Lucent Technologies Inc.

At&t Bell Laboratories

Alcatel-lucent USA Inc.

Bbn Technologies Corporation

Ahmad Khalid Aman

Hong Jiang

Mohsen Sarraf

Charles Albert Webb, Iii

Cecil William Farrow

Robert Louis Cupo

Agesino Primatic, Jr

Masoud Sajadieh

Nicholas A Zervos

Masood Yousefi

Hermann J Weckenbrock

John Michael Bourdelais

A multi-band RF transceiver for transmitting communications data and radar signals includes a transmitter having a source of communications data and radar signals. A modulator combines the data and radar signals and then modulates the combined signal with a carrier signal generated by a synthesizer. A processor instructs the synthesizer to change the carrier frequency and the source to provide data and radar signals corresponding to the carrier frequency so that multiple bands are transmitted over a desired spectrum. A receiver includes a demodulator that demodulates the received signal and a synthesizer that generates a signal that tunes the demodulator to the desired carrier frequency. A processor instructs the synthesizer to change the carrier frequency so that the demodulator demodulates the multiple bands of data and the radar signals over the desired spectrum.

Coherent multi-band radar and communications transceiver

Error bursts are randomized by an interleaver which makes use of 'set leaders' to generate permutation indices. The permutation indices are used to route bits from initial positions in an input bit stream to re-arranged or randomized positions in an output bit stream. When the output bit stream is then transmitted and subsequently received by a de-interleaver which returns the received bits to their initial, pre-randomized positions, the resulting received signal has an acceptable bit error rate.

Methods and devices for randomizing burst errors

A digital carrier recovery system includes at least two modes of operation, namely, an acquisition mode and a tracking mode. The bandwidth of the carrier recovery loop filter is different for the acquisition mode and the tracking mode. In the acquisition mode, the digital phase-locked loop seeks and locks to the long term frequency offset of the received carrier signal. In the tracking mode, the digital phase-locked loop tracks the instantaneous variations in the carrier phase. Switching between the acquisition mode and the tracking mode is realized digitally, and includes programmable hysteresis, resulting in optimal performance in the presence of signals having high levels of phase noise (jitter). More specifically, the carrier recovery loop filter &ldquo;locks&rdquo; to the pilot signal of an incoming signal, e.g., a vestigial side band (VSB) video signal, by employing a so-called digital vector tracking phase-locked loop that demodulates the VSB signal. The digital vector tracking phase-locked loop includes a complex filter, i.e., a so-called vector tracking filter, that very quickly locks to the pilot signal of the passband VSB signal and once locked to the pilot signal, switches to the tracking mode that provides significantly better tracking of phase noise. The demodulation is achieved by employing a complex multiplication of the incoming signal with a complex exponential sequence to obtain an in-phase (I-phase) component and a quadrature-phase (Q-phase) component. The complex exponential sequence is generated, in one embodiment, by employing a SIN/COS look up table that is driven by a phase difference signal generated by the digital vector tracking phase-locked loop. A residual direct current (dc) component in the I-phase component caused by the pilot signal is removed, resulting in a baseband I/Q signal. A technical advantage of this carrier recovery invention is that the bandwidth of the phase-locked loop filter can be different for the acquisition mode and the tracking mode. This allows for optimal performance in both the acquisition and tracking modes of operation.

Carrier recovery system

A memory addressing scheme suitable for use for either interleaving or de-interleaving data bytes of, e.g., a broadcast digital television (DTV) data stream. A number of memory branches are configured in a random access memory (RAM), wherein at least some of the branches have different numbers of memory locations for reading out and for storing data bytes, thus defining memory branches of different lengths in the RAM. A start address is determined for each of the memory branches in the RAM, corresponding to a first memory location of each branch. An offset value is determined for each memory branch, to be added to the start address for the branch for addressing a memory location of the branch. If an offset value does not exceed the length of a corresponding branch, an address corresponding to the sum of the branch start address and the offset value is generated for addressing a successive memory location of the branch, and the offset value for the branch is incremented by one. When an offset value equals the length of a corresponding branch, an address corresponding to a last memory location of the branch is generated, and the offset value for the branch is reset to zero.

Addressing scheme for convolutional interleaver/de-interleaver

A digital timing recovery system advantageously employs both demodulated I-phase and Q-phase components to more accurately locate the synchronization signal of an incoming VSB signal. The Q-phase component is advantageously employed to detect the phase error. The use of the Q-phase component provides a more accurate measure of the phase error and results in a larger (wider) acquisition range for timing frequency offset. More specifically, the timing recovery system of this invention performs symbol clock recovery based on the VSB signal segment synchronization (sync) signal and generates a pulse density modulated (PDM) phase difference signal that controls a voltage controlled crystal oscillator (VCXO) in the phase-locked loop. This is realized, in one embodiment of the invention, by correlating received sync segment data with the known sync signal pattern and searching for 'peaks' in the correlation values that are periodic at the known sync segment data rate. Once the sync pattern is found, the correlation values for adjacent samples are advantageously employed to generate the necessary feedback control signal value for the VCXO. Technical advantages of applicants' unique invention are that the need for an analog synchronous detector is eliminated, a more accurate measure than that obtained by prior known systems is obtained and a wider acquisition range is obtained for timing frequency offset.

Timing recovery system

In a telephone local loop transmission arrangement, data is communicated from the customer premises to the central office utilizing a multidimensional, passband signal illustratively at 480 kb/s. Specifically, the transmitted signal is encoded in a trellis code and precoded using a generalized partial response filter. The received signal is processed by a circuitry that implements a trellis decoding in combination with nonlinear filtering.

Technique for achieving the full coding gain of encoded digital signals

In a telephone local loop transmission arrangement, data is communicated from the customer premises to the central office utilizing a multi-dimensional, passband signal illustratively at 480 kb/s. Specifically, the transmitted signal is encoded in a trellis code and precoded using a generalized partial response filter. The received signal is processed by a circuitry that implements a trellis decoding in combination with nonlinear filtering.

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Ocean, NJ, United States of America

Ahmad Khalid Aman