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.

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

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.