The pattern forming method is capable of forming a projected image or photoresist pattern that is faithful to a designed pattern without performing complex correction of a mask pattern. A projection exposure system and a semiconductor device fabrication method employing this pattern forming method are also disclosed. Exposure is performed by setting a pupil filter with a variable amplitude transmittance to the pupil position of the projection lens of a projection exposure system. The pupil filter has a transparent substrate, a phase retarding layer, a translucent film, and an opaque stencil. The pupil filter is replaced or rotated during either a plurality of exposures or during a single exposure onto the same position on the surface of a wafer substrate that is to be exposed. It is possible to improve the fidelity of the contour of a pattern transferred image without improving the numerical aperture (NA) of a projection lens, decreasing the wavelength of exposure light, or locally correcting a mask pattern. It is also possible to prevent imperfect resolution from occurring and fabricate semiconductor integrated circuit devices with a high yield.

In general, improvement of the integration density of semiconductor integrated circuits in recent years has been achieved mainly through a reduction in size of the various circuit patterns. These circuit patterns are presently formed mainly by optical lithography processes using a wafer stepper.
FIG. 1 shows the structure of such a prior art stepper. Mask 14 is illuminated by the light emitted from illumination system 11. An image of mask 14 is projected onto a photoresist film coated on wafer 19 which is the substrate to be exposed through projection system 15. As shown in FIG. 1, illumination system 11 includes a source 10, condenser lens 12, and aperture 13 for specifying the shape and size of the effective source. Projection system 15 includes a projection lens 16, pupil filter 17, and aperture 18 arranged in or near the pupil plane of projection lens 16 to set the numerical aperture (NA) of the lens.
The minimum feature size R of patterns transferable by an optical system is approximately proportional to the wavelength .lambda. of the light used for exposure and inversely proportional to the numerical aperture (NA) of the projection optical system. Therefore, size R is expressed as R=k.sub.1 .lambda./NA, where k.sub.1 is an empirical constant and k.sub.1 =0.61 is referred to as the Rayleigh limit.
As shown by the above expression, the resolution (minimum feature size R) can be increased by decreasing wavelength .lambda. or by increasing the numerical aperture NA. In the past, both approaches have been taken. However, it has recently become difficult to decrease the wavelength further, because of the limited availability of optical materials. Also, lens design issues set a limit to further increases in the numerical aperture. Therefore, pattern dimensions of integrated circuits are now at or near the limit of resolution of the projection exposure system used to define them.
In general, when the pattern dimensions approach the Rayleigh limit, the projected image is no longer a faithful reproduction of the mask pattern shape. This phenomenon is known as optical proximity effects and results in corner rounding, line-end shortening, and line width errors, among other things. To solve this problem, algorithms have been proposed that can be used to pre-distort the mask pattern so that the shape of a projected image takes on the desired shape.
Moreover, approaches have been described which improve the resolution limit of a given optical system, resulting effectively in a decreased value of k.sub.1. Adoption of a phase shifting mask is a typical example of this approach. A phase shifting mask is used to provide a phase difference between adjacent apertures of a conventional mask. Examples of this technique are shown by Mark T. Levenson et al. in an article entitled "Improving Resolution in Photolithography with a Phase-Shifting Mask" in IEEE, Trans. on Electron Devices, Vol. ED-29, No. 12, pp. 1828-1836 (1982)".
A chromeless phase shifting mask method is known as a phase shifting method suitable for the transfer of a fine isolated opaque line pattern, which is needed, for example, for the gate pattern of a logic LSI. A mask used according to this method uses a transparent layer to provide a phase difference of 180.degree. in a transparent area. A very narrow dark line on a bright background is formed along the outline of the transparent layer. This chromeless phase shifting mask method is taught by Toh et al in an article entitled "Chromeless Phase-Shifted Masks: A New Approach to Phase-Shifting Masks" in SPIE vol. 1496 10th Annual Symposium on Microlithography, pp. 27-53 (1990).
An off-axis illumination method and a pupil filtering method are also known methods for improving images. According to the off-axis illumination method, the transmittance of aperture 13 is modified in the illumination system 11 of FIG. 1. One particular embodiment of this method changes the illumination intensity profile so that the transmittance at the margin becomes larger than that of the central portion, which is particularly effective to improve the resolution of a periodic pattern and the depth of focus. The pupil filtering method is a method of performing exposure through a filter (pupil filter) located at the pupil position of a projection lens to locally change the amplitude and phase of the transmitted light. For example, this approach makes it possible to greatly increase the depth of focus of an isolated pattern. The off-axis illumination method is, for example, discussed by Noguchi et al. in an article entitled "Resolution Enhancement of Stepper by Complementary Conjugate Spatial Filter" in SPIE vol. 1674 Optical/Laser Microlithography V, pp. 662-668 (1992). The pupil filtering method is disclosed by Fukuda et al. in the Jpn. J. Appl. Phys. 32 (1993) pp. 5845-5849. Furthermore, it is shown in an article by Orii et al., entitled "Quarter Micron Lithography System with Oblique Illumination and Pupil Filter", SPIE vol. 2197 pp. 854-868 (1994), and shown in European Patent Publication No. 0562133 A1 (1993), that the resolution of a periodic pattern can further be improved by combining the off-axis illumination method and the pupil filtering method.

Pattern forming method, projection exposure system, and semiconductor device fabrication method


A patient support including turn assist, low air loss or integrated lateral transfer. The patient support is adapted to support a bariatric patient and includes a turning bladder for turning or assisting in turning a bariatric patient.

Patient Supports, including those used in hospitals, long term care facilities, and for home are used to support a patient and can include the support of a bariatric patient. Bariatric beds are designed for use by obese, heavy, or large patients. Bariatric beds typically include a larger than average heavy duty frame to support the patient size and weight. Such bariatric beds can be configured to support patients up to 1,000 lbs. or more.
During a patient's stay at a hospital or other healthcare facility including a home environment, patients on occasion may be turned on one of their sides by a caregiver to provide for care of the patient. For instance, it is common to place a patient on one or the other side to reduce or to eliminate the occurrence of pressure ulcers. In addition, a patient can be placed on a side to provide for bathing as well as to provide for changing the linens used on a patient support surface or mattress. In addition, turning of a patient can be helpful when a caregiver provides assistance to a patient when changing clothing.

Patient support including turn assist, low air loss, or integrated lateral transfer


Systems and techniques for assuring proper presentation of a bar code for imaging scanning in a hybrid laser and imaging bar code scanner. A scanner includes elements for laser bar code scanning and imaging bar code scanning, and includes indicia for assuring proper presentation by a user of a bar code suited to imaging scanning. Indicia may include targeting features on a scan window, designed so as to minimize interference with bar code scanning, or may alternatively include features alongside a scan window. Alternative indicia may include removable holders for securing an object bearing a bar code in an appropriate position, and further alternative indicia may include visible targeting beams so that a user can be assured that imaging scanning may be satisfactorily performed on bar code placed in a visible targeting beam.

Bar code scanners have been used for many years for fast and convenient identification of objects, such as products entered into a sales transaction. As technology has improved, the variety of bar codes and other identification indicia has increased. One particularly promising additional technology is the use of imaging for scanning indicia such as a bar code. In contrast to conventional laser bar code scanning, imaging scanning captures a visual image of an object of interest and processes the image in order to extract relevant information. An imaging scanner often provides improved capability of reading very small bar codes and two dimensional bar codes, as compared to a conventional laser scanner. The use of an imaging scanner is made more efficient if the object to be scanned, such as a bar code, is presented to the imager in a position and orientation that provides the best perspective for the imager.
Integrating an imaging scanner into a conventional laser scanner provides improved versatility in scanning operations, allowing for laser scanning of some bar codes and imaging scanning of bar codes more suited to imaging scanning. The need to accommodate the facilities needed for both types of scanning, and to provide proper presentation stages for both types of scanning, imposes various constraints on the design and operation of the scanner. Constraints may be imposed, for example, on the manner of presentation of a bar code to be subjected to imaging scanning. If an imager is integrated into a conventional scanner, the positioning of the imager within the conventional scanner, and the need to operate the imager in conjunction with the conventional scanner, may dictate that a bar code be positioned facing away from the operator when presented to the imager. Such positioning prevents an operator from easily seeing the bar code and may make it more difficult for an operator to place the bar code in an ideal position for scanning by an imager.

Methods and apparatus for positioning objects for scanning by a hybrid laser and imaging scanner


The invention provides a stable oxide material system for a capacitor, electronic device or a memory device having an effective high-k value with an effective zero alpha while exhibiting low leakage current density. The stable oxide material comprises Mx-Si1-xO2, wherein the elements M & Si are mixed such that the insulator layer comprises staggered edge-linked SiO2-MO2 bonding chains to provide a stable 3-dimensional single crystal system.

