In a semiconductor integrated circuit device (700) in which variation in a minimum propagation time of a transmission signal from a source node (SN) to a destination node (DN) is sufficiently large, relative to a clock period (T) at an intended clock frequency of the device, to cause variation in a clock cycle in which the transmission signal reaches the destination node (DN) a plurality of clocked elements (8000 to 8003) are connected in series between the source and destination nodes for causing a shift signal (SS0 to SS4), representing the transmission signal present at the source node (SN) in a first clock cycle, to be shifted from the source node (SN) to the destination node (DN) through the series of clocked elements (8000 to 8003) one clocked element (800i) per predetermined number of clock cycles. The series of clocked elements (8000 to 8003) is connected and arranged such that variation (vi) in a propagation time of the shift signal (SSi) from one clocked element (800i-1) to the next clocked element (800i) is sufficiently small, relative to the clock period (T), that a clock cycle in which the shift signal (SSi) reaches the next clocked element (800i) does not vary, whereby the shift signal (SS4) always reaches the destination node (DN) a fixed number of clock cycles after the first clock cycle.

1. Field of the Invention
The present invention relates to the distribution of signals in high-speed digital circuitry, particularly where the variation in the propagation delay to various parts of the circuitry is relatively large in relation to timing constraints imposed on the operation of the circuitry by, for example, a fast system clock.
2. Description of the Related Art
FIG. 1 of the accompanying drawings shows a printed circuit board (PCB) 1 carrying a source chip 2 and a destination chip 3. Signal producing circuitry 4 on the source chip 2 generates n individual channels of data D0 to Dn−1 which are communicated respectively to n signal processing circuitry portions 50 to 5n−1 on the destination chip 3 via n respective output pins 60 to 6n−1 of the source chip 2, n respective connection lines 80 to 8n−1 connecting the source chip 2 with the destination chip 3 and n respective input pins 70 to 7n−1 of the destination chip 3. Each of the data channels D0 to Dn−1 is a serial stream of 1-bit data which is synchronised in the source chip 2 with a clock signal CK generated within the signal producing circuitry 4.
In the FIG. 1 example, the distance "a" separating the source chip 2 and the destination chip 3 is relatively small, for example of the order of 2 to 3 cm, making it feasible to operate a synchronous interface between the two chips. With a synchronous interface, each of the serial data channels D0 to D−1 is synchronised on the source chip 2 with the clock signal CK generated on the source chip 2, and the clock signal CK is itself communicated from the source chip 2 to the destination chip 3 via an output pin 6CK on the source chip 2, a connection line 8CK and an input pin 7CK on the destination chip 3. Since the separation "a" between the source chip 2 and the destination chip 3 is relatively small, the relative timings of the signals communicated between the chips are not influenced too greatly by variations in interconnect loading and therefore the data channels D0 to Dn−1 can be expected to exhibit a reasonable degree of synchronicity with the clock signal CK upon their arrival at the input pins 7 of the destination chip 3. Were an asynchronous interface to be used instead, where the clock signal CK is not communicated from the source chip 2 to the destination chip 3, n separate clock recovery circuits would be required on the destination chip 3 in order to recover n respective individual clocks from the n separate data channels D0 to Dn−1, with consequent problems relating to the realignment of the data channels.
The clock signal CK which is received at the input pin 7CK of the destination chip 3 is distributed to each of the signal processing circuitry portions 50 to 5n−1 for use in controlling the timing of operations by those circuitry portions.
A reset signal R is also produced by the signal producing circuitry 4 of the source chip 2 which is used to reset each of the circuitry portions 5. This reset signal R is also communicated from the source chip 2 to the designation chip 3 via an output pin 6R of the source chip 2, a connection line 8R and an input pin 7R of the destination chip 3. From the input pin 7R the reset signal R is distributed to each of the signal processing circuitry portions 50 to 5n−1.
The input pins 70 to 7n−1 are separated from each other by a distance "b". Circuitry layout and signal distribution considerations dictate that each of the n signal processing circuitry portions 50 to 5n−1 is advantageously positioned as close as possible to its corresponding input pin 7, with the n signal processing circuitry portions 50 to 5n−1 being laid out in a line substantially parallel with the line of input pins 70 to 7n−1 and with each of the signal processing circuitry portions 50 to 5n−1 being opposite its corresponding input pin 7. Therefore the distance "c" separating the signal processing circuitry portions 5 from one another is advantageously substantially the same as the pin separation "b". The distance between the first signal processing circuitry portion 50 and the last signal processing circuitry portion 5n−1 is "d", or approximately (n−1)*c.
In a typical application, the pin separation "b", and therefore also the separation "c" between adjacent signal processing circuitry portions 5, is of the order of 0.5 mm. With sixteen channels of data D0 to D15, and sixteen corresponding signal processing circuitry portions 50 to 515, the overall separation "d" between the first and final signal processing circuitry portions 50 and 515 is of the order of 8 mm. The overall dimensions of such a destination chip 3 would be of the order of 10 mm by 10 mm.
With a destination chip 3 having such dimensions, the capacitive and resistive loading of the interconnect wiring between the input pins 7 and the signal processing circuitry portions 5 is highly significant, and even at moderate clock frequencies this leads to relatively large and highly variable signal transition times (i.e. unpredictable signal propagation delays). Consequently, some sort of signal distribution and buffering network is required to control the propagation of signals from the input pins 7 to the signal processing circuitry portions 5 in the destination chip 3.
FIG. 2(A) of the accompanying drawings shows a simple example of a clock distribution tree which can be used in the destination chip 3 of FIG. 1 to route the received clock signal CK from the clock input pin 7CK to each of four signal processing circuitry portions 50 to 53. In the example shown in FIG. 2(A), only four signal processing circuitry portions 50 to 53 are shown for ease of illustration. The clock distribution circuitry 9 of FIG. 2(A) comprises ten buffers 100 to 109 arranged in a tree-like formation with a single buffer 100 at the root of the tree and four buffers 103, 106, 108 and 109 at the ends of the tree branches. The received clock signal CK branches into four separate clock signals CK0 to CK3 which are input to respective signal processing circuitry portions 50 to 53.
FIG. 2(B) of the accompanying drawings shows similar distribution circuitry 11 for distribution of the received reset signal R. The reset signal distribution circuitry 11 also comprises ten buffers 120 to 129 arranged in a similar configuration to the ten buffers 100 to 109 of FIG. 2(A).
Each of the signals CK0/R0 to CK3/R3 in FIGS. 2(A)/2(B) propagates through a different set of four buffers. For example, clock signal CK1 arrives at its destination having travelled through buffers 100, 104, 107 and 108. Each signal therefore passes through the same number of buffers to arrive at its destination. The wiring portions are not all of the same length, which leads to some small differences in propagation time amongst the signals CK0 to CK3 and amongst the signals R0 to R3. However, provided that the wiring propagation times are small in comparison with the switching times of the buffers, the signals CK0 to CK3 and R0 to R3 arrive at the signal processing circuitry portions without significant timing differences.
In practice a more efficient distribution tree having fewer buffering stages than those illustrated in FIGS. 2(A) and 2(B) would be used. However, even with signal distribution arrangements where measures have been taken to equalise the path lengths and propagation delays of each of the signals CK0 to CK3 or R0 to R3, there can be substantial differences, i.e. skew, in the arrival times of different clock signals CK and different reset signals R at the signal processing circuitry portions 5. This is because the path taken through the distribution network by one of the signals CK0 to CK3 in FIG. 2(A) or R0 to R3 in FIG. 2(B) is different to the path taken by another such signal, with each signal travelling through a different set of buffers. As a consequence, the overall delay of each distributed signal will be different. Furthermore, even when a single signal is considered, there can be substantial variation, i.e. jitter, in its arrival time at its particular intended signal processing circuitry portion 5. There are several reasons for such skew and jitter.
Firstly, manufacturing or process variations will result in variations between the size or strength of the individual buffers, their switch times, and their loading effects. Such process variations will tend to be small across a single chip but can be much larger from one chip to another. Secondly, there will be random or systematic variations in supply voltage applied to each of the individual buffers, for example up to ±5%. Thirdly, there will be variation in the operating temperature at different parts of the circuitry and from device to device. Such temperature variations will tend to be small across a single chip at any one time but the circuitry may be required to operate over a wide range of operating temperatures, for example from −40° C. to +125° C. These uncertainties in operating conditions are referred to generally as "process-voltage-temperature" variations, or PVT variations.
