"ScottW" wrote in message
news:AmUvb.4608$ML6.2599@fed1read01
"Erik Squires" wrote in message
ervers.com...

So, here's my question. If I digitize a 15 kHz signal, using a 44.1
kHz sampling rate, I'm going to get about 3 samples / cycle.

Are the normal digital filters good enough to reproduce a 15 kHz
singal with varying amplitude?

Deconstruct this signal to frequency domain and it won't be a pure
15 kHz.

Wrong.

There has to be another component imposed on the 15 kHz that "varies the
amplitude".

Wrong.

Three samples is sufficient to define a sine wave that has unique frequency,
phase and amplitude. In fact, just slightly more than two samples is
sufficient.