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EST_filter_design.h
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/*************************************************************************/
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/* */
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/* Centre for Speech Technology Research */
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/* University of Edinburgh, UK */
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/* Copyright (c) 1995,1996 */
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/* All Rights Reserved. */
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/* the following conditions: */
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/* 1. The code must retain the above copyright notice, this list of */
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/* conditions and the following disclaimer. */
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/* 2. Any modifications must be clearly marked as such. */
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/* 3. Original authors' names are not deleted. */
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/* 4. The authors' names are not used to endorse or promote products */
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/* derived from this software without specific prior written */
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/* permission. */
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/* */
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/* THE UNIVERSITY OF EDINBURGH AND THE CONTRIBUTORS TO THIS WORK */
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/* DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING */
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/* ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT */
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/* SHALL THE UNIVERSITY OF EDINBURGH NOR THE CONTRIBUTORS BE LIABLE */
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/* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES */
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/* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, */
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/* ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF */
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/* THIS SOFTWARE. */
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/* */
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/*************************************************************************/
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#ifndef __EST_FILTER_DESIGN_H__
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#define __EST_FILTER_DESIGN_H__
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#include "EST_Wave.h"
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#include "EST_FMatrix.h"
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#include "EST_Track.h"
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/**@name Filter Design
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FIR Filtering is a 2 stage process, first involving design and then
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the filtering itself. As the design is somewhat costly, it is usually
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desirable to design a filter outside the main loop.
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For one off filtering operations, functions are
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provided which design and filter the waveform in a single go.
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It is impossible to design an ideal filter, i.e. one which exactly
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obeys the desired frequency response. The "quality" of a filter is
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given by the order parameter, with high values indicating good
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approximations to desired responses. High orders are slower. The
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default is 199 which gives a pretty good filter, but a value as low as
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19 is still usable if speech is important.
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*/
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//@{
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/** Create an arbitrary filter or order {\tt order} that attempts to
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give the frequency response given by {\tt freq_response}. The vector
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{\tt freq_response} should be any size 2**N and contain a plot of the
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desired frequency response with values ranging between 0.0 and
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1.0. The actual filtering is done by \Ref{FIRfilter}.
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@see design_lowpass_FIR_filter, design_highpass_FIR_filter
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@see FIRfilter, FIRlowpass_filter, FIRhighpass_filter
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*/
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EST_FVector
design_FIR_filter(
const
EST_FVector
&
freq_response
,
int
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filter_order
);
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/** Design a FIR lowpass filter of order {\tt order} and cut-off
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frequency {\tt freq}. The filter coefficients are returned in the
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FVector and should be used in conjunction with \Ref{FIRfilter}.
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@see design_FIR_filter, design_highpass_FIR_filter, FIRfilter,
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FIRlowpass_filter, FIRhighpass_filter
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*/
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EST_FVector
design_lowpass_FIR_filter(
int
sample_rate,
int
freq,
int
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order);
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/** Design a FIR highpass filter of order {\tt order} and cut-off frequency
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{\tt freq}. The filter coefficients are returned in the FVector and should be used in conjunction with \Ref{FIRfilter}
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@see design_FIR_filter, design_lowpass_FIR_filter, design_highpass_FIR_filter
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@see FIRfilter, FIRlowpass_filter, FIRhighpass_filter
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*/
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EST_FVector
design_highpass_FIR_filter(
int
sample_rate,
int
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freq,
int
order);
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//@}
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#endif
/* __EST_FILTER_DESIGN_H__ */
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EST_FVector
Definition
EST_FMatrix.h:114
EST_Hash_Pair
Definition
EST_THash.h:75
include
sigpr
EST_filter_design.h
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