Abstract: A wireless telephone system comprises a base transceiver having a base receiver and a plurality of wireless handsets. Each handset comprises a handset transceiver for establishing a DSSS link over a shared channel with the base unit via the base transceiver. Each receiver the base transceiver and the handset transceivers receives a spread-spectrum signal representing symbol data from a transmitter of the system, where each such receiver comprises a derotator that derotates the spread-spectrum signal in accordance with a counter-rotating signal to provide a derotated signal; a correlator for receiving the derotated signal and for providing output symbol data based on the derotated signal; a carrier tracking loop (CTL) phase error estimator for receiving the output symbol data and for generating a CTL phase error signal based upon the rotation of the spread-spectrum signal; and a CTL for generating the counter-rotating signal based on the CTL phase error signal.

Abstract: A satellite television ground system, particularly for a make or break satellite television signal system, includes an outdoor unit and an indoor unit that are in communication with each other via a single coaxial cable and an optional separate single conductor for power. The satellite television ground system is operative to measure and reverse frequency conversion errors utilizing DSP techniques, allowing for more precise generation and transmission of uplink signals from the satellite television ground system. Control data for the system is sent via a low data rate connection on a power cable thereof, or by a narrowband signaling channel via a coax cable. The system also utilizes a single reference oscillator to drive the various frequency synthesizers and the like. The satellite television ground system utilizes related oscillators for the uplink and downlink sections. Carrier frequency offset in the downlink is measured in a carrier tracking loop part of a television signal demodulator.

Abstract: A satellite television ground system, particularly for a make or break satellite television signal system, includes an outdoor unit and an indoor unit that are in communication with each other via a single coaxial cable and an optional separate single conductor for power. The satellite television ground system is operative to measure and reverse frequency conversion errors utilizing DSP techniques, allowing for more precise generation and transmission of uplink signals from the satellite television ground system. Control data for the system is sent via a low data rate connection on a power cable thereof, or by a narrowband signaling channel via a coax cable. The system also utilizes a single reference oscillator to drive the various frequency synthesizers and the like. The satellite television ground system utilizes related oscillators for the uplink and downlink sections. Carrier frequency offset in the downlink is measured in a carrier tracking loop part of a television signal demodulator.

Abstract: A satellite television ground system, particularly for a make or break satellite television signal system, includes an outdoor unit and an indoor unit that are in communication with each other via a single coaxial cable and an optional separate single conductor for power. The satellite television ground system is operative to measure and reverse frequency conversion errors utilizing DSP techniques, allowing for more precise generation and transmission of uplink signals from the satellite television ground system. Control data for the system is sent via a low data rate connection on a power cable thereof, or by a narrowband signaling channel via a coax cable. The system also utilizes a single reference oscillator to drive the various frequency synthesizers and the like. The satellite television ground system utilizes related oscillators for the uplink and downlink sections. Carrier frequency offset in the downlink is measured in a carrier tracking loop part of a television signal demodulator.

Abstract: A system for receiving a plurality of broadcast channels transmitted with different polarizations includes a first demodulator for demodulating a first channel having a first polarization to produce a first demodulated channel signal, and a second demodulator for demodulating a second channel having a second polarization, opposite to the first polarization, to produce a second demodulated channel signal. An adaptive interference cancellation network, coupled to the first and second demodulators, cancels interference, derived from the second channel, in the first demodulated channel signal to produce a received signal.

Abstract: A receiver of a handset transceiver, in a wireless telephone system having a plurality of wireless handset and a base unit having a base transceiver. Each handset has a handset transceiver for establishing a time-division multiple access (TDMA) link over a shared channel with the base unit via the base transceiver, in which each handset communicates during an exclusive time slot of a TDMA scheme that allocates time slots to handsets during an exclusive time slot of a TDMA scheme that allocates time slots to active handsets for receiving a spread spectrum signal comprising successive chips representing successive symbols. Each receiver has one or more demodulation loops for demodulating the received spread spectrum signal, wherein each demodulation loop is characterized by one or more demodulation loop parameters. A parallel correlator of the receiver detects a peak bin and provides the peak bin and two adjacent bins.