A particular type of capacitor design is a Metal-Insulator-Metal (MIM) capacitor. MIM Capacitor devices are pervasively used in all modern day electronic devices, and in particular radio frequency and analogue circuitry. MOS capacitor structures are an integral part of MOS Field-Effect Transistors (MOSFETs) used extensively in digital circuitry. Portable consumer and communication devices are driving miniaturisation of these devices along with ultra lower power consumption requirements to extend battery life.
Miniaturisation of digital components has centred on the scaling of MOSFET devices, and this has been achieved so far with the introduction of metal gate/high-k/Si MOS structures. Nevertheless, future scaling will likely require the replacement of Si with a higher mobility semiconductor like Ge and/or In0.53Ga0.47As in combination with alternative architecture (e.g. trigate MOSFET, junctionless MOSFET, etc.), introducing different problem issues in controlling device performance. One problem with high-k materials is the capacitance hysteresis observed for high-k material systems, causing variability in the electrical characteristics and thereby directly affecting device performance.
Miniaturisation of RF and analog components is a real problem in the electronics industry. Four key requirements of a dielectric in the design of a capacitor device are to: (i) aim for a low frequency capacitance density as high as possible at zero DC bias; (ii) have as low a leakage current density as possible at the device operating voltage to ensure reliable operation; (iii) have as high a breakdown voltage (BV) as possible for a given thickness (Electric Field Breakdown [MV/cm]), preferably at twice the operating voltage; and (iv) have negligible charge trapping (negligible Capacitance-Voltage hysteresis).
The behaviour of capacitance with applied DC bias is measured using (Cmax−Cmin)/Cmin=Cdif=αV2+βV+c, where Cmin is the minimum measured capacitance, Cmax is the capacitance at the maximum applied voltage, α is the quadratic voltage coefficient of capacitance, β is the linear voltage coefficient of capacitance, and c is a constant accounting for any asymmetry in capacitance about 0V.
If α were approximately ≦|50-100| ppm/V2, the capacitor would exhibit approximate linear rather than quadratic behaviour with voltage, showing a slope determined by α, since β can be reduced to zero by circuit design methods, hence α is the determining factor whether capacitance varies with applied voltage. Units for measuring α are ppm/V2 when β=0; but when β≠0 then the units for measuring β are ppm/V, since Cdif, α, and β are constants.
An additional requirement for many capacitor applications is that the capacitor exhibit linear capacitance behaviour with respect to the applied voltage, as a large non-linearity creates detrimental harmonics in electronic circuits, especially at high frequencies, as well as other non-ideal effects. A measure of this linearity is α, since β and c can be made to equal zero through careful circuit and device design.
For these same applications, capacitance should also remain linear as the temperature and frequency change: α(Tmax)−α(Tmin)≦|100| units/K, and α(Fmax)−α(Fmin)≦1% units per decade, respectively. There are also many capacitor applications for which this linearity of capacitance with voltage, temperature, and frequency is not required. To date, for a given relative permittivity (k) and oxide thickness (t), higher capacitance has been achieved by using larger area capacitors, since C=kε0A/t, where C is capacitance, ε0 is a constant (the permittivity of free space), and A is the area of the capacitor. The requirement of large area for the capacitors prevents any significant reduction in the surface footprint size of analogue circuitry.
Reducing the oxide thickness (t) of the capacitor could in theory achieve the same capacitance (C) for a smaller capacitor area (A) for a given k, but this would detrimentally increase the leakage current and reduce the breakdown voltage of the capacitor.
The ideal solution for surface planar capacitors would be to increase the relative permittivity (k) of the oxide and reduce the area (A) for the same oxide thickness (t) to achieve the same or greater capacitance (C). However, to date this approach has been undermined by the high leakage and low breakdown voltages associated with high-k dielectrics, demonstrating high-k MIM devices but with unacceptable leakage and breakdown characteristics. Such structures also generally exhibit a high a value. Some high-k materials require annealing to achieve the highest k-value, and this can also contribute to higher leakage and lower breakdown voltages.
In addition, high-k materials are generally ionic systems and tend to have a significant density of charge trapping sites and therefore a significant hysteresis, which can be improved by selective deposition techniques, processing, and annealing but not entirely removed. Charge trapping, and the associated electrical variability, remain serious problems for high-k dielectrics.
Present MIM capacitors with control of a and hysteresis rely on low k-value and covalently bonded systems such as silicon oxide, silicon nitride, or silicon oxynitride dielectrics (k˜4-6), as these oxides also allow control of the leakage and breakdown characteristics. A maximum capacitance is achieved through the use of large area capacitors. Minimal hysteresis is achieved through careful concentration ratio selections, processing and annealing.
Increased capacitance with reduced surface area can be achieve through stacking capacitors on top of each other in a 2-dimensional way and connecting in parallel. If the number of dielectric layers is n, then C=n×kε0A/t, and the same capacitance can be achieved with reduced area. In reality there is a limit to the number of layers achievable due to processing constraints on conformal growth and connectivity requirements, and typical values of n are ≦4. MIM capacitors with high-k materials can also be made in this way permitting further scaling.
Another way to increase capacitance is by making 3-dimensional MIM capacitors inside trenches etched into silicon and surface treated to obtain an SiO2 isolation layer. Conformal growth methods could then be used to grow single or stacked layers of metal-insulator-metal structures. This method permits the possibility of the area being increased to as large as possible alongside n and k in C=n×kε0A/t. For this scenario it is the capacitor footprint on the surface that is minimised, not the device area. In reality, most deposition methods in industry have serious constrictive difficulties in making these type of capacitors. MIM capacitors with high-k materials can also be made in this way using conformal growth methods, permitting further scaling.
US patent publication number US 2006 0281264 A1, assigned to Matsushita Electric Industrial Co. Ltd., describes a gate insulator on a semiconductor substrate having a plurality of oxide layers perpendicular to the semiconductor surface and associated with respective phases.
The US patent publication discloses three stable layers formed from the ALD|CVD of SiO2, MSiO4, and MO2 stable phases (M=Hf|Zr). However, problems with this approach are: (i) that an unstable interface is formed between the SiO2 layer and the claimed MSiO4 layer; (ii) the thickness of the amorphous SiO2 layer increasing with time taking SiO2 from the claimed MSiO4 layer; and (iii) the claimed MSiO4 layer actually moves increasingly towards a crystalline MO2 concentration with time. Namely, the claimed MSiO4 layer will reduce in SiO2 concentration with time, and exhibit spontaneous phase separation to form amorphous SiO2 and crystalline MO2 (MxSi1-xO2, x=0.5→x=1.0) with time.
The deposition of a higher x concentration MxSi1-xO2 (M=Hf|Zr, x>0.5) will ensure a nucleation and growth phase separating structure due to two factors: (i) the deposited oxide (from bulk theory) will be intrinsically metastable at such x concentrations (not stable), and (ii) the oxide is deposited on SiO2 ensuring the growth of SiO2 from Si and O supplied by the decomposition of the MxSi1-xO2 oxide.
Hence, phase separation is driven by the unstable bottom interface with amorphous SiO2, the bulk phase separation and forming of amorphous SiO2 and crystalline MO2 clusters, and the changing x concentration to form amorphous SiO2 and crystalline MO2 (MxSi1-xO2, x>0.5→x=1.0) with time.
It is clear that a MIM or MOS capacitor exhibiting such a structure of three stable phases claimed of SiO2, MSiO4, and MO2 is neither stable with time nor free from crystalline grain boundaries that would cause high operating voltage leakage current densities and a low breakdown field.
To date the research and development community have only been able to synthesis amorphous or polycrystalline MxSi1-xO2 metal silicates (0<x<1; M=Zr and/or Hf), which can be synthesised fairly easily. If synthesised films form amorphous systems, including the amorphous forms of zircon and hafnon, and they are exposed to a high enough temperature anneal in an appropriate ambient, they can be made polycrystalline.
However, the amorphous to crystalline transition does not form a single crystal for any significantly large crystallite length scale, but instead forms many small crystals all oriented in different directions with crystallite sizes very much smaller than the thickness of the films. The boundaries between these crystallite regions, called grain boundaries, render these dielectric films effectively useless for electronics applications due to the very high leakage and low breakdown voltages associated with such grain boundary rich films.
A paper publication by Ting-Ting Jiang et al., J. Phys. D: Appl. Phys. 44, 185402, 1-5 (2011) a theoretical simulation which tries to compare the electronic band gaps modelled and experimental amorphous high-k materials that could be used in a semiconductor device. However Ting-Ting Jiang does not demonstrate any type of device characteristics. The device properties referred to in the introduction section of the Ting-Ting Jiang et al. paper, with respect to the ZrSiO4 and HfSiO4 systems, are for amorphous systems only. Moreover modelling programs are not able to model amorphous systems because of their size and complexity. Geological studies of crystallites in naturally formed rock give lattice parameters for modelling crystalline systems, and these geological studies are the experimental results referred to in the paper for the unit cells used in the simulations. To date no one has been able to reproduce these materials for use in electronic devices and the prior art relates to purely amorphous or polycrystalline materials that are limited for electronic devices.
Another publication by T. S. Böscke et al., Appl. Phys. Lett. 91, 072902 (2007) reports on HfO2 and the addition of 10% SiO2 to form an amorphous Hf0.9Si0.1O2 metal silicate (x=0.9, M=Hf). The T. S. Böscke et al. paper claims that crystallisation of amorphous HfO2 into the monoclinic form of HfO2 after a thermal anneal leads to increased leakage and the formation of local defects. By adding 10% SiO2 to the amorphous HfO2, T. S. Böscke et al claim that tetragonal HfO2 is formed instead of monoclinic HfO2 during the thermal anneal process. Doping amorphous HfO2 with 10% SiO2 and crystallising with a temperature anneal does not constitute the formation of amorphous, or polycrystalline HfSiO4 (x=0.5) but the formation of Hf0.9Si0.1O2 (x=0.9).
A further paper by K. Kukli et al., Material Science and Engineering B 109 (1-3), 2-5 (2004) reports experimental findings for two types of substrate layers on which they deposit their oxide:                I. Si/SiO2 (1.2-1.8 nm)        II. Si (chemically etched, nominally Si—H)
The paper refers to Hf—Si—O which has a 2:1 Hf:Si concentration ratio (x˜0.67) and is amorphous, and as such due to x and the amorphous properties of the material suffers from the same drawbacks as described above.
A further publication by Lizhi Ouyang and W. Y. Ching, J. Appl. Phys. 95 (12), 7918-7924 (2004) discloses a modelling paper similar to the Ting-Ting Jiang paper and simulates (ZrO2)x(SiO2)1-x with x<0.5. Again the simulations use the lattice parameters from geological studies of crystallites in rock and then substitute Zr with Si cations to get x<0.5. The experimental comparison they refer to for ZrSiO4 or zircon is from experiment XPS studies on powders with x=0.5 but in an amorphous or polycrystalline state.
An object of the invention is to provide a stable oxide material system for a capacitor or electronic device having an effective high-k value with an effective zero alpha while exhibiting low leakage current density and a high electrical breakdown field.

