| CPC H04R 3/00 (2013.01) [H04R 1/00 (2013.01)] | 7 Claims |

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1. A microphone circuit including:
an amplifier for receiving a signal output by an external microphone, and amplifying the signal;
a bias resistor having a first end connecting to a preset bias voltage and a second end connecting to an output end of the microphone and connecting to an input end of the amplifier;
wherein,
the amplifier serves as an input end of the microphone circuit; the output end of the amplifier serves as the output end of the microphone circuit;
the microphone circuit further includes a bias network module connected to the input end of the microphone circuit for judging a voltage value of the signal;
when the voltage value of the signal exceeds a preset voltage value of a threshold voltage group range, connect an impeder corresponding to the bias network module to the input end of the microphone circuit to reduce the vibration amplitude of the signal, the threshold voltage group includes an upper threshold voltage and a lower threshold voltage; the voltage value of the threshold voltage group is less than or equal to that of the upper threshold voltage and greater than or equal to the voltage value of the lower threshold voltage; and
the impeder corresponds to the threshold voltage group one-to-one.
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