Developer Reference

  • 2020
  • 10/21/2020
  • Public Content
Contents

FIRMRInit

Initializes the context structure for multi-rate FIR filtering.

Syntax

Case 1: Operation on a signal that has the same data type as the coefficients
IppStatus ippsFIRMRInit_<mod>(const Ipp<dataType>*
pTaps
, int
tapsLen
, int
upFactor
, int
upPhase
, int
downFactor
, int
downPhase
, IppsFIRSpec_<dataType>*
pSpec
);
Supported values for
mod
:
32f
64f
32fc
64fc
Case 2: Operation on a signal that has a data type different from the data type of the coefficients
IppStatus ippsFIRMRInit32f_32fc(const Ipp32f*
pTaps
, int
tapsLen
, int
upFactor
, int
upPhase
, int
downFactor
, int
downPhase
, IppsFIRSpec32f_32fc*
pSpec
);
Include Files
ipps.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
Libraries:
ippcore.lib
,
ippvm.lib
Parameters
pTaps
Pointer to the array containing filter coefficients. The number of elements in the array is
tapsLen
.
tapsLen
Number of filter coefficients.
upFactor
Multi-rate upsampling factor.
upPhase
Phase for upsampled signal.
downFactor
Multi-rate downsampling factor.
downPhase
Phase for downsampled signal.
pSpec
Pointer to the internal FIR specification structure.
Description
This function initializes the multi-rate FIR filter specification structure in the external buffer. Before using this function, compute the size of the specification structure and the size of the work buffer using the
FIRMRGetSize
function.
The parameter
upFactor
is the factor by which the filtered signal is internally upsampled (see description of the function SampleUp for more details). That is,
upFactor
-1 zeros are inserted between each sample of the input signal.
The parameter
upPhase
is the parameter, which determines where a non-zero sample lies within the
upFactor
-length block of the upsampled input signal.
The parameter
downFactor
is the factor by which the FIR response obtained by filtering an upsampled input signal, is internally downsampled (see description of the function SampleDown for more details). That is,
downFactor
-1 output samples are discarded from each
downFactor
-length output block of the upsampled filter response.
The
downPhase
parameter determines where non-discarded sample lies within a block of upsampled filter response.
For an example on how to use this function, refer to the example provided with the FIRMR function description.
Return Values
ippStsNoErr
Indicates no error.
ippStsNullPtrErr
Indicates an error when one of the specified pointers is
NULL
.
ippStsFIRLenErr
Indicates an error when
tapsLen
is less than, or equal to zero.
ippStsFIRMRFactorErr
Indicates an error when
upFactor
or
downFactor
is less than, or equal to zero.
ippStsFIRMRPhaseErr
Indicates an error when
upPhase
/
downPhase
is negative, or greater than or equal to
upFactor
/
downFactor
.

Product and Performance Information

1

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Notice revision #20110804