Single crystal high dielectric constant material and method for making same

University College Cork—National University of Ireland


An optical disc drive according to the present invention can read and write data from/on an optical disc 100 including record tracks to write data thereon and guide tracks for guiding a light beam 40. The drive includes: an optical pickup 101 with a converging optical system to focus the light beam 40 and form a spot thereof on the optical disc 100 for reading or writing the data; a tracking control section for controlling the converging optical system of the optical pickup 101 such that the light beam spot 40 follows a selected track on the optical disc 100 rotating; and a control unit 35 for operating the tracking control section in a first mode or in a second mode. In the first mode, the tracking control section makes the light beam spot 40 follow the recording tracks. In the second mode, the tracking control section makes the light beam spot 40 follow the guide tracks.

Recently, optical discs are used extensively as storage media for computers and audiovisual appliances. Various formats have been proposed for optical discs so far. For example, there are read-only optical discs such as CD-ROM and DVD-ROM, write-once optical discs such as CD-R and DVD-R, and rewritable optical discs such as CD-RW, DVD-RW and DVD-RAM.
Among these various types of optical discs, CD-R, DVD-R, CD-RW and DVD-RW each include a substrate, on which lands and grooves are provided spirally, and a recording film that has been deposited on the substrate. In the optical discs of these types, data is written on tracks that are defined on the grooves.
In the write-once optical discs, the recording film thereof is made of an organic dye material. In the rewritable optical discs on the other hand, the recording film thereof is made of a phase change material. The organic dye recording film absorbs a pulsed write laser radiation, emitted from the light source of an optical disc drive, thereby causing an irreversible structural change. On the other hand, the phase-change recording film is melted when exposed to the write laser radiation, and then solidified. In this case, by adjusting the intensity and the pulse width of the write laser radiation, amorphous recording marks and crystalline spaces can be defined in the phase-change recording film. In the rewritable optical discs, the phase change of the recording film is reversible, and therefore, the recording marks are rewritable.
In any case, in writing data on an optical disc, the recording film thereof needs to be irradiated with a laser radiation that has a power that is high enough to change the structure or optical property (e.g., reflectivity, in particular) of the recording film locally. On the other hand, in reading data from an optical disc, the recording film thereof also needs to be irradiated with a laser radiation so as to detect a variation in reflectance. In this case, however, the reflectivity of the recording film should not be changed due to the exposure to the laser radiation. For that reason, the read laser radiation normally has a much smaller power than the write laser radiation.
Also, the wavelength of a read/write laser radiation changes according to the specifications to which a given optical disc conforms. For example, the read/write laser radiation for a CD has a wavelength of about 780 nm, while the read/write laser radiation for a DVD has a wavelength of about 650 nm. Generally speaking, the storage density of an optical disc depends on the beam spot size of the laser radiation. Thus, to further increase the storage density, the wavelength of the laser radiation needs to be even shorter. For that purpose, a Blu-Ray disc, which is known as a next-generation optical disc to replace DVDs in the near future, uses a violet laser radiation with a wavelength of about 405 nm.
Also, to increase the storage density and storage capacity of an optical disc, the recording film thereof needs to exhibit increased sensitivity so as to cause a structural change or phase change responsive to smaller optical energy applied. Furthermore, to perform a read or write operation on an optical disc at a higher rate, the optical disc needs to be rotated at a higher velocity. Thus, the light beam should have relatively high power not just during data writing but also during data reading.
However, as such an optical disc with an increased sensitivity is read numerous times, the recording film thereof should gradually deteriorate due to the repetitive exposure to the read laser radiation. Then, the quality of the resultant readout signal should decrease, too. Such deterioration will be referred to herein as "weak-radiation-induced deterioration". This weak-radiation-induced deterioration is particularly significant in a recording film made of an organic dye material, but is sometimes observed in a recording film made of a phase change material, too.
Methods for avoiding such weak-radiation-induced deterioration are proposed in Japanese Laid-Open Publication No. 7-85478 and in U.S. Pat. No. 6,295,260, for example. The optical disc drive disclosed in U.S. Pat. No. 6,295,260 adaptively changes the power of the read laser radiation according to the type of an optical disc to be read. For example, in reading a CD-R in which the weak-radiation-induced deterioration occurs particularly frequently, this optical disc drive minimizes the laser radiation power.
In such an optical disc drive, however, when the power of the read laser radiation is lowered, the quality of the resultant readout signal will decrease. Also, if the laser power is decreased excessively, then the tracking error signal is detected with too low sensitivity to stabilize the tracking operation sufficiently.
In order to overcome the problems described above, preferred embodiments of the present invention provide an optical disc drive, which can perform a read operation constantly by minimizing the weak-radiation-induced deterioration of the recording film, and also provide a method for controlling such an optical disc drive.

Optical disc drive and method for controlling the same

Matsushita Electric Industrial Co., Ltd.


A method of determining the total playing time T.sub.G and the residual playing time T.sub.R of a magnetic tape (4) stored on two reels (2, 3) in a cassette (1) in which in a brief winding operation of the magnetic tape (4), the numbers of tacho pulses (i.sub.1, i.sub.2) at the take-up reel (3) and the supply reel (2) are determined. Moreover, by extracting the magnetic tape (4) from the cassette (1) over a given length (L.sub.H), the numbers of tacho pulses (j.sub.1, j.sub.2) at the take-up reel (3) and the supply reel (2) are determined. From the values thus determined for these pulses (i.sub.1, i.sub.2, j.sub.1, j.sub.2) for a given thickness d and speed v of the magnetic tape (4), a given reel-hub diameter K of the take-up reel and the supply reel (2, 3) and a given number u of pulses per reel revolution, it is possible to calculate the total playing time T.sub.G in accordance with the relationship: ##EQU1## and the residual playing time T.sub.R in accordance with the relationship: ##EQU2##

1. Field of the Invention
The invention relates to a method of determining the playing time of a magnetic tape, on a supply reel and a take up reel in a magnetic-tape cassette.
2. Description of the Related Art
DE 28 56 509 A1, corresponding to U.S. Pat. No. 4,232,371, describes a method of indicating the length of the tape on one reel of a cassette comprising two reels. In this device, a loading mechanism extracts a specific length of tape from the cassette with a constant linear velocity, one of the two reels of the cassette being retained. A pulse generator then generates a pulse frequency proportional to the angular velocity. On the basis of the constant linear velocity, the tape thickness and the reel diameter, a microprocessor then calculates the available quantity of tape. In order to calculate the quantity of tape wound on the reel in a specific time T.sub.S, the following equation is used: ##EQU3## where v is the linear velocity, .delta. is the thickness of the magnetic tape, P.sub.S is the signal representing the angular velocity of said one reel, and R.sub.H is the diameter of the inner turn of the magnetic tape wound on this reel. A disadvantage of this known device is that one of the two reels has to be retained by a special braking device.
Moreover, DE 36 22 895 A1 describes a method of determining the residual tape length of a magnetic tape wound on a reel spindle, wherein a time measurement device first determines the revolution times t.sub.L, t.sub.R of one full revolution of the two tape spools, from which the total time t=t.sub.L +t.sub.R is derived. Subsequently, by comparing the total time t with a given limit value, the reel spindle diameter D.sub.O for the relevant cassette is determined in order to calculate the number of turns n.sub.L and n.sub.R in accordance with the equations: ##EQU4## where .upsilon. is the standard velocity and d is the thickness of the magnetic tape. From the numbers of turns thus obtained, the winding times T.sub.L and T.sub.R are then derived in accordance with the equations ##EQU5## The sum of the two times T.sub.L and T.sub.R represents the residual time T from which the actual thickness of the magnetic tape ##EQU6## is calculated by comparison with possible nominal times. The actual thickness is finally used for the calculation of the real winding times.
Moreover, it is known from U.S. Pat. No. 4,963,999 to calculate the residual playing time T1 in accordance with the equation ##EQU7## Here, t is the thickness, .upsilon. is the velocity and L is the total length of the magnetic tape, R.sub.o is the radius of the reel hub, R.sub.t is the radius of the take-up spool and R.sub.s is the radius of the supply spool in the cassette. The velocity of the magnetic tape is derived from the angular velocity of a capstan driving the magnetic tape.

Method of determining the playing time of a magnetic tape and device for carrying out the method


A process for depositing on a sample surface a smooth, wear-resistant coating including the steps of providing a vacuum processing chamber for holding the sample to be coated, introducing into the processing chamber coating-forming reactants for deposition on the sample surface, and supplying to the processing chamber a plasma stream with an electron temperature of up to 10 eV, a directed ion energy of 5 to 50 eV, and an ion flux at the sample in the range of 0.1 to 100 milliamps per square centimeter for transferring energy to the deposited material to form the smooth coating.

