Abstract: A method of coding speech under background noise conditions wherein during active voice speech segments an analysis-by-synthesis method is used. However, when a background noise segment is detected, an adaptive code book (pitch prediction) contribution is used as a source of a pseudo-random sequence in order to provide a better representation of the background noise. An improved gain quantization scheme is also employed when a background noise segment is detected, wherein an energy of the total excitation with quantized gains is matched to an energy of total excitation with unquantized gains.

Abstract: The invention's reference precharge circuit and bit line precharge circuits are comprised of two NFET transistors and one PFET transistor. In the preferred embodiment of the invention where the supply voltage is 3.0 volts, the two NFET transistors result in a voltage drop of 2.0 volts so as to produce a reference precharge signal or a bit line precharge signal having a voltage of 1.0 volts. When a precharge enable signal is on, the PFET transistor is connected to ground and is barely on such that the path from the reference precharge signal or the bit line precharge signal to ground is a low impedance path. Moreover, the path from the reference precharge signal or the bit line precharge signal to the supply voltage is also of low impedance. Accordingly, the voltages present at the reference precharge signal or the bit line precharge signal are substantially noise free.

Abstract: A device connectable to a telephone line including detection circuitry for detecting telephone line events, such as telephone line-in-use, extension pick-up, and remote hang-up. The telephone line events are detected by monitoring the line voltage and loop current transmitted through the telephone line from a central office. A voltage sensor is connected to the telephone line to detect changes in the line voltage appearing in the telephone line. The changes detected in the line voltage are used in a line-in-use detection circuit to determine if the telephone line is already being used by another extension, while changes in loop current are used in a remote hang-up detection circuit to determine when a remote party ends their connection with the telephone line. An extension pick-up circuit is further provided for sensing changes in the telephone loop current in order to determine if a telephone extension has been picked up.

Abstract: An electronic inductor circuit comprises a pair of cascoded Darlington bipolar or MOSFET transistors, configured such that the impedance presented by the collector (drain) of the top transistor of the electronic inductor is increased, relative to the other resistive components in the electronic inductor circuit and DAA. The impedance is increased to a magnitude such that small fluctuations in the collector (drain) impedance do not vary the over-all electronic inductor circuit impedance. Therefore, as heat generated by the circuit causes the impedance of the transistor in the electronic inductor to change, the impedance change does not adversely affect over-all modem circuit performance.

Abstract: A multi-rate speech codec supports a plurality of encoding bit rate modes by adaptively selecting encoding bit rate modes to match communication channel restrictions. In higher bit rate encoding modes, an accurate representation of speech through CELP (code excited linear prediction) and other associated modeling parameters are generated for higher quality decoding and reproduction. The encoder applies adaptive gain reduction to optimize selection of appropriate gain contributions from the adaptive and fixed codebooks. Specifically, the encoder uses a first target signal to identify a contribution (a best code vector and a gain) from the adaptive codebook. Thereafter, a contribution from the fixed codebook is selected. The gain associated with the adaptive codebook contribution is then reduced by a factor, and the gain contribution from the fixed codebook is searched a second time, permitting fine tuning of the overall contribution.

Abstract: A desired signal having a wide frequency band and including sequential symbols representing digital values is discriminated from a narrow band interfering signal having a carrier frequency in the wide band by initially applying both signals to a filter so both signals are passed to an output of the filter. In response to the filter output, estimates of the values of received symbols of the desired signal are derived and compared to the filter output to derive an error representing signal. A characteristic of the filter is controlled in response to the error representing signal so the filter is adjusted to reject the interfering signal and pass the desired signal.

Abstract: A control module which controls battery cells is disclosed which can be used in a charging station, a battery pack and in portable devices such as cellular and cordless phones. The control module comprises a first port configured to connect to a battery cell and an input port configured to connect to an external power supply. Further, the control module comprises a detector module configured to generate a detection signal when the external power supply is connected to the input port, a switching module configured to connect to the input port and the first battery port and to select one of said ports, and a selection module configured to connect to the switching module to receive a signal indicative of an electrical characteristic, and to generating status signals indicative of a charging status. Additionally, the control module has a feedback module associated with the selection module to receive the status signals and to generate a drive signal for controlling input from the external power supply.

