AGCMultiplierFract32

Overview

Mono x N-channel multiplier

Discussion

The AGCFract32 Multiplier is used to multiply N interleaved audio channels by a single mono audio signal. A common use for the AGCMultipler is in automatic gain control systems, where the gain signal is taken from the limiter core or gain computer module. Using a single (mono) gain control signal for a multichannel input ensures that the balance between the audio channels is maintained, and allows for sidechain processing.

The postShift parameter can be used to adjust the scaling of the output, or allow multiplies of values larger than 1.

e.g. A postShift of -1 will scale the output between -2 and 2, if the input was between -1 and 1.

The user can multiply 0.75 with a shift of -1 and assume normal scaling and achieve a multiply of 1.5. A positive postShift can increase the dynamic range when multiplying with small numbers. It is up to the user to track all shifts in the layout.

Type Definition

CODE

typedef struct _ModuleAGCMultiplierFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 postShift;                              // Number of bits to shift
} ModuleAGCMultiplierFract32Class;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
postShift	int	parameter	0	7	0:31	postShift

Pins

Input Pins

Name: g

Description: Gain to apply

Data type: fract32

Channel range: 1:1:1

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Name: in

Description: N-channel audio input signal

Data type: fract32

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: N-channel audio output signal

Data type: fract32

MATLAB Usage

File Name: agc_multiplier_fract32_module.m

CODE

 M=agc_multiplier_fract32_module(NAME)
 Creates a 1 x N-channel fractional multiplier module for use with the Audio
 Weaver.  Arguments:
    NAME - name of the module.