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)
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RTF_CREATE_FIR_LOWPASS(3) rtfilter library RTF_CREATE_FIR_LOWPASS(3)NAME
rtf_create_fir_lowpass, rtf_create_fir_highpass, rtf_create_fir_bandpass - Creates FIR lowpass, highpass and bandpass windowed sinc filters
SYNOPSIS
#include <rtf_common.h>
hfilter rtf_create_fir_lowpass(unsigned int nch, int proctype,
double fc, unsigned int hlen,
KernelWindow wndtype);
hfilter rtf_create_fir_highpass(unsigned int nch, int proctype,
double fc, unsigned int hlen,
KernelWindow wndtype);
hfilter rtf_create_fir_bandpass(unsigned int nchann, int proctype,
double fc_low, double fc_high,
unsigned int hlen,
KernelWindow wndtype);
DESCRIPTION
rtf_create_fir_lowpass() creates a lowpass windowed sinc filter processing nchann channels of data type specified by proctype with fc as
normalized cutoff frequency and hlen as the half length of the window.
rtf_create_fir_highpass() is the same as rtf_create_fir_lowpass() but creates a highpass filter.
rtf_create_fir_bandpass() is the same but creates a bandpass filter with fc_low and fc_high as respectively the lowpass and highpass nor-
malized cutoff frequencies.
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 parameter proctype has the same meaning as in rtf_create_filter(3). Refers to its manpage for more details.
The parameter wndtype specifies the type of window applied to the impulse response and can take the following values: BLACKMAN_WINDOW, HAM-
MING_WINDOW or RECT_WINDOW (see a book on signal processing for details about their meaning).
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_FIR_LOWPASS(3)