Decomposes a frame into a complex subband representation.
Syntax
IppStatus ippsSubbandAnalysis_32f32fc(const Ipp32f* pSignal, Ipp32fc* pSubbands, IppsSubbandProcessState_32f* pState, Ipp8u* pBuf);
IppStatus ippsSubbandAnalysis_16s32sc_Sfs(const Ipp16s* pSignal, Ipp32sc* pSubbands, IppsSubbandProcessState_16s* pState, int scaleFactor, Ipp8u* pBuf);
Parameters
pState |
Pointer to the subband process state structure. |
pSignal |
Pointer to the source vector. Vector length must be equal to the frame size which was used to initialize the subband process algorithm by the function ippsSubbandProcessInit. |
pSubbands |
Pointer to the resulting subband vector. Vector length is equal to the number of subbands calculated as 2order-1 + 1, where order is specified in the function ippsSubbandProcessInit. |
pBuf |
Pointer to the work buffer of size specified by the parameter pBufSize in the ippsSubbandProcessGetSize function. This buffer must be allocated by the user. |
Description
The functions ippsSubbandAnalysis are declared in the ippsc.h file. These functions perform subband analysis using the oversampled DFT filter bank.
Computation steps are as follows:
1) Calculate the weighted sum as
for j = 0,..., fftLen - 1, fftLen = 2 order.
Here x denotes the input sample buffer of size windowLen.
2) Calculate and return the Fast Fourier Transform of X.
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when one of the specified pointers is NULL. |