ScalerControl

Overview

Smooth scaler in which the gain (in linear units) is taken from an input pin

Discussion

The Scaler Control module smoothly scales multichannel input data by a single gain value. The first pin is the control pin, where the gain (in linear units) values for the module will be obtained from. If the input data is complex or there is only one gain value per block, the same gain value will be applied accross all channels (obtained from the first sample). However, if the data is real and the control pin gets more than one value per block (aka block size is greater than 1), the input data will be divided into blocks of data, one per gain value. Each block will be scaled sequentially by each gain value. This could be used, for example, to scale different bin magnitudes by different values. The module has one more input pin compared to number of output pins as a result of the control pin. Internally, currentGain represents the instantaneous smoothed gain that is applied. currentGain exponentially approaches gain with a time constant equal to smoothingTime.

Note: when the module is used to scale complex data no smoothing is performed and the gain value is applied to both the real and imaginary parts.

Module Pack

Standard

ClassID

classID = 24

Type Definition

typedef struct _ModuleScalerControl
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
FLOAT32 smoothingTime;                        // Time constant of the smoothing process
FLOAT32 currentGain;                          // Instantaneous gain applied by the module.
FLOAT32 smoothingCoeff;                       // Smoothing coefficient
} ModuleScalerControlClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range	Units
smoothingTime	float	parameter	0	10	0:1000	msec
currentGain	float	state	1	0	Unrestricted
smoothingCoeff	float	derived	1	0.002081	Unrestricted

Pins

Input Pins


Name	g
Description	linear gain to apply
Data type	float
Channel range	1
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real


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

Output Pins


Name	out1
Description	audio output
Data Type	float

Matlab Usage

File Name: scaler_control_module.m 
 M=scaler_control_module(NAME,NUMPINS) 
 Creates a smoothly varying scaler module which has variable number of  
 input and output pins and each pin can be multichannel. The first pin is  
 the control pin, where the gain values will be obtained from.  If the  
 data is complex or there is only one gain value per block, the same gain 
 value will be applied accross all channels.  However, if the data is real 
 and the control pin gets more than one value, the input data will be 
 divided into blocks of data, one per gain value. Each block will  
 be scaled sequentially by each gain value. This could be used, for 
 example, to scale different bin magnitudes by different values. Note:  
 when the module is used to scale complex data, the smoothing coefficient  
 is ignored and no smoothing is performed in this case. 
   Arguments: 
    NAME - name of the module. 
    NUMPINS - number of audio input/output pins.  By default, NUMPINS=1.