fdel

Delete specified data from frequency response data (FRD) models

Syntax

```sysout = fdel(sys, freq) ```

Description

`sysout = fdel(sys, freq)` removes from the `frd` model `sys` the data nearest to the frequency values specified in the vector `freq`.

Input Arguments

 `sys` `frd` model. `freq` Vector of frequency values.

Output Arguments

 `sysout` `frd` model containing the data remaining in `sys` after removing the frequency points closest to the entries of `freq`.

Examples

collapse all

Create a frequency response data (FRD) model at specified frequencies from a transfer function model.

```w = logspace(0,1,10); sys = frd(tf([1],[1 1]),w)```
```sys = Frequency(rad/s) Response ---------------- -------- 1.0000 0.5000 - 0.5000i 1.2915 0.3748 - 0.4841i 1.6681 0.2644 - 0.4410i 2.1544 0.1773 - 0.3819i 2.7826 0.1144 - 0.3183i 3.5938 0.0719 - 0.2583i 4.6416 0.0444 - 0.2059i 5.9948 0.0271 - 0.1623i 7.7426 0.0164 - 0.1270i 10.0000 0.0099 - 0.0990i Continuous-time frequency response. ```

`w` is a logarithmically-spaced grid of 10 frequency points between 1 and 10 rad/second.

Remove the data nearest 2, 3.5, and 6 rad/s from `sys`.

```freq = [2, 3.5, 6]; sys2 = fdel(sys,freq)```
```sys2 = Frequency(rad/s) Response ---------------- -------- 1.0000 0.5000 - 0.5000i 1.2915 0.3748 - 0.4841i 1.6681 0.2644 - 0.4410i 2.7826 0.1144 - 0.3183i 4.6416 0.0444 - 0.2059i 7.7426 0.0164 - 0.1270i 10.0000 0.0099 - 0.0990i Continuous-time frequency response. ```

Note that you do not have to specify the exact frequency of the data to remove. The `fdel` command removes the data corresponding to frequencies that are nearest to the specified frequencies.

Tips

• Use `fdel` to remove unwanted data (for example, outlier points) at specified frequencies.

• Use `fdel` to remove data at intersecting frequencies from `frd` models before merging them with `fcat`. `fcat` produces an error when you attempt to merge `frd` models that have intersecting frequency data.

• To remove data from an `frd` model within a range of frequencies, use `fselect`.

Version History

Introduced in R2010a