The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 28, 1980
Filed:
Aug. 28, 1978
Frank Fellinger, Delaware, OH (US);
James M Ruffing, Delaware, OH (US);
International Telephone and Telegraph Corporation, New York, NY (US);
Abstract
A carrier terminal unit for interfacing 1.544 MHz PCM lines to a digital switch, wherein voice samples are switched at 2.048 MHz, provides bit synchronization, in-frame monitoring, delay equalization and correction, framing detection, and rate and format conversion. A common memory is utilized for the delay equalization and correction, framing detection and rate and format conversion functions. The memory acts as an elastic store for delay equalization. Delay correction is provided by monitoring the relative positions of the memory read and write addresses and initializing the write addresses after an overtaking of the read or write addresses by the other is detected. Rate and format conversion are provided by storing incoming PCM samples in the memory and reading the samples out in accordance with a predetermined sequence. Framing detection is provided by storing in memory every nth bit of three alternate frames of incoming data. Subsequently, every nth incoming bit is compared with the corresponding bit stored in memory four frames earlier to determine if the predetermined pattern exists. A signal indicating the results of the comparison is also stored in memory. The stored indication signals are used to determine whether an incoming bit position contains a framing bit.