| 摘要 |
<p>PURPOSE:To obtain this pointer processing circuit of a small circuit scale by starting down-count taking a fixed length of information pay load as its period from the pointer value of a reception data read at the position of a reference phase with an offset counter and using a zero detection circuit so as to detect a state that an offset counter is circulated to reach zero. CONSTITUTION:An offset counter 7 reads the pointer value of a reception data (b) at the position of a reference phase according to a control pulse outputted from a frame counter 1 whose count is started by a frame pulse (a) and down- counts the pointer value. Thus, the counted value (c) of the counter 7 is zero at the head position of information pay load, the counted value is detected by a zero detection circuit 6 and a pulse (d) indicating the head position of information pay load is outputted. When the head position is once identified, the counter 7 continues counting by taking the fixed length of the information pay load as a period and the head position of the information pay load is identified when the counted value (c) is circulated to zero. Thus, the pointer processing circuit of a small circuit scale is obtained.</p> |
