[sdiy] theremin waveform variation

[Paul Perry]

The traditional RCA theremin owes much of its charm to the variation in
vaveform with frequency.
I believe the lowest frequencies, in particular, are nothing like a sine
wave (and one would expect considerable distortion from the heterodyning
process, if the oscillators tended to pull each other).
It occurs to me that a useful module might be VCO that was designed to
replicate the theremin waveshape as it varies over the full range.
Does anyone know where to find pictures of the actual waveforms?

Paul perry Melbourne Australia