[BC] Frequency Measurements and 1000 Hz tone...

[Glen Kippel]

I assume that the 1000-Hz tone does not have to be exactly 1000 Hz due to
the fact that a cart may not be running at the correct speed.  Also, if a
tone generator is being fed directly to air, wouldn't it would be necessary
to use a frequency counter ensure that it is indeed running at exactly 1000
Hz -- or is the exact frequency of the modulation of no import?