An Improved Audio-Frequency Generator

This paper describes in detail the construction of an audio-frequency generator, for use in making radio-frequency measurments. The variable audio-frequency output is the beat note between two sources of radio frequency; the one a piezo oscillator, and the other a variable oscillator. The output is continuously variable from 50 to 1500 cycles per second. The entire unit is assembled very compactly and the essential parts are mounted in a temperature-controlled compartment. The calibration curve is practically linear over a range of 50 cycles per second and repeated calibrations indicate that it is constant to better than 0.1 cycle per second over the entire range.