82 lines
2.6 KiB
C
82 lines
2.6 KiB
C
// lasp_sosfilterbank.h
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//
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// Author: J.A. de Jong - ASCEE
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//
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// Description: Implemententation of a discrete parallel filterbank using
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// cascaded second order sections (sos) for each filter in the filterbank. In
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// parallel mode, the filters are allocated over a set of Worker threads that
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// actually perform the computation. In serial mode, all filters in the bank
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// are computed in series.
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//////////////////////////////////////////////////////////////////////
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#pragma once
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#ifndef LASP_FILTERBANK_H
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#define LASP_FILTERBANK_H
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#include "lasp_config.h"
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#include "lasp_types.h"
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#include "lasp_mat.h"
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#define MAX_SOS_FILTER_BANK_SIZE 40
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#define MAX_SOS_FILTER_BANK_NSECTIONS 10
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typedef struct Sosfilterbank Sosfilterbank;
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/**
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* Initializes a Sosfilterbank. Sets all coefficients in such a way that the
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* filter effectively does nothing (unit impulse response).
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* @param[in] nthreads: The number of threads used in computation should be 1
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* <= nthreads <= LASP_MAX_NUM_THREADS. If set to 0, a sensible value is
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* computed based on the number of filterbanks.
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* @param[in] filterbank_size: The number of parallel filters in the bank
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*
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* @return Sosfilterbank handle
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*/
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Sosfilterbank* Sosfilterbank_create(const us nthreads,
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const us filterbank_size,
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const us nsections);
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/**
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* Returns the number of channels in the filterbank (the filberbank size).
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*
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* @param[in] fb: Filterbank handle
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* @return The number of filters in the bank
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* */
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us Sosfilterbank_getFilterbankSize(const Sosfilterbank* fb);
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/**
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* Initialize the filter coeficients in the filterbank
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*
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* @param fb: Filterbank handle
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* @param filter_no: Filter number in the bank
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* @param coefss: Array of filter coefficients. Should have a length of
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* nsections x 6, for each of the sections, it contains (b0, b1, b2, a0,
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* a1, a2), where b are the numerator coefficients and a are the denominator
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* coefficients.
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*
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*/
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void Sosfilterbank_setFilter(Sosfilterbank* fb,const us filter_no,
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const vd coefs);
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/**
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* Filters x using h, returns y
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*
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* @param x Input time sequence block. Should have at least one sample.
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* @return Filtered output in an allocated array. The number of
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* columns in this array equals the number of filters in the
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* filterbank. The number of output samples is equal to the number of
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* input samples in x (and is equal to the number of rows in the output).
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*/
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dmat Sosfilterbank_filter(Sosfilterbank* fb,
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const vd* x);
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/**
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* Cleans up an existing filter bank.
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*
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* @param f Filterbank handle
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*/
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void Sosfilterbank_free(Sosfilterbank* f);
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#endif // LASP_FILTERBANK_H
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//////////////////////////////////////////////////////////////////////
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