SMixer2x1Fract32

Overview

2-input x 1-output smoothly varying mixer module

Discussion

Mixes 2 inputs into a single output. The mixing gain parameters are exponentially smoothed (first order IIR) at the sample rate, with the smoothingTime parameter determining the smoothing rate for both of the gain values. The module's .gain1 and .gain2 variables specify the target gains for the mixing process. The module's .currentGain1 and .currentGain2 variables specify the instantaneous gains applied, and these exponentially approach the target gains. At build time, .currentGain1 is set to .gain1 and .currentGain2 is set to .gain2. This causes the mixers to startup in a converged state.

Module Pack

Standard

ClassID

classID = 198

Type Definition

typedef struct _ModuleSMixer2x1Fract32
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
FLOAT32 gain1;                                // Desired gain applied to first input channel
FLOAT32 gain2;                                // Desired gain applied to second input channel
FLOAT32 smoothingTime;                        // Time constant of the smoothing process
fract32 targetGain1;                          // Fractional portion of the desired (or target) gain of the first channel
fract32 currentGain1;                         // Fractional portion of the instantaneous gain of the first channel
fract32 targetGain2;                          // Fractional portion of the desired (or target) gain of the second channel
fract32 currentGain2;                         // Fractional portion of the instantaneous gain of the second channel
fract32 smoothingCoeff;                       // Smoothing coefficient
INT32 postShift;                              // Number of bits to shift after the fractional multiply.  This is based on gain.range.
FLOAT32 twoPowMinusPostShift;                 // 2^(-postShift).  Used by to streamline the operation of the set function
} ModuleSMixer2x1Fract32Class;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range	Units
gain1	float	parameter	0	1	-10:10
gain2	float	parameter	0	1	-10:10
smoothingTime	float	parameter	0	10	0:1000	msec
targetGain1	fract32	derived	1	0.0625	Unrestricted
currentGain1	fract32	state	1	0.0625	Unrestricted
targetGain2	fract32	derived	1	0.0625	Unrestricted
currentGain2	fract32	state	1	0.0625	Unrestricted
smoothingCoeff	fract32	derived	1	0.0020811	Unrestricted
postShift	int	derived	1	4	Unrestricted
twoPowMinusPostShift	float	derived	1	0.0625	Unrestricted

Pins

Input Pins


Name	in1
Description	audio input
Data type	fract32
Channel range	Unrestricted
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real


Name	in2
Description	audio input
Data type	fract32
Channel range	Unrestricted
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real

Output Pins


Name	out
Description	audio output
Data Type	fract32

Matlab Usage

File Name: smixer2x1_fract32_module.m 
 M=smixer2x1_fract32_module(NAME) 
 Creates a 2-input 1-output smoothly varying mixer for use in the 
 Audio Weaver environment.  Arguments: 
    NAME - name of the module. 

 Copyright 2007.  DSP Concepts, Inc.  All Rights Reserved. 
 Author:  Paul Beckmann 


 AudioWeaverModule [This tag makes it appear under awe_help] 
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 Create the high-level object with interface variables only. 
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