PVT variation within a single device results in timing skew or jitter being manifested in the signals at the end of a distribution network such as that of FIG. 2(A) or FIG. 2(B), which can typically be of the order of 15% of the overall distribution delay which is experienced by a signal through the distribution network, even between adjacent distributed signals. Electrical (voltage) variations tend to dominate this "local" PVT variation since temperature and process variations tend to be small across a single device at any one time. For example, a fluctuating supply voltage may lead to fluctuating signal rise and fall times, which will result in jitter.
"Global" PVT variations, which are PVT variations from one device to another or from one time to another in a single device, also have significant timing implications. For example the propagation time of a particular signal in a device will change markedly as the operating temperature of the device varies between, for example, −40° C. and +125° C., and process variations between devices will also have a significant effect.
In the context of clocked circuitry such as that shown in FIG. 1, these local and global PVT variations can be large enough to make it impossible to guarantee that a signal will arrive at its destination in a predetermined clock cycle, for example. This problem becomes particularly serious where the frequency of the clock signal is very high, bordering on the maximum speed of operation of the circuit elements making up the circuitry, for example of the order of 600 or 700 MHz for a 0.18 μm CMOS process.
FIGS. 3(A) to 3(C) illustrate these effects of local and global PVT variation on the timing characteristic of a distributed clock signal. FIG. 3(A) shows the received clock signal CK at the clock input pin 7CK. The clock signal has a clock cycle period of T. The delay effects will be illustrated with reference to the rising edge E of the clock signal CK of FIG. 3(A). All timing values are measured with respect to the 50% amplitude threshold of a rising edge.
FIG. 3(B) illustrates the delay of a distributed clock signal (for example CK3 of FIG. 2(A)) with PVT conditions at one extreme of the global PVT variation range for a particular set of tolerances. The minimum delay time Tf in the rising edge under these conditions is illustrated by the solid-line rising edge f of FIG. 3(B). Local PVT variations as explained above will also cause a timing jitter Jf of approximately 15% of the overall minimum PVT delay Tf, so that while a clock signal distributed to one part of the circuitry (for example CK3 of FIG. 2(A)) may be delayed by a time Tf, another clock signal distributed to a different part of the circuitry (for example CK0 of FIG. 2(A)) may be delayed by a different time Tf* with respect to the rising edge E. The maximum delay time for the same set of extreme global PVT conditions is illustrated by the dashed-line rising edge f* in FIG. 3(B).
FIG. 3(C) shows the delay experienced by the rising edge of clock signal CK with PVT conditions at the other extreme of the global PVT tolerance range, that is to say the maximum global PVT delay. The maximum delay experienced by the rising edge E under these conditions is Ts, as illustrated by the solid-line rising edge s of FIG. 3(C). Local PVT variation causes jitter Js between different clock signals of approximately 15% of Ts, so that for clock signals distributed to different parts of the circuitry the rising edge delay time could be any time between Ts* and Ts when the PVT conditions are at this end of the PVT tolerance range.
Referring to the timing symbols of FIGS. 3(A) to 3(C), in one practical example of clock distribution circuitry the clock signal CK has a frequency of 673 MHz, so that the clock cycle period T is 1.48 ns. The minimum clock delay Tf is 720 ps, so that Tf* (=Tf+15%) is 830 ps. The clock distribution jitter Jf in these circumstances is then 110 ps. The rising edge time is of the order of 180 ps. The maximum clock delay Ts in this example is 1830 ps, so that Ts* (=Ts−15%) is 1555 ps. The clock distribution jitter Js in these circumstances is then 275 ps. The rising edge speed is of the order of 280 ps.
It can be seen from the above illustration with reference to FIGS. 3(A) to 3(C) that the clock distribution delay can actually be longer than the clock cycle period T, with the time overshoot Tp of FIG. 3(C) varying from 75 ps to 350 ps under "maximum delay" PVT conditions. The clock distribution delay can also be as low as 720 ps, which is less than half a clock cycle period, under "minimum delay" PVT conditions.
Since the reset signal R is also distributed in a similar way to the clock signal CK (see FIGS. 2(A) and 2(B)), the reset signal R also exhibits wide variation in propagation delay. The adverse consequences of these variations in propagation delay across PVT will now be illustrated with reference to FIGS. 4(A) to 4(C) of the accompanying drawings.
FIG. 4(A) shows the clock signal CK and the reset signal R which are received at the input pins 7CK and 7R respectively of the destination chip 3 of FIG. 1. The first clock cycle CYCLE 1 commences with the rising edge E of the clock signal CK. Suppose that the clock signal CK and reset signal R are intended to be used as the clock and reset inputs respectively of a register. The reset signal must be present and stable a minimum set-up time ts before the rising edge of the clock signal CK.
FIG. 4(B) shows the clock signal CKA and reset signal RA which are received at one of the signal processing circuitry portions 5 of FIG. 1 after distribution through circuitry such as that shown in FIGS. 2(A) and 2(B). In the FIG. 4(B) example, the clock signal CKA is delayed by a time dCKA with respect to the original clock signal CK. The reset signal RA is delayed by a time dRA with respect to the original reset signal R. In the FIG. 4(B) example, the clock delay dCKA and reset delay dRA are approximately the same, with the result that the rising edge in RA occurs more than the set-up time ts before the rising clock edge A of the clock signal CKA in CYCLE 1 of FIG. 5(B). Thus, as intended the reset signal given in CYCLE 1 of FIG. 5(A) causes the register to be reset at the rising edge A.
FIG. 4(C) illustrates the clock signal CKB and reset RB which are received at a different one of the signal processing circuitry portions 5 of FIG. 1 within the same destination chip 3. The clock signal CKB is delayed by a time dCKB with respect to the original clock signal CK, and the reset signal RB is delayed by a time dRB with respect to the original reset signal R. In the FIG. 4(C) example, the clock delay dCKB is approximately equivalent to the delay dCKA experienced by clock signal CKA of FIG. 4(B), but due to PVT variations the delay dRB experienced by the reset signal RB is greater than the delay dRA experienced by the reset signal RA of FIG. 4(B). In the FIG. 4(C) example, the reset signal RB has been delayed to such an extent that it would no longer meet the set-up time ts of the register in CYCLE 1 of FIG. 4(C). Thus the register would not be reset until the rising edge B.
It is apparent from FIGS. 4(B) and 4(C) that due to PVT variations the clock cycle in which the reset signal reaches its destination can vary. This variation can occur even where there is no clock variation or jitter at all, the variation in the clock cycle timing of arrival arising entirely from the variation in the propagation time of the reset signal itself. The variation is of course exacerbated when clock timing variations, which inevitably also occur in practice, are taken into account. This is true even though the clock and reset distribution trees of FIGS. 2(A) and 2(B) are matched such that the delay of each distributed clock signal CK0 to CKn−1 nominally matches the delay of its corresponding distributed reset signal R0 to Rn−1. In practice, the matching of delays is only precisely possible for a particular set of PVT conditions, and cannot always be achieved across the entire range of PVT conditions. Therefore circuitry which may be operating correctly at one particular point in the PVT range may not operate correctly at a later time when, for example, the temperature has drifted higher over that period of time.
This timing problem can also arise even if the reset signal R is synchronised to one of the rising edges of the clock signals CK, for example by synchronising circuitry connected with the clock and reset input pins 7CK and 7R in FIG. 1. In this case, as shown in FIG. 5(A) of the accompanying drawings the rising edge of the reset signal R is synchronised with the rising edge E of the clock signal CK in CYCLE 1. FIG. 5(B) of the accompanying drawings shows the situation where the clock signal CKA is delayed with respect to the original clock signal CK by a relatively large time dCKA, which is larger than the overall clock cycle period. On the other hand, the reset signal RA is delayed by a shorter time dRA with respect to the original reset signal R, the difference between dRA and dCKA arising from PVT variations. As a result the reset signal is received at the register at a time which meets the set-up requirements of the register in CYCLE 0 of FIG. 5(B), which is the cycle preceding the CYCLE 1 in which the reset signal was given in FIG. 5(A). Thus the register would be reset on rising edge B rather than rising edge A of the clock signal CKA, as intended.
Although FIGS. 1 to 5 have illustrated the problems of distribution of a signal from a source node of a chip to a plurality of destination nodes on a chip the same problem will also arise even when a reset signal (or other such signal) is being distributed from a source node to a single destination node. For example, although FIGS. 4(B) and 4(C) were described above as showing the timing of a clock signal CK and reset signal R distributed from a single node point to two different destination nodes A and B within the same circuitry, those figures could also represent the timing of signals distributed from a source node to a single destination point at two different times A and B for the same device, or between equivalent source and destination nodes in two different devices A and B.
The problem will arise in any device in which variation in a minimum propagation time of a transmission signal, such as a reset signal as described above, from a source node to a destination node is sufficiently large, relative to a clock period at an intended clock frequency of the device, to cause variation in a clock cycle in which the transmission signal reaches the destination node. In practice, a transmission path between the source and destination nodes having the minimum propagation time may be exclusively passive (wiring portions or tracking), or may include active elements such as gates or buffers. The minimum propagation time relates to the fastest practically-realisable such transmission path for a particular device.

