1RTF_CREATE_CHEBYCHEV(3)        rtfilter library        RTF_CREATE_CHEBYCHEV(3)
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NAME

6       rtf_create_chebychev,  rtf_create_butterworth  -  Creates IIR Chebychev
7       and Butterwoth filters
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SYNOPSIS

10       #include <rtf_common.h>
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12       hfilter rtf_create_chebychev(unsigned int nchann, int proctype,
13                                    double fc, unsigned int num_pole,
14                                    int highpass, double r);
15       hfilter rtf_create_butterworth(unsigned int nchann, int proctype,
16                                      double fc, unsigned int num_pole,
17                                      int highpass);
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DESCRIPTION

20       rtf_create_chebychev() creates a IIR chebychev filter processing nchann
21       channels  of data type specified by proctype with fc as normalized cut‐
22       off frequency, whose the Z-transform has num_pole poles and  whose  the
23       impulse  response  has  a  ripple  of r This latter is expressed as the
24       ratio between the overshoot (difference between the max  value  of  the
25       response to a unit step and the unit length) and the unit length (ratio
26       not expressed in decibels).
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28       rtf_create_butterworth() is the same as rtf_create_chebychev() but cre‐
29       ates  a  butterworth filter (which a special case of a chebychev filter
30       with a ripple of 0).
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32       A normalized frequency is the ratio between the absolute frequency  and
33       the sampling frequency (i.e. a value of 1.0 refers to the sampling fre‐
34       quency).
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36       If highpass is 0, it specifies the filter should be a lowpass. If high‐
37       pass is non-zero, the should be a highpass.
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RETURN VALUE

40       Returns  the handle to the created filter in case of success, NULL oth‐
41       erwise.
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SEE ALSO

44       rtf_create_filter(3), rtf_destroy_filter(3)
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50EPFL                                 2010              RTF_CREATE_CHEBYCHEV(3)
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