Hello!
Based on my understanding you want only plot of filtered signal.
You can refer to output arguments section of the documentation attached below-
As mentioned in the document that highpass function returns two variables as output.
First variable is y, which is filtered signal and other variable is d which is digitalFilter Object.
So you can make minor modification in your code to achieve only the plot of filtered signal.
The code which can help you to achieve this is given below-
[x,fs] = audioread("sample.wav");
N = length(x);
t = (0:N-1)/fs;
[y,~]=highpass(x,500,fs);
plot(y);
Hope it helps!
