide range of temperatures.
More specifically, an object of the present invention is to provide an improved burner such that efficiency approaches the predicted 38% calculated from a simple energy balance using a one point radiation efficiency measurement, while assuming that the surface and gas phase temperatures are equal.
An additional object of the present invention is to provide an improved burner that converts 99.9% of the hydrocarbons in the gas and produces very low emissions of nitrogen oxides and carbon monoxide.
A further object of the present invention is to provide a catalyst with a more efficient support and a more economical amount of coating while still maintaining a wide range of temperatures (or a high turndown ratio) including very high operating temperatures.
Yet an additional object of the present invention is to provide large amounts of oxygen at a high rate in order to maintain high temperatures.
These and other objects of the present invention are discussed or will be apparent from the detailed description of the invention.


A control apparatus that access first cameras capturing a first subject of a first area, and second cameras capturing a second subject of a second area, detects a viewing direction of a spectator group in the first subject on the basis of image data of the first subject captured by any one of first cameras, identifies a focus area in the second area that is focused on by the spectator group on the basis of the viewing direction of the spectator group, identifies a focus subject, focused on by the spectator group, that is present in the focus area on the basis of image data of the second subject captured by each of the second cameras, determines a specific second camera to be a transmission source of image data from among the second cameras on the basis of the focus subject, and transmits image data from the specific second camera.

The present invention pertains to a control apparatus, a control system, and a control program.
JP 2008-5208 A discloses a camera automatic control system, a camera automatic control method, a camera automatic control apparatus, and a program used in imaging sporting events and the like. However, in JP 2008-5208 A, sporting event imaging cameras are switched according to a switching instruction from an operator. In other words, switching of cameras for television broadcasting continues to be performed according to instructions from a responsible person referred to as a director, and thus, the document does not consider automation of switching.

Control apparatus, control system, and control program


The present invention relates to a method and apparatus for determining channel degradation information in which a known data sequence is compared to a transmitted version of the known data sequence to provide such information. To assess performance of a public land mobile network, it is convenient if assessment apparatus is located in the network rather than in a mobile station. The invention provides a technique for efficiently sending data characterizing channel degradation caused by the network to mobile station communication channel from the mobile station back to the network, where the channel degradation information is reconstructed.

