A forward error correction decoder receives a received word comprising a plurality of characters. The decoder also receives a reliability value for each character. The decoder calculates a syndrome for each member of the set of possible received words by transforming each member with the parity check matrix. Members of the set having the same syndrome are grouped together into cosets. A weight based on the reliability value is then assigned to each member in each coset. The weight is defined to be the number of low reliability, non-zero characters in each member of the set of possible received words. For each coset, the member that has the lowest weight is selected as a coset leader. A syndrome is computed for the soft codeword by transforming it with the parity check matrix. The coset leader with the same syndrome as the received word is subtracted from the received word resulting in a codeword estimate.

Digital data decoder that derives codeword estimates from soft data

There is disclosed a global positioning system receiver method and system which converts the analog signals to digital signals prior to performinng signal acquisition and GPS unique processing functions. The A/D converter (201) uses full null zone processing to increase anti-jamming capability and 4-level output to reduce signal processing. A. single analog and digital channel (302) is used for both the L1 and L2 channels as well as for all P(Y)-code and C/A-code thus allowing full multi channel tracking with several channels (202, 203, 204) each tracking a separate signal while the remainder of the channels rove over all of the signals on the alternate L-band with programmable duty cycles. The system allows for Y-code substitution for P-code by multiplexing a portion of the Y-code generated between multiple channels.

System and method for a digital navigation satellite receiver

A Signal Conditioning Filter (SCF) and a Signal Integrity Unit (SIU) address the coupled problem of equalization and noise filtering in order to improve signal fidelity for decoding. Specifically, a received signal can be filtered in a manner to optimize the signal fidelity even in the presence of both significant (large magnitudes of) ISI and noise. The present invention can provide an adaptive method that continuously monitors a signal fidelity measure. Monitoring the fidelity of a multilevel signal can be performed by external means such as by the SIU. A received signal y(t) can be “conditioned” by application of a filter with an electronically adjustable impulse response g(t). A resulting output z(t) can then be interrogated to characterize the quality of the conditioned signal. This fidelity measure q(t) can be used to adjust the filter response to maximize the fidelity measure of the conditioned signal.

Adaptive noise filtering and equalization for optimal high speed multilevel signal decoding

In a data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: adding error correction codes for correcting error to said additional information data; embedding said additional information data added with said error correction codes into the information data by plural times, repetitively; and transmitting the information data embedded with the repetitive additional information data therein, and comprising, at a receiver side, following steps: receiving the transmitted information data embedded with the repetitive additional information data therein; detecting the repetitive additional information data embedded from said transmitted information data received; determining said additional information data on a basis of a majority rule when receiving said information data; and correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.

Data transmission method for embedded data, data transmitting and reproducing apparatuses and information recording medium therefor

1,203,306. Determining impulse response. NORTH AMERICAN ROCKWELL CORP. June 5, 1968 [June 5, 1967], No.26849/68. Heading G1U. [Also in Division H4] In an automatically adjusting equalizer the impulse response of the transmission channel is determined by correlating previously received data in shift register 52 Fig. 1, with the incoming signal from sampling device 51 in the cross correlators 53 a-n to produce signals hi to hn which are proportional to the amplitude of the impulse response at the sampling instants of the data channel immediately following an impulse. The impulse response signals hi to hn are combined in summing device 72, with signs, provided by multipliers 71, derived from the previously received data as stored in shift register 52. The combination signal is subtracted from the received signal in 73 in order to reproduce the originally transmitted signal. The transmitted signal is made pseudo random at the transmitter either by mod 2 adding the data signal to a pseudo random sequency of pulses, or by passing the signal through a linear sequential coding network. At the receiver the inverse operation is performed using a similar pseudo random generator 75 or an inverse coding network, to retrieve the original data. The transmitted pulses may be shaped, e.g. by a cos 2 fn. to reduce distortion. In a modification, Fig. 8 (not shown) in which two data streams are transmitted by modulation of two carrier signals in quadrature, the received data in each channel is correlated not only with the received signal of its own channel but also with the received signal of the other channel in order to define an effective impulse response due to cross talk, and to derive a correction signal to eliminate cross talk.

Impulse response correction system

Simplified two-stage error-control decoder

An error correcting decoder circuit for decoding redundantly coded received digital signals. Estimator bits are generated from selected bits of a received code word, and estimator reliability signals are generated in accordance with word-bit error probability signals derived from the received analog signal amplitudes associated with the same selected bits of the code word as are used for generating the estimator bits. The estimator reliability signals are used as a basis for weighting the bipolar estimator bit voltages, by increasing or decreasing their absolute values, whereby the more reliable estimator bits are given greater weights at the input of a threshold decision circuit. The threshold decision circuit generates an output bit in accordance with the arithmetic sum of the weighted estimator bit voltages, except that it substitutes the appropriate received bit in place of the unreliable threshold decision that arises in the event that the sum is small in magnitude. Control circuitry is provided for causing repetitive shifting of the word bits in a first shift register and of word-bit error probability signals in a second shift register, for performing step-by-step decoding of a received word with the aid of the received signal reliability indications. The invention thus provides a means of augmenting the digital error correction capability of decoders through the use of auxiliary outputs from the receiver which indicate the received signal quality.

Augmented digital-error-correcting decoder

An error-correcting decoder circuit is disclosed, for decoding redundantly coded digital signals. The disclosed circuit includes a plurality of modulo 2 adders for generating estimator function bits from selected bits of a received code word, and a decision circuit that generates an output bit in accordance with the majority of the estimator functions if a majority decision is possible, and which substitutes the appropriate received bit in place of the undefined majority decision output that arises in the event of a ''''tie'''' between the estimator functions (i.e., when half of the estimator functions are ''''1'''' and the other half are ''''0'''').

Error correcting decoder utilizing estimator functions and decision circuit for bit-by-bit decoding

A passenger vehicle consist includes a plurality of passenger vehicles and an electrical power transmission line interconnecting the plurality of passenger vehicles. A system for communicating data in the vehicle consist includes first unit on a first vehicle in the consist and a second unit on a second vehicle in the consist. The first and second units are electrically coupled to an electrical power transmission line in the consist that interconnections adjacent vehicles. The electrical power transmission line is an existing line used in the vehicle consist for transferring electrical power to the vehicles in the consist. The first and second units are configured to transmit and/or receive at least one of high-bandwidth data or network data over the electrical power transmission line.

Michael E Mitchell

Papers

Simplified two-stage error-control decoder

Augmented digital-error-correcting decoder

Error correcting decoder utilizing estimator functions and decision circuit for bit-by-bit decoding

System and method for communicating data in a passenger vehicle or other vehicle consist

Semiconductor multiple-word correlator