Broadband amplifier based on 51 microcontroller

This design uses the variable gain wideband amplifier VCA810 to increase the gain and expand the AGC control range, and uses software compensation to reduce the step interval of the gain adjustment and improve the accuracy. The input part uses a high-speed voltage feedback op amp 0 P A842 as a follower to increase the input impedance, and a protection circuit is added to the input part without affecting performance. Various anti-interference measures are used to reduce noise and suppress high-frequency self-excitation. The power output part is made of discrete components. The passband of the entire system is 4.4 k Hz ~ 8.4 MH z, with a minimum gain of 0 dB and a maximum gain of 70 dB. The gain step is ld B/6dB/arbitrarily set. The error between the preset gain and the actual gain below 60 dB is less than 0.2 dB. The effective value of the undistorted output voltage reaches 10.1 V, and the AGC control range is 52 dB when outputting 4.5 ~ 5.5 V.