Query: rtf_create_downsampler
OS: debian
Section: 3
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RTF_CREATE_DOWNSAMPLER(3) rtfilter library RTF_CREATE_DOWNSAMPLER(3)NAMErtf_create_downsampler - Creates downsampling filterSYNOPSIS#include <rtfilter.h> hfilter rtf_create_downsampler(unsigned int nch, int type, unsigned int r);DESCRIPTIONrtf_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 VALUEReturns the handle to the created filter in case of success, NULL otherwise.NOTESOn 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 ALSOrtf_filter(3), rtf_create_filter(3), rtf_destroy_filter(3)EPFL2010 RTF_CREATE_DOWNSAMPLER(3)