Device and method for ensuring that a signal always reaches its destination after a fixed number of clock cycles


Disclosed is an adaptive method for reducing power consumption in a standby mode of a digital radio communication terminal. The method comprises the following steps of: calculating the difference of edge timings between a main clock and a low clock; comparing the calculated timing difference with a predetermined difference reference value; and upgrading or downgrading a catnap period according to a result of the step of comparing.

1. Field of the Invention
The invention relates generally to a method for reducing power consumption in a mobile radio terminal such as a radio telephone, and more particularly, to a method for reducing power consumption in a standby mode of a radio terminal when the radio terminal is operated in a slotted paging mode in a CDMA (Code Division Multiple Access) radio telephone system.
2. Description of the Related Art
The slotted paging mode is a form of DRX (Discontinuous Reception) operations for a mobile radio terminal actuated by a battery such as a cellular radio telephone. The mobile radio terminal is adapted to radio communication with at least one remote base station in the radio telephone system. In the slotted paging mode, when the radio terminal (also referred to as a mobile station) is in an idle mode (or is not in conversation), the radio telephone is generally in a low power state without continuously monitoring a paging channel.
The slotted paging mode is important in the battery life of the radio telephone. It is an object of operating the slotted mode to reduce the operating time of a radio apparatus into the smallest amount and interrupt the power of the radio apparatus as little as possible during a sleep period. In an idle mode, the radio telephone wakes up only in a previously allocated slot by the radio telephone system or for treating certain other conditions such as a user input.
In returning from the sleep period, the radio apparatus should re-acquire an RF (Radio Frequency) link with the base station of the radio telephone system. Acquisition of the link and other operations including communication protocols for such a system are defined in air interface standards. An example of such a standard may include the TIA/EIA (Telecommunications Industry Association/Electronic Industry Association) IS-95: "Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System." The IS-95 defines a DS (Direct Sequence)-CDMA or CDMA radio telephone system.
In order to re-acquire the RF link, the radio telephone of the CDMA system synchronizes with the system time that is maintained by the base station and a network controller of the CDMA system. The timing for a forward link (base station to mobile station) should be maintained by the radio telephone in anticipation that the radio apparatus is promptly started when an allocated slot is generated. The timing uncertainties are modified and the paging channel is acquired to prepare for treatment.
The synchronization with the forward link includes an alignment of a PN (Pseudorandom Noise) sequence transmitted to a pilot channel by the base station and a locally generated PN sequence. The transmitted sequences include a "short PN" sequence, which is repeated every 26⅔ ms, and a "long PN" sequence, which is repeated every 41 days. The radio telephone includes a sequence generator for generating short and long PN sequences same as those used by the base station. The radio telephone uses a searcher receiver or other mechanism for aligning the short PN sequence with that received from the base station. Once the pilot channel is acquired, the radio telephone acquires a synchronizing channel and the paging channel. Then, the radio telephone correctly demodulates a traffic channel to establish a full-duplex link with the base station.
In the start after the sleep time, the radio telephone synchronizes with the long PN sequence and the short PN sequence. The PN sequences and a frame boundary are repeated with a logical frequency in the IS-95 system. The frame boundary is generated in every third PN roll boundary. The PN roll boundary is defined by a short PN sequence which reverse rolls to the initial value thereof. In the mobile station, the short PN sequence and the long PN sequence are defined as a linear sequence. The short PN sequence and the long PN sequence are generated by using a LSG (Linear Sequence Generator). The LSG is described as a polynomial, and obtained by using a shift register and an exclusive OR gate. Since the short PN sequence is repeated only in every 26⅔ ms, the LSG, when withdrawing from the sleep state, can be conveniently stopped in a specific phase of the sequence until the phase has a correlation with a system PN. Then, the short PN LSG synchronizes with the system timing and starts again.
However, the long PN sequence is repeated only once in every 41 days. It is unpractical that the long PN generator of the radio telephone is stopped (for example, when entering the sleep state) and then the generator is clocked at high speed to catch up the long PN of the system in the start thereafter.
Since the short PN sequence and the long PN sequence are transmitted by the system which varies predictably according to time, the PN sequence acquisition requires that a correct reference time is maintained in the mobile station during the sleep mode. A PN sequence can be suitably determined for the correlation with the system PN sequence in withdrawing from the sleep mode. However, maintaining a precise timing reference requires a relatively high power consumption which is contradictory to the sleep mode designed for low power consumption.
In addition to withdrawing from the sleep mode during the allocated slot, the radio telephone is also required to start for handling other asynchronously generated events in the radio apparatus or for responding to the same. An example of this type of event can include a user input such as pressing a keypad of the radio telephone. The response to such an input should be prompt without any delay which can be recognized by the user.
As it is important in the foregoing related art, a technique for reducing power consumption uses a method in which a receiver in a standby mode is activated only at a pre-designated time to perform a receiving operation during a certain time and then returns to the low power mode by using the slotted paging mode supported by the system. Here, even in the low power mode, minimum clocking is required for the purpose of maintaining synchronization with the system being re-activated and responding to the external input such as an interrupt.
However, while an edge timing should be suitably used in order to use the low frequency clock, actually a mode operated in a high frequency clock is present between receiving modes to maintain the correct edge timing required by the system. Such a mode is referred to as catnap mode in the following description. The operation of this catnap mode is defined with a certain period, and this period is defined via a trade-off according to an experiment.
However, if the operating period of the catnap mode is shorter than required, a loss is caused in power consumption, and if too long, the system may not be suitably synchronized in some cases.

Adaptive method for reducing power consumption in a standby mode of a digital radio communication system


A wireless electronic device may be provided with antenna structures. The antenna structures may be formed from an antenna ground and an array of antenna resonating elements formed along its periphery. The antenna resonating elements may be formed from metal traces on a dielectric support structure that surrounds the antenna ground. The electronic device may be tested using a test system for detecting the presence of manufacturing/assembly defects. The test system may include an RF tester and a test fixture. The device under test (DUT) may be attached to the test fixture during testing. Multiple test probes arranged along the periphery of the DUT may be used to transmit and receive RF test signals for gathering scattering parameter measurements on the device under test. The scattering parameter measurements may then be compared to predetermined threshold values to determine whether the DUT contains any defects.

This relates to wireless electronic devices and, more particularly, to testing electronic devices with wireless communications circuitry.
Electronic devices such as computers, media players, cellular telephones, wireless base stations, and other electronic devices often contain radio-frequency communications circuitry. For example, cellular telephone transceiver circuitry or wireless local area network circuitry may be used to allow a device to wirelessly communicate with external equipment. Antenna structures in the radio-frequency circuitry may be used in transmitting and receiving wireless signals.
The antenna performance of an electronic device may depend on how accurately the radio-frequency communications circuitry is manufactured and assembled within the electronic device. Manufacturing defects present in radio-frequency circuits (i.e., defects due to process variation and non-ideal fabrication environments) may have a negative impact on device performance. For example, if defective parts are assembled in a finished device, the finished device may exhibit unsatisfactory wireless performance during production testing. Detection of faults only after assembly is complete results in costly device scrapping or extensive reworking.
Mishandling during device assembly operations can also have a detrimental impact on device performance. During device assembly, workers and automated assembly machines may be used to connect connectors for antennas and other components to mating connectors, form welds, machine features into conductive device structures, and otherwise form and interconnect electronic device structures. If care is not taken, however, faults may result that can impact the performance of a final assembled device. For example, a connector may not be seated properly within its mating connector or a metal part may not be machined correctly. In some situations, it can be difficult or impossible to detect and identify these faults, if at all, until assembly is complete and a finished device is available for testing. Detection of faults only after assembly is complete can results in costly device scrapping or extensive reworking.
It would therefore be desirable to be able to provide improved ways in which to detect faults during the manufacturing of electronic devices.

Methods and apparatus for testing electronic devices with antenna arrays


A three dimensional printing system includes a vertical support, a support plate, a resin vessel, a fluid spill containment vessel, and a light engine. The support plate is affixed to the vertical support at a proximal end. The support plate has an inner surface defining a first central opening. The resin vessel is supported above the support plate and has an inner edges surrounding a second central opening. The resin vessel includes a transparent sheet that closes the second central opening. The fluid spill containment vessel is supported below the support plate and includes a transparent window. The light engine is supported below the fluid spill containment vessel. The first central opening, the second central opening, and the window laterally overlap to provide an optical path whereby the light engine can project light upwardly to a build plane in the resin vessel.

Three dimensional (3D) printers are in rapidly increasing use. One class of 3D printers includes stereolithography printers having a general principle of operation including the selective curing and hardening of radiation curable (photocurable) liquid resins. A typical stereolithography system includes a resin vessel holding the photocurable resin, a movement mechanism coupled to a support surface, and a controllable light engine. The stereolithography system forms a three dimensional (3D) article of manufacture by selectively curing layers of the photocurable resin. Each selectively cured layer is formed at or proximate to a "build plane" within the resin.
One challenge with stereolithography systems is the reliability and maintenance in working with liquid resins. As stereolithography systems become more automated, there is a need to continually improve safety, reliability, and repeatability of the systems.

This patent is subject to a terminal disclaimer.

Three dimensional printing system with improved reliability, safety, and quality


A reversible thermochromic composition is formed by blending: (a) an electron donating compound; (b) an electron accepting compound; (c) a metachromatic temperature adjuster; (d) an electron accepting, light-fastness providing agent represented by Formula I based on 1.0 part by weight of the component-(a) electron donating compound: ##STR1## wherein n represents an integer of 5 to 17; X and Y each represent C.sub.1-4 or halogen; and p and m each represent an integer of 0 to 3.

1. Field of the Invention
This invention relates to a method for improving the light-fastness (resistance of degradation of color to light) of reversible thermochromic compositions by use of a specific electron accepting light-fastness providing agent.
2. Description of the Related Art
Thermochromic compositions comprised of a combination of electron donating compounds with electron accepting compounds are known in the art, e.g., in U.S. Pat. No. 3,560,229. Since metachromatic temperatures of such compositions depend on the combination of the compounds used, it has been very difficult to obtain compositions capable of varying in color at the desired temperature.
The present inventors have invented a method in which a specific alcohol, ester or ketone is used as a metachromatic temperature adjuster to adjust the metachromatic temperature to the desired temperature (Japanese Patent Publications No. 51-44706, No. 51-44708, No. 52-7764 and No. 6-59746).
The invention previously made by the present inventors is important in that the metachromatic temperature can be controlled to any desired temperature even if the combination of an electron donating and electron accepting compounds is not varied.
However, the combination of these electron donating and electron accepting compounds has a disadvantage that the electron donating compound has poor light-fastness and hence any thermochromic compositions making use of it also have poor light-fastness. Accordingly, the color may become faded by light or, in an extreme instance, may become completely decolored.

Method for improving light-fastness of reversible thermochromic compositions at the time of color extinguishment


A display device includes a display panel including data lines, gate lines crossing the data lines, and pixels arranged in a matrix form, a touch screen which is embedded in the display panel or is installed on the display panel, a data driving circuit supplying a data voltage to the data lines, a gate driving circuit supplying a gate pulse to the gate lines, and a touch sensing circuit which supplies a driving signal to lines of the touch screen and senses a touch input. The gate driving circuit alternately drives pull-down transistors connected in parallel to one gate line. The gate driving circuit drives one of the pull-down transistors or simultaneously drives the pull-down transistors during a drive period of the touch screen.

