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Re: No, no, no

I am aware that 22.05Khz will be filtered out by the antialiasing filter and will not occur in the actual sample set...it is just a useful thought tool for coming up with the worst case scenario. I guess there is some contention whether a frequency of exactly 22.05 violates the nyquist criteria - and it doesn't for every phase of that frequency except where the two samples align with the zero crossings and the alias frequency is 0 Hz with no amplitude. So in essence you can really only keep frequencies <, rather than <= ... and this is all in the theoretical sense. For practical purposes you will be filtering well below this frequency.

It should be noted that the phase resolution for a 20Khz will be almost as bad (in the uS) as the 22.05 for a signal that peaks at just the LSB since the phase resolution is dependent on frequency _and_ how many bits you have available to represent them. The graph shows the 1 degree phase resolution at about half scale, but this resolution is _diminished_ as the level goes down and extremely poor when the level is down to the LSB.

Actually, the more I think about it - I am not sure you can actually even represent said 20 Khz sine wave with 1 bit of amplitude. You need a minimum of three samples to define the wave and there is no "wiggle room" at 1 bit to produce the correct relative sample heights you need to define the wave.

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