zkmod

zkmod — Facilitates the modulation of one signal by another.

Description

Facilitates the modulation of one signal by another.

Syntax

kres zkmod ksig, kzkmod

Performance

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.

Examples

Here is an example of the zkmod opcode. It uses the file zkmod.csd.

Example 1042. Example of the zkmod opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in    No messages
-odac           -iadc     -d     ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o zkmod.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

; 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


</CsInstruments>
<CsScore>

; 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


</CsScore>
</CsoundSynthesizer>


See Also

zamod, zkcl, zkr, zkwm, zkw

Credits

Author: Robin Whittle
Australia
May 1997

New in version 3.45

Example written by Kevin Conder.