Delay

Overview

Time delay in which the delay is specified in samples

Discussion

A delay module, where the delay is specified as an integer number of samples. The delay is implemented such that delays as short as 0 samples can be realized. The module has one multichannel input and one multichannel output. The module can operate on multiple channels and applies the same delay to each channel.

At construction time, specify the maximum delay (maxDelay) of the module. The variable, maxDelay determines the size of the internal state buffer. The size of the internal state buffer equals maxDelay*numChannels. In addition, the instantaneous delay is specified through the interface variable, currentDelay. currentDelay is in the range of [0 maxDelay] and can be changed at run-time. Note that the module is not smoothly updating and you may get audible clicks when adjusting the currentDelay at run-time.

Module Pack

Standard

ClassID

classID = 0

Type Definition

typedef struct _ModuleDelay
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
INT32 maxDelay;                               // Maximum delay, in samples. The size of the delay buffer is maxDelay*numChannels.
INT32 currentDelay;                           // Current delay.
INT32 stateIndex;                             // Index of the oldest state variable in the array of state variables.
INT32 stateHeap;                              // Heap in which to allocate memory.
FLOAT32* state;                               // State variable array.
void * hardware_specific_struct_pointer;      // Usually NULL, but for optimizations, this may point to a struct that varies based on the target platform
} ModuleDelayClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range	Units
maxDelay	int	const	0	100	Unrestricted	samples
currentDelay	int	parameter	0	0	0:1:100	samples
stateIndex	int	state	1	0	Unrestricted
stateHeap	int	const	1	2	Unrestricted
state	float*	state	1	[1 x 101]	Unrestricted
hardware_specific_struct_pointer	void *	state	1		Unrestricted

Pins

Input Pins


Name	in
Description	audio input
Data type	{float, int, fract32}
Channel range	Unrestricted
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real

Output Pins


Name	out
Description	audio output
Data Type	{float, int, fract32}

Matlab Usage

File Name: delay_module.m 
 M=delay_module(NAME, MAXDELAY, MEMHEAP) 
 Creates an integer time delay for use in the Audio Weaver environment.   

 Arguments: 
    NAME - name of the module. 
    MAXDELAY - maximum delay, in samples. 
    MEMHEAP - specifies the memory heap to use to allocate the main 
         state buffer. This is a string and follows the memory allocation 
         enumeration in Framework.h. Allowable values are: 
            'AWE_HEAP_FAST' - always use internal DM memory. 
            'AWE_HEAP_FASTB' - always use internal PM memory. 
            'AWE_HEAP_SLOW' - always use external memory (the default). 
            'AWE_HEAP_FAST2SLOW' - use internal memory. If this fails 
               then use external memory (the default).