Integral

Overview

Discrete-time running-sum integral

Discussion

Approximates the integral of a discrete-time signal using the rectangle method. The integral is defined as:

\(y[n] = T/K * \sum_{k=0}^n x[k]\) where T is the sample period and K is an optional gain parameter.

The discrete integral is similar to the continuous time integral. For example, if the input is a sine wave at 1 kHz, then the output will be a cosine at 1 kHz scaled by -1/(2pi1000).

The hidden internal array .cumSum stores the previous value of the running sum of x[n] between blocks. The length of the array is set by the prebuild function to the number of channels.

Module Pack

Advanced

ClassID

classID = 1290

Type Definition

typedef struct _ModuleIntegral
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
FLOAT32 gain;                                 // Additional gain.
FLOAT32* cumSum;                              // Running sum of input samples since last reset.
} ModuleIntegralClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range	Units
gain	float	parameter	0	1	-10:10	linear
cumSum	float*	state	1	[1 x 1]	Unrestricted

Pins

Input Pins


Name	in
Description	Input signal
Data type	float
Channel range	Unrestricted
Block size range	Unrestricted
Sample rate range	Unrestricted
Complex support	Real

Output Pins


Name	out
Description	Output signal
Data Type	float

Matlab Usage

File Name: integral_module.m 
 This module computes the running-sum approximation of the integral of 
 the input signal.  Mathematically, this is: 
   y[n] = dt/K * sum(x[0] .. x[n]) 
 where dt is the time step, dt = 1/SR and K is a gain.  The module has a 
 multichannel input and computes the integral per channel.  Arguments: 
    NAME - name of the module.