ksig -- the input signal
kzkmod -- controls which zk variable is used for modulation. A positive value means additive modulation, a negative value means multiplicative modulation. A value of 0 means no change to ksig. kzkmod can be i-rate or k-rate
zkmod facilitates the modulation of one signal by another, where the modulating signal comes from a zk variable. Either additive or mulitiplicative modulation can be specified.
Here is an example of the zkmod opcode. It uses the files zkmod.orc and zkmod.sco.
Example 453. Example of the zkmod opcode.
/* zkmod.orc */ ; Initialize the global variables. sr = 44100 kr = 4410 ksmps = 10 nchnls = 2 ; Initialize the ZAK space. ; Create 2 a-rate variables and 2 k-rate variables. zakinit 2, 2 ; Instrument #1 -- a signal with jitter. instr 1 ; Generate a k-rate signal goes from 30 to 2,000. kline line 30, p3, 2000 ; Add the signal into zk variable #1. zkw kline, 1 endin ; Instrument #2 -- generates audio output. instr 2 ; Create a k-rate signal modulated the jitter opcode. kamp init 20 kcpsmin init 40 kcpsmax init 60 kjtr jitter kamp, kcpsmin, kcpsmax ; Get the frequency values from zk variable #1. kfreq zkr 1 ; Add the the frequency values in zk variable #1 to ; the jitter signal. kjfreq zkmod kjtr, 1 ; Use a simple sine waveform for the left speaker. aleft oscil 20000, kfreq, 1 ; Use a sine waveform with jitter for the right speaker. aright oscil 20000, kjfreq, 1 ; Generate the audio output. outs aleft, aright ; Clear the zk variables, prepare them for ; another pass. zkcl 0, 2 endin /* zkmod.orc */
/* zkmod.sco */ ; Table #1, a sine wave. f 1 0 16384 10 1 ; Play Instrument #1 for 2 seconds. i 1 0 2 ; Play Instrument #2 for 2 seconds. i 2 0 2 e /* zkmod.sco */