How to change the default x-axis unit in a Bode diagram to Hertz?

683 次查看（过去 30 天）
marcel hendrix
marcel hendrix 2018-9-22
评论： Meth Hai 2024-7-15
Rad/s is nice for mechanical people, but I'm an EE, and I much prefer Hertz. It should be something simple, but I can't find it in the help.
  1 个评论
dpb
dpb 2018-9-22
Don't believe there is a way in the base routine; it's built entirely around rad/timeunits per the system object.
You could write a wrapper routine to convert frequency units and update the plot labels.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2018-9-22
Use bodeplot (link) instead of bode.
It gives you that option, and the documentation specifically mentions that.
  4 个评论
显示 2更早的评论
marcel hendrix
marcel hendrix 2018-9-22
I've put the below function in my userpath . It'll do for now.
% a new bode() command that has Hz as default
function h = bodef(x)
P = bodeoptions; P.FreqUnits = 'Hz';
h = bodeplot(x,P);
Star Strider
Star Strider 2018-9-22
编辑：Star Strider 2018-9-22
That is what I would do.
I defer to bodeplot because it allows some customization. I use and plot the bode outputs only if I want other options.
EDIT —
I add that this was my original recommendation!

请先登录，再进行评论。

更多回答（2 个）

Tjeerd Ickenroth
Tjeerd Ickenroth 2023-5-31
Type 'ltiview' in your command window. The Linear System Analyzer will pop up. Click on: File --> Toolbox Preferences... --> Units --> Frequency: Hz
  3 个评论
显示 1更早的评论
Tjeerd Ickenroth
Tjeerd Ickenroth 2023-5-31
You need to change it once in the GUI and you always obtain bode plots in Hz. The setting remains even when you restart Matlab.
marcel hendrix
marcel hendrix 2023-5-31
And what when I share my function/script with others? Or use different (older) versions of MATLAB?

请先登录，再进行评论。

Dimitris Kalogiros
Dimitris Kalogiros 2018-9-22
clc;close all; clc
% test system
s=tf('s');
H=(s-1)/((s-3)*(s-2))
% bode
[mag,phase,wout] = bode(H);
%plot results, with frequency expressed at Hz
figure;
subplot(2,1,1);
semilogx(wout(:,1)/(2*pi), 20*log10(squeeze(mag)), '-b'); zoom on; grid on;
title('magnitude'); xlabel('Frequency (Hz)'); ylabel('Magnitude (dB)');
subplot(2,1,2);
semilogx(wout(:,1)/(2*pi), squeeze(phase), '-r'); zoom on; grid on;
title('Phase'); xlabel('Frequecy (Hz)'); ylabel('Phase (deg)');
  2 个评论
Charl
Charl 2024-3-15
编辑：Charl 2024-3-15
This is the correct answer. Some of the others simply change the label to Hz without rescaling.
Meth Hai
Meth Hai 2024-7-15
%%% G1 & and G2 is your TFs
[mag1, phase1, wout1] = bode(G1);
[mag2, phase2, wout2] = bode(G2);
% Convert angular frequency (rad/s) to frequency (Hz)
freq1 = wout1 / (2 * pi);
freq2 = wout2 / (2 * pi);
% Plot the magnitude response
figure;
subplot(2,1,1);
semilogx(freq1, 20*log10(squeeze(mag1)), '-b');
hold on;
semilogx(freq2, 20*log10(squeeze(mag2)), '-g');
grid on;
title('Magnitude');
xlabel('Frequency (Hz)');
ylabel('Magnitude (dB)');
legend('G1', 'G2');
%%%%%%%%%%%%
% Plot the phase response
subplot(2,1,2);
semilogx(freq1, squeeze(phase1), '-r');
hold on;
semilogx(freq2, squeeze(phase2), '-m');
grid on;
title('Phase');
xlabel('Frequency (Hz)');
ylabel('Phase (deg)');
legend('G1', 'G2');

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Plot Customization 的更多信息

标签

产品


版本

R2018a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by