## clip

clip — Clips a signal to a predefined limit.

## Description

Clips an a-rate signal to a predefined limit, in a “soft” manner, using one of three methods.

## Syntax

`ares clip asig, imeth, ilimit [, iarg]`

## Initialization

imeth -- selects the clipping method. The default is 0. The methods are:

• 0 = Bram de Jong method (default)

• 1 = sine clipping

• 2 = tanh clipping

ilimit -- limiting value

iarg (optional, default=0.5) -- when imeth = 0, indicates the point at which clipping starts, in the range 0 - 1. Not used when imeth = 1 or imeth = 2. Default is 0.5.

## Performance

asig -- a-rate input signal

The Bram de Jong method (imeth = 0) applies the algorithm:

```|x| > a:     f(x) = sin(x) * (a+(x-a)/(1+((x-a)/(1-a))2 |x| > 1: f(x) = sin(x) * (a+1)/2
```

This method requires that asig be normalized to 1.

The second method (imeth = 1) is the sine clip:

```|x| < limit: f(x) = limit * sin(π*x/(2*limit)) f(x) = limit * sin(x)
```

The third method (imeth = 3) is the tanh clip:

```|x| < limit: f(x) = limit * tanh(x/limit)/tanh(1) f(x) = limit * sin(x)
```

Note Method 1 appears to be non-functional at release of Csound version 4.07.

## Examples

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

Example 72. Example of the clip 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 clip.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
; Generate a noisy waveform.
arnd rand 44100
; Clip the noisy waveform's amplitude to 20,000
a1 clip arnd, 2, 20000

out a1
endin

</CsInstruments>
<CsScore>

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

</CsScore>
</CsoundSynthesizer>
```

## Credits

 Author: John ffitch University of Bath, Codemist Ltd. Bath, UK August, 2000

New in Csound version 4.07