error with function bode

So I defined my transfer function and used the bode function to plot a bode plot but I keep getting this error and a blank output for my bode plot.

Error Message:

rror in resppack.ltisource/magphaseresp (line 36)

[mag,phase,w,FocusInfo] = freqresp(SysData(ct),grade,wspec,true);

Error in wavepack.waveform/draw (line 25)

feval(this.DataFcn{:});

Error in wrfc.plot/draw (line 17)

draw(wf)

Error in wrfc.plot/init_listeners>LocalRefreshPlot (line 79)

draw(this)

Warning: Error occurred while evaluating listener callback.

> In DynamicSystem/bodeplot (line 142)

In DynamicSystem/bode (line 93)

In untitled3 (line 2)

Code:

GU=zpk([-1],[-2 -3 -4],240);
bode(GU);

[Star Strider]

I cannot reproduce the error. The posted code runs without error, and produces an appropriate plot (in R2020b).

[Steven Lord]

That doesn't look like the entire error message. What is the full and exact text (everything displayed in red and/or orange in the Command Window) of the error and/or warning messages you receive when you run your code? The exact text of the messages may include information that will help us determine the problem or at least the next step to take in investigating the problem.

[Abdulrahman Emad Al-Badawi]

I tried using the bode function with a different transfer function, this time using the function tf([ ],[ ]) instead but it didnt work. This is the error message that I got:

Attempt to execute SCRIPT conv as a function:

/MATLAB Drive/conv.m

Error in freqgrid>LocalAddPhaseExtrema (line 374)

lhs1 = psum(conv(n1,n2),2*[psum(conv(polyder(n2),n1),-conv(polyder(n1),n2)) 0]);

Error in freqgrid (line 162)

w = LocalAddPhaseExtrema(w,z{1},p{1});

Error in ltipack.ltidata/freqresp (line 45)

w = freqgrid(z,p,Ts,Grade,Focus);

Error in resppack.ltisource/magphaseresp (line 36)

[mag,phase,w,FocusInfo] = freqresp(SysData(ct),grade,wspec,true);

Error in wavepack.waveform/draw (line 25)

feval(this.DataFcn{:});

Error in wrfc.plot/draw (line 17)

draw(wf)

Error in wrfc.plot/init_listeners>LocalRefreshPlot (line 79)

draw(this)

Warning: Error occurred while evaluating listener callback.

> In DynamicSystem/bodeplot (line 142)

In Q17_5 (line 2)

Q17_5

Attempt to execute SCRIPT conv as a function:

/MATLAB Drive/conv.m

Error in freqgrid>LocalAddPhaseExtrema (line 374)

lhs1 = psum(conv(n1,n2),2*[psum(conv(polyder(n2),n1),-conv(polyder(n1),n2)) 0]);

Error in freqgrid (line 162)

w = LocalAddPhaseExtrema(w,z{1},p{1});

Error in ltipack.ltidata/freqresp (line 45)

w = freqgrid(z,p,Ts,Grade,Focus);

Error in resppack.ltisource/magphaseresp (line 36)

[mag,phase,w,FocusInfo] = freqresp(SysData(ct),grade,wspec,true);

Error in wavepack.waveform/draw (line 25)

feval(this.DataFcn{:});

Error in wrfc.plot/draw (line 17)

draw(wf)

Error in wrfc.plot/init_listeners>LocalRefreshPlot (line 79)

draw(this)

Warning: Error occurred while evaluating listener callback.

> In DynamicSystem/bodeplot (line 142)

In Q17_5 (line 2)

Answer 1

[Star Strider]

Rename your ‘conv.m’ file to something else, perhaps to ‘myconv.m’ or to something else that makes sense in the context of its use.