There are virtually endless applications for wear-resistant coatings. For example, mechanical parts that are subject to moving contact with other parts will eventually wear to the point that the part must be reshaped or replaced. Similarly, cutting edges, when dulled, must be resharpened or replaced. Each of these applications would benefit greatly by the use of a wear-resistant coating that is thin enough not to substantially alter the part size, has good adhesion to the substrate so it does not flake or chip in use, and is extremely smooth so that it does not increase the friction of the coated part.
There are additional applications in which wear-resistant coatings would be extremely useful in protecting an underlying part to increase the part life by acting as a barrier layer and a wear-resistant layer. For example, manufactures of plastic eyeglass lenses use lens molds that must be extremely smooth, wear-resistant, and able to easily release the molded lens. Other substrates such as long-life digital recording media compact discs require a coating that is optically transparent, wear-resistant, and will act as a moisture barrier to protect the underlying material containing the encoded information from degradation.
Many processes have been developed to provide wear-resistant coatings for these varied applications. One commonly employed process coats parts with titanium nitride using an ion plating process that employs an intense arc to evaporate the titanium target as titanium ions. The surface to be coated is held near the target at ground so that the titanium ions impact the surface at high energy. Typically, this process takes place in a nitrogen atmosphere for supplying ionized nitrogen that is similarly accelerated into the surface, where it reacts with the titanium ions to form the titanium nitride coating. These coatings, however, are typically smooth to only approximately a few thousand Angstroms and thus are insufficient for applications requiring extremely smooth coatings. In addition, the substrate temperatures of several hundred degrees celsius make these high temperature processes inappropriate for materials with low melting temperatures such as plastics, substrate materials that cannot stand the thermal stress associated with high temperature operation, or substrate-coating combinations that are mismatched in coefficient thermal expansion so that unacceptable stresses are introduced when the part is cooled from the high deposition temperature.
Another coating deposition process employs RF plasma chemical vapor deposition in which two closely spaced electrodes are used to create an electric field between the electrodes in which a plasma is formed. The substrate is placed in or adjacent to the plasma for chemical vapor deposition of coating compounds. This CVD process, however, operates at a high voltage, which would cause sputtering of the substrate surface, resulting in an unacceptably rough surface in any applications requiring an extremely smooth surface. Further, this RF plasma process is not suitable for coating pointed or irregularly-shaped objects, as non-planar surfaces may cause arcing between an electrode and the surface.
Silicon carbide is an extremely hard compound that is a commonly used abrasive which exhibits hardness and wear characteristics superior to many other abrasives. Silicon carbide films have been found to be useful x-ray lithography windows due to the mechanical properties and transparency of the compound. These silicon carbide x-ray lithography windows are typically fabricated by depositing the silicon carbide on a silicon substrate using microwave-energized electron cyclotron resonance (ECR) apparatus. This process typically takes place at a relatively high temperature of approximately 500.degree. C. to 800.degree. C. to create films of low tensile stress so that the window created by etching away part of the silicon substrate from the backside after deposition of the silicon carbide layer is under sufficient tension that it will not buckle.

Process for depositing wear-resistant coatings


A fiber bed mist eliminator has a fiber bed which is formed of a composite fiber bed collecting media strip including a collection layer which is not subjected to needle punching. The fiber bed can be made very thin while retaining high efficiency in removing small particles of aerosol from a gas stream passing through the fiber bed. The fiber bed collecting media strip lends itself to be applied to the mist eliminator by spirally wrapping the element onto the mist eliminator. The fiber bed collecting media strip can overlap itself to seal at the locations where the fiber element overlaps itself. The fiber bed collecting media strip can be provided to the field in different formats for use in making a mist eliminator fiber bed.

This invention relates generally to fiber bed mist eliminators, and fiber beds and collecting media therefor.
Fiber bed mist eliminators have wide industrial application in the removal of aerosols from gas streams. The generation of aerosols ("mist") in gas streams is common in the course of manufacturing processes. Aerosols can be formed, for instance, as a result of mechanical forces (e.g., when a flow including a liquid runs into a structure) that atomize a liquid. Cooling of a gas stream may result in the condensation of vapor to form a mist, and chemical reactions of two or more gases may take place at temperatures and pressures where the reaction products are mists. However the aerosol comes to be in the gas stream, it can be undesirable to inject the aerosol into other processing equipment because the aerosol may be corrosive or otherwise lead to damage or fouling of the processing equipment. Moreover, it can be undesirable to exhaust certain aerosols to the environment. Some of the more frequent applications of fiber bed mist eliminators include removal of acid mists, such as sulfuric acid mists, in acid manufacturing, removal of plasticizer mists in the manufacture of polyvinyl chloride floor or wall coverings and removal of water-soluble solid aerosols from the emissions of ammonium nitrate prill towers. In these various applications, fiber bed mist eliminators may achieve separation efficiencies of 99% or greater depending upon, among other things, the thickness of the fiber bed.
It is generally known that fibers made of various materials may be used to construct fiber beds for fiber bed mist eliminators. The fiber bed is designed to collect fine liquid mist and soluble solid particles entrained in a moving gas stream and drain them through the structure of the bed. Typically, beds of collecting fibers are associated with metal wire screens or similar external support structures. The combination of a bed of collecting fibers and external support structure is known as a fiber bed assembly. As used hereinafter, fiber bed refers to that portion of the fiber bed assembly apart from any such support structure. Fiber beds may be formed by packing bulk fiber between two opposing support screens (bulk-packed beds), pre-forming a tube of fiber bed material, or winding a roving made of fibers around a cylindrical support screen (wound beds). Although not limited to such a configuration, fiber bed assemblies are most often configured in the form of a vertical cylinder. Cylindrical fiber bed assemblies permit a high effective fiber bed surface area in a minimum of space. Flat fiber bed assemblies on the other hand, find particular application for smaller gas flows.
In operation, a horizontal stream of gas containing a liquid and/or wetted soluble solid aerosol is made to penetrate-and pass through the fiber bed of the fiber bed assembly. The fibers in the fiber bed capture the aerosol in the gas by the mechanisms of impaction, interception, and Brownian diffusion. The captured aerosol coalesces on the fibers to form droplets of liquid in the fiber bed. The moving gas urges the droplets to move toward the downstream face of the fiber bed where the captured liquid exits the fiber bed and drains downward under the force of gravity.
The fibers which make up the fiber bed may be made from a variety of materials. Materials utilized to make bed fiber include, for example, metals such as stainless steel, titanium, etc., fibers of polymeric materials such as polyesters, polyvinylchloride, polyethylene terphthalate, nylons, polyethylene, polypropylene etc., and glass. In applications where corrosive conditions and/or high temperatures are encountered, long staple, chemical grade glass fibers have found particularly widespread use in fiber beds of fiber bed mist eliminators. Fibers ranging in diameter from 5 microns or less to more than 200 microns, as well as combinations of fibers of varying diameters, have been used in fiber beds. The bulk density of prior art fiber beds ranges from about 5 lb/ft3 (80 kg/m3) to greater than 20 lb/ft3 (320 kg/m3), while fiber bed thickness ranges from about 0.5 to about 6 inches (1 to 15 cm) or more, depending upon the desired separation efficiency.
In order for a fiber bed to function effectively, the bed must be mechanically stable. A mechanically stable fiber bed is one which will retain its structural integrity without substantial shifting of the fibers relative to adjacent fibers when exposed to the forces exerted by the gas being treated and the captured and draining liquid during aerosol collection. If mechanical stability is not maintained, the performance characteristics of the bed will be unfavorably altered. In a fiber bed lacking mechanical stability, the moving gas stream forces the fibers to shift substantially, causing the liquid ladened fibers in some portions of the fiber bed to mat or felt while increasing the void space between adjacent fibers in other portions of the fiber bed. Matted portions of the fiber bed are more resistant to both the flow of gas and the drainage of captured liquid. Captured liquid which is unable to drain is often reentrained by the moving gas stream, resulting in reduced separation efficiency. Also, the pressure drop across matted portions of an unstable fiber bed is increased. On the other hand, in those portions of a mechanically unstable fiber bed where fiber shifting has increased the average void space between adjacent fibers, macroscopic pores or channels form which reduce separation efficiency by allowing the aerosol containing gas to pass through the fiber bed without sufficient contact with the collecting fibers. In bulk-packed and wound fiber bed assemblies, mechanical stability is largely dependent upon the bulk density of the fiber bed. In these conventionally constructed fiber bed assemblies, a fiber bed bulk density within the range disclosed by the prior art typically provides sufficient contact between adjacent fibers to prevent substantial movement of the fibers when exposed to the forces exerted by the moving gas stream. In bulk-packed fiber beds, density of the fiber bed and resistance to fiber movement is maintained by the reactive compressive force applied against the packed fibers by the two opposing support screens. In preformed fiber bed tubes, the materials may be needled punched or heat formed so that there is significant fiber entanglement or fiber bonding to strengthen the overall bed. Preformed fiber bed tubes have to be reset or adjusted overtime because the fibers shift within the bed. In wound fiber beds, density of the fiber bed necessary to provide mechanical stability is a result of several factors including the tension in the roving as it is wound around the cylindrical support screen and compression of the fiber bed by a wire screen or similar structure which may be wound on the cylinder adjacent to the exterior surface of the fiber roving.
However, bulk density cannot be increased indiscriminately to achieve mechanical stability. If the bulk density of a fiber bed is increased too much, the bed will be prone to flooding. An effective fiber bed is a relatively open structure that allows free gas flow and liquid drainage even when the collecting fibers are coated with collected liquid. There must be sufficient void space between adjacent fibers in the bed so that collected liquid is not able to bridge the space between adjacent fibers to such an extent that the adherence of collected liquid to the surface of fibers prevents the liquid from draining.
A measure of the open space in a fiber bed is void fraction which is defined by the bulk density of the fiber bed and the average density of the fiber material according to the following formula:fiber bed void fraction=1−[fiber bed bulk density/average fiber material density]Fiber beds typically have a void fraction of greater than about 0.89.
It is generally known that the thickness of a fiber bed can be decreased without a loss in separation efficiency by decreasing the average fiber diameter of the fiber material comprising the fiber bed. However, for bulk-packed and wound fiber beds comprising fibers having an average diameter of less than about 5 microns, when the bulk density is high enough to ensure mechanical stability, the resulting void fraction is so low that the bed tends to flood under typical operating conditions. Also, it has been found that conventional thin wound beds are inherently less uniform. A flooded bed is a fiber bed in which captured liquid largely fills the void spaces between adjacent fibers in the fiber bed. A flooded fiber bed is much like the matted portions of an unstable fiber bed. The captured liquid in a flooded fiber bed cannot properly drain and instead may be reentrained in the moving gas stream at the downstream face of the fiber bed. Furthermore, the pressure drop across a fiber bed assembly is increased when the fiber bed is flooded. If a pressure differential across the fiber bed sufficient to overcome the force of adhesion and dislodge the collected droplets from the fibers is employed, the collected liquid is blown from the downstream face of the fiber bed where it is reentrained by the gas stream resulting in low separation efficiency and increased operating cost.
In order to prevent a fiber bed comprising small average diameter fibers from flooding, the specific fiber surface area, expressed as the area of fiber per unit volume of the fiber bed, may be decreased by decreasing the bulk density of the bed (i.e., increasing the void fraction). However, if the bulk density of a bulk-packed or wound fiber bed comprising fibers having an average diameter less than about 5 microns is reduced to a value sufficient to avoid flooding, such fiber beds lack the mechanical stability necessary to withstand the forces exerted by the moving gas stream. As a result, the moving gas stream causes the fibers to shift substantially resulting in the fiber bed matting and/or channeling as previously described. Therefore, in practice, conventionally constructed high efficiency fiber bed assemblies comprise fiber beds 2 to 6 inches (6 to 15 cm) thick constructed of fibers having an average fiber diameter between 5 and 15 microns and having a bulk density between 5 and 15 lb/ft3 (80 and 240 kg/m3).
In contrast to fiber beds used in mist eliminators, some other types of gas filters, such as baghouse, clean room and breathing filters, may successfully utilize glass fibers with average diameters below 5 microns and may even include fibers having a diameter less than 1 micron. However, these types of gas filters are distinguished from fiber bed mist eliminators in that they are typically designed to utilize pore and surface filtration in collecting solid particulates or only relatively small amounts of liquid aerosols. If used to collect liquid aerosols, they easily flood at the liquid loading rates typically encountered in fiber bed mist eliminators. By comparison, fiber bed mist eliminators are designed to allow comparatively large quantities of liquid entrained in a moving gas stream to penetrate the fiber bed where the liquid is captured and continuously drained. Therefore, a solution to the problems associated with utilizing small diameter fibers in fiber beds of fiber bed mist eliminators is neither shown nor suggested by the prior art concerned with such other gas filters.
Reentrainment of collected liquid by the moving gas stream at the downstream face of a fiber bed is often a problem in fiber bed mist eliminator applications, especially in operations characterized by high liquid loading rates or high gas stream velocities. Satisfactory solutions to this problem have included combining a layer of primary filtration fibers and a layer of drainage fibers to form a fiber bed. The drainage layer is downstream of the primary filtration layer and usually comprises fibers with a larger average diameter than those fibers comprising the primary filtration layer.
Despite their success, fiber bed assemblies of the prior art have several disadvantages resulting from shortcomings in the fiber bed. Wound fiber bed assemblies are typically formed using a fiber roving which is roughly cylindrical in shape. The roving is wound around a cylindrical forming screen and back and forth along the length of the screen. This requires skill and the appropriate machinery. Even if the winding is executed correctly, the resultant wound fiber bed may have significant differences in gas flow over the surface area of the bed. These variations are a result of the inherent difficulty of forming a uniform surface on a cylinder using a cylindrical roving. Normal variations in the roving material cause the roving to flatten to different degrees, which affects the uniformity of the fiber bed formed by the roving. The non-uniformity is particularly observed in wound fiber beds having smaller thicknesses.
Another disadvantage associated with bulk-packed and wound fiber bed assemblies is the need to remove the assemblies from the mist eliminator and return them to the manufacturer when the fiber bed needs replacement. Aside from the inconvenience of transporting the heavy support structure, an interchangeable spare fiber bed assembly must be available for the fiber bed mist eliminator to be returned to service and avoid extensive down time. Field replacement of the fiber bed is hampered by difficulties in assembling the fiber bed. Considerable skill and time are required to properly pack new bulk fiber between opposing support screens so that inhomogeneities in the fiber bed are minimized, while winding fiber onto a cylindrical support structure requires extensive machinery. Precast or preformed fiber bed sections have been used by some manufacturers but these have suffered from leakage at joints or settling, requiring extra field maintenance and adjustment. This reduces the productivity of the plant in which the fiber bed is used because the plant must be shut down to carry out the maintenance and/or adjustments.
A third disadvantage is that because fibers having an average fiber diameter of less than about 5 microns cannot be used effectively in constructing a conventional fiber bed without additional processing (e.g., needle punching), fiber bed thickness in applications requiring high separation efficiency cannot be reduced. If thinner high efficiency fiber beds were possible in severe industrial process environments, fiber beds could be configured into shapes that maximize the fiber bed surface area in a given volume available for a fiber bed mist eliminator. This would be analogous to the dry filter art where thin filter papers and felts allow high surface area filter forms via pleating. Thinner, high efficiency fiber beds having increased fiber bed surface area would allow the operating cost of fiber bed mist eliminators to be decreased by decreasing the pressure drop across the fiber bed.

