(8.D.1.2) ZeroCrossingDetector
- Catherine Spain
Overview
Detects when a signal crosses zero and changes sign
Discussion
Multichannel zero-crossing detector, running at the sampling rate. The module outputs a 1.0 whenever a zero crossing is detected and 0.0 otherwise. The detectorType parameter controls the behavior of the detector.
If detectorType = 0, then all zero crossing are detected.
If detectorType > 0, then only positive transitions (negative->positive) are detected.
If detectorType < 0, then only negative transitions (positive->negative) are detected.
Type Definition
typedef struct _ModuleZeroCrossingDetector
{
ModuleInstanceDescriptor instance; // Common Audio Weaver module instance structure
INT32 detectorType; // Determines which zero crossings are detected: 0=all, >0 negative->positive, <0 positive->negative.
INT32* lastSign; // Holds the sign of the last input value. This is an array so that multiple channels can be supported.
} ModuleZeroCrossingDetectorClass;Variables
Properties
Name | Type | Usage | isHidden | Default value | Range | Units |
detectorType | int | parameter | 0 | 0 | -1:1 | Â |
lastSign | int* | state | 1 | [1 x 1] | Unrestricted | Â |
Pins
Input Pins
Name: in
Description: audio input
Data type: float
Channel range: Unrestricted
Block size range: Unrestricted
Sample rate range: Unrestricted
Complex support: Real
Output Pins
Name: out
Description: audio output
Data type: float
MATLAB Usage
File Name: zero_cross_detector_module.m
M=zero_cross_detector_module(NAME)
Creates a zero crossing detector module for use in the Audio Weaver
environment. The module has a single multichannel input pin and a single
output pin of the same size as the input pin. The module outputs a 1.0
whenever a zero crossing is detected and 0.0 otherwise.
Arguments:
NAME - name of the module.Â