The present invention relates to a method and apparatus for determining channel degradation information in which a known data sequence is compared to a transmitted version of the known data sequence to provide such information.
Signals carried over telecommunications links can undergo considerable transformations, such as digitisation, encryption and modulation. They can also be distorted due to the effects of lossy compression and transmission errors.
Objective processes for the purpose of measuring the quality of a signal are currently under development and are of application in equipment development, equipment testing, and evaluation of system performance.
A number of patents and applications relate to this field, for example, European Patent 0647375, granted on 14 Oct. 1998. In this invention two initially identical copies of a test signal are used. The first copy is transmitted over the communications system under test. The resulting signal, which may have been degraded, is compared with the reference copy to identify audible errors in the degraded signal. These audible errors are assessed to determine their perceptual significance—that is, errors that are considered significant by human listeners are given greater weight than those that are not considered so significant. In particular inaudible errors are perceptually irrelevant and need not be assessed.
The automated system provides an output comparable to subjective quality measures originally devised for use by human subjects. More specifically, it generates two values, YLE and YLQ, equivalent to the "Mean Opinion Scores" (MOS) for "listening effort" and "listening quality", which would be given by a panel of human listeners when listening to the same signal. The use of an automated system allows for more consistent assessment than human assessors could achieve, and also allows the use of compressed and simplified test sequences, which give spurious results when used with human assessors because such sequences do not convey intelligible content.
In the patent specification referred to above, an auditory transform of each signal is taken, to emulate the response of the human auditory system (ear and brain) to sound. The degraded signal is then compared with the reference signal in the perceptual domain, in which the subjective quality that would be perceived by a listener using the network is determined from parameters extracted from the transforms.
Such automated systems require a known (reference) signal to be played through a distorting system (the communications network or other system under test) to derive a degraded signal, which is compared with an undistorted version of the reference signal. Such systems are known as "intrusive" measurement systems, because whilst the test is carried out the channel under test cannot, in general, carry live traffic.
The present invention has applications in, but is not limited to, measuring the signal degradation caused by transmission over a digital radio channel. European patent application EP 01306950.5 describes how the perceived transmission quality of a digital radio channel can be evaluated using channel degradation information in the form of error patterns to generate a reference and degraded signal pair for use with an intrusive measurement system. Error patterns store the difference between a reference digital sequence and a degraded version received after transmission over an error-prone channel. In patent application EP 01306950.5, a novel means of generating a known test sequence for the purposes of generating error patterns is presented.
When testing the performance of a public land mobile radio network (PLMN), it is desirable to locate the apparatus used to perform the signal quality measurement apparatus in the network rather than the mobile station. Network based apparatus can be utilized more efficiently than mobile station based apparatus, by dynamically allocating it to active channels. Apparatus located in a mobile station will only be utilized when the mobile station is active, which in most cases represents a small fraction of time. This requirement to perform the quality measurement in the network presents a problem when measuring the performance of the downlink (network to mobile station) channel, because the degraded digital sequence used to form an error pattern is received at the mobile station.
European Patent application No. 00304497.1 describes a method and apparatus for measuring the performance of a communications channel while in normal use by exploiting periods of spare capacity. The invention described therein can be implemented according to the arrangements described below. The inventors of said patent solve the problem of downlink measurement by making provision to send an error protected version of the degraded digital sequence received at the mobile station back to the network, where it can be compared with a copy of the original to produce an error pattern.
A problem with transmitting an error corrected version of the degraded digital sequence is that the forward error correction process increases the amount of data that must be sent. If the transmission of the degraded signal is to be robust over a wide range of radio conditions, a powerful forward error correction code must be used, causing a substantial increase in the amount of data to be sent. For example, a rate 1/6 convolutional code will increase the amount of data to be transmitted by more than a factor of six. In many systems this increase in data will exceed the capacity of the transmission channel, especially if transmission is limited to periods of spare capacity, and the fraction of time for which signal quality measurements can be reported will be reduced. There will also be a need for a large buffer in which to store the degraded data sequences awaiting transmission.
The present invention provides a means of generating channel degradation information on the network side of a digital transmission channel that is derived from the error performance of the downlink channel. The invention alleviates the problem of buffering and transmitting large amounts of data over the uplink channel by sending a statistical representation characterising the errors in the degraded data sequence. This information is used to generate a representation of the channel degradation information with characteristics similar to the channel degradation information generated directly from the degraded data sequence. The statistical representation can be represented in relatively few bits, and can therefore be protected by powerful forward error correction codes without exceeding the transmission capacity of the channel. If transmission is limited to periods of spare capacity, the smaller amount of information also reduces the memory requirements of the buffer.
In some PLMN systems, provision is made to characterise the error performance in one direction, and return this information over the reverse channel. An example of this technique is the RXQUAL value that is calculated in GSM receivers (see GSM 05.08). However, the present invention is distinct from RXQUAL type measurements, because errors are accurately identified by comparing the received sequence with a local copy of the original sequence; RXQUAL is based on an estimate of the error rate calculated over 480 ms, and has been shown in the literature to provide an unreliable predictor of speech quality (Radio link parameter based speech quality index-SQI Karlsson, A.; Heikkila, G.; Minde, T. B.; Nordlund, M.; Timus, B.; Wiren, N. and Electronics, Circuits and Systems, 1999. Proceedings of ICECS '99. The 6th IEEE International Conference on , Volume: 3, 1999 Page(s): 1569–1572 vol.3.)

Method and apparatus for measurement of channel transmission accuracy


Computer method and apparatus for communicating information between a plurality of client computers by means of a communications network. A data server computer coupled to the network communicates data from the data server computer to one or more of a plurality of client computers in response to a request for data by a client computer in the form of a hypertext transfer protocol update request. The data server computer sends the data made available from the data server computer in response to a data update request from one of the plurality of client computers to said data server computer. A communications server computer coupled to the communications network for communicating the fact that the data on the server has been updated by communicating a client to client message from the client computer that updated the data on the data server computer to other client computers thereby prompting said other client computers to request updated data from the data server computer.

Communications between users over computer networks is routinely used to perform collaborative tasks. E-mail, for example, is frequently used to allow collaborators to share ideas and share in the performance of tasks. Sending messages back and forth during a collaborative project can occur on a company wide network as well as over the Internet. As network based messaging becomes more common, network users have legitimately become concerned about the security of such communications.
Messages from outside a company maintained network are routinely screened by means of software and hardware firewalls that accept only messages conforming to certain protocols. One common protocol that is understood by such firewalls is the hypertext transfer protocol (HTTP). A second commonly recognized protocol is the Internet relay chat protocol (IRC). The hypertext transfer protocol is commonly used by server computers to communicate data to client computers. One features of HTTP is the typing and negotiation of data representation, allowing systems to communicate independently of the data being transferred. A client locates a server by means of a unique identifier and then polls the server for data using the HTTP protocol. The process of updating the contents transmitted to the client is dependent on the client periodically polling the server for new information.
The Internet relay chat (IRC) protocol has evolved over a number of years for use in text based conferencing and is also recognized by security firewalls commonly used to protect networks and/or computers from undesirable communications. A server forms the backbone of an IRC communications link. Multiple clients identified by a unique nickname connect to the server and communicate with each other. A channel within the IRC construct is a group of one or more clients which all receive messages addressed to that channel. Further details of the IRC protocol are contained in RFC (request for comments) 1459 of the network working group.