Fiber collecting media strip for a mist eliminator


The precharging device is part of a hydraulic brake system of a vehicle and serves to impose brake fluid under pressure selectively on a brake assembly, by means of a charging unit. To activate the imposition of brake fluid, the charging unit is operatively connected to a fuel supply system. The charging unit is preferably embodied as a piston unit.

1. Field of the Invention
The invention relates to a precharging device of a hydraulic brake system of a vehicle for selective imposition of brake fluid under pressure on a brake assembly, by means of a charging unit.
2. Description of the Prior Art
Precharging devices of the type with which this invention is concerned are used for targeted braking of individual vehicle wheels in the context of an electronic stability program (ESP) for the sake of stabilizing a vehicle that is unstable and is spinning. A targeted braking of individual vehicle wheels is done by active brake pressure fixtures by means of a brake assembly in the form of a hydraulic block. To achieve effective stabilization of an unstable, spinning vehicle, relatively high dynamics must be assured by active brake pressure fixtures, so that a targeted braking of the wheels of the vehicle can be done at an operationally optimal instant and with a desired intensity. However, the dynamics of the active brake pressure fixtures is affected by several ambient conditions, especially the prevailing ambient temperature at the time and the ambient air pressure, which is also variable. A low ambient temperature and a low ambient air pressure leads to relatively poor brake pressure buildup dynamics. The brake pressure buildup dynamics are also affected in terms of their effectiveness by the composition, and in particular the water content, of the brake fluid used. To achieve the most persistently uniform, effective brake pressure buildup dynamics, which should essentially be independent of the prevailing, variable ambient conditions, in an electronic stability program (ESP) so-called xe2x80x9cprechargingxe2x80x9d is performed, in which a brake fluid is pumped from a supply tank or from a master cylinder to a hydraulic block of the vehicle by means of a precharging device. By means of such precharging, a precharge pressure is generated on the intake side of a return pump located in the hydraulic block. In known precharging devices, such precharging is done for instance by means of a precharging pump, intended especially for the purpose, or by means of so-called xe2x80x9cbooster prechargingxe2x80x9d, that is, by means of a driver-independent actuation of a brake booster of the vehicle. Disadvantageously, the known precharging devices are relatively complicated in terms of their construction.
The precharging device of the invention is characterized in that for activating the imposition of the brake fluid, the charging unit is operatively connected to a fuel supply system of the vehicle. The precharging device offers the advantage that a pressure generating unit already existing in the vehicle and used to supply fuel to the driving engine of the vehicle can be additionally used for precharging for active braking interventions. Thus additional, separate pressure generating units needed solely for creating active brake pressure fixtures are omitted, making a compact and structurally relatively simple design of a precharging device possible. Utilizing a fuel pressure that is preferably permanently present in the fuel supply system, the charging unit can be activated in a reliable, operationally favorable way for brake fluid imposition on a given brake assembly.
Advantageously, the charging unit is embodied as a piston unit. A piston unit is relatively simple to make and is suitable for producing a reliable operative connection with the fuel supply system of the vehicle. Because of the design flexibility of a piston unit, an adapted, operationally favorable precharging can be generated.
The fuel supply system is advantageously embodied as a fuel injection device. Both modern Otto engines and modern Diesel engines have fuel injection systems in which relatively high fuel pressures prevail, regardless of the engine operating state at the time, in specially provided fuel chambers (such as a so-called xe2x80x9crailxe2x80x9d, in Diesel engines). From these fuel chambers, when the applicable driving engine is in operation, a controlled imposition of fuel on the individual cylinders takes place, in which cylinders combustion occurs in a known manner. A fuel injection device is thus especially suitable, because of the fuel pressures that are typically always present during operation of the internal combustion engine, for establishing an operative connection with a charging unit, which in particular can be embodied as a piston unit.
In a preferred embodiment, the piston unit has a fuel piston and a brake fluid piston operatively connected to the fuel piston by means of a connecting rod, which are displaceable in an adapted cylinder by means of the fuel injection device as a function of a switchable fuel imposition. In this way, it is possible to divide the piston unit into a fuel operation region and a brake fluid operation region, and different operating pressure can prevail in the two operation regions.
Advantageously, the piston unit has a fuel pressure chamber, which is operatively connected by means of a switchable valve to the fuel injection device for selective fuel imposition. A switchable valve, which preferably has a plurality of different functional positions, is especially well suited to producing a reliable, flexible fuel imposition on the fuel pressure chamber and thus for effective precharging.
Advantageously, the piston unit is operatively connected to a fuel reservoir. The fuel reservoir is part of the fuel injection device and is preferably embodied in the form of a so-called rail. It is under a relatively high operating pressure. This operating pressure of the stored fuel serves on the one hand to provided controlled fuel imposition on the corresponding driving or internal combustion engine, and on the other, it can be used simultaneously for activating and generating a precharging operation.
In an alternative embodiment, the piston unit is operatively connected to a fuel pump means. The fuel pump means is likewise part of a fuel injection device and is preferably embodied as a so-called xe2x80x9ccommon-rail pumpxe2x80x9d. Once again, the relatively high fuel pressure generated can be used both for imposing fuel on the applicable internal combustion engine and for performing a precharging operation.
Advantageously, the operational face of the fuel piston is smaller than the operational face of the brake fluid piston. By a selection of the particular size of the operational face of the fuel piston and of the brake fluid piston, it is possible to obtain a hydraulic boost (or reduction) by means of the piston unit. In this way, the relatively great differences in pressure between the fuel region and the brake fluid region of the piston unit can be compensated for relatively simply.
Advantageously, the piston unit has a brake fluid pressure chamber, which is operatively connected to the brake assembly and to a brake fluid tank by means of a respective supply line that has an associated check valve. The check valves serve to prevent deflection of the brake fluid piston, and thus also of the fuel piston, caused by an incident operating brake pressure during braking performed by the driver, and to assure correct filling of the brake fluid pressure chamber.
Advantageously, the valve is embodied as a switchable control and/or regulating valve. A switchable control and/or regulating valve is especially well suited to establishing a flexible, reliable and correct operative connection between the charging unit and the fuel supply system.
In a preferred embodiment, the valve has a functional position that separates the piston unit from the fuel injection device. In such a separating functional position of the valve, additional or alternative security is obtained in terms of the prevailing operating position of the fuel piston at the time, and thus also of the brake fluid piston, especially during driver-performed braking (increased driver braking pressure).
Preferably, the valve together with the fuel pump means and/or the fuel reservoir forms a structural unit. In this way, a compact, easily installed structural unit is obtained, and the requisite high-pressure lines for establishing an operative connection between the valve and the fuel supply system can advantageously be kept relatively short. The piston unit is preferably disposed in the engine compartment of the vehicle.

