Overview

M-input x N-output smoothly varying mixer

Discussion

This module implements a fixed point version of full M-input x N-output mixer with a total of MxN coefficients. The coefficients are contained in the coeffs matrix with the gain from the ith input to the jth output is found at coeffs(i, j). This mixer implements smoothing on a sample-by-sample basis. Standard 1st order exponential smoothing is used. Gain adjustments are made to the coeffs matrix. Internally, the module holds a second matrix of instantaneous gains, currentCoeff, which smoothly approaches coeffs. The rate of the smoothing operation is controlled by smoothingTime.

When the module is bypassed, it copies the ith input channel to the ith output channel. If the module has more output channels than input channels, the remaining output channels are set to 0.

Type Definition

typedef struct _ModuleMixerSmoothedFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    FLOAT32 smoothingTime;                        // Time constant of the smoothing process
    fract32 smoothingCoeff;                       // Smoothing coefficient
    INT32 postShift;                              // Number of bits to shift
    FLOAT32* gain;                                // Linear gain
    fract32* targetGain;                          // Linear gain
    fract32* currentGain;                         // Linear gain
} ModuleMixerSmoothedFract32Class;

Variables

Properties

Pins

Input Pins

Name: in

Description: audio input

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Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: audio output

Data type: fract32

MATLAB Usage

File Name: mixer_smoothed_fract32_module.m

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