Deemphasize

Performs de-emphasis filtering.

Syntax

IppStatus ippsDeemphasize_GSMFR_16s_I (Ipp16s* pSrcDst, int len, Ipp16s* pMem);

Parameters

pSrcDst	Pointer to the input short-term synthesized signal and output post-processed speech vector [len].
len	Length of the input residual and output speech vectors.
pMem	Pointer to the filter memory element.

Description

The function ippsDeemphasize_GSMFR is declared in ippsc.h file. This function performs de-emphasis of the input synthesized signal by filtering it through the filter with the following transfer function:

H(z) = 1/(1 - α*z^-1)

where α = 0.86 (28180 in Q15).

The initial memory of the filter will be set to zero. The filtered speech signal is scaled up by multiple of 2 and then stored in pSrcDst with truncation of the three least significant bits.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when one of the specified pointer is NULL.
ippStsRangeErr	Indicates an error when len is less than or equal to 0.