Audiphone combining AGC with dynamic amplification

An audiphone combining AGC (automatic gain control) with dynamic amplification comprises a collector, a pre-amplifier, an anti-aliasing filter, an A/D converter, a smoothing filter, a rear amplifying circuit and a loudspeaker; the collector converts a voice signal into an electrical signal; the electrical signal enters the anti-aliasing filter after being pre-amplified by a pre-amplifying circuit and being processed through automatic gain control; the A/D converter converts an analog signal into a digital signal and stores the signal into a memorizer; the digital signal is amplified by a processor and then restored in the memorizer; and the amplified signal is converted into analog electrical signal via a D/A converter, enters the rear amplifying circuit after smoothing filtering, and is finally output from the loudspeaker. The audiphone has the characteristics of automatic gain control and dynamic amplification control.