| 摘要 |
PURPOSE:To realize the detection of a carrier suppression signal without the conversion of the delta M system signal into a PCM signal by using a detection circuit of a carrier suppression AM signal so as to detect zero points of a carrier, retarding the signal by 90 deg. and adding signals quantized by the delta M system accumulatingly. CONSTITUTION:A 0 deg. detection circuit 3 generates a pulse when a carrier suppression AM signal passes through a zero point so as to reset a register of an accumulating adder 1. A counter 4 retards a 0 deg. detection output by nearly 90 deg. of the carrier and fetches the output of the adder 1 to a register. Thus, the content of the register shows an envelope of the carrier suppression AM signal, which is thus detected.
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