Signal Processing Toolbox |

CPhase delay of digital filters

**Syntax**

[phi,w] = phasedelay(b,a,n) [phi,w] = phasedelay(b,a,n,

**'whole'**) phi = phasedelay(b,a,w) [phi,f] = phasedelay(b,a,n,fs) [phi,f] = phasedelay(b,a,n,**'whole',**fs) phi = phasedelay(b,a,f,fs) [phi,w,s] = phasedelay(...) [phi,f,s] = phasedelay(...) phasedelay(b,a,...)

**Description**

```
[phi,w] = phasedelay(b,a,n)
```

returns the `n`

-point phase delay response vector `phi`

and the `n`

-point frequency reponse vector `w`

(in radians/sample) of the filter defined by numerator coefficients `b `

and denominator coefficients `a`

. The phase delay response is evaluated at `n`

equally spaced points around the upper half of the unit circle. If `n`

is omitted, it defaults to 512.

`[phi,w] = phasedelay(b,a,n,`

uses **'whole'**)
`n `

equally spaced points around the whole unit circle.

```
phi = phasedelay(b,a,w)
```

returns the phase delay response at frequencies specified in vector `w `

(in radians/sample). The frequencies are normally between 0 and .

```
[phi,f] = phasedelay(b,a,n,fs) and
[phi,f] = phasedelay(b,a,n,
```

return the phase delay vector **'whole',**fs)
`f`

(in Hz), using the sampling frequency `fs`

(in Hz).

```
phi = phasedelay(b,a,f,fs)
```

returns the phase delay response at the frequencies specified in vector `f`

(in Hz), using the sampling frequency `fs`

(in Hz)..

```
[phi,w,s] = phasedelay(...) and [phi,f,s] = phasedelay(...)
```

return plotting information, where `s`

is a structure with fields you can change to display different frequency response plots.

```
phasedelay(b,a,...)
```

with no output arguments, plots the phase delay response of the filter.

**Example 1**

Plot the phase delay response of a constrained least squares FIR filter:

**Example 2**

Plot the phase delay response of an elliptic filter:

**See Also**

`freqz`

, `fvtool`

, `phasez`

, `grpdelay`

periodogram | phasez |

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