A flexible, submersible compartment for underwater work in dry conditions which is particularly suited for work on petroleum drilling structures. The flexible, submersible compartment includes a flexible bell of reinforced elastomeric material having an opening surrounded by a collar at its top portion. A rigid platform-brace having a contractible outer ring is located beneath and attached to the flexible bell. The platform-brace also includes an inner ring which can be secured to a submerged portion of the petroleum drilling structure. In the event of contact with a rigid obstacle, the flexible bell adapts to the shape of the obstacle while the platform-brace contracts.

The need to perform operations of assembly, maintenance and/or repair on structures located under water is well documented. A variety of equipment has been developed to help facilitate such operations. Currently, various devices allowing submarine work to be performed in a dry environment are known. These known devices are generally complicated in design, difficult to transport, and costly to manufacture. Moreover, the known devices are constructed with rigid materials. This provides a significant impediment to their use in areas where there are obstacles or irregularities in the work space. A particularly acute problem is presented when structure that is to be repaired is located in places of limited space or where equipment parts or components impede the placement or installation of known rigid devices. This condition frequently arises when performing operations on petroleum drilling platforms having legs that are closely spaced.
In addition, due to the rigid nature of the known devices and to the action of the ocean (currents and tides), considerable stresses are transmitted to the structure or tubing about which a given device is installed. Hence, normally use of these devices is limited to areas such as an ocean floor or to positions where the devices can remain horizontal.


An offset canceling dual stage sensing method includes sensing a data value of a resistive memory data cell using a first load PMOS gate voltage generated by a reference value of a resistive memory reference cell in a first stage operation. The method also includes sensing the reference value of the resistive memory reference cell using a second load PMOS gate voltage generated by the data value of the resistive memory data cell in a second stage operation of the resistive memory sensing circuit. By adjusting the operating point of the reference cell sensing, an offset canceling dual stage sensing circuit increases the sense margin significantly compared to that of a conventional sensing circuit.

Unlike conventional random access memory (RAM) chip technologies, in magnetic RAM (MRAM) data is not stored as electric charge, but is instead stored by magnetic polarization of storage elements. The storage elements are formed from two ferromagnetic layers separated by a tunneling layer. One of the two ferromagnetic layers, which is referred to as the fixed layer or pinned layer, has a magnetization that is fixed in a particular direction. The other ferromagnetic magnetic layer, which is referred to as the free layer, has a magnetization direction that can be altered to represent either a "1" when the free layer magnetization is anti-parallel to the fixed layer magnetization or "0" when the free layer magnetization is parallel to the fixed layer magnetization or vice versa. One such device having a fixed layer, a tunneling layer, and a free layer is a magnetic tunnel junction (MTJ). The electrical resistance of an MTJ depends on whether the free layer magnetization and fixed layer magnetization are parallel or anti-parallel with each other. A memory device such as MRAM is built from an array of individually addressable MTJs.
To write data in a conventional MRAM, a write current, which exceeds a critical switching current, is applied through an MTJ. The write current exceeding the critical switching current is sufficient to change the magnetization direction of the free layer. When the write current flows in a first direction, the MTJ can be placed into or remain in a first state, in which its free layer magnetization direction and fixed layer magnetization direction are aligned in a parallel orientation. When the write current flows in a second direction, opposite to the first direction, the MTJ can be placed into or remain in a second state, in which its free layer magnetization and fixed layer magnetization are in an anti-parallel orientation.
To read data in a conventional MRAM, a read current flows through the MTJ via the same current path used to write data in the MTJ. If the magnetizations of the MTJ's free layer and fixed layer are oriented parallel to each other, the MTJ presents a resistance that is different than the resistance the MTJ would present if the magnetizations of the free layer and the fixed layer were in an anti-parallel orientation. In a conventional MRAM, two distinct states are defined by two different resistances of an MTJ in a bitcell of the MRAM. The two different resistances represent a logic "0" and a logic "1" value stored by the MTJ.
MRAM is an inherently scalable type of memory because the MTJ critical switching current (Ic) scales linearly with device area. However, as the critical switching current for writing to an MTJ decreases, the sensing current used to measure the resistance of the MTJ for reading its logical state (magnetization orientation) also decreases to prevent a read disturbance. For example, due to process variations the sensing current used to measure the resistance of an MTJ could exceed the critical switching current and change the logical state of the MTJ being read. Thus, increased scaling of MRAM leads to a reduced sensing margin. The reduction of sensing current may also causes reduced switching speed of the MTJ.
The critical switching current of an MTJ increases sharply when the pulse width of the switching current is decreased. One technique that may be used to avoid read disturbance is to apply a sensing current having a short pulse width to read the state of the MTJ. For example, a sensing current pulse width less than about 10 nano-seconds (ns) may be used to avoid read disturbance because the critical switching current is high for such a short pulse of current. Although the read pulse width may be reduced with technology scaling to avoid read disturbance, the read pulse width has a lower limit of about 3 ns for correct sensing operation. Therefore, decreasing the sensing current will still occur as MTJ technology scaling increases.

Offset canceling dual stage sensing circuit