how to measure the frequency of the data plotted on the waveform chart

[preet]

i have made a virtual instrument in labview that acquire data (say sine wave) into a spreadsheet file and also on the chart from the function generator. I measured the frequency of the data from the chart but it is coming out to be very less. How can i calculate the frequency of the plotted sine wave and also from the spreadsheet file.

[PdB]

LabVIEW has a lot of powerfull built-in analyzer functions. I suggest to use them, like the FFT vi's.
Be careful to enter all desired inputs, like the sample-frequency. Else it will take a default value, likely to be not the same as your sample-frequency.

[preet]

sir i could not understood your answer.
can you please explain it in more detail?
i want to find out the frequency of the data from the chart manually by measuring the cycle rate or something else.
Is there any method for doing that??
i will be very thankful if you can answer my question.

[PdB]

If you want to get an idea of the base-frequency of an periodic signal, you can measure the number of samples in between two maxima or in between two minima of the periodic signal.
Multiply the number of samples by the sample-interval (1/Fsample in [sec]) gives you a rough estimate.
FFT, I mentioned is one of the more advanced calculation-methods.
The method calculates the spectrum from a waveform.

Hope this helps,
Patrick

[preet]

thank you sir for your interest in my question
suppose i give the