downsamp

downsamp — Modify a signal by down-sampling.

Description

Modify a signal by down-sampling.

Syntax

kres downsamp asig [, iwlen]

Initialization

iwlen (optional) -- window length in samples over which the audio signal is averaged to determine a downsampled value. Maximum length is ksmps; 0 and 1 imply no window averaging. The default value is 0.

Performance

downsamp converts an audio signal to a control signal by downsampling. It produces one kval for each audio control period. The optional window invokes a simple averaging process to suppress foldover.

Examples

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

Example 121. Example of the downsamp 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 downsamp.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
  ; Create a noise signal at a-rate.
  anoise noise 20000, 0.2

  ; Downsample the noise signal to k-rate.
  knoise downsamp anoise

  ; Use the noise signal at k-rate.
  a1 oscil 30000, knoise, 1
  out anoise
endin


</CsInstruments>
<CsScore>

; Table #1, a sine wave.
f 1 0 16384 10 1

; Play Instrument #1 for one second.
i 1 0 1
e


</CsScore>
</CsoundSynthesizer>


See Also

diff, integ, interp, samphold, upsamp

Credits

Example written by Kevin Conder.