| 摘要 |
PURPOSE:To surely identify an input pulse code modulation PCM signal by using two voltage comparators having a different identification level and selecting outputs of the comparators based on an output of an exclusive OR circuit. CONSTITUTION:The identification level of a 1st voltage comparator 11 is set to a high voltage by resistors 5, 6, and the identification level of a 2nd voltage comparator 12 is set to a low voltage by resistors 5, 7. The output of the 1st and 2nd voltage comparators 11, 12 connects to an output terminal 2 via a signal selector 15. Moreover, a part of the output of the voltage comparators 11, 12 is inputted to an exclusive OR circuit 10. The output terminal of the exclusive OR circuit 10 is provided with a capacitor 14 and connects to a pulse detection circuit 13, whose output is given to the signal selector 15. Thus, the identification level of the PCM signal is selected automatically in matching with the deterioration of waveform.
|
