Adtran Gmbh

Timothy G Mester

Matthew A Kliesner

Eric Malcolm Rives

A communication system for transmitting (T) digital communication signals between a transmit site and a receiver site includes an M:1 multiplexer, coupled to a rate 1/N convolutional encoder, which is operative to output an encoded output signal modulated in quaternary phase shift keyed (QPSK) space having a prescribed symbol rate. The receive site has a rate 1/N Viterbi decoder which is operative to decode the encoded output signal output by the rate 1/N convolutional encoder, and a 1:M demultiplexer having an input coupled to the Viterbi decoder and M plurality of outputs, and being operative to demultiplex the decoded signal from the Viterbi decoder into a plurality of M time division multiplexed digital communication signals. For any selected values for of M and N, the product of M and N is constant.

T1 radio having coding gain adjustable for number of channels

A clock regeneration scheme for a digital communication receiver has a first-in, first-out (FIFO) storage buffer into which received data is clocked in accordance with an input clock signal and a data valid signal. A fixed fractional delay line is coupled to provide respectively different phase delayed versions of the input clock signal and feeds a multiplexer that is controllably operative to couple one of the outputs of the fixed fractional delay line to a regenerated clock output port. A control loop, which includes the FIFO storage buffer, the output port and a steering control input of the multiplexer circuit, is operative to selectively change which output of the fixed fractional delay line is coupled by the multiplexer to the output port, so as to controllably cause the output clock signal to track the effective frequency of the valid data signal.

Data buffer-controlled digital clock regenerator

A system for protecting configuration data of a programmable execution unit (PEU) comprises a programmable array and programming logic. The programming logic is configured to receive configuration data and to program the programmable array, based on the configuration data, such that the programmable array comprises functional logic and activation logic. The activation logic is configured to enable the functional logic upon detection of an activation key.

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Huntsville, AL, United States of America

Timothy G Mester