Precharging device in a hydraulic brake system of a vehicle


A method of fabricating a bond and the bond. The process includes providing a lower level (M1,13, 15) of electrically conductive metal disposed on a substrate having a pair of spaced apart sections. An electrically insulating layer (11) is then disposed over the lower level and vias (23) are formed in the electrically insulating layer, individual ones of the vias extending to one of the spaced apart section of the lower level. An upper level of electrically conductive metal (M2, 17, 19) is disposed on the electrically insulating layer, the upper level having a pair of spaced apart sections, each coupled to one of the sections of the lower level through a via. One of the pair of spaced apart sections of the lower level is preferably essentially U-shaped (13) and the other section (15) of the lower level is essentially rectangular shaped and extends into the open end of the "U". One of the pair of spaced apart section of the upper level is essentially rectangular (17) with a rectangular aperture at its central region and the other section of the upper level (19) is essentially rectangular and disposed within the rectangular aperture. A bond (23) is formed completely enclosing the spaced apart sections of the upper level.

1. Field of the Invention
This invention relates to a method and structure which permits measurement to be taken of individual circuits and/or circuit components of an integrated circuit which could otherwise not be individually measured when connected within the integrated circuit.
2. Brief Description of the Prior Art
It is often desirable to test individual circuit portions and/or individual components of an integrated circuit prior to completion of fabrication. Such testing can avoid completion of fabrication of devices which already have a defect, thereby providing an economic saving and removing potentially inferior or non-working devices from the line. This type of testing has importance and several solutions have been provided by the prior art.
For example, in one prior art procedure as shown in FIG. 1, in order to improve the safe operating area (SOA) of a power transistor, a clamp in the form of a diode stack having a standard diode and a zener diode in back to back relation is placed across the gate and drain of the transistor. The diode stack will break down prior to the breakdown of the power transistor. This places the transistor in a forward biased SOA which is much stronger than placing the transistor in a reverse biased SOA (RBSOA). A problem with this arrangement is that, if the breakdown voltage of the stack is close to or above that of the transistor, the transistor may go into an RBSOA mode and will break down first with the stack having essentially no effect. It is therefore apparent that, in order for such an arrangement to be successful, it is imperative that the breakdown voltage of the transistor be much greater than the breakdown voltage of the diode stack. However, there is no good way to determine that this relation exists, so it cannot be accurately determined upon testing whether a breakdown is being caused by the diode stack or the power transistor. Disadvantage of this type of arrangement are that (1) the BV.sub.dss of the transistor cannot be tested, (2) the BV.sub.dss of the transistor cannot be distinguished from the BV of the diode stack, (3) leakage in the transistor cannot be distinguished from leakage in the diode stack and (4) the unclamped energy capability of the transistor cannot be tested because the BV of the diode stack is less than BV.sub.dss.
In a second prior art arrangement as shown in FIG. 2, the diode stack and the transistor are separated from each other at the output by providing a split bond pad having two separated sections, one section attached to the diode stack and the other section attached to the transistor. In this way, testing of the stack can take place separately at probe with the split bond pad later being connected together during bonding by having the bond extend across both bond pad sections. Problems that arise with this procedure are that the bond pad must be large, thereby decreasing the number of components that can be placed in a given area, there is an inefficient use of high current bonding since only half of the bond area is used for high current switching, there is the possibility of contaminant ingress due to the nitride opening at the bond pad metal edge of the field oxide and there is the possibility that an undesirable hump may be formed during the bonding procedure rather than a conformal bond to the pads.

Connection of active circuitry via wire bonding procedure


A memory component comprises a memory cell array, signal inputs, input amplifiers connected to respective ones of the signal inputs, for receiving, amplifying and outputting data, address or control signals, a data, address or control signal generator for the memory cell array, a first supply network for supplying power to the input amplifiers and a second supply network for supplying power to the data, address or control signal generator, wherein the first supply network and the second supply network do not have a direct connection.

1. Field of the Invention
The present invention relates to a memory component and particularly to a memory component with improved noise insensitivity of the input amplifiers or receivers, respectively.
2. Description of the Related Art
In previous memory components, the noise sensitivity of the input amplifiers does not represent a limiting factor or a decisive characteristic of the performance of the input amplifiers due to the low speed of the data exchange with external data sources, for example, with a bus or a processor. For this reason, the noise sensitivity of the input amplifiers has not yet been investigated in greater detail or optimized.
High performance input amplifiers of present-day high-speed dynamic Random Access Memories or DRAMs, for example, DDRII SDRAMs, or graphics chips provide a data exchange at speeds or data rates which are so high that the performance of the high performance input amplifiers is restricted by noise being coupled in via the supply, signal and reference signal connections.
Thus, there is a need for an improved memory component which exhibits improved insensitivity particularly with respect to the coupling-in of noise.

Memory component with improved noise insensitivity


A coordinate detection system detects coordinates of a position to which an electronic pen points on a surface of a display. The coordinate detection system includes a plurality of detecting elements configured to detect light emitted from each of light emission points of the electronic pen, and a coordinate detection unit configured to detect the coordinates of the position to which the electronic pen points based on a distance relationship between first images of the light emission points in an image formed by the light detected by each of the plurality of detecting elements and second images of the light emission points formed by reflection of the first images on the surface of the display.

1. Field of the Invention
The present invention relates to a coordinate detection system, an information processing apparatus, and a recording medium.
2. Description of the Related Art
A system in which an optical information input device is disposed on a board surface of an electronic whiteboard device and handwritten information depicted on the board surface by a user is input in real time to a computer such as a personal computer via the optical information input device is known.
For example, Japanese Laid-Open Patent Publication No. 2004-038528 discloses an optical coordinate detection device including a large-sized coordinate detection plane (display). This coordinate detection device is equipped with a position indicator (a pen-shaped instrument) having light emission points. In this position indicator (electronic pen), two light emission points are provided on a grip part of the position indicator, and a position of the tip of the position indicator is computed based on positions of the light emission points detected by optical sensors.
However, in the above-described coordinate detection device, the impact of mirror-reflection characteristics of a board surface of the display on the computation results is not taken into consideration. In a case where the image quality deteriorates (e.g., when two images of the light emission points overlap each other), the computation of the position of the tip of the position indicator is prone to having a significant error. Hence, the above-described coordinate detection device has a problem that the detection of coordinates of the tip of the position indicator in such a case may be inaccurate.

