Andy O Chan

US Patent:

6393599, May 21, 2002

Filed:

Jul 6, 1999

Appl. No.:

09/347873

Inventors:

Andy Chan - Los Angeles CA

Assignee:

TRW Inc. - Redondo Beach CA

International Classification:

G06F 1108

US Classification:

714797

Abstract:

A multi-chip data decoder implemented for symmetric differential phase shift keying (SDPSK) or symmetric differential quadriphase shift keying (SDQPSK) modulation formats which uses multiple-chip observation intervals to improve performance over conventional symbol-to-symbol differential detection. Input phases , , , and are detected by comparing a received vector of data bits and parity bits, which contains phase transition information over multiple chips, to the set of ideal vectors of data bits and parity bits, which contain all phase transition possibilities over that set of chips in a noiseless environment. The multi-chip data detector for decoding incoming modulated data comprises a phase-difference encoder ( ) arranged to encode phase-differences - , - , - , - , - , and - of the incoming modulated data during a multiple-chip observation interval to produce a received vector of a predetermined number of data bits and parity bits; a decoder ( ) arranged to decode the received vector to produce multiple bit decisions by mapping the received vector with a set of ideal vectors; and a majority voter ( ) arranged to choose a bit estimate from the multiple bit decisions by way of a majority rule to produce a final detected symbol from the incoming modulated data during the multiple-chip observation interval. The multi-chip data detection technique performs multiple-chip comparisons in an efficient manner, providing a significant performance and implementation improvement over conventional symbol-to-symbol differential detection while realizing design gate savings of up to 90%.

US Patent:

6812783, Nov 2, 2004

Filed:

Aug 31, 2001

Appl. No.:

09/944982

Inventors:

Anthony D. Patire - Hiroshima, JP
Andy Chan - Redondo Beach CA
Ronald P. Smith - Redondo Beach CA

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

H03D 300

US Classification:

329300, 329304

Abstract:

Methods and devices for demodulators for continuous phase modulation waveforms. A modulated sampled signal is received. A consecutive sequence of the modulated sampled signal is buffered. The consecutive sequence is compared with all possible valid modulated sampled signals. A bit decision representing a demodulation of the consecutive sequence of the modulated sampled signal is determined based on a closest valid modulated sampled signal located closest to the consecutive sequence of the modulated sample signal in a constellation.