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conv


Manual Reference Pages  - CONV (1)

NAME

conv - Convolution.

CONTENTS

Syntax
Description
Options
Copyright

SYNTAX

conv [options] signal_file impulse_response_file

DESCRIPTION

The response of a linear filter to an arbitiary input signal is the convolution of the signal with the filter’s impulse response. The ‘impulse_response_file’ contains the impulse response which characterises the filter, and the result of the convolution operation is the response of that filter to the signal contained in the ‘signal_file’.

The ‘signal_file’ must consist of binary 16-bit numbers (ie. shorts). The ‘impulse_response_file’ must consist of binary floats. The output signal is the same length as the input signal and is written on the stdout in binary 16-bit numbers.

If the ‘signal_file’ consists of an impulse train, then the output should be a repeated impulse response, ie. should be a repeated version of the ‘response_file’.

OPTIONS

1. length

The amount of the signal file to convolve in time units (s or ms) or in samples (no units). Time units are converted to samples using the given ‘samplerate’ option. The string "max" is recognised as the remainder of input.

2. domain

Select algorithm for convolution. In the time domain ("domain=time") the discrete convolution formula is applied directly as a local averaging operation on the input signal with weights obtained by time-reversing and shifting the impulse response. The impulse response is assumed to be zero for all time outside the given file. In the frequency domain ("domain=frequency") the FFT of the whole input signal is multiplied by a frequency response function (the FFT of the impulse response), and the result inverse FFT’d.

3. scale

A scale factor for scaling the output.

SEE ALSO

options smooth fft acf

COPYRIGHT

Copyright (c) Applied Psychology Unit, Medical Research Council, 1995

Permission to use, copy, modify, and distribute this software without fee is hereby granted for research purposes, provided that this copyright notice appears in all copies and in all supporting documentation, and that the software is not redistributed for any fee (except for a nominal shipping charge). Anyone wanting to incorporate all or part of this software in a commercial product must obtain a license from the Medical Research Council.

The MRC makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.

THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.


SunOS 5.6 CONV (1) 1 September 1993
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