1. Field of the Invention
Embodiments of the invention relate to a display device including a touch screen.
2. Discussion of the Related Art
User interface (UI) is configured so that users are able to communicate with various electronic devices and thus can easily and comfortably control the electronic devices as they desire. Examples of the user interface include a keypad, a keyboard, a mouse, an on-screen display (OSD), and a remote controller having an infrared communication function or a radio frequency (RF) communication function. User interface technologies have continuously evolved to increase user's sensibility and handling convenience. The user interface has been recently developed to touch UI, voice recognition UI, 3D (three-dimensional) UI, etc., and the touch UI has been basically installed in portable information devices. A touch screen is installed on a display panel of household appliances or the portable information devices, so as to implement the touch UI.
A capacitive touch screen has greater durability and definition than conventional resistive touch screens and is able to carry out multi-touch recognition and proximity-touch recognition. Hence, the capacitive touch screen may be applied to various applications. Because the capacitive touch screen is attached to a display panel or is embedded in the display panel, the capacitive touch screen is electrically coupled with the display panel. A noise that is added to a capacitive voltage of the capacitive touch screen changes when a driving signal of the display panel or a parasitic capacitance of the display panel changes. The noise reduces sensing sensitivity of the capacitive touch screen.


A braking force generator includes a primary piston displaceable in a housing to enclose a primary pressure chamber. A pedal simulation device is connected to the force input element. A pedal actuation detection device detects the pedal actuation and an actuating force booster stage. During normal operation the force input element is mechanically uncoupled from the primary piston, and the actuating force booster stage exerts an actuating force on the primary piston. In the event of failure of the actuating force booster stage the force input element is workingly connectable to the primary piston such that a contact extension extends from the primary piston towards the force input element. During normal operation the contact extension is held by a release gap at a distance from the force input element and in the event of failure of the actuating force booster stage the force input element after travelling the release gap is applied workingly against the contact extension.

The invention relates to a braking force generator for a hydraulic brake system comprising a force input element, which is connected to a brake pedal, a housing and a primary piston displaceable in the housing, wherein the primary piston together with the housing encloses a primary pressure chamber for generation of a hydraulic brake pressure, a pedal simulation device connected to the force input element, a pedal actuation detection device for detecting a pedal actuation and an actuating force booster stage for exerting an actuating force on the primary piston, wherein during normal operation the force input element is mechanically uncoupled from the primary piston and the actuating force booster stage in accordance with the detected pedal actuation exerts an actuating force on the primary piston and wherein in the event of failure of the actuating force booster stage the force input element is workingly connectable to the primary piston.
Such braking force generators are known from the background art and used in electrohydraulic brake systems, in which during normal operation a brake pedal to be actuated is completely mechanically uncoupled from the downstream brake system. This mechanical uncoupling of the brake pedal from the actual brake system has the advantage that the driver request according to a pedal actuation is detected by sensor equipment and in accordance with the detected pedal actuation the remaining brake system is electronically controlled. It is then possible to take into account further parameters characterizing the instantaneous state of the vehicle.
In such brake systems, however, in case electronic control or servo-power assistance components fail, it is a requirement to provide an emergency operating mode, in which even without the assistance of the actuating force booster stage, in particular without hydraulic or pneumatic servo-power assistance or without electronic sensor elements, a braking operation may be carried out. In such an emergency operating mode, a mechanical coupling between the brake pedal and the hydraulic brake circuit is then to be established relatively quickly in order by means of the direct mechanical coupling to be able to act upon the hydraulic brake system and initiate a braking operation.
From an embodiment (FIGS. 2 and 3) of the species-defining EP 1 003 658 B1, and corresponding U.S. Pat. No. 6,233,932, both of which are incorporated by reference herein, a braking force generator of the initially described type is known, which provides both the previously described normal operating mode and the emergency operating mode. During normal operation, a pedal actuation is detected by means of the pedal simulation device and in accordance with the detected pedal actuation an actuating force booster stage is activated, which then acts upon the actual hydraulic brake system. The uncoupling of brake pedal and primary piston of the hydraulic brake system is achieved by means of a non-self-locking threaded connection. For this purpose, a threaded sleeve rotates freely on a threaded bolt and hence enables a non-working linear movement between the force input element connected to the brake pedal and the primary piston. During emergency brake operation, i.e. in the event of failure of the actuating force booster stage, the threaded sleeve upon pedal actuation is displaced into a locking position, so that the threaded bolt coupled to the primary piston is no longer able to move freely relative to the threaded sleeve. Rather, the result is an interlocking of threaded sleeve and threaded bolt and ultimately a working connection between the force input element and the primary piston. The solution according to EP 1 003 658 B1 admittedly has the desired effect of an extensive mechanical uncoupling of force input element and primary piston during normal operation and moreover presents a rapid response characteristic in the case of the emergency operating mode, but its construction is relatively complicated and entails exact and therefore laborious manufacture, which adds to the cost thereof.
EP 1 003 658 B1 shows a further embodiment (FIG. 1), which, whilst being of a simple construction, has the drawback that in the emergency operating situation it responds only after a relatively long pedal stroke. A similar system is known from EP 1 070 006 B1, and corresponding U.S. Pat. No. 6,494,546, both of which are incorporated by reference herein. In this system also, the force input element in the emergency operating situation has to travel a relatively long distance before a braking effect is achieved. In other words, with this background art, in an emergency operating situation the brake pedal has to be pressed down relatively far before a braking effect is achieved.
From DE 36 00 729, and corresponding U.S. Pat. No. 4,667,476, both of which are incorporated by reference herein, a braking force generator is known, in which the force input element extends into a recess of the primary piston and during normal operation is held inside this recess at a slight distance from a corresponding lay-on surface of the primary piston. For this purpose, a spring arrangement is used, which is held under bias by means of the actuating force booster stage. In the event of a defect of the actuating force booster stage, the spring arrangement remains ineffective. If in such a situation the driver actuates the brake, he presses down the brake pedal initially without resistance until the force input element is applied against the primary piston. A further brake pedal actuation is then transmitted to the primary piston. However, for a moment the driver has the unpleasant sensation that the brake pedal may be depressed without resistance.

Brake power generator for a hydraulic motor vehicle brake system, and hydraulic motor vehicle brake system


A diagnostic test kit is disclosed for assessing whether patient chest pain is cardiac in origin and for differentiating between unstable angina and myocardial infarction at early onset of patient chest pain. The test kit comprises a receptacle for receiving and retaining a sample of blood or serum of the patient and at least three monoclonal or polyclonal antibodies suspended on a carrier. Each antibody is complementary to a different protein released by the heart muscle during early stages of a myocardial infarction and has corresponding reagents which are independently responsive to each antibody reacting the complementary protein. The combined response of reagents indicates the diagnostic condition of the patient.

