Testing device for low-frequency amplifiers

Disclosed is a testing device for low-frequency amplifiers, comprising two sets of circuits connected to the output of the amplifier being tested. The first set of circuits is intended for measuring linear distortion, and the second set of circuits being designed for measuring non-linear distortion and interference. Each of the circuits forming the first set of circuits comprises a filter, a rectifier, a comparison means, and a squaring means which are connected in series. Each of the circuits forming the second set of circuits includes a filter, a rectifier, and a squaring means which are connected in series. The filters of the circuits of the first set of circuits are tuned to the frequency components of the test signal generated by sine wave voltage oscillators; and the filters of the circuits of the second set are tuned to frequencies differing from the frequency components of the test signal. The squaring means outputs are connected to the respective inputs of an indicating unit. Adders are being inserted between the outputs of the squaring means of the circuits whose filters are tuned to the frequency components of the output signal characterizing one and the same parameter of the low-frequency amplifier, and the respective inputs of the indicating unit.