lfo
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lfo

lfo — A low frequency oscillator of various shapes.

Description

A low frequency oscillator of various shapes.

Syntax

kres lfo kamp, kcps [, itype]
ares lfo kamp, kcps [, itype]

Initialization

itype (optional, default=0) -- determine the waveform of the oscillator. Default is 0.

  • itype = 0 - sine

  • itype = 1 - triangles

  • itype = 2 - square (bipolar)

  • itype = 3 - square (unipolar)

  • itype = 4 - saw-tooth

  • itype = 5 - saw-tooth(down)

The sine wave is implemented as a 4096 table and linear interpolation. The others are calculated.

Performance

kamp -- amplitude of output

kcps -- frequency of oscillator

Examples

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

Example 225. Example of the lfo 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 lfo.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1

; Instrument #1.
instr 1
  kamp = 10
  kcps = 5
  itype = 4

  k1 lfo kamp, kcps, itype
  ar oscil p4, p5+k1, 1
  out ar
endin


</CsInstruments>
<CsScore>

; Table #1: an ordinary sine wave.
f 1 0 32768 10 1

; p4 = amplitude of the output signal.
; p5 = frequency (in cycles per second) of the output signal.
; Play Instrument #1 for two seconds.
i 1 0 2 10000 220
e


</CsScore>
</CsoundSynthesizer>


Credits

Author: John ffitch
University of Bath/Codemist Ltd.
Bath, UK
November 1998

New in Csound version 3.491

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