Emergency diagnosis of myocardial infarction has depended on physician acuity, and an assessment of a patient's symptoms, such as chest pain or pressure, possibly radiating down the arm and up the neck, fatigue, sense of impending doom, shortness of breath, pallor, cold clammy skin, peripheral cyanosis or rapid thready pulse.
Most North American patients experiencing chest pain will report to a doctor or emergency room within six (6) hours after the onset of the chest pain. It is therefore essential that a diagnostic test be effective in the early stages of an MI.
Several cardiac tests have been used to detect MI. These tests include: ECG, SGOT/AST, LDH, CK-MB Immunoassay and NA Latex Myoglobin Particle Enhanced Assay. However, there are no single enzyme cardiac test which enables the emergency department physician to identify the source of chest pain as cardiac or non-cardiac. Further, it is only after a myocardial infarction has been confirmed may thrombolytic therapy be initiated. The earlier such therapy is initiated, the greater likelihood of full recovery of the patient or at least minimization of cardiac damage. It is therefore essential for a physician to identify the pain as cardiac or non cardiac.
The electrocardiogram (ECG) may be used to detect an MI. However ECG is not diagnostic until after the heart has suffered severe damage. The diagnostic specificity of the ECG is only 51% in the initial phases of chest pain. Therefore, ECG is not suitable for early detection of MI.
Serum glutamic oxalacetic transaminase/aspartate transferase (SGOT/AST) is a predominant enzyme found in high concentration in heart muscle. Serum tests to determine levels of SGOT are used in diagnosing myocardial infarction. However, SGOT only begins to rise about 8-10 hours following the onset of chest pain, peaks within 24-36 hours and returns to normal after 5-7 days. SGOT is not particularly helpful in diagnosing myocardial infarction in an emergency setting at an early stage of patient chest pain. Also, SGOT is not specific to cardiac muscle. It is found in many tissues including skeletal muscle, liver and kidney, being released as a result of intra muscular injections, shock, during liver disease, and hepatic congestion, and is therefore of little value in detecting specific cardiac tissue injury.
Lactate Dehydrogenase (LDH) is an enzyme found in high concentration in many tissues, including heart, skeletal muscle and liver. Tests to detect the presence of LDH in serum are used to diagnose myocardial infarction. There are five common isotypes of which the heart contains predominantly LDH1 and LDH2. LDH levels begin to rise 24-36 hours after the onset of chest pain, and peak after 48-72 hours, returning to normal after 4-8 days. LDH is therefore not useful as an indicia of MI at an early stage of patient chest pain. In addition, LDH is not specific to cardiac damage, and appears with pulmonary embolism, haemolysis, hepatic congestion, renal disease and skeletal muscle damage. This lack of specificity also decreases the utility of LDH as a diagnostic aid.
Creatine kinase (CK) is an enzyme found in muscle tissue. CK catalyses the conversion of creatine and adenosine triphosphate (ATP) to phosphocreatine and adenosine diphosphate (ADP). One of several CK isoenzymes is CK-MB which is found in cardiac tissue. CK-MB is a sensitive marker for the detection of myocardial infarction, as it is released from damaged myocardium tissue. CK-MB thereafter is present in the serum of an affected individual. FIG. 1 illustrates the concentration of CK in the serum of a patient as a function of time. (ref. Lee T. H. et al. (1986) Ann. Intern. Med. 105, 221-233)
The CK-MB immunoassay is the standard diagnostic test for myocardial infarction. A method describing the use of CK-MB is disclosed in U.S. Pat. No. 4,900,662 entitled "CK-MM Myocardial Infarction Immunoassay".
Shah, U.S. Pat. No. 4,900,662 discloses a method for determining the initial elevated concentration level of CK-MM-a, an isoform of CK-MM, and CK-MM-a and CK-MM-b concurrently in patient serum following a myocardial infarction. Use of the method provides an accurate estimation of the time of the infarction. The method involves determining the combined concentration of CK-MM-a and CK-MM-b and the concentration of CK-MM-a in serum, in order to determine the time of the acute phase of myocardial infarction. Reagents are disclosed and comprise novel polyclonal and monoclonal antibodies for CK-MM-a which do not bind significantly with CK-MB, CK-MM-b or CK-MM-c, an anti-CK-MM-b antibody which does not bind significantly with CK-MB, CK-MM-a or CK-MM-c, an anti-CK-MM-a+b antibody which binds with CK-MM-a and CK-MM-b but does not bind significantly with CK-MB or CK-MM-c, labelled derivatives of these antibodies, insoluble supports to which these antibodies are adhered, and kits containing one or more of these reagents. Enzyme labelled and radiolabelled CK reagents are particularly useful.
There are difficulties with the use of CK-MB alone as a diagnostic marker. First, serum levels of CK-MB are not elevated until 6-8 hours after the onset of myocardial infarction, and do not peak until after 12 hours, making early emergency diagnosis and treatment difficult.
Secondly, the CK-MB test must be conducted in a laboratory by trained laboratory technicians. In non-urban locations, it may not be feasible to have the test conducted and the results interpreted expeditiously, resulting in increased delay in diagnosis and hence increased costs to the health care system in terms of hospitalization costs of a patient awaiting diagnosis.
Thirdly, CK-MB has been located in normal skeletal muscle tissue, consequently rendering the test less cardiac specific, and the diagnosis less certain.
Myoglobin is another protein located near the skeletal or myocardial cell membrane. It is expelled from the cell as soon as the cell membrane becomes abnormally permeable, for example, during myocardial ischemia, a reversible state. Myoglobin is detectable in the serum within 1.5 hours of the onset of chest pain. The medical research community believes that myoglobin is released by myocardial necrosis, and it is therefore a useful early marker of myocardial injury. FIG. 2 illustrates the concentration of myoglobin in the serum as a function of time. (ref. Grenadier E. et al. (1981) Am. Heart J. 105, 408-416; Seguin J. et al. (1988) J. Thorac. Cardiovasc. Surg. 95, 294-297)
In determining the origin of chest pain, an acute myocardial infarction can be excluded if no elevation of serum myoglobin is detected within 2-3 hours after the onset of pain.
An NA Latex Myoglobin Particle Enhanced Assay is a commercially available assay kit for the detection of myoglobin. The assay is based on the reaction between antigen present in human body fluids and antimyoglobin antibodies covalently coupled to polystyrene particles. The sample, N Myoglobin Reagent, a solution for the elimination of nonspecific reactions and N Reaction Buffer are pipetted automatically into a cuvette. Light scattering is measured by a nephelometric procedure after 12 minutes of incubation time and the myoglobin concentration is calculated from a calibration curve.
Myoglobin may also be assayed using a radioimmunoassay but there is no enzyme-linked immunosorbent assay (ELISA) format yet available.
There are difficulties with the use of myoglobin alone as a diagnostic marker. Myoglobin does not indicate a particular type of myocardial injury, such as myocardial infarction. Myoglobin can also be present during such diverse conditions as shock, renal disease, rhabdomyolysis, and myopathies. Additionally, myoglobin concentrations in serum and plasma generally depend on age and sex and vary over a wide range in normal healthy humans. Serum concentrations up to 90 ug/l are generally regarded as the upper limit of the reference range for healthy people. Therefore, what may be a normal level for one individual may be indicative of a serious problem in another individual, making diagnosis somewhat less accurate than would be desirable.
Myosin light chains (MLC) are integral parts of the myosin myofibril, but their functional role is still unclear. MLCs exist in slow, fast, atrial, and ventricular muscles. It is known that MLCs are highly sensitive for myocardial ischemia. MLCs appear in the serum rapidly, and their levels remain elevated for up to 10 days following myocardial necrosis. FIG. 3 illustrates the concentration of MLC in patient serum as a function of time. (ref. Wang J. et al. (1989) Clin. Chimica. Acta 181, 325-336; Jackowski G., Symmes J. C. et al. (1989) Circulation Suppl. 11 80, 355.) MLC also has prognostic value in determining the success of thrombolytic therapy. Higher levels of MLC, indicate a worse prognosis, and also corresponds to a larger infarction. Falling levels over several days indicate a tendency towards patient recovery, whereas spiking or stadico pattern indicate a tendency towards infarction and a need for intervention.
There are two principal types of MLC known as MLC1 and MLC2, which exist as a soluble pool in the myocardial cell cytoplasm and also integral with the myosin myofibril. In the ventricular muscle, MLC2, and perhaps MLC1, is identical with the isotype expressed in slow skeletal muscle. MLC1 is elevated in 80-85% of the patients with cardiac pain. MLC1 is a very sensitive indicator of unstable angina and coronary heart disease.
Other cardiac markers, low molecular weight cardiac proteins (LMWCP) may be used as cardiac markers. Examples of such cardiac markers include components of the contractile apparatus, namely, troponin, including troponin-T, troponin-I and troponin C, mitochondrial enzymes, such as triose P isomerase, low molecular weight polypeptides which are readily released from the heart, and sarcolemmal membrane proteins or protein fragments which may be released early after the onset of ischemia, in particular, a 15 kd sarcolemma protein and a 100 kd complex glycoprotein which are cardiac specific.
The cardiac isotype troponin-I inhibits the interaction between actin and myosin molecules during rest periods between contractions of the heart muscle. Troponin-I appears in serum of patient within 4-6 hours after MI and remains elevated for 7- 8 days. FIG. 4 illustrates the concentration of troponin-I as a function of time. (ref. Cummins B., Auckland M. L. and Cummins P. (1987) Am. Heart J. 113, 1333-1344.). It is cardiac specific and has a greater sensitivity than other markers in detecting cardiac versus skeletal muscle injury.
Troponin-T is part of the troponin-tropomyosin complex of the thin filament and serves as a link between the tropomyosin backbone and the troponin-I troponin C complex. Troponin-T is a basic protein and has isotypes in cardiac and fast and slow skeletal muscles. It appears in serum within 3 hours and remains elevated for at least 10 days following MI. FIG. 5 illustrates the concentration of troponin-T as a function of time. (ref. Katus H. A. et al. (1989) J. Mol. Cell Cardiol. 21, 1349-1353.). Troponin-T follows a biphasic release pattern. It is cardiac specific and very sensitive for MI.
Myosin heavy chains (MHC), and tropomyosin, are heavier molecular weight proteins which may also be used as cardiac markers. MHC is part of the major contractile protein of muscle. Fragments of MHC can be released from the ventricule into serum after myocardial cell necrosis and subsequent irreversible membrane injury. Although MHC fragments do not appear quickly in the serum following myocardial cell necrosis, MHCs remain elevated for at least 10 days following MI, and peak levels of MHC are observed 4 days after MI. FIG. 6 illustrates the concentration of MHC as a function of time. (ref. Leger J. O. C. et al. (1985) Eur. J. of Clin. Invet. 15, 422-429, Seguin J. R. et al. (1989) J Thorac. Cardiovasc. Surg. 98, 397-401.). The area under the MHC release curve correlates very well with the extent of myocardial cell damage. However, MHC levels are of little clinical value during the acute phase of MI.
Tropomyosin is a dimer formed from two polypeptide which are part of the regulatory system in muscle contraction. Tropomyosin is detectable in serum approximately 7-8 hours after myocardial infarction, and like CK-MB, is very sensitive for myocardial infarction. FIG. 7 illustrates the concentration of tropomyosin as a function of time. (ref. Cummins P. et al. (1981) Clin. Sci. 60, 251-259). However, tropomyosin is not cardiac specific since it is elevated in conditions of skeletal muscle trauma.
There are limitations for each of the current standard diagnostic methods for myocardial infarction. None provide a highly sensitive, specific, rapid, and simple diagnostic test which may be conducted soon after the onset of chest pain, for example, in an ambulance or doctor's office.
The present invention combines and measures at least three different markers of cardiac damage present in the blood or serum of a patient in early onset of chest pain in order to provide an improved method of diagnosis of myocardial infarction for use in the early stages of unstable angina or MI.

Diagnostic kit for diagnosing and distinguishing chest pain in early onset thereof


A method of fabricating a semiconductor device having a silicon nitride layer substantially free of impurities includes forming a silicon nitride layer on a semiconductor substrate and annealing the semiconductor substrate having the silicon nitride layer in an atmosphere of ammonia (NH3) gas to remove impurities from the silicon nitride layer. The silicon nitride layer may be formed using BTBAS as a silicon precursor.

