An Audio-Frequency-Response Curve Tracer

A device is described for automatically showing frequency-response characteristics of audio-frequency apparatus on the screen of a long-persistence cathode-ray tube, without mechanical equipment. This device can be used to trace a curve of output voltage on either linear or logarithmic scale versus frequencies from 20 to 15,000 cycles. The frequency scale can be either logarithmic or take special forms in which desired portions are expanded. Typical results of tests on amplifiers and electroacoustic equipment are presented.