0
$\begingroup$

I have a device that connect with USB to my computer. This device have digital signal that I can sample it every few seconds. The signal that the device perform, is a digital signal with $X$ seconds of $1$ and $Y$ seconds of $0$ ($X$ and $Y$ are integers and consts).

What I want to do is to estimate if in $Z$ seconds from now, the signal will be $1$. The problem is that I don't know what are $X$ and $Y$ (I don't know how much time $1$ and $0$ are), so I don't know how can I estimate it, and I can sample it every 10 seconds ($X$ and $Y$ can be less then 5). But if I sample $0$ at some moment, the device tells me in how much seconds $1$ will appear again.

I have basic knowledge in signal analysis and I don't know how to do that.

Is it possible at all? If it is, how can I do it?

$\endgroup$
2
  • $\begingroup$ If you really mean that you are sampling the digital signal in a USB port once every few seconds (emphasis added), then for all practical purposes, the value of $Z$ can be assumed to be independent of any $X$ and $Y$ that you might have measured some time ago. $\endgroup$ – Dilip Sarwate Aug 2 '14 at 11:06
  • $\begingroup$ @DilipSarwate How can I measure the X and Y if I can sample the device every 10 seconds? X and Y never changed and they are integers. $\endgroup$ – nrofis Aug 2 '14 at 11:45
1
$\begingroup$

If X plus Y is longer than twice your sample rate, 20 seconds, but not an exact rational multiple of your sample rate, then with a large enough number of samples you might be able to make a frequency and duty cycle estimate by calculating the statistics and spectrum of the sample vector.

$\endgroup$
1
  • $\begingroup$ Thank you, but what can I do if $X + Y$ is shorter then the sample rate? Is there a way to find them? $\endgroup$ – nrofis Aug 2 '14 at 18:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.