| 摘要 |
PURPOSE:To ensure assured and acurate discrimination for the data of an input signal, by detecting the upper and lower widths of pulse of a digital signal independently of each other and feeding the differential voltage back to a voltage comparator. CONSTITUTION:An input waveform 4 applied to an input terminal 8 is compared with a level 15 through a voltage comparator 9. Thus a digital signal 16 is obtained. At the same time, upper and lower pulse lengths 17 and 18 are obtained through upper and lower pulse length detecting circuits 11 and 12, respectively. The difference of count numbers between circuits 11 and 12 is calculated by a subtractor circuit 13. The analog voltage corresponding to the result of operation of the circuit 13 is delivered from a D/A converter 14, and the output of the converter 14 is fed back to the comparing voltage of the comparator 9. As a result, the comparing voltage is set at a position as shown by 19 so as to obtain coincidence between the lengths 17 and 18. Then the digital signal output is shown by 20, and this signal undergoes a digital signal process through a processing circuit 101. |
