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)