BIT RECOVERY CIRCUIT

摘要

PURPOSE:To attain correct bit recovery by inputting a digital signal at the period of 1/N (N>1) times one-bit length and comparing the digital signal with a reference synchronizing pattern to check their coincidence and process the signal. CONSTITUTION:A received digital signal Pd is supplied to a shift register SR1 and a clock CK having the period of 1/N the one-bit length of the signal Pd is supplied from a crystal oscillator circuit 8 to the SR1 as a shift pulse. A prescribed bit of the SR1 is compared with a reference synchronizing pattern from a synchronizing pattern formation circuit 3 by a comparator 2, and in case of coincidence, a comparison output Pr of level ''1'' is extracted from the circuit 2. The signal Pr is processed by a counter 4, a load pulse formation circuit 7 and a presetter counter 5, the center point of one period of the signal Pr is found out from the counter value of the clock CK and the signal Pd is sampled and held by an FF6 in every one-bit length period of the signal Pd on the basis of the center point to output a bit recovery.