1. Field of the Invention
The present invention relates to a method of fabricating a semiconductor device, and more particularly to a method of fabricating a semiconductor device including removing impurities from a silicon nitride layer.
2. Discussion of the Related Art
Semiconductor device fabrication includes processes for forming thin films such as a conductive layer or an insulating layer. Silicon nitride is commonly used in semiconductor fabrication. For example, a silicon nitride layer can be applied as a hard mask layer in patterning thin films by photolithography and anisotropic etching. In addition, silicon nitride can be used for a passivation layer, an oxidation barrier layer, an etch stop layer or a gate spacer of a MOS transistor.
The silicon nitride layer can be formed by a chemical vapor deposition (CVD) process using a reaction of dichlorosilane (DCS; SiCl2H2) gas and ammonia (NH3) gas. However, the CVD process using DCS gas as a silicon source requires that the silicon nitride layer be formed at a high temperature, e.g., 700° C. to 800° C. The high-temperature processing can cause abnormal diffusion of impurity ions in the semiconductor substrate, degrading device performance. Furthermore, the ammonium chloride (NH4Cl) generated as a reaction by-product corrodes the metal parts of a process chamber, resulting in metal contaminants on the semiconductor substrate. In semiconductor device fabrication, it is desirable that particles and contaminants be minimized.
A silicon nitride layer can be formed using BisTertiaryButylAminoSilane (BTBAS; C8H22N2Si) as a precursor. Since the silicon nitride layer can be formed at a lower temperature of about 600° C. using BTBAS, the problems caused by high-temperature processing can be avoided, and undesirable reaction by-products such as ammonium chloride can be prevented. Examples of methods of forming a silicon nitride layer using BTBAS are disclosed in U.S. Pat. Nos. 5,874,368 and 6,515,350.
However, BTBAS includes a large amount of carbon and hydrogen. As a result, the silicon nitride layer formed using BTBAS as a silicon precursor may contain a large amount of impurities in the form of carbon and hydrogen. In particular, the carbon impurities may deteriorate the dielectric characteristic of the silicon nitride layer. In the case that the silicon nitride layer formed using BTBAS is used as a gate spacer of a MOS transistor, the carbon impurities can penetrate into a gate insulating layer of the MOS transistor, deteriorating electrical characteristics of the device.

Method of fabricating semiconductor device including removing impurities from silicon nitride layer


The present invention relates to integrated circuits. In particular, it relates to an IC comprising a receiving stage for receiving an input signal, an output stage for generating an output signal having a larger voltage range than the input signal and a level shifter. Embodiments of the invention provide a structure and a method for fabricating the IC wherein the level shifter is incorporated within the IC to improve reliability of the IC.

In an integrated circuit (IC), it is not uncommon for both high and low voltage devices to be included on the same IC. For example, the IC may include 1.5V digital core device and 6V high voltage devices. The supply voltages for such 1.5V and 6V devices are 0.95V (DVDD) and 3.4V (VH), respectively.
Level shifters are used to transform a digital core device or transistor digital power supply (DVDD) voltage signal to a high power device or transistor power supply (VH) voltage signal. FIG. 1 shows a conventional level shifter for transforming a DVDD voltage signal to a VH voltage signal. As shown, the level shifter includes an input stage 101 and an output stage 103. The input stage receives an input voltage Vin and generates an output voltage Vout. Vin is a DVDD voltage signal having a voltage range of about 0-0.95V while Vout is a VH voltage signal having a voltage range of about 0-3.5V.
The various stages of the level shifter employ 6V high voltage devices with a VH supply source. Devices typically have a minimum 'turn on' threshold voltage (Vth) of about 15% of the supply voltage, i.e., for 6V high voltage devices, this equates to approximately 0.9V. As such, Vin has about a 5% margin to switch on the 6V devices. Taking into consideration temperature fluctuation as well as process variations, such a small margin can lead to situations where the high voltage devices fail to switch on, rending the level shifter inoperable.
From the foregoing, it is desirable to provide an improved level shifter for transforming a low voltage range signal to a high voltage range signal.

Reliable level shifter of ultra-high voltage device used in low power application

Chartered Semiconductor Manufacturing, Ltd.


A communication system including a transmit antenna that transmits an output signal including output information, a network interface that receives state data regarding a first remote platform, and a processing circuit. The processing circuit predicts a performance of a communication link that the transmit antenna uses to transmit the output signal based on the state data, evaluates a performance condition based on the estimated performance and a threshold performance, responsive to the performance condition being satisfied, uses the transmit antenna to transmit the output signal, and responsive to the performance condition not being satisfied, at least one of (i) adjusts at least one of a time parameter or a frequency parameter that the transmit antenna uses to transmit the output signal, or (ii) provide an instruction to a second remote platform to cause the second remote platform to transmit the output information to the first remote platform.

The present disclosure relates generally to the field of network communications. More particularly, embodiments of the inventive concepts disclosed herein relate to systems and methods of data link networking performance improvement using machine learning.
Antennas, such as directional antennas, can be used for point-to-point communications. For example, aircraft and other platforms or entities can use the common data link (CDL) protocol for point-to-point communications. However, as entities move in space, connectivity may be lost between entities.

System for data link networking based on machine learning


A collapsing truss that completes a four-bar mechanism of a vehicle seat coupled to a vehicle floor. The vehicle seat includes a seat back coupled to a cushion structure via the collapsing truss which incorporates a pivot and a latch which engages on a pin. The collapsing truss includes a floor bracket coupled to the vehicle floor. A seat back bracket is coupled to the seat back and floor bracket. A cushion bracket is pivotally coupled to the cushion structure, the floor bracket, and the seat back bracket. The joints of the collapsing truss are defined by the seat back pivot, the cushion back/seat back bracket pivot, and the latch engagement pin. The seat back moves about the pivot when the collapsing truss operates.

It is known in the art that vehicle seats are configured to fold for purposes of storage of the vehicle seat. Such storage increases the cargo carrying capability of the vehicle such as in an SUV or a van. Due to the type of packaging on many vehicles, there is a need for a seat back latch that minimizes the required packing environment when the seat is stored.
Thus, there is a need for a vehicle seat structure, when in a stowed condition that consumes no more space than a conventional seat. There is a further need for a collapsing truss that can be utilized in a bench seat, a 60/40% seat and a single seat, for example, bucket seat type seat.


A charging apparatus for applying a uniform electrostatic charge to a charge retentive surface is provided. The charging apparatus is operably electrically connectable to a power supply for supplying an electrical bias to the charging apparatus. The apparatus includes a housing and an electrode mounted to the housing and positioned adjacent the surface in a non-contact relationship therewith. The apparatus also includes an electrical connector, electrically connected to the electrode and electrically connectable to the power supply. The electrical connector provides an electrical bias to said electrode. The electrical connector extends from the electrode and is integral therewith.

This invention relates to electrostatographic reproduction machines, and more particularly to an economical and capacity-extendible all-in-one process cartridge for easy adaptive use in a family of compact electrostatographic reproduction machines having different volume capacities and consumable life cycles. Specifically this invention relates to such a cartridge including charging device having an electrode with integral electrical connector.
Generally, the process of electrostatographic reproduction, as practiced in electrostatographic reproduction machines, includes charging a photoconductive member to a substantially uniform potential so as to sensitize the surface thereof. A charged portion of the photoconductive surface is exposed at an exposure station to a light image of an original document to be reproduced. Typically, an original document to be reproduced is placed in registration, either manually or by means of an automatic document handler, on a platen for such exposure.
Exposing an image of an original document as such at the exposure station, records an electrostatic latent image of the original image onto the photoconductive member. The recorded latent image is subsequently developed using a development apparatus by bringing a charged dry or liquid developer material into contact with the latent image. Two component and single component developer materials are commonly used. A typical two-component dry developer material has magnetic carrier granules with fusible toner particles adhering triobelectrically thereto. A single component dry developer material typically comprising toner particles only can also be used. The toner image formed by such development is subsequently transferred at a transfer station onto a copy sheet fed to such transfer station, and on which the toner particles image is then heated and permanently fused so as to form a "hardcopy" of the original image.
It is well known to provide a number of the elements and components, of an electrostatographic reproduction machine, in the form of a customer or user replaceable unit (CRU). Typically such units are each formed as a cartridge that can be inserted or removed from the machine frame by a customer or user. Reproduction machines such as copiers and printers ordinarily include consumable materials such as toner, volume limiting components such as a waste toner container, and life cycle limiting components such as a photoreceptor and a cleaning device. Because these elements of the copying machine or printer must be replaced frequently, they are more likely to be incorporated into a replaceable cartridge as above.
There are therefore various types and sizes of cartridges, varying from single machine element cartridges such as a toner cartridge, to all-in-one electrostatographic toner image forming and transfer process cartridges. The design, particularly of an all-in-one cartridge can be very costly and complicated by a need to optimize the life cycles of different elements, as well as to integrate all the included elements, while not undermining the image quality. This is particularly true for all-in-one process cartridges to be used in a family of compact electrostatographic reproduction machines having different volume capacities and elements having different life cycles. There is therefore a need for a quality image producing, economical and capacity-extendible all-in-one process cartridge that is easily adapted for use in various machines in a family of compact electrostatographic reproduction machines having different volume capacities and elements with different life cycles.
The charging of the photoconductive surface is an important step in the xerographic process. The photoconductive surface is typically charged by a charging device and is exposed to form a latent image which is developed with the marking particles to form the copy. An electrical power source is electrically connected to a charging device such that the electrical power supply is utilized to generate ions within the charging device to charge the photoconductive surface. Connecting of the charging device to a power supply is an expensive and difficult process. The electrical connector may require intricate assembly which may be difficult, costly and may result in fragile, unreliable components.
Further, the electrical connector may be inaccessible to the power supply requiring a complicated electrical connecting system to interconnect the power supply to the charging device.
The following disclosures may be relevant to various aspects of the present invention:

Charging device having an electrode with integral electrical connector


Herein disclosed is a surveillance camera apparatus which comprises a camera unit, a camera retaining assembly for retaining the camera unit, a camera checking unit for checking whether or not the camera unit is normally operated, a camera driving unit for driving the camera unit to be moved in a surveillance area where the camera unit performs a surveillance operation, and a non-surveillance area where the camera unit performs no surveillance operation, and where the camera unit is capable of being checked, a light emitting unit designed to assume two different states consisting of a first state under which the light emitting unit emits the light, and a second state under which the light emitting unit stops emitting the light, a state setting unit for setting the light emitting unit to selectively assume the first and second states, and a drive control unit for controlling the camera driving unit, the drive control unit being operative to assume a first operation state under which the camera unit is driven to be moved within the surveillance area, and a second operation state under which the camera unit is driven to be moved into engagement with the state setting unit in the non-surveillance area to allow the light emitting unit to emit the light to have the camera unit take the image of the light, and the camera checking unit being operative to check the camera unit based on the image of the light.

