I dont really get the section ** 126.96.36.199 Octave doubler** in the pd-tutorial.com ..
If you delay a periodic signal by the half the duration of one period and add it to the original, the fundamental tone (and all odd partials) is cancelled out
- if my signal is a sinusoid the result is a 0 signal ;
- if my signal come from a phasor (like in the example) the result is a sawtooh at the double freq ranging in [0.5 , 1.5] ;
- if my signal come from a natural instrument (e.g. a cello) how do we explain that it will remove the odd partials ?