Framing circuit for digital receiver

Details Framing circuit for digital receiver Framing circuit for digital receiver

1975-12-12

1977-04-05

Olms, Douglas W.

Telegraphy

Systems

Printing

178 691, H04J 306

Patent

active

040163687

ABSTRACT:
In the T1 PCM carrier system there are 193 bits per frame, 192 of which are used for the channels. The D1 channel bank uses the 193rd bit to identify the division between frames, with a pattern from frame to frame of . . . 010101 . . . . The D2 channel bank uses the 193rd bit of alternate frames, or every 386th bit for framing. Both D1 and D2 have a framing circuit to identify the framing bit by the pattern with a normal mode and a search mode. There is a violation monitor for comparing the pattern of framing bits from frame to frame and indicating a violation if there is a deviation. In the normal mode only the framing bits are examined, and some error tolerance is allowed. Violations are registered in a memory device to check if a preset threshold is exceeded. When the threshold is exceeded, a misframe is declared, and the circuit goes into a search mode to examine other bit positions for the framing pattern. No error tolerance is allowed in the search mode. After a framing pattern is found, a confidence circuit with a memory checks whether the pattern persists for a predetermined number of frames before returning to the normal mode, and searching other bit positions if the pattern does not persist.

REFERENCES:
patent: 3742139 (1973-06-01), Boehly et al.
patent: 3766316 (1973-10-01), Hoffman et al.
patent: 3830980 (1974-08-01), Peron et al.
patent: 3854011 (1974-12-01), Mallory et al.
patent: 3903371 (1975-09-01), Colton et al.
patent: 3920900 (1975-11-01), Fineman
patent: 3940563 (1976-02-01), Susset

Affiliated with

Also associated with

Rating

Framing circuit for digital receiver does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Framing circuit for digital receiver, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Framing circuit for digital receiver will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2267143