Abstract: A method and system for combining a set of n still image frames into a single reduced noise still image. The invention reduces visible noise, along with some television color artifacts, in still images captured from a video stream by combining data from multiple video frames. Each frame comprises an XY array of picture element (pixel) data. In the preferred embodiment, each pixel includes data defining an intensity level as well as color values. A weighted average of several frames of video is taken to generate a single still output frame. The weighting is determined adaptively in order to reduce inter-frame motion artifacts. The resulting output has substantially less visible noise than a simple unweighted average. The algorithm is much faster and simpler to implement than true multi-pixel motion estimation, which is not really necessary in a series of nominally-still images.

Abstract: Two FET transistors provide an electrical circuit characterized by a stable capacitance across a wide range of input voltages and temperture fluctuations. Additionally, the transistors provide a capacitive compensation circuit which stabilizes the output voltage of a band-gap reference circuit. The compensation circuit encompasses the electrical connecting of a PFET capacitor across the terminals of an NFET capacitor (preferably a low threshold voltage NFET), wherein the gate of the of the NFET capacitor is directly connected to an input lead, the substrate is grounded, and the source and drain are directly connected to a common output lead. The PFET is also directly connected to the the input lead and the output lead, however, instead of the substrate being grounded, the substrate of the PFET is electrically connected to the common output lead.

Abstract: A modem utilizing a DAA having line side circuitry including a telephone network interface and system side circuitry including a host system interface, the line side circuitry and the system side circuitry being separated by a high voltage isolation barrier. A CODEC is provided in the line side circuitry, such that encoded information generated by the CODEC, as well as information for decoding by the CODEC, are communicated across the high voltage isolation barrier. These communications are accomplished in a digital manner. In an alternate embodiment of the invention, the line side circuitry of the modem further includes programmable detection and measurement circuitry that is programmable to measure electrical characteristics (e.g., tip/ring voltage and loop current) of the telephone line interface connection and is capable of corresponding adjustments to enable compliance with applicable regulations.

Abstract: A pulse code modulation modem system is configured to transmit data from a first modem to a second modem over the public switched telephone network (PSTN). The PSTN employs robbed bit signaling (RBS) such that symbols affected by RBS arrive at the second modem in a periodic manner based on a period of six symbols. The modem system is configured such that signal segments are formatted and transmitted with six symbols per segment. After obtaining symbol synchronization, the second modem initializes a modulo-6 symbol counter such that the zero count corresponds to the first symbol of each received signal segment. Those symbols affected by RBS are identified and analyzed to determine optimized signal point constellations that may be used to compensate for the RBS on a symbol-by-symbol basis during subsequent encoding and decoding. Upon a loss of synchronization, the second modem resets its modulo-6 counter in response to the detection of the first symbol in a subsequent signal segment.

Abstract: An improved apparatus for implementing shell mapping in a PCM modem incorporates .mu.-law signal mapping points. An improved signal point encoding technique effectively employs ring indices that are generated in accordance with known principles. The ring indices are applied to a reordering module, which rearranges the ring indices produced by a conventional shell mapping algorithm. A preferred reordering scheme takes advantage of the non-uniform probability distribution provided by the conventional shell mapping algorithm. The rings are rearranged such that the sets of signal points having relatively small separation distances are assigned to rings with relatively low frequencies of occurrence, while the sets of signal points having relatively large separation distances are assigned to rings with relatively high frequencies of occurrence. The reordering scheme optimizes the signal point assignment while maintaining acceptable limits for average transmission power.

Abstract: A voltage upconverter circuit wherein a switching voltage regulator circuit is used to charge a capacitor from a battery during an idle interval of portable phone transmission and wherein the charged capacitor is thereafter switched in series with the battery voltage for supply to a load during signal transmission, resulting in a smaller, less expensive and more efficient voltage upconverter circuit.

