Time Period calculation for a Signal Waveform!

Hell Experts,

I need sugestions on calculation of time period for different parameters of my motion sensor like ROLL, PItch, Heave etc. Currently I am using method of zero crossing for calculating the period of signals. Period is calculated using number of zero crossings. I am using timer and counters for that purpose, once the signal value cross zero and enters negative region counterincrements again when it crosses zero crossing to go into positive region counter increments. But now I am looking at a case when my signal waveform never crosses zero value and remains in positive region always or negative region then in that case how can I calulate the period of my signals' waveform. Any ideas will be appreciated, if someone has implemented such scenario then please help me with this!

Please suggest asap!

Thanks in advance!

Hi Khyzer,

You could try the following:
- Detect maximum value of the signal = MAX
- Detect minimum value of the signal = MIN
- Max - Min value will give you amplitude of the signal AMPLI= MAX-MIN
- Divide amplitude by 2: OFFSET= AMPLI/2
-New signal = Signal - MAX + OFFSET
The new signal will have zero crossings again, so you can apply your previous method.

This should work although i have serious doubts of accuracy of this method, especially when frequency gets higher.
If you want accurate measuring, i think you'll need (high speed) counter card.

Kind regards,
BV

Thanks a lot for your suggestion, but the signal is not periodic and the real time value of the signal are changing very fast, how can I implement your method on the realtime changing values because max and min values will also be changing frequently?

thanks

Please suggest how can I do the above two scenarios when there is no zero crossings. Hope now you have a clearer picture of what I intend to achieve.

Thanks!

Thanks for your suggestion, can you please advice any programming solution to my problem. Like I have made fucntions to calculate the period of one complete cycle of my parameters waveform using zero crossings, can you advice any solution in which zero crossing concept is not used!

Thanks!

My zero crossing concept code is same as sign changing concept of yours. I am lookign at a scenario when a signal waveform doesn't change a sign and remains always in positive or negtive region. How can I calculate he period in that case?

Regards,

Syed