Overview

Block statistics of a block of samples

Discussion

This module calculates the Block Statistics of the input signal on a block-by-block basis. The input pin can have an arbitrary number of interleaved channels and the Block Statistics calculation occurs over all channels. The output pin has a single channel and a blockSize of 1.

The statistic is computed on a block-by-block basis and stored in the instantaneousValue variable. The module is stateless and the statistic is recomputed for each block.

An optional constructor argument OUTPUTVALUE specifies whether the computed statistic should be output on an output pin.

• OUTPUTVALUE=0 (default) - the statistic is only stored internally in instantaneousValue.

• OUTPUTVALUE=1 then the value of the statistic is output of the first output pin as a floating-point value.

• OUTPUTVALUE=2 then the module has two output pins. The first output pin is the statistic value and the second output pin is the index at which the value occurs.

  • Using OUTPUTVALUE=2 only makes sense when statisticType=0 (max), 1 (min), or 2 (maxAbs).

Type Definition

typedef struct _ModuleBlockStatisticsFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 statisticsType;                         // Type of statistics needed
    fract32 instantaneousValue;                   // Instantaneous output value
} ModuleBlockStatisticsFract32Class;

Variables

Properties

Pins

Input Pins

Name: in

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: Block statistics output

Data type: fract32

MATLAB Usage

File Name: block_statistics_fract32_module.m

 M=block_statistics_fract32_module(NAME, OUTPUTVALUE)
 This modules calculates statistics of the input signal on a block-by-
 block basis.  A number of different statistics can be calculated based
 on the statisticsType parameter.  The computed value is stored in the
 internal state variable instantaneousValue.  Arguments:
    NAME - name of the module.
    OUTPUTVALUE - Boolean  value which specifies whether the module has
                  an output pin.  If OUTPUTVALUE=0, then the module has no
                  output pin.  If OUTPUTVALUE=1 (the default), then
                  the instantaneousValue variable is output as a single
                  sample on the output pin.
 The argument statisticsType determines what statistics computed:
   0 = maximum
   1 = minimum
   2 = maximum absolute value
   3 = mean
   4 = RMS
   5 = standard deviation
   6 = variance
   7 = average energy