Abstract: A constant envelope modulator and transmit architecture for a wireless communication system is provided and a method for operating the same. The constant envelope modulator includes a differential encoder which receives data to be transmitted and creates in-phase and quadrature components of a modulation signal to be transmitted. The in-phase and quadrature components are passed through digital filters in order to give the modulation a particular shape. The in-phase and quadrature components of the modulation signal have both phase information and amplitude information on the modulation, where the constant envelope modulator removes the amplitude modulation (AM) information from the modulation signal to provide constant envelope in-phase and quadrature modulation signals and an accompanying AM envelope signal. The resultant constant envelope in-phase and quadrature modulation signals are combined at a radio frequency for transmission into a constant envelope phase modulation signal.

Abstract: Disclosed is an amplifier module suitable for automated mounting and connecting to a motherboard of a cellular phone. The amplifier module comprises a substrate which has at least two layers of electrically conducting material. On the substrate, a first and second semiconductor chip are mounted. The first semiconductor chip includes a first integrated circuit which forms part of a first power amplifier adapted for a first radio frequency band. The second semiconductor chip includes a second integrated circuit which forms part of a second power amplifier adapted for a second radio frequency band. The first and second chips are positioned on the substrate and electrically connected to components mounted on the substrate.

Abstract: The invention is directed to multi-line data exchange systems. The invention comprises one or more telephony devices, each coupled to one or more telephone communication lines, such as a standard telephone line, T1 line, T3 line, coaxial cable, or fiber optic line. The telephony devices are equipped with data communication interfaces. These interfaces allow the telephony devices to operate on more than one telephone communication line. The telephone communication lines operate on several bandwidths, including an audio bandwidth. The telephony devices can communicate among themselves apart from the audio bandwidth of the telephone communication lines. When another telephony device is activated or ceases use on one of the telephone communication lines, the telephony devices detect this event and communicate information on the usage of the telephone communication line on the telephone communication lines at a bandwidth other than the audio bandwidth used in voice communications.

Abstract: A method and apparatus for sensing audio frequency-pressure modulation of the moisture content of the atmosphere caused by a moisture-laden audio source, such as a live human voice, is disclosed. A first light emitter is provided to generate a first light beam. An audio source that emits moisture, and the environment, modulate the first light beam to generate a first modulated light beam. A first detector is provided to detect and demodulate the first modulated light beam to recover an uncompensated audio signal. A second light emitter is provided to generate a second light beam. The second light beam is modulated by the environment and not by the audio source to produce a second modulated light beam. A second detector is provided to detect and demodulate the second modulated light beam to recover the signal component caused by environmental conditions.

Abstract: A method is disclosed for encoding and modulating bits of an information stream and transmitting them over a designated channel in a high speed communication system. The method includes the steps of dividing a set of the entire constellation of available points into a finite plurality of zero parity vectors defined by two criteria, namely that (1) the column vectors have odd parity and (2) a group of a predefined integer number of column vectors have a 0 modulus (i.e. be divisible by a given number). Column vectors forming only a partially dimensioned portion of the code (e.g. 4D) corresponding to one discrete baud interval are preferably transmitted in a systematic form and with sufficient coding gain for adaptive DFE equalization and whereby a group of column vectors corresponding to an integer number of successive baud intervals that form the fully dimensioned code (e.g.

Abstract: A phase interpolated frequency synthesizer with on chip tuning includes a voltage controlled oscillator, a fractional-N divider, phase compensation and on chip tuning circuits, a phase detector, and a loop filter. The phase compensation and on chip tuning circuits compensate for the phase lag from the fractional-N divider. The phase compensation circuit can include a series of voltage controlled delay elements with the tuning circuit providing a control voltage.

Abstract: An improved multiple modulus conversion (MMC) procedure is provided that employs an alternate scheme for obtaining the MMC outputs in response to a binary input of a number of bits. The alternate MMC procedure utilizes short-word division operations such that a practical digital processor may efficiently perform the required binary divisions. An exemplary short-word division process partitions the original long-word binary input into a plurality of short binary words, each having an equal number of bits. Individual short words or a combination of two short words are then divided by the appropriate modulus in a systematic manner to obtain the quotient and remainder associated with the particular division operation. The short-word divisions technique may be employed throughout the entire MMC procedure to suitably obtain the output values associated with each modulus.