In forensic
practice expert must have tools to see micro frequency modulations of some
traces. To investigate wave editing traces for example. Bellow samples show
benefits of PASFilm to solve theses questions. You can compare triple PASFilm:
Amplitude (old-kind sonograms), Phase-A and Phase-F to conclude that PASFilm
Phase-F (the last one in the row) is the best one to solve problem. All these
frequency traces are artificially generated. All mean frequency, pitch of
frequency modulation and amplitude of these signals are equal. But differs the
value of frequency modulation.
Mean
frequency F0 = 2756.25 Hz (2756.25 = 11025/4).
Pitch of
frequency modulation = 7 Hz.
You can listen the sounds which traces are
shown on corresponding pictures.