"Arny Krueger" wrote in message


Correction:

Comparing the amplitudes of the first two sidebands around 1 KHz and
4 KHz, I find that there is an approximate difference of 2 dB in levels
relative to the carriers. The
sidebands around the 4 KHz average about 2 dB higher than those
around the 1 KHz tone. If this was pure FM distortion, I would expect
a 12 dB difference. I conclude that there is a mixture of AM and FM,
predominantly AM.