公开(公告)号：US3626298A

公开(公告)日：1971-12-07

申请号：US3626298D

申请日：1969-07-08

Applicant: NASA

Inventor： ANDERSON TAGE O ,  HURD WILLIAM J ,  LINDSEY WILLIAM C

IPC: H04L7/033 ,  H04B7/18 ,  H04B7/20 ,  H04L7/02

CPC classification number: H04L7/0332

Abstract: A bit synchronization system, incorporating a digital data transition tracking phase-locked loop. The system, to which an input signal in the form of a noise-distorted constant amplitude bipolar stream of data bits, is assumed to be supplied, includes two integration channels. In one channel integrations are performed over assumed bit times, each bit time being equal to a bit period, while in the other channel integrations are performed over integration windows, each window being less than a bit period. The outputs of the two channels are combined to provide a pair of binary signals which are supplied to a digital filter, comprising a variable length counter and a variable gain register. The contents of two registers are combined to provide an error signal indicative of the direction of the phase difference between periods of bits in said stream and the assumed bit times.

公开(公告)号：US3588883A

公开(公告)日：1971-06-28

申请号：US3588883D

申请日：1968-02-09

Applicant: NASA

Inventor： ANDERSON TAGE O ,  STIFFLER JACK J

IPC: G01S13/30 ,  G06F1/025 ,  G06F17/15 ,  H04L7/033 ,  H03K13/00 ,  G06F5/00

CPC classification number: G06F1/025 ,  G01S13/30

Abstract: AN ENCODER/DECODER SYSTEM IS DISCLOSED, DESIGNED TO GENERATE A BINARY CODE WHICH IS A FUNCTION OF THE OUTPUTS OF A PLURALITY OF BISTABLE ELEMENTS. THE GENERATED CODE IS ASSUMED TO BE TRANSMITTED TO AND RECEIVED BY A RECEIVING UNIT, WHERE A REPLICA CODE A GENERATED. TO GENERATE THE REPLICA CODE IN PHASE WITH THE RECEIVED CODE, THE OUTPUTS OF EACH OF A PLURALITY OF BISTABLE LEMENTS ARE CORRELATED DURING A DIFFERENT DECISION-MAKING PERIOD WITH THE RECEIVED CODE. AT THE END OF THE PERIOD, BASED ON THE CORRELATION RESULTS, A DECISION IS REACHED WHICH OUTPUT OF THE ELEMENT IS TO BE USED. AFTER ALL THE DECISION,MAKING PERIODS, THE CHOSEN OUTPUTS OF ALL THE ELEMENTS, WHEN SUPPLIED TO A MAJORITY CIRCUIT, PRODUCE A REPLICA CODE, IN PHASE WITH THE RECEIVED CODE.

公开(公告)号：US3579122A

公开(公告)日：1971-05-18

申请号：US3579122D

申请日：1969-12-23

Applicant: NASA

Inventor： ANDERSON TAGE O ,  HURD WILLIAM J

IPC: H03C3/00 ,  H03H17/02 ,  H03K21/18

CPC classification number: H03H17/0223 ,  H03C3/00

Abstract: A digital filter comprising two up-down counters A and B. Counter A which is responsive to a sampled input signal which is quantized into three levels +1, -1 and 0, is incremented in response to each +1 input, decremented in response to each -1 input, and remains unchanged in response to a 0 input. Counter B, which includes N stages, is incremented at each sampling time when A is positive, decremented when A is negative and remains unchanged when A is zero. When B overflows in a positive direction A is decremented by one while a negative overflow of B results in A being incremented by one. The filter output is +2 N when A is positive, -2 N when A is negative and zero (0) when the count in A is zero.

公开(公告)号：US3566268A

公开(公告)日：1971-02-23

申请号：US3566268D

申请日：1968-02-09

Applicant: NASA

Inventor： ANDERSON TAGE O ,  GALLO ALBERT J

IPC: H04L7/04 ,  H04B1/00

CPC classification number: H04L7/043

Abstract: A SYSTEM IS DISCLOSED FOR REDUCING SYNC-ACQUISITION TIME IN A DATA COMMUNICATION SYSTEM, IN WHICH SYNCHRONIZATION IS ACHIEVED AS A FUNCTION OF THE PHASE CORRELATION OF A PN CODE, GENERATED IN A GROUND STATION AND RECEIVED BY A SPACECRAFT, AND A SIMILAR PN CODE WHICH IS GENERATED IN THE SPACECRAFT. THE SYSTEM INCLUDES CIRCUITRY WHICH IS INCORPORATED IN THE SPACECRAFT TO SAMPLE THE PHASE OF THE PN CODE GENERATED THEREIN AND TO COMMUNICATE THE PHASE OF THE SAMPLED CODE TO THE GROUND STATION, VIA A TELEMETRY CHANNEL. AT THE GROUND STATION, THE PHASE OF THE SAMPLED SPACECRAFT PN CODE IS USED TO SET A GROUND PN CODE GENERATOR TO A STATE SO THAT WHEN THE GROUND PN CODE IS TRANSMITTED TO AND ARRIVES AT THE SPACECRAFT, IT IS SUBSTANTIALLY IN PHASE WITH THE PN CODE, GENERATED THEREIN.

公开(公告)号：US3474413A

公开(公告)日：1969-10-21

申请号：US3474413D

申请日：1965-11-22

Applicant: DRYDEN HUGH L ,  NASA

Inventor： ANDERSON TAGE O ,  LUSHBAUGH WARREN A

IPC: G06F7/58 ,  G06F11/00

CPC classification number: G06F7/584 ,  G06F2207/581