1. Field of the Invention
The present invention relates to a surveillance camera apparatus, and more particularly to a surveillance camera apparatus partially constituting a surveillance system for watching a specific object such as for example unqualified people and other intruders intruding into a special room that permits people with permission to enter.
2. Description of the Related Art
Up until now, there have been proposed a wide variety of conventional surveillance camera apparatuses. One of the typical examples of the surveillance camera apparatuses thus known is shown in FIGS. 21 and 22 as having a reference number 200. The conventional surveillance camera apparatus 200 comprises a camera unit 202 for taking an image of a specific object, and a camera retaining assembly 203 for retaining the camera unit 202. The camera retaining assembly 203 includes a stationary member 201 secured to a fixed structure such as for example a ceiling wall forming part of a building, and a side wall forming part of an elevator cage, a holder shaft 205 revolvably supported on the stationary member 201 and having a holder revolution axis 205a around which the holder shaft 205 is revolvable with respect to the stationary member 201, a holder member 206 fixedly mounted on the holder shaft 205, a camera shaft 207 revolvably supported on the holder member 206 and having a camera revolution axis 207a in perpendicular relationship with the holder revolution axis 205a of the holder shaft 205 and around which the camera shaft 207 is revolvable with respect to the holder member 206 in unison with the camera unit 202.
The conventional surveillance camera apparatus 200 further comprises a dome cover 204 for accommodating the camera unit 202, and a case member (not shown) integrally formed with the dome cover 204. The dome cover 204 is in the form of hemispheric shape, and made of a transparent material to have the camera unit 202 take the image of the specific object therethrough. The dome cover 204 has an opening 204a and a spherical portion 204b as seen by a two-dot chain line in FIG. 21.
As best shown in FIG. 22, the conventional surveillance camera apparatus 200 further comprises a camera driving unit 223 for driving the camera unit 202 to have the camera unit 202 revolve around the camera revolution axis 207a of the camera shaft 207 with respect to the holder member 206, and a holder driving unit 215 for driving the holder member 206 to have the holder member 206 revolve around the holder revolution axis 205a with respect to the stationary member 201. The camera driving unit 223 includes a camera electric motor 216 for transmitting revolution torques to the camera shaft 207 to have the camera unit 202 revolve around the camera revolution axis 207a with respect to the holder member 206, and a camera encoder 217 for counting and encoding the revolution number of the camera electric motor 216, while the holder driving unit 215 includes a holder electric motor 208 for transmitting revolution torques to the holder shaft 205 to have the holder member 206 revolve around the holder revolution axis 205a with respect to the stationary member 201, and a holder encoder 209 for counting and encoding the revolution number of the holder electric motor 208.
The conventional surveillance camera apparatus 200 electrically connected to an exterior controller producing a position signal indicative of the position of the camera unit 202, and a camera drive control unit 218 for controlling the camera driving unit 223 to have the camera driving unit 223 drive the camera unit 202 to have the camera unit 202 revolve around the camera revolution axis 207a with respect to the holder member 206, and a holder drive control unit 210 for controlling the holder driving unit 215 to have the holder driving unit 215 drive the holder member 206 to have the holder member 206 revolve around the holder revolution axis 205a with respect to the stationary member 201.
The camera drive control unit 218 includes an input terminal 222 for inputting the position signal, a camera position range memory 220 for previously storing therein a camera position range, for example plus or minus 90 degree of the angle, in which the camera unit 202 is revolvable around the camera revolution axis 207a with respect to the holder member 206 to have the camera unit 202 take the image of the object, a camera position detector 221 for detecting a camera position at which the camera unit 202 is positioned based on the revolution number of the camera electric motor 216 encoded by the camera encoder 217, and a camera motor controller 219 for controlling the camera electric motor 216 based on the camera position range stored by the camera position range memory 220, the camera position detected by the camera position detector 221, and the position signal inputted through the input terminal 222.
The holder drive control unit 210 includes an input terminal 214 for inputting the position signal, a holder position range memory 212 for previously storing therein a holder position range, for example plus or minus 90 degree of the angle, in which the holder member 206 is revolvable around the holder revolution axis 205a with respect to the stationary member 201 to have the camera unit 202 take the image of the object, a holder position detector 213 for detecting a holder position at which the holder member 206 is positioned based on the revolution number of the holder electric motor 208 encoded by the holder encoder 209, and a holder motor controller 211 for controlling the holder electric motor 208 based on the holder position range stored by the holder position range memory 212, the holder position detected by the holder position detector 213, and the position signal inputted through the input terminal 214.
The camera unit 202 is movable with respect to the stationary member 201 in a surveillance area which is restricted by the camera position range stored by the camera position range memory 220 and the holder position range stored by the holder position range memory 212.
The conventional surveillance camera apparatus thus constructed as previously mentioned, however, encounters such a problem that a movable area where the camera unit is capable of mechanically moving with respect to the stationary member 201 is slightly larger than the surveillance area to minimally take account of different sizes and installation of structural members constituting part of the conventional surveillance camera apparatus. The slightly large area, heretofore, has not been used due to an excessive small area for use in other purposes.
On the other hand, there has been various operations involving this kind of surveillance camera apparatus. These operations includes a camera unit test for checking a lens, a filter changing operation for changing different infrared filters, a lens cleaning operation for cleaning the lens, and a camera locking operation for locking the camera unit to the camera retaining assembly when the surveillance camera apparatus is transported from one place to other place. These operations has so far been carried out by operators so that these operations are laborious and tedious for the operators.

Matsushita Electric Industrial Co., Ltd.


An anti-theft device for an automobile audio system automatically prevents the audio system from functioning whenever the audio system is removed from its authorized vehicle and placed into another vehicle. This anti-theft device includes a microprocessor which operates with a bus interface for communicating a vehicle identifier from a vehicle multiplex bus to the central microprocessor. The device also has non-volatile memory within which the first received or authorized vehicle identifier is stored. The subsequently received identifiers are stored on RAM. A battery detector connected to the microprocessor alerts the microprocessor whenever the audio system has been disconnected from the battery source. When the audio system is reconnected to the battery source, the microprocessor automatically compares the vehicle identifier stored within the non-volatile memory to the subsequent vehicle identifier received in the RAM over the multiplex bus, and shuts down the audio system whenever these two vehicle identifiers do not match.

Because audio equipment installed in vehicles are essentially expensive, light weight and small in size, audio equipment has historically been the subject of much theft. With the thriving aftermarket network, the stolen equipment may be installed in almost any other vehicle.
Automobile manufacturers have employed numerous methods to prevent the audio equipment from being stolen out of the vehicles. For ease of description, the audio equipment will be referred to as a car radio. It is, however, understood that the audio equipment would encompass any sound system installed within an automobile, including cassette tapes and compact disc ("CD") players. One such method employed by automobile manufacturers to reduce car radio theft is to use special security screws to fasten the radio to the vehicle. These screws may only be unfastened using specially adapted tools.
Another method used to prevent audio equipment theft is to equip the car radio with a security code and a flashing anti-theft LED. Such a system requires the operator to manually input a multi-digit security code to "unlock" the car radio whenever the radio has been disconnected from the vehicle battery. A variation of this anti-theft method is to allow for after-market initialization of the car radio. Here, the consumer inputs a security code into the car radio's memory during initialization. Once the car radio is disconnected from its power source, for example, the car battery, the radio locks up. The operator must then reinsert the same security code to unlock the car radio. For example, U.S. Pat. No. 4,720,700 to Seibold et al., U.S. Pat. No. 4,743,894 to Bochmann, and U.S. Pat. No. 4,683,462 to Takeda et al. all disclose car radio security systems that automatically sense whenever the car radio is disconnected from its power source. Whenever the operating voltage is interrupted, the car radio shuts off until a code word, known only to the authorized user, is reentered by the authorized user. Similarly, U.S. Pat. No. 4,808,981 to Seibold discloses an automotive electronic communication apparatus which prevents the connection of an external battery to a car radio prior to stealing it, in order to prevent an interruption in the power supplied to the car radio. Here, the system measures the impedance of a connected accessory, for example the loudspeaker, and if the impedance of the loudspeaker does not match the impedance stored in the memory of the car radio, the radio will not operate, until the appropriate code word is reinserted.
Yet another method used to prevent car radio theft is to equip the car radio with a removable face plate. Whenever the operator leaves the vehicle, the operator removes the radio face plate, thereby rendering the car radio inoperative. Along these same lines, removable radios have also been designed. Here, the customer removes the entire radio when leaving the vehicle.
Each of these prior art methods are either cumbersome or inconvenient to the consumer. For the methods where the radio, or parts of the radio, are removed from the vehicle, the consumer is required to carry the radio around with him/her. For the methods employing a security code, the consumer is required to memorize this security code in order to "unlock" a radio which has been removed from a permanent power source. Also, the security code would have to be reentered every time the battery is changed or disconnected for ordinary maintenance of the vehicle.

