standard separation of x axis tick marks

Hello,

I'm writing a program for a class that plots a transfer function to the omega(rad/s) and the phase angle to omega(rad/s) but I'm running into the problem of the graph not looking the way it needs to. below is the code i wrote so you can see what the graph currently looks like and i figured out how to label the ticks correctly but HOW DO YOU GET THE TICKS SPACED EVENLY when the the numbers are xticks([10^0 10^2 10^4 10^6])?

% Input Variable Section:

R = 10000%input('What is the resistance (in ohms)? ');

L = 1%input('What is the inductance (in henries)? ');

omega1 = 1%input('what is the starting frequency (in radians/sec)? ');

omega2 = 1000000%input('what is the ending frequency (in radians/sec)? ');

dw = (omega2-omega1)/1000;

% Parameter Section:

omega = omega1:dw:omega2;

% Calculation Section:

T = R./(L.*omega);

H = 1./(sqrt(1+(T).^2));

decibels = 20.*log10(H);

phi = atand(T);

table = [omega',T',H',decibels',phi'];

% Output Variable Section:

subplot(1,2,1)

plot(omega,decibels),xlabel('Omega (rad/s)'),ylabel('Hv'),title('High Pass RL Filter Transfer Function')

xticks([10^0 10^2 10^4 10^6])

subplot(1,2,2)

plot(omega,phi), xlabel('Omega (rad/s)'),ylabel('Phase Angle'),title('High Pass RL Filter Phase Angle')

xticks([10^0 10^2 10^4 10^6])

Answer 1

[Star Strider]

Plot them using semilogx:

% Output Variable Section:
subplot(1,2,1)
semilogx(omega,decibels),xlabel('Omega (rad/s)'),ylabel('Hv'),title('High Pass RL Filter Transfer Function')
xticks([10^0 10^2 10^4 10^6])
subplot(1,2,2)
semilogx(omega,phi), xlabel('Omega (rad/s)'),ylabel('Phase Angle'),title('High Pass RL Filter Phase Angle')
xticks([10^0 10^2 10^4 10^6])

Equivalently, you can use:

set(gca, 'XScale','log')

for each subplot.

[Adam Dilley]

Thank you so much! I looked this up in our text book and its not covered until our next chapter, I don't know why we had an assignment that needed this plot function before we covered it. It worked though, thanks again.

[Star Strider]

As always, my pleasure!

Answer 2

[Bobby Huxford]

I believe you are looking to change the scale of the X-axis to log:

set(gca, 'XScale', 'log')

Full code:

% Input Variable Section:
R = 10000%input('What is the resistance (in ohms)? ');
L = 1%input('What is the inductance (in henries)? ');
omega1 = 1%input('what is the starting frequency (in radians/sec)? ');
omega2 = 1000000%input('what is the ending frequency (in radians/sec)? ');
dw = (omega2-omega1)/1000;
 
% Parameter Section:
omega = omega1:dw:omega2;
 
% Calculation Section:
    T = R./(L.*omega);
    H = 1./(sqrt(1+(T).^2));
    decibels = 20.*log10(H);
    phi = atand(T);
    table = [omega',T',H',decibels',phi'];
    
% Output Variable Section:
subplot(1,2,1)
plot(omega,decibels),xlabel('Omega (rad/s)'),ylabel('Hv'),title('High Pass RL Filter Transfer Function')
xticks([10^0 10^2 10^4 10^6])
subplot(1,2,2)
plot(omega,phi), xlabel('Omega (rad/s)'),ylabel('Phase Angle'),title('High Pass RL Filter Phase Angle')
set(gca, 'XScale', 'log')
xticks([10^0 10^2 10^4 10^6])