"Twice the bandwidth" but that doesn't account for the 0 Hz "hole" where the incoming signal is exactly at the sampling rate. Or am I missing something?
On Wed, Nov 4, 2020 at 3:28 PM Fons Adriaensen <f...@linuxaudio.org> wrote: > On Wed, Nov 04, 2020 at 05:14:00PM +0100, Kristoff wrote: > > > For us, "even if we would be able to look at a rotating object up-front > and > > from a 90 degrees angle at the same time, if the object would be frozen > in > > time we would still not be able to determine if the doll rotates left of > > right". > > The way complex samples are treated in theory means that the I and Q > parts refer to the same time, They are considered to be a single > sample having a complex value. > > But you can never detect rotation (or a frequency in DSP terms) from > a single sample, be it real or complex. You always need a sequence. > > A sequence of real valued samples (either I or Q separately) allows > you to detect the rotation, but the sense remains ambiguous. Having > both the I and Q sequences resolves that ambiguity. > > You could object that using complex samples requires twice the > memory for the same sample rate, since every sample consists of > two numerical values. But since you can now separate positive > and negative frequencies, you get twice the bandwidth as well. > So there is no penalty for using complex signals. > > -- > FA > > > -- K1FZY (WA4TPW) SK 9/29/37-4/13/15
