Detects the signal of 2100 Hz frequency with every 450 ms phase reversal.
Syntax
IppStatus ippsToneDetect_EC_16s(const Ipp16s* pSignal, int len, int* pResult, IppsToneDetectState_EC_16s* pState);
IppStatus ippsToneDetect_EC_32f(const Ipp32f* pSignal, int len, int* pResult, IppsToneDetectState_EC_32f* pState);
Parameters
pState |
Pointer to the tone detector state structure. |
pSignal |
Pointer to signal vector. |
len |
Number of samples in signal vector. |
pResult |
Pointer to the result value. If the value is not zero, this means that the tone was detected. |
Description
The functions ippsToneDetect_EC are declared in the ippsc.h file.
These functions apply an infinite impulse response (IIR) band-pass filter centered at 2100 Hz frequency. Functions compare powers of the signal before and after the filter.
High-level signal after the filter with periodical short blips is considered as the tone detected.
Note
Detection can occur when summary length of processed signal vectors is equal to or greater than 900 ms.
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when one of the specified pointers is NULL. |
ippStsBadArgErr |
Indicates an error when len is less than or equal to 0. |