| 摘要 |
PURPOSE:To realize an extremely quick follow-up to a level change of the input digital signal and obtain a proper slice level, by using a certain data pattern of the data pattern within a sampling period for a slice level adjusting pattern. CONSTITUTION:An input digital signal 101 is compared with the slice level through a comparator 1. On the other hand, the reference clock f0 is applied to a counter 6 through a sampling gate circuit 9 and for the H level period of an output 102 which received a waveform shaping within a sampling pulse, and the count value of counter 6 becomes identical with a value which is proportional to the H level of signal 102. A pattern discriminating circuit 10 discriminates whether the input digital signal within a sampling pulse is identical with the code pattern for slice level adjustment. And in the case of a code pattern, the counting value of counter 6 is held at a latch circuit 7. Then the slice level voltage VS obtained by giving a D/A conversion 8 to the value held at the circuit 7 is adjusted automatically in accordance with the input level of the signal 101 every time a coincidence is obtained between the code pattern of signal 101 and the adjusting pattern. |
