Abstract: A system for transmitting a signal through a reverberant environment characterized by multipath communication which causes dispersion and fading of the signal. The signal is phase modulated onto a carrier which is also modulated by a repeating series of digital pseudo noise code words. The length of each word is equal to the length of a symbol of the signal and synchronized thereto, individual symbols being of shorter duration than the signal fading time. A receiver views symbols via a selector switch which serves as a window for successively viewing portions of substantially identical reverberation patterns of each symbol. A set of matched filters coupled to the selector switch sequentially demodulates the code words to provide a repeating sequence of pulses of amplitude modulated carrier these amplitude modulated pulses having symbol data thereon and being applied to a delay locked loop for the generation of a reference signal for recovering the symbols.

Abstract: A differentially adaptive receiver system in which correction is provided for degradation of performance caused by overlapping of adjacent data pulses. A reference signal is produced having the same complex envelope as the received signals and having a constant phase state independent of changes of phase state of the received signals. The received signals are detected against the reference signal as in an ideal matched filter receiver. The detected signals are integrated by an integrate and dump filter over the duration of the pulse period. A correction signal representing the amount of overlap between overlapping adjacent pulses is summed with the output of the integrated dump filter. The sum of the correction signal and integrate and dump filter output is sampled and held by sample and hold circuit to produce the digital data output.