[Pd] Complex audio signals

[Piotr Majdak]

Chuckk Hubbard wrote:
> I'm teaching myself some DSP stuff, using Miller's Techniques, a
> Digital Filters book, and some other references, and I'm loving it.
> I am wondering, though, how one comes up with a complex audio signal
> for use in Pd.  I want to experiment with [czero~], and I've also
> wondered where complex signals come from for [fft~].

I'm not sure I understand your question: Do you want to know why 
processing a real signal with the Fourier Transormation can result in a 
complex signal?

> It doesn't seem like it would be possible to create a complex signal
> from a real one, but maybe there are ways to synthesize them?

A real signal can be regarded as a special case of a complex signal with 
the imaginary part set to zero. To create a complex signal just add an 
imaginary part, e.g. real signal x -> hilbert transformation of x -> x', 
which is the imaginary part of the analytic signal z=x + jx', z is 
complex now.

br, Piotr