.. . iadd . a bit clock reproducing circuit incorporates a counter for counting pulses of a clock pulse source after the arrival of an edge of a data pulse , at which time the counter is loaded with one of a number of preset values stored in a read - only memory , the contents of which are addressed by the counter output . input data pulses are gated to an output terminal when the counter arrives at a predetermined state . some values loaded into the counter may be the same for various different states of the counter immediately prior to the times when it is preset , and other values loaded into the counter are uniquely associated with the state of the counter at such times . . iaddend .