^ ^ ^ ^ ^ ^ ^ ^ ^ ^ So the waveform IS changed -- it could be a modulated square wave, but you wouldn't know after mixer or LPF! You had stated:
When I read "amplitude and waveform relationships", I think sidebands AND harmonics, the components of a wave which give rise to small-time-scale shapes (rise time, PWM, overshoot, etc.), as well as long-time-scale forms (amplitude and frequency modulation).
When I read "look at IF mixed down to within scope BW", I see the further implication that all aspects of the wave shape are preserved, allowing me to see the same waveform at a lower time/div scale. But this isn't possible, because the harmonics are stripped, only the sidebands are preserved.
So if I superhet a square carrier, I get a square IF carrier back?
Envelope yes, waveform during any given cycle of the carrier, no.
Exactly no correspondence -- it is exactly the sampling signal's harmonics which preserves the harmonic relationship in the conversion. Note that, in my example, 0.1, 1.9, 2.1, 3.9, etc., do not form a harmonic series, while
0.1, 0.3, 0.5, 0.7, etc. do, and their amplitudes correspond to those of the original signal's.Tim