RTF_CREATE_BANDPASS_ANALYTIC(3) rtfilter library RTF_CREATE_BANDPASS_ANALYTIC(3)NAME
rtf_create_bandpass_analytic - Creates an IIR filter estimating the analytic signal in a bandpass.
SYNOPSIS
#include <rtf_common.h>
hfilter rtf_create_bandpass_analytic(unsigned int nch, int proctype,
double fl, double fh,
unsigned int num_pole);
DESCRIPTION
rtf_create_chebychev() creates a IIR chebychev filter processing nch channels of data type specified by proctype. The output of the filter
is the analytic signal of the bandpassed data between the normalized frequencies fl and fh. The num_pole parameter specifies the number of
poles of the Chebychev filter used as the basis of the analytic filter.
A normalized frequency is the ratio between the absolute frequency and the sampling frequency (i.e. a value of 1.0 refers to the sampling
frequency).
The Z-transform of this filter has complex coefficients. So like rtf_create_filter(3) the created filter will output complex values keeping
the precision specified by proctype.
It is important to note that this filter can quickly become unstable as the number of pole specified increased. Please refers to the
authors of the library to know the stability domain (TODO: provides the stability domain here)
RETURN VALUE
Returns the handle to the created filter in case of success, NULL otherwise.
SEE ALSO rtf_create_filter(3), rtf_destroy_filter(3)EPFL 2010 RTF_CREATE_BANDPASS_ANALYTIC(3)
Check Out this Related Man Page
RTF_CREATE_CHEBYCHEV(3) rtfilter library RTF_CREATE_CHEBYCHEV(3)NAME
rtf_create_chebychev, rtf_create_butterworth - Creates IIR Chebychev and Butterwoth filters
SYNOPSIS
#include <rtf_common.h>
hfilter rtf_create_chebychev(unsigned int nchann, int proctype,
double fc, unsigned int num_pole,
int highpass, double r);
hfilter rtf_create_butterworth(unsigned int nchann, int proctype,
double fc, unsigned int num_pole,
int highpass);
DESCRIPTION
rtf_create_chebychev() creates a IIR chebychev filter processing nchann channels of data type specified by proctype with fc as normalized
cutoff frequency, whose the Z-transform has num_pole poles and whose the impulse response has a ripple of r This latter is expressed as the
ratio between the overshoot (difference between the max value of the response to a unit step and the unit length) and the unit length
(ratio not expressed in decibels).
rtf_create_butterworth() is the same as rtf_create_chebychev() but creates a butterworth filter (which a special case of a chebychev filter
with a ripple of 0).
A normalized frequency is the ratio between the absolute frequency and the sampling frequency (i.e. a value of 1.0 refers to the sampling
frequency).
If highpass is 0, it specifies the filter should be a lowpass. If highpass is non-zero, the should be a highpass.
RETURN VALUE
Returns the handle to the created filter in case of success, NULL otherwise.
SEE ALSO rtf_create_filter(3), rtf_destroy_filter(3)EPFL 2010 RTF_CREATE_CHEBYCHEV(3)