Overview

Sample and hold module

Discussion

An audio rate sample and hold module for use with the Audio Weaver environment. The module has two input pins: trigger and data. The trigger signal block size must be either 1 or the same block size as the input signal. If the trigger signal block size is 1 then the trigger applies to all the samples.

The output samples follow the input samples whenever the trigger sample is not zero. The first zero sample in the trigger holds the prior input sample for output until the next non-zero trigger sample. The module is designed to work with multichannel data.

There are two operating modes. If the trigger pin has a single channel, then the trigger is applied to all of the interleaved data channels. Otherwise, if the trigger has the same number of channels as the data, then a separate trigger is applied to each channel.

Internally, the module stores the sampled data within the value array. This array has 1 sample per input channel.

Type Definition

typedef struct _ModuleSampleAndHold
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    FLOAT32* value;                               // Holds the last data value which was sampled. This is an array so that multiple channels can be supported.
} ModuleSampleAndHoldClass;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
value	float*	state	0	[1 x 1]	Unrestricted

Pins

Input Pins

Name: trig

Description: trigger signal

Data type: int

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Name: in

Description: input data

Data type: {float, int, fract32}

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: output data

Data type: {float, int, fract32}

MATLAB Usage

File Name: sample_and_hold_module.m

 M=sample_and_hold_module(NAME)
 Creates a sample and hold module for use with the Audio Weaver
 environment.

  Arugments:
    NAME - name of the module.