Coordinate detection system, information processing apparatus, and recording medium


A wheel condition determination apparatus includes a primary sensor unit and a secondary sensor unit that are provided in the wheels of a vehicle. The primary sensor unit detects a predetermined parameter indicating the condition of the wheel and controls the operation mode of the secondary sensor unit in accordance with the detected predetermined parameter. The secondary sensor unit detects a predetermined parameter indicating the condition of the wheel that is different from the predetermined parameter detected by the primary sensor unit. The operation mode of the secondary sensor unit may be changed between an active mode and a sleep mode. In the sleep mode, detection of the wheel condition may be suspended or performed less frequently than as the active mode.

1. Field of the Invention
The invention relates to a wheel condition determination apparatus that determines the condition of a wheel provided in a vehicle.
2. Description of the Related Art
Japanese Patent Application Publication No. JP-A-11-240315 describes an example of an apparatus that determines the condition of a wheel provided in a vehicle. The apparatus includes a tire tag and a transponder. The tire tag, provided inside a tire, includes a sensor and a battery. The sensor detects a predetermined parameter indicating the wheel condition. The transponder, provided in the wheel rim, transmits the parameter detected by the sensor of the tire tag to the vehicle. Japanese Patent Application Publication No. JP-A-11-254926 also describes an apparatus that determines the condition of a wheel. The apparatus includes a unit, provided in the wheel rim, that includes a sensor, a battery, a microchip, and an antenna. The sensor detects a predetermined parameter indicating the wheel condition. The unit transmits the parameter detected by the sensor to the vehicle.
In the described apparatuses, the battery can supply electric power for a relatively long period. However, the amount of electric power supplied to the sensor and related components should be minimized to determine the wheel condition for a long time. Japanese Patent Application Publication No. JP-A-11-020427 describes an example of a tire air-pressure detection apparatus for a wheel. The tire air-pressure detection apparatus includes an air-pressure sensor, a transceiver, and a centrifugal-force switch that is turned on when centrifugal force generated by the rotation of a wheel becomes equal to or greater than a predetermined value. The air-pressure sensor detects the air pressure and the transceiver transmits and receives data only when the centrifugal-force switch is ON, that is, only when the vehicle is moving. This reduces the amount of electric power consumed to determine the wheel condition.
The information useful for improving the running performance and safety of the vehicle includes not only the aforementioned tire air-pressure but also other parameters. Therefore, a technology where a plurality of sensor units are provided in a wheel, and each sensor detects a different parameter indicating the wheel condition has been recently proposed. In this technology as well, the amount of electric power required for detection of the condition of the wheel and data communication should be minimized. However, if the centrifugal-force switch is provided in each of the plurality of sensor units as in the conventional tire air-pressure detection apparatus, the cost of the entire apparatus increases, and each sensor unit occupies a large space.


A system, method and computer program product for estimating a vehicle arrival time. The system receives information representing prior travel times of vehicles between pre-determined vehicle stops along a vehicle route. The system receives real-time data representing a current journey. The current journey refers to a movement of a vehicle currently traveling along the route. The system calculates a regular trend representing the current journey based on the received prior travel times information and the received real-time data. The system computes a deviation from the regular trend in the current journey. The system determines a future traffic status in subsequent vehicle stops in the current journey. The system estimates, for the vehicle, each arrival time of each subsequent vehicle stop based on the calculated regular trend, the computed deviation and the determined future traffic status.

The present application generally relates to determining a bus arrival time at each bus stop of a plurality of bus stops. More particularly, the present application relates to predicting a bus arrival time based on prior travel times between bus stops and real-time data representing a current journey.
Predicting arrivals of buses and/or other transportation vehicles at bus stops or designated locations is important in making a public transporting system more appealing and more efficient for passengers. With accurate bus arrival predictions communicated or presented to passengers, the passengers can make informed decisions about how to travel.
Improving a public transporting system is critical for reducing congestions on urban roadways. Providing timely accurate predictions about bus arrivals at bus stops along bus routes is one important step to improve public transporting system. Current systems for predicting arrival times of buses at bus stops rely on GPS (Global Positioning System) location information of the buses. While those current systems represent improvements over prior systems that have no available information of predicting bus arrival times, predictions of the current systems are not accurate, e.g., buses arrive more than 5 min later from the predictions. What occurs then is that the passengers, having perceived the predictions to be inaccurate, can no longer rely on the predictions at all. Thus, in many cities, such current systems have been abandoned for this reason, i.e., inaccuracies.
There may be several reasons why the current systems predict inaccurately bus arrival times: 1. The current systems use algorithms that may need further improvements; 2. Input data to the current system is not rich enough to permit an accurate estimation of bus arrival times. For example, the current systems use GPS information of bus positioning only to obtain data of bus travel time on segments that the bus already traversed. The GPS information does not provide information on traffic in an upcoming route.

Vehicle arrival prediction using multiple data sources including passenger bus arrival prediction

International Business Machines Corporation


An array substrate (20) is formed with a plurality of first grooves (28a), in a sealant region (SL), being apart from each other in the width direction of the sealant region (SL) and extending along a sealant (40) and a plurality of second grooves (28b), in the region where a common transition electrode (26c) is formed, being apart from each other in the length direction of the sealant region (SL) and extending along the width direction of the sealant region (SL).

The thickness of liquid crystal display devices can be reduced, and power consumption of the liquid crystal display devices is low. Thus, the liquid crystal display devices have been broadly used as displays for OA equipment such as television sets and personal computers, mobile electronic devices such as mobile phones and smartphones, and cockpits of automobiles and aircrafts.
The liquid crystal display device includes a display panel and a backlight unit attached to a rear side of the display panel. The display panel has such a configuration that an array substrate and a counter substrate disposed so as to face the array substrate are bonded together with a sealant, and a liquid crystal material is sealed in the space between both substrates. A substrate slightly smaller than the array substrate is used as the counter substrate, and a drive circuit is, using a system on film (SOF) or tape automated bonding (TAB), mounted on terminals of the array substrate exposed by the foregoing size difference.
The display panel has a display region where an image is displayed and a non-display region surrounding the display region. In the display region, a plurality of pixels are arranged in a matrix. A switching element such as a thin film transistor and a pixel electrode connected to the switching element are provided corresponding to each pixel on the array substrate. Moreover, a common electrode is provided so as to cover at least the entirety of the display region of the counter substrate. Current flows through each pixel electrode in synchronization with ON/OFF of an associated one of the switching elements. The common electrode is electrically connected to common transition electrodes provided on the array substrate, a common potential is applied from a common transition electrode lead line to the common electrode through each common transition electrode.
An alignment film is, on the surface of the array substrate contacting a liquid crystal layer, formed so as to cover at least the display region. Similarly, an alignment film is, on the surface of the counter substrate contacting the liquid crystal layer, formed so as to cover at least the display region.
The alignment film can be formed in such a manner that a resin film formed using, e.g., flexographic printing or an ink-jet method and made of, e.g., polyimide is subjected to rubbing or photo-alignment. The ink-jet method is preferably used for formation of the resin film such as a polyimide film because of the following excellent characteristics: a solution can be directly applied to the substrate; a low contamination can be achieved because of the ink-jet method being a non-contact process; a solution consumption amount is low; and a process time can be shortened.
In the case of forming the alignment film by the ink-jet method, resin having a lower viscosity than that used in the case of the flexographic printing is used as a raw material of the alignment film, and therefore, it is likely that the raw material of the alignment film leaks out to the region around the region (display region) targeted for printing. Thus, if the non-display region around the display region is small and a large clearance between the display region and the sealant region cannot be ensured, the alignment film spreads out to the sealant region. In this case, the liquid crystal material of the liquid crystal layer cannot be completely sealed due to insufficient adhesion between the sealant and the alignment film, resulting in leakage of the liquid crystal material of the liquid crystal layer.
In order to solve the foregoing problem, Patent Document 1 discloses a liquid crystal display device configured such that grooves extending along the outer periphery of a display region are formed in a substantially-circular region outside the display region and inside the region where a sealant is applied. According to such a configuration, even if a liquid resin material applied using the ink-jet method spreads outward of the display region, the grooves can prevent spreading of the resin material, and spreading-out and leakage of an alignment film on the outside of the display region can be reduced. Patent Document 1 further discloses the configuration in which a conductive film such as an ITO film is formed on the surfaces of the grooves. Since the liquid resin material, i.e., an alignment film material, has a low wettability to the ITO film, the foregoing configuration can prevent spreading-out and leakage of the liquid resin material from the grooves.


The present invention has for its object to provide, in an environment where plural radio systems coexist, a feed forward amplifier capable of adaptively selecting a frequency band. The feed forward amplifier of the present invention comprises a distortion detection circuit and a distortion elimination circuit and has n first vector adjusters 4 which have different operating frequency bands and are inserted in a first vector adjustment path 14 of the distortion detection circuit; and n second vector adjusters 11 which have frequency bands corresponding to those of first vector adjusters 4 and are inserted in a second vector adjustment path 8 of the distortion elimination circuit. By means of a first switching means 3 selecting one first vector adjuster 4 and a second switching means 10 selecting a second vector adjuster 11, the frequency band for which distortion component is compensated in the feed forward amplifier is controlled by switching.

