Framing and elastic store circuit apparatus

Abstract

Apparatus for providing, in a multiplexed fashion, both the operations of framing to determine the position of a framing bit in a stream of data bits and, after framing has occurred, the job of providing slip control for an elastic store. Since these are essentially exclusive functions in that framing only need occur at the initial portion of a cycle and slip control need only occur after framing has been successfully completed, there is no interference between the two functions. The framing is obtained by supplying input data bits to a memory for intermediate storage and then an integral number of frames later comparing the presently received data with that received previously, and if a negative comparison occurs, eliminating that particular bit as a candidate for the framing bit. The same memory is then used along with the same addressing means for providing an elastic store along with slip control.