A Simple 1.2kHz Audio Tone Generator

From the “bible” Experimental Methods in RF Design [W7ZOI, KK7B, W7PUA].

This is intended to be used to generate a low distortion audio tone, to simulate a microphone input, and to allow the signal to be traced through the audio input of a transmitter, e.g. to locate where distortion may be being added to the signal.

Spice Simulation

Ugly Construction

Results

\(\Delta{}Y\) (between the fundamental and the 2nd harmonic) = -40dB, pk-pk was 140mV.

This pretty much meets the design featured in EMRFD…