The utility model discloses a
broadband amplifier, which belongs to the technical field of amplifiers, and comprises a pre-stage amplification circuit, an
automatic gain control circuit, a post-stage amplification circuit, a
peak detection circuit and a main control module, the input end of the pre-stage amplification circuit is respectively connected with a
signal input end, the output end of the
automatic gain control circuit and the output end of the main control module; the output end of the pre-stage amplification circuit is respectively connected with the input end of the
automatic gain control circuit and the input end of the post-stage amplification circuit, the output end of the post-stage amplification circuit is respectively connected with the
signal output end and the input end of the
peak detection circuit, and the output end of the
peak detection circuit is connected with the input end of the main control module; automatic
gain control is achieved in a
voltage feedback control mode, the AGC range is wide, the
peak value output by the
amplifier is taken out to serve as the
gain control
voltage, the finally output
voltage signal is kept between a certain peak-to-
peak value, and a stable signal is output.