Signal Processing Toolbox is installed but i cant use freqz

I use MATLAB online, the initial toolboxes are all already installed and cant be uninstalled

[H, F] = freqz(b , a, 512, Fe);

freqz requires one of the following:

Audio Toolbox

Communications Toolbox

DSP System Toolbox

Signal Processing Toolbox

Wavelet Toolbox

[R]

You can check if the license for Signal Processing Toolbox exists and is in use by executing the following commands in the MATLAB Command Window:

>> license('test','signal_toolbox')
>> license('inuse','signal_toolbox')

If it exists, and is not in use, you can check it out using the following code:

[status,errmsg] = license('checkout','signal_toolbox')

Refer to this documentaton for more information:

https://www.mathworks.com/help/matlab/ref/license.html

Answer 1

[Cris LaPierre]

I suspect you may have connected to a bad worker. Creating a new session will connect you to a new worker, and should fix the issue. If not, then there may be a temporary outage impacting the experience. Those tend to be resolved relatively quickly.

If you continue to have issues, please contact support: https://www.mathworks.com/support/contact_us.html

[Cris LaPierre]

The current recommendation is the exit your session and then launch a new session. There is an intermitent issue, so until a fix is in place, you may need to do this multiple times before you get a good session.