1. Field of the Invention
This invention pertains to a transmission amplifier for radio communications which adaptively changes the frequency band. In particular, it pertains to a band selection type feed forward amplifier for multiple frequency bands which selects and amplifies an arbitrary frequency band from among a plurality of frequency bands.
2. Description of Related Art
The base configuration of a feed forward amplifier is shown in FIG. 1. The feed forward amplifier includes two signal processing circuits. One is a distortion detection circuit 100 and the other is a distortion elimination circuit 101. Distortion detection circuit 100 is composed of a main amplifier signal path 103 and a linear signal path 104. Distortion elimination circuit 101 is composed of a main amplifier output signal path 108 and a distortion injection path 109. Main amplifier signal path 103 (also called a vector adjustment path) is composed of a vector adjuster 105 and a main amplifier 106. Vector adjuster 105 has a variable phase shifter 105a and a variable attenuator 105b. Linear signal path 104 is composed of delay lines. Also, main amplifier output signal path 108 is composed of delay lines. Distortion injection path 109 is composed of a vector adjuster 110 and an auxiliary amplifier 111. Vector adjuster 110 is composed of a variable phase shifter 110a and a variable attenuator 110b. A divider 102, a power combiner/divider 107, and a power combiner 112 are simple lossless power dividers and power combiners composed of transformer circuits, hybrid circuits, and the like.
First, an explanation of the basic operation of the feed forward amplifier will be given. The signal input into the feed forward amplifier is divided into main amplifier signal path 103 and linear signal path 104 by means of divider 102. At this point, variable phase shifter 105a and variable attenuator 105b of main amplifier signal path 103 are adjusted so that the signals of main amplifier signal path 103 and linear signal path 104 have equal amplitude and opposite phase. As methods for bringing the paths to opposite phases, there is the method wherein power divider 102 or power combiner/divider 107 sets a phase shift quantity appropriately between the input and output terminals or the method wherein main amplifier 106 inverts the phase.
Since distortion detection circuit 100 is configured in this way, power combiner/divider 107 can output the differential component of the signal passing through main amplifier signal path 103 and the signal passing through linear signal path 104. This differential component is precisely the distortion component generated in main amplifier 106. Due to this fact, the block from power divider 102 to power combiner/divider 107 shown in FIG. 1 is called a distortion detection circuit.
Next, an explanation regarding distortion elimination circuit 101 will be given. The output of distortion elimination circuit 100 is divided, via power combiner/divider 107, into main amplifier output signal path 108 and distortion injection path 109. The output of main amplifier 106 from main amplifier signal path 103 (the signal passing through main amplifier signal path 103) is input into main amplifier output signal path 108. Also, the distortion component of main amplifier 106 detected in distortion detection circuit 100 (the differential component of the signal passing through main amplifier signal path 103 and the signal passing through linear signal path 104) is input into distortion injection path 109. As for variable phase shifter 110a and variable attenuator 110b of distortion injection path 109, the distortion component of the signal passing through main amplifier output signal path 108 and the signal passing through distortion injection path 109 are adjusted so as have equal amplitude and opposite phase. By making an adjustment in this way, power combiner 112 can combine the signal passing through main amplifier signal path 103 with the distortion component of main amplifier 106 having equal amplitude and opposite phase. And then, power combiner 112 outputs a signal in which the distortion components of the whole amplifying circuit are cancelled. Further, even if it is a matter of common knowledge, a linear amplifier is used as an auxiliary amplifier in order to eliminate the distortion component generated in the main amplifier used in a feed forward amplifier. The aforementioned operation is an ideal operation of a feed forward amplifier. In practice, it is not simple to completely maintain a balance of the distortion detection circuit and the distortion elimination circuit. Also, even if tentatively the initial settings are perfect, since the properties of the amplifier change due to fluctuations in ambient temperature, power supply, and the like, it is extremely difficult to preserve an excellent balance which is stable over time.
As a method for maintaining with high accuracy a balance of the distortion detection circuit and the distortion elimination circuit of this feed forward amplifier, there is known an self-adjusting method using a pilot signal. E.g., there exist the Japanese Patent Application Laid-Open Publication No. 1 (1989)-198809 (Patent Reference 1) and the like. As devices putting these methods into practical use, there is known the article "Extremely Low-Distortion Multi-Carrier Amplifier For Mobile Communication Systems-Self-adjusting Feed-Forward Amplifier (SAFF-A)" by Toshio Nojima and Shoichi Narahashi, Institute of Electronics, Information, and Communication Engineers, Wireless Communication Systems Society, RCS90-4, 1990 (Non-patent Reference 1). These feed forward amplifiers were put into practice in the 800 MHz band and the 1.5 GHz band of the PDC (Personal Digital Cellular) mobile communications standard in Japan. This kind of feed forward amplifier is generally designed and adjusted to amplify separately for each frequency band.
In the radio systems developed this far, a single system in accordance with any one of PDC, GSM (Global System for Mobile communications), IMT-2000 (International Mobile Telecommunications 2000), and the like, was used. As against this, there is the technology of carrying out a transfer to software of some functionality of radio devices so that it becomes possible for a single hardware to handle a plurality of radio systems. If it is possible for a single hardware to handle a plurality of radio systems, the user can use the mobile communication environment without any awareness of the radio system or the core network in the background thereof. However, a single hardware actually handling a plurality of radio systems is something that has not reached implementation.
Also, it can be considered that, for each region or operator, the services offered with the radio system will be different and that the radio systems will also gradually become diversified. For this reason, it can be considered that, in the future, there will arise a need to make radio systems coexist which are optimal for each purpose, at the same time and in the same place.
As a method of using these plural radio systems, there is the multiband radio system. This radio system adaptively changes the frequency band used or the number of frequency bands used in response to the propagation environment and the traffic conditions. Also, in order to ensure a prescribed transmission quality or transmission volume, multiband transmission using frequency bands not in use is effective. Consequently, in a multiband radio system, in order to ensure the transmission quality or transmission volume to be guaranteed by the same radio system, the number of frequency bands is changed. Moreover, changes are also carried out in the same way within the same frequency band. Further, a multiband radio system, in case there coexist frequency bands used by several operators, can raise the frequency utilization efficiency by carrying out adaptive control using available frequency bands by means of interference recognition technology, frequency sharing technology, interference cancellation technology, produced interference reduction and avoidance technology, multiband control technology, and the like.
The feed forward amplifier is used as a linear amplifier for base stations handling multiband radio systems like this. However, in case the plural frequency bands to be amplified are widely separated, compared to the bandwidth of each frequency band, the adjustment levels of the variable phase shifter and the variable attenuator for keeping the balance of the distortion detection circuit and the distortion elimination circuit within a prescribed range vary with the frequency band to be amplified, because the electrical length of the delay line for each frequency band differs.
To put it in concrete terms, in case a delay line is used in common for all frequency bands, there is, due to the frequency differences of the input signals, ordinarily a need for the setting value of the vector adjuster to track a signal rotating with the angular velocity of the frequency difference. However, in the vector adjusters developed this far, it has not been possible to track a signal rotating at a velocity like that. Also, as for the vector adjusters discussed this far, it has not been possible to simultaneously set an optimal amplitude and phase, with respect to plural input signals, for structural reasons.
E.g., in case 800 MHz band and 1.5 GHz band signals are input into the same vector adjuster, it is possible to carry out optimal vector adjustment with respect to any one of the frequency bands. However, it is not possible to carry out optimal vector adjustment which tracks a frequency difference of 700 MHz. Consequently, the conventional feed forward amplifier has not been able to simultaneously amplify the 800 MHz band signal and the 1.5 GHz band signal at or below a prescribed distortion compensation level.
As a method of resolving this, a dual-band feed forward amplifier is proposed in the article "Dual-band Feed Forward Amplifier" by Yasunori Suzuki and Shoichi Narahashi, the 2005 General Meeting of the Institute of Electronics Information and Communication Engineers, C-2-2, March 2005 (Non-patent Reference 2). With this configuration, there is provided a vector adjuster having a band extraction means for each frequency band. In other words, this dual-band feed forward amplifier extracts the signal of the vector adjusted frequency band from the signals of two frequency bands input by means of a filter provided in a pre-stage of the vector adjuster. And then, vector adjustment is carried out for each frequency band. This dual-band feed forward amplifier configuration is capable of distortion compensation in a plurality of frequency bands. Further, the compensated band is fixed by the filter.
In multiband radio systems having a plurality of transmission bands, it can be considered to change the frequency band due to the service situation of the radio system, interference of other radio systems, and the like. However, as mentioned above, the bandwidth of the distortion compensation of the feed forward amplifier is determined by the adjustment accuracy of each loop of the distortion detection circuit and the distortion elimination circuit. Consequently, in the conventional feed forward amplifier, the adjustment of distortion compensation could not be made to correspond with the frequency band changes. Nor was it possible for the conventional dual-band feed forward amplifier in which the distortion compensated frequency band was fixed to adaptively change the operating frequency. For a feed forward amplifier used over a long time, the change in frequency band accompanies repairs or a change of the feed forward amplifier in the base station. Consequently, an enormous amount of labor and time is required to readjust a large number of feed forward amplifiers. A feed forward amplifier configuration making this kind of labor and time expense unnecessary was required.
E.g., in case, for a dual-band feed forward amplifier which simultaneously compensated the distortion of a signal in a frequency band f1 and a signal in a frequency band f2, the frequency band was changed from f2 to f3, it was not possible to simultaneously compensate the distortion of the signal in frequency band f1 and the signal in frequency band f3. This was so because loop adjustment by the frequency difference of f1 and f3 was not possible, as mentioned above, due to the fact that the operating frequencies of a conventional dual-band feed forward amplifier are fixed.
Also, there can be considered the method of providing, in the dual-band feed forward amplifier, fixed filters and vector adjusters handling all the frequency bands that may be thought to be available for future service. However, having fixed filters and vector adjusters able to handle all the frequency bands amounts to having fixed filters and vector adjusters which are not used something which runs counter to configuring an economical feed forward amplifier. There was demanded a feed forward amplifier with no need for the exchange of constituent parts and having no redundancy to accompany in this way the changes in frequency band or the increase and/or decrease in the number of carrier waves.

Band selection type feed forward amplifier