Automotive radio anti-theft device via multiplex bus


The present invention relates to a multi-input and multi-output communication method in a large-scale antenna system. An MIMO transmission method according to the present invention includes: obtaining statistical channel information on at least one terminal, dividing terminals into a plurality of classes and a plurality of groups based on the statistical channel information, wherein the groups depend on the classes; determining a group beam-forming matrix for each of the divided groups; performing a group beamforming transmission by group based on the group beam-forming matrix to obtain instantaneous channel information; and scheduling terminals based on the instantaneous channel information. Thus, it is possible to decrease the complexity in a scheduling and precoding calculation without an increase in the amount of wireless resources that are required for providing feedback for a reference signal and channel status information.

Due to a drastic increase in data traffic, a Beyond-Fourth-Generation (B4G) mobile communication system requires 10 times an increase in frequency efficiency or more compared to a 4G system such as Third Generation Partnership Project (3GPP) Long Term Evolution (LTE). As physical layer techniques necessary to increase frequency efficiency 10 times or more as stated above, network MIMO, interference alignment, relay network, heterogeneous network, a large-scale MIMO technique, etc. are currently being mentioned.
The present invention relates to a massive MIMO (or large-scale antenna) system capable of obtaining a very strong effect as a technique for improving frequency efficiency. Existing large-scale antenna systems have been limited to a time-division duplex (TDD) scheme. This is because a frequency-division duplex (FDD) scheme has a problem that a large-scale antenna transmitter requires as many reference signals (RSs) and radio resources for CSI feedback as substantially impossible to obtain CSI.
In addition, since the number of users that can be simultaneously accommodated by a large-scale transmitting antenna remarkably increases, there occurs a practical problem in that the complexity of scheduling and precoding calculation becomes very higher than that of an existing system.

Multi-input and multi-output communication method in large-scale antenna system

Electronics and Telecommunications Research institute


The present invention relates to a method, transmitting device (10) and system for providing user plane traffic during a state of inactive user plane of a connection to an access network. A sequence of successive packet headers, adapted to continue a header sequence transmitted until the start of the state of inactive user plane is generated, and respective dummy portions are added to the sequence of successive packet headers. The generated stream of data packets is then transmitted from the transmitting device (10) via the unlicensed mobile access network during the state of inactive user plane so as to obtain a continuous stream of user data irrespective of the state of inactive user plane. Thereby, user plane traffic can also be provided during states of inactive user plane of the transmitting device (10), e.g. holding states, call setup states or mute states, and real-time traffic requirements can be met.

UMA technology enables alternative access to cellular mobile services, e.g. GSM (Global System for Mobile communication), WCDMA (Wideband Code Division Multiple Access) or GPRS (General Packet Radio Services) over an unlicensed spectrum, including WLAN (Wireless Local Area Network), Bluetooth™ and WiFi™. The UMA technology enables seamless delivery of mobile voice and data services over unlicensed wireless networks. The same mobile identity is provided on cellular radio access networks and unlicensed wireless networks, so that seamless transitions (e.g. roaming and handover) between these networks is possible.
In particular, UMA provides an extension of GSM/GPRS mobile services into the customer's premises that is achieved by tunneling certain GSM/GPRS protocols between the customer's premises and the core network over a broadband IP (Internet Protocol) network, and relaying them through an unlicensed radio link inside the customer's premises. UMA is a complement to traditional GSM/GPRS radio coverage, used to enhance customer premises coverage, increase network capacity and potentially lower costs. UMA constitutes a part of the radio access network and is introduced by adding a UMA Network Controller (UNC) as a link between the WLAN and the GSM core network using standard A and Gb interfaces. Hence, from the GSM core network's perspective, the UNC is perceived as just another Base Station Controller (BSC). The UNC functionality could also be introduced into existing BSC infrastructure, thus offloading the core network from signaling and multiple resource handling related to users shifting between WLAN and GERAN (GSM/EDGE Radio Access Network) in the same area.
In UMA, it is possible to put a call on hold, like in normal circuit-switched (CS) call. Real-time traffic, such as audio or video, of the CS domain user plane is received at the UNC via the Up interface and conforms to the RTP (Real Time Protocol) framing format defined in the IETF (Internet Engineering Task Force) specifications RFC 3267 and RFC 3551. RTP provides end-to-end network transport functions suitable for applications transmitting real-time data over multicast or unicast network services. The data transport is augmented by the Real Time Control Protocol (RTCP) to allow monitoring of data delivery in a manner scalable to large multicast networks and to provide minimal control and identification functionality. RTP and RTCP are designed to be independent of the underlying transport and network layers. An RTP packet consists of a fixed RTP header, a possibly empty list of contributing sources, and payload data. The RTP payload comprises the data transported by RTP in the RTP packet, for example, audio samples or compressed video data. The source of a stream of RTP packets is identified by a 32-bit numeric synchronization source (SSRC) identifier carried in the RTP header so as not to be dependent upon the network address. Additionally, a source of the stream of RTP packets that has contributed to the combined stream produced by an RTP mixer can be identified in a contributing source (CSRC) list. Such a list can be used, for example, in audio conferencing to identify all participants whose speech was combined to produce an outgoing packet, allowing the receiver to indicate the current talker, even though all audio packets contain the same SSRC identifier.
Additionally, the RTP header includes a payload type (PT) field of 7 bits, which identifies the format of the RTP payload and determines its interpretation by the application, a sequence number (SN) field of 16 bits, which is incremented by one for each RTP data packet sent and which may be used by the receiver to detect packet loss and to restore the original packet sequence, and a time stamp (TS) of 32 bits, which reflects the sampling instant of the first octet in the RTP packet. The sampling instant can be derived from a clock that increments monotonically and linearly in time to allow synchronization and jitter calculations.
However, UMA Protocols (Stage 3) R1.0.4 require that a mobile terminal or user equipment (UE) sends RTP packets at least every 480 ms. During a holding state (call-on-hold) of the UE the audio encoding is stopped. Thus, there is no input to the RTP protocol to send to the network. Also, the UMA protocols do not describe at all how the call-on-hold situation should be handled in RTP packet point of view. In this regard, the UMA Protocols require that all RTP data traffic during one UMA call (including a call-on-hold situations) relates to the same RTP stream. This means RTP headers' SSRC and PT fields are identical, the TS field is incremented according to the payload decoding (will not be incremented if there is no payload) and the SN field is incremented in each packet.

Traffic generation during inactive user plane


A computer assisted system and related method for interacting with an audience by combining questions from a group of questioners, analyzing the questions, and presenting the questions in summary form for answering by a speaker or interviewee. The answers are then delivered to the questioners. The entire interview may be delivered to the questioners, or portions may be selectively delivered to separate questioners based on questions asked by the respective questioner. In one embodiment, questions may be grouped by similar subject matter; groups may be arranged by the number of associated questions or by other priority criteria. In a further embodiment, a representative question may be generated for each group. The representative question may be selected from the group or may be generated from analysis results. In one embodiment, a subscriber based service is provided. Profiles may be developed for the questioners, and targeted advertising may be delivered based on the profiles.

1. Field of the Invention
The present invention pertains generally to the field of digital processing, more particularly to the processing of question and answer information relating to a speaker and an audience.
2. Background of the Invention
Celebrity interviews are typically conducted by a program host (interviewer) who asks questions and interacts with the celebrity to guide the conversation on behalf of the audience. Throughout the interview, the audience, for whom the entire show is produced, cannot participate in the dialog. It is up to the interviewer to figure out the relevant issues of interest to the audience and formulate appropriate questions. Success of the show depends on the interviewer knowing the subject and knowing the audience. There is no mechanism for immediate audience input or feedback as the interview progresses.
In some situations, the interview may be staged before a studio audience to bring audience reaction into the program. The interviewer can gauge the success of a particular line of questioning by eye contact and body language of the audience. The audience may react by applause, laughter, booing and such, but if there is a burning question within the audience, there is typically no way to get the question voiced. Not all program situations allow a studio audience. In such cases the interviewer and celebrity depend entirely on their own skills, without real time feedback, throughout the conduct of the interview.
One attempt to include the audience is by call-in from a few selected callers. A live call-in requires skill on the part of the interviewer, who must now handle a potentially uncooperative caller as well as the celebrity. The unknown caller also presents risk to the network for questions that are irrelevant or of limited interest and thus a waste of time, or for questions that present controversies beyond the intended scope of the program. Further, the live call-in process takes only a very small random sample of audience interests and does not give the interviewer or program directors a direct feel or measure of the major interests of the audience.
A further issue is that in some situations, a particular audience member may have a significant question that the particular audience member feels is of little interest to other audience members. The question would likely never get asked, even though, in fact many other audience members may have similar questions. There is also no mechanism to answer an individual with a particular question.
Another method for getting audience feedback is to conduct a poll. Polls, however, can only answer simple questions, are subject to bias in the question, and cannot articulate a new question.
Other types of interviews, and related speaker/audience situations also suffer from similar issues—nightly news, documentaries, sports interviews, political interviews, seminars, and classroom education.
Thus, there is a need for an interview process that allows more direct audience participation without wasting time or risking adverse questions, a process that better addresses audience concerns and improve speaker contact and communication with the audience.

Computer based method for generating representative questions from an audience