FILTER(1SP)

NAME
filter - performs FIR digtal filtering on speech files

SYNOPSIS
<stdin> | filter [options] | <stdout>

DESCRIPTION

filter applies the named FIR filter (-n filtername ) to the input speech file, read either from the specified input file name (-f inputfile ) or from <stdin> and writes the filtered signal to either the specified output file (-o outputfile ) or to <stdout>

OPTIONS

-f input speech file name
    [stdin]

-o output filtered file name
    [stdout]

-n filter name
    [0-075]

-h online help

SUPPORTED FILTERS

The table below contains the list of supported filters. The passband values are in normalized frequencies. The 16KHz and 8KHz columns are examples of what frequencies are passed through for a given sample rate.
Filters |
Name | Passband | 16KHz | 8KHz
 | Low | Hight | Low | High | Low | High
0-075 | 0.0 | 0.075 | 0 | 1200 | 0 | 600
0-15625 | 0.0 | 0.15625 | 0 | 2500 | 0 | 1250
0-04375 | 0.0 | 0.04375 | 0 | 700 | 0 | 350
0625-125 | 0.0625 | 0.125 | 1000 | 2000 | 500 | 1000
0625-21875 | 0.0625 | 0.21875 | 1000 | 3500 | 500 | 1750
075-5 | 0.075 | 0.5 | 1200 | 8000 | 600 | 4000
125-21875 | 0.125 | 0.21875 | 2000 | 3500 | 1000 | 1750
0125-05 | 0.0125 | 0.05 | 200 | 800 | 100 | 400
15625-28125 | 0.15625 | 0.28125 | 2500 | 4500 | 1250 | 2250
15625-5 | 0.15625 | 0.5 | 2500 | 8000 | 1250 | 4000
015625-21875 | 0.015625 | 0.21875 | 250 | 3500 | 125 | 1750
21875-5 | 0.21875 | 0.5 | 3500 | 8000 | 1750 | 4000
3125-5 | 0.3125 | 0.5 | 5000 | 8000 | 2500 | 4000
0-25 | 0.0 | 0.25 | 0 | 4000 | 0 | 2000
01875-2 | 0.01875 | 0.2 | 300 | 3200 | 150 | 1600

EXAMPLES

Filter tmp.wav with filter 0125-05 and place the results in tmp2.wav:

    % cat tmp.wav | filter -n 0125-05 > tmp2.wav

SEE ALSO
FiltByName(3SP), SpeechRead(3SP), WavWrite(3SP)

BUGS

AUTHORS
Center for Spoken Language Understanding
Department of Computer Science and Engineering
Oregon Graduate Institute of Science & Technology