grpdelay (MathScript RT Module Function)
Owning Class: filter design
Requires: MathScript RT Module
Syntax
grpdelay(b)
grpdelay(b, a)
grpdelay(b, a, n)
grpdelay(b, a, n, 'whole')
grpdelay(b, a, n, f)
grpdelay(b, a, n, 'whole', f)
grpdelay(b, a, w)
grpdelay(b, a, w, f)
gd = grpdelay(b, a)
gd = grpdelay(b, a, n)
gd = grpdelay(b, a, n, 'whole')
gd = grpdelay(b, a, n, f)
gd = grpdelay(b, a, n, 'whole', f)
gd = grpdelay(b, a, w)
gd = grpdelay(b, a, w, f)
[gd, fr] = grpdelay(b)
[gd, fr] = grpdelay(b, a)
[gd, fr] = grpdelay(b, a, n)
[gd, fr] = grpdelay(b, a, n, 'whole')
[gd, fr] = grpdelay(b, a, n, f)
[gd, fr] = grpdelay(b, a, n, 'whole', f)
[gd, fr] = grpdelay(b, a, w)
[gd, fr] = grpdelay(b, a, w, f)
Description
Computes the group delay of a filter. If you do not request an output, this function plots the group delay in the current plot window. grpdelay(b) is equivalent to grpdelay(b, [1], 512). grpdelay(b, a) is equivalent to grpdelay(b, a, 512).
Inputs
| Name | Description |
|---|---|
| b | Specifies the forward filter coefficients. b is a real vector. |
| a | Specifies the backward filter coefficients. a is a real vector. The default is [1]. |
| n | Specifies the number of frequencies to use. n is a nonnegative integer. The default is 512. |
| w | Specifies predefined frequencies. If you do not specify w, LabVIEW evaluates the frequency response at n points equally spaced around the upper half of the unit circle. w is a vector. |
| f | Specifies the sampling frequency. f is a scalar. |
| 'whole' | Indicates that you want to use the whole unit circle. |
Outputs
| Name | Description |
|---|---|
| gd | Returns the group delay of the filter defined by a and b. gd is a real vector. |
| fr | Returns the corresponding frequencies of the filter. fr is a real vector. |
Details
This function is supported in the LabVIEW Run-Time Engine only if you request an output from the function. This function can remain in your scripts when you build a stand-alone application or shared library, but if you do not request an output, the LabVIEW Run-Time Engine does not execute this function. If you request an output, the LabVIEW Run-Time Engine executes this function as normal.
Examples
W = 0:0.01:0.5;
A = [1];
B = [1, 4, 1, 6];
GD = grpdelay(B, A, W)
b = [2, 3, 7, 1];
a = [1, 7, 3, 10];
n = 250;
f = 20;
[GD, FR] = grpdelay(b, a, n, 'whole', f)