ZeroCrossing
Calculates the number of zero crossings of a vector.
The calculation mode is specified by the zcType parameter. The calculation result is saved in the address pointed to by pValZC. The calculation modes are as follows:
- When ZCType = HMPPZCR, the calculation formula is:
- When ZCType = HMPPZCXor, the calculation formula is:
- When ZCType = HMPPZCC, the calculation formula is:
The declaration of the interface function is as follows:
HmppResult HMPPS_ZeroCrossing_16s32f(const int16_t *src, uint32_t len, float *valZcr, HmppZCType zcType);
HmppResult HMPPS_ZeroCrossing_32f(const float *src, uint32_t len, float *valZcr, HmppZCType zcType);
Parameters
Parameter |
Description |
Value Range |
Input/Output |
|---|---|---|---|
src |
Pointer to the source vector |
The value cannot be NULL. |
Input |
valZcr |
Pointer to the calculation result |
The value cannot be NULL. |
Output |
zcType |
Mode of calculating zero crossings |
HMPPZCR, HMPPZCXor, HMPPZCC |
Input |
len |
Vector length |
Positive number |
Input |
Return Value
- Success: HMPP_STS_NO_ERR
- Failure: An error code is returned.
Error Codes
Error Code |
Description |
|---|---|
HMPP_STS_NULL_PTR_ERR |
The input parameter src or valZCR contains null pointers. |
HMPP_STS_SIZE_ERR |
The value of len is 0. |
HMPP_STS_RANGE_ERR |
zcType is an invalid value. |
Important Notes
When calling a function, ensure that the value type of len is unsigned and not a negative number.
Example
#define BUFFER_SIZE_T 10
void ZeroCrossingExample(void)
{
float src[BUFFER_SIZE_T] = {1.64, 1.63, -1.09, 0.71, -3.20, -0.43, 0.41, -4.83, 5.36, -4.40};
float valZCR[BUFFER_SIZE_T];
(void)HMPPS_Zero_32f(valZCR, BUFFER_SIZE_T); //Initialize all elements of valZCR to 0.
HmppZCType HmppZCR = HMPP_ZCR;
HmppResult result = HMPPS_ZeroCrossing_32f(src, 10, valZCR, HmppZCR);
printf("result = %d.\n", result);
if (result != HMPP_STS_NO_ERR) {
return;
}
printf("valZCR =");
for (int i = 0; i < BUFFER_SIZE_T; i++) {
printf(" %.2f", valZCR[i]);
}
printf("\n");
}
Output:
result = 0. valZCR = 7.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00