Codex Corporation

About: Codex Corporation is a based out in . It is known for research contribution in the topics: Network packet & Signal. The organization has 189 authors who have published 241 publications receiving 32205 citations.

A High-Speed Sequential Decoder: Prototype Design and Test

Abstract: We describe the design of a rate-1/2 hard-decision sequential decoder capable of operation at data rates up to 5 M bit/s. Test results are given for digitally generated errors, white noise, and real channels. The results are substantially in agreement with predictions of a coding gain of the order of 5 dB at a 10-5error rate.

Convolutional coding for channels with memory

Abstract: This paper discusses the use of two types of convolutional codes, diffuse threshold-decoded codes and Gallager codes, on channels with memory (burst channels) The operation of these codes is explained and test results are given for a variety of equipments operated over phone line, HF radio, and troposcatter channels Error propagation in the threshold-decoded codes is discussed and, in the Appendix, we prove that, for one important diffuse code, propagation is finite and small

Associative cam apparatus and method for variable length string matching

Abstract: A variable length string matcher finds the longest string in a stored sequence of data elements (e.g., in a history buffer) that matches a string in a given sequence of data elements. The matcher includes circuitry that operates iteratively to compare data elements of the strings and determine the longest matching string based on when an iteration does not result in issuance of a match signal. In another aspect, the history buffer is an associative content addressable memory (CAM), and the string matcher uses absolute addressing of the CAM to determine the longest matching string.

Coded modulation system with feedback

Abstract: A receiver for use in deciding which signal points were sent from a transmitter based on corresponding noise affected signals received over a channel, the transmitter including an encoder which encodes a stream of information symbols into the signal points, the noise affected signals carrying information about a particular sequence of possible states occupied in a succession of time intervals by a finite state process. The receiver includes feedback circuitry for generating a plurality of different modified versions of each received signal, and a decoder for deciding which signal points were sent, given the received signals, based on estimating the particular sequence of states, and using at least two different modified versions.

High speed modem, method and system for achieving synchronous data compression

Abstract: The present invention provides a novel scheme for automatically increasing data throughput in a communication system by having data compression with delay minimization done with a modem. A high speed modem includes a logical link negotiation unit (102) for probing and determining data compression parameters (DCPs) for a synchronous data compression link with a remote modem and for inserting the DCPs and predetermined instructions into compressed data. The modem also includes a physical layer connection unit (104) coupled to synchronous data terminal equipment to provide a delay minimizing scheme that adjustably accommodates data delivery delay to the receiving modem. A method and system incorporate the functions of the high speed modem.