Abstract: A wireless telephone system comprising a base unit coupleable to one or more external telephone lines and having a base transceiver, and at least one wireless handset. The wireless handset has a handset transceiver for establishing a digital link with the base unit via the base transceiver over a wireless channel, wherein the handset and base unit communicate via the digital link by fixed-size audio packets comprising a plurality of audio data samples and a plurality of error correction bits. Qualities of the digital link are monitored to determine whether a change in error rate occurs. In response to the determination, a packet structure of subsequent audio packets is changed from a first packet structure to a second packet structure to change the relative number of bits devoted to audio data samples and to error correction bits.

Abstract: A remodulator timing signal (35) is generated by a phase locked loop (33) which is coupled to a broadcast vestigial sideband signal (5). Within the signal (5) is highly accurate timing data which is coupled to a demodulator (31). Timing signals to the demodulator are provided by a variable frequency oscillator (32) which receives a correction signal from a phase locked loop (33) housed within the demodulator. The phase locked loop generates the correction signal by comparing the VFO output frequency (36) with the timing data embedded within the broadcast signal (5). A value register (203,303,403) maintains the recent average VFO frequency. A multiplexer (204,304,404) selects the value register data to control the VFO (32,220,320) in the absence of the broadcast timing data.

Abstract: A wireless telephone system having a plurality of wireless handsets and a base unit, the base unit having a base transceiver. Each handset has a handset transceiver for establishing a wireless link over a shared channel with the base unit via the base transceiver, wherein the base transceiver transmits to a handset transceiver a first signal representing successive symbols at a first symbol rate. The handset transceiver has a receiver and a transmitter, and a local clock signal generator that provides clock signals at a local clock frequency. The receiver receives samples representing the first signal, and generates symbol error measurements used to cause a receiver interpolator to produce, in response to the received samples, samples taken at times synchronized to the successive symbols of the first signal.

Abstract: A wireless telephone system having a plurality of wireless handsets and a base unit, the base unit having a base transceiver. Each handset has a handset transceiver for establishing a wireless link over a shared channel with the base unit via the base transceiver, wherein the base transceiver transmits to a given handset transceiver a forward signal at a carrier frequency. Each handset transceiver has a receiver having a carrier tracking loop for detecting and removing a carrier offset from the forward signal; a transmitter for transmitting to the base transceiver a return signal; and an oscillator, independent of a base oscillator of the base transceiver on which the carrier frequency is based, for driving the receiver and transmitter of the handset. The handset transmitter comprises a prerotator that prerotates the return signal in accordance with the carrier offset detected by the carrier tracking loop so that the return signal will be received by the base transceiver with substantially no carrier offset.

Abstract: A wireless telephone system having a plurality of wireless, battery-powered handsets and a base unit, the base unit having a base transceiver. Each handset has a handset transceiver for establishing a wireless link over a shared channel with the base unit via the base transceiver, wherein the base transceiver transmits to a given handset transceiver a forward data message, which contains forward power level information identifying a forward power level at which the forward data message was transmitted by the base transceiver. The receiver receives and locks onto the forward data message. The transmitter transmits to the base transceiver a return data message at a return power level determined in accordance with the forward power level information.

Abstract: A wireless telephone system and related method are described, the system having a plurality of wireless handsets and a base unit, the base unit having a base transceiver, each handset having a handset transceiver for establishing a wireless link over a shared channel with the base unit via the base transceiver. The base unit transmits a signal comprising a current packet of a plurality of packets of an epoch. Each handset transceiver has a receiver having a parallel correlator for generating timing error signals and end-of-packet signals for the signal, and a timing loop for receiving the timing error signals and for establishing symbol-level timing synchronization. An enable resynch gate of the receiver receives the end-of-packet signals from the parallel correlator to establish packet-level synchronization, and a de-packetizer of the receiver reads epoch location information from the current packet which identifies the location of the current packet within the epoch.

Abstract: A symbol timing recovery (STR) error detector includes a complex multiplier and a Gardner-type symbol timing error estimator for operation with carrierless amplitude phase (CAP) signals. Quadrature Ir and Qr signals from the system are input to the complex multiplier, which also receives signals from a numerically controlled oscillator operating at the CAP center frequency. The output of the complex multiplier is provided to the input of the Gardner STR error estimator. An added frequency shift allows the Gardner error estimator to function with CAP signals. The output from the error estimator is provided to a loop filter the output of which is provided to an oscillator which generates the symbol timing information for a symbol sampling network.

Abstract: A timing recovery system for a digital signal receiver receives a signal, representing successive symbols, from a transmitter. The symbols are subject to exhibiting multiple symbol rates. The system derives a sample enable signal from the received input signal and employs a single, fixed frequency oscillator. A source of samples representing the received signal are sampled at a fixed frequency. An interpolator is coupled to the sample source and is responsive to a control signal. The interpolator produces samples taken at times synchronized to the successive symbols from the transmitter. A phase error detector is coupled to the interpolator, detects a phase error between the sample times of the transmitter synchronized samples produced by the interpolator and times of the successive transmitter symbols, and supplies a phase error signal. The phase error signal is coupled to one input terminal of a summer and a source of a nominal delay signal is coupled to the other.

Abstract: A CAP signal is processed by a QAM demodulator network. The QAM network causes the CAP signal to rotate about its center frequency, which rotation is removed prior to conveying the CAP signal to utilization networks. In an analog implementation, the CAP signal is frequency upconverted to be centered at Fad/4 so that the QAM processor can use the usual 1, 0, -1, 0 demodulation sequence to bring the CAP signal to baseband. Alternatively, using digital techniques, frequency upconverting is not needed and the 1, 0, -1, 0 demodulation sequence is replaced with a Numerically Controlled Oscillator and full multiplier to allow the QAM processor the bring the CAP signal to baseband.

Abstract: A receiver is arranged for receiving a transmitted quadrature amplitude modulated (QAM) signal representing successive symbols, and including an in-phase (I) component and a quadrature (Q) component. In such a receiver, a timing recovery system includes a source of samples representing the QAM signal produced at a fixed frequency. A first chain of processing circuitry for the I component includes a first demodulator, coupled to the sample source, for demodulating the I component of the QAM signal to baseband; and a first interpolator, coupled to the first demodulator and responsive to a control signal, for producing I component samples taken at times synchronized to the transmitted symbols.

Abstract: A filtering circuit suitable for use in a video sample rate converter provides a constant direct current (DC) gain irrespective of realization errors, and reduces hardware requirements. The circuit includes an input terminal for receiving an input signal. A first delay unit delays the input signal to generate a first delayed signal. A subtracting unit subtracts the input signal from the first delayed signal to generate a difference signal. A second delay unit delays the difference signal to generate a second delayed signal. A reference delay unit delays the first delayed signal by a predetermined reference time period to generate a reference signal. A filtering unit filters the second delayed signal to generate a filtered signal. An adding unit adds the reference signal to the filtered signal to generate an output signal.

Abstract: A digital high definition television receiver equalizer system includes an input adaptive feed forward filter (FFF 20), a carrier recovery network (46), and a slicer (40) in addition to an adaptive decision feedback filter (DFF, 30) for removing intersymbol interference. At the beginning of a blind equalizing interval the FFF is not adapted and the DFF operates as a linear filter with adapted coefficients for equalizing post-ghosts. Afterwards in the blind interval the FFF coefficients are adapted blindly for equalizing pre-ghosts. In a subsequent decision-directed mode the slicer output is used for adapting both the FFF and DFF non-linearly.