BURST SIGNAL DETECTION CIRCUIT

摘要

PURPOSE: To surely detect the start of a burst signal and a duration time of the burst signal without being affected by noise and by a change in the burst duration time by detecting the rise and fall of each bit of a burst signal after a protection time. CONSTITUTION: A burst transmission signal 101 is turned to an inverse signal 105 through a NOT circuit 11. A change point detection circuit 12 receives the inverse signal 105 and provides an output of a change point detection signal 106 consisting of bits rising after a detection protection time t4 slightly narrower than a minimum bit width of the input signal when each bit of the input signal rises and falling down with a pulse width t5 slightly wider than a maximum bit interval of the input signal. Then a change point detection circuit 16 provides an output of a similar change point detection signal 109 at each bit fall of the input signal and an AND circuit 13 ANDs the signals 106, 109 to obtain a burst detection signal 104.