Phase shift between a pulse and sin wave

[Baran]

Yes. I am having 3khz sampling rate and they are both acquiring from the same DAQ with same sampling rate. and I think the sampling rate is high enough not to cause any problem.

[johnsold]

What is the signal frequency?

Lynn

[Baran]

Since I turn the motor with my hand the frequency change from test to test, but it is in order of less than 10 Hz. and my sampling rate is 3kHz.

[Chris V]

Hi Baran,

So is the problem that you don't know why you get slightly different results using the different methods?

Since these measurements are in degrees, the different between the two is less than 0.6%.

Because you are using real signals and not ideal ones, there is not going to be only 1 frequency in the signal, but several (in-fact this is inherent to square waves).  As such different methods, when analyzing these signals, will often return slightly different results.

Have a great day,

Chris V

[Baran]

The problem is both getting higher phase shift than what it should be (in order of 10 deg or higher) and getting different results for different tries.

Thanks,

Baran.

[Chris V]

Hi Baran,

Why are you expecting a smaller phase shift? (on the order of a few degrees, I'm assuming)

Just looking at the graph you posted, somewhere in the region of 15 degrees looks about right.

Have a great day,

Chris V