kr follow asig, idt
Envelope follower unit generator.
idt - This is the period, in seconds, that the average amplitude of asig is reported. If the frequency of asig is low then idt must be large (more than half the period of asig )
asig - This is the signal from which to extract the envelope.
k1 line 0, p3, 30000 ; Make k1 a simple envelope a1 oscil k1, 1000, 1 ; Make a simple signal using k1 ak1 follow a1, .02 ; ak1 is now like k1 a2 oscil ak1, 1000, 1 ; Make a simple signal using ak1 out a2 ; Both a1 and a2 are the same
To avoid zipper noise, by discontinuities produced from complex envelope tracking, a lowpass filter could be used, to smooth the estimated envelope.
Paris Smaragdis
MIT, Cambridge
1995