NAME

       rtf_create_downsampler - Creates downsampling filter

SYNOPSIS

       #include <rtfilter.h>

       hfilter rtf_create_downsampler(unsigned int nch, int type,
                                      unsigned int r);

DESCRIPTION

       rtf_create_downsampler()  creates a filter that downsamples signals coming from nch channels of type type
       (see rtf_create_filter(3)) by a decimation factor of r (i.e. the sampling frequency of the input will  be
       r  times the sampling frequency of the output). This is achieved internally by applying a lowpass 4-order
       Chebychev filter to the input data using a normalized cutoff frequency of 0.8/(2*r)  and  decimating  the
       result every r samples.

RETURN VALUE

       Returns the handle to the created filter in case of success, NULL otherwise.

NOTES

       On  the contrary of most other filters, the number of samples returned by rtf_filter(3) is different than
       the input (as expected) but also may vary at each call if the number of sample supplied in input is not a
       multiple of r.

SEE ALSO

       rtf_filter(3), rtf_create_filter(3), rtf_destroy_filter(3)