Analysing PWM duty cycle of a signal

I have recorded a PWM signal from a given device.

I require to determine the duty cycle(s) of the signal as the transitions from one state to another.

How may I output the duty cycle of the PWM thoughout the signal?

I am using Matlab 2016b

Answer 1

[David Hill]

s=pwm>threshold;%pwm is your signal, threshold is when it is considered on or off
d=diff(s);
idx1=find(s,1);
idx2=find(d==-1);
idx3=find(d==1);
num=idx2-[idx1-1,idx3(1:end-1)];
denom=diff([idx1-1,idx3]);
dutyCycle=num./denom;

[Sherzaad Dinah]

thank you for the snippet.

I tried the followin

s=CH01_01>0.75;%Ch01_01 is a 200x200x1 single matrix
d=diff(s);
idx1=find(s,1);
idx2=find(d==-1);
idx3=find(d==1);
num=idx2-[idx1-1,idx3(1:end-1)];
denom=diff([idx1-1,idx3]);
dutyCycle=num./denom;

but I'm getting the following error:

Error using horzcat
Dimensions of matrices being concatenated are not consistent. 

Error in plot1 (line 8)
num=idx2-[idx1-1,idx3(1:end-1)];

could you please advise on how to resolve this issue?

[David Hill]

I assumed your data was a horizontal array. For a better response, attach your data.

s=CH01_01(:)';%convert to horizontal array
s=s>.75;

[Sherzaad Dinah]

Thank you for your help,

After making the change, I no longer have any error.

However all the calculated duty cycles are greater than 1?!

Is there something else that needs to be done with the data please?

I have attached the data as requested. Kindly please advise.

s = CH01_01(:)';
s=s>0.75;%pwm is your signal, threshold is when it is considered on or off
d=diff(s);
idx1=find(s,1);
idx2=find(d==-1);
idx3=find(d==1);
num=idx2-[idx1-1,idx3(1:end-1)];
denom=diff([idx1-1,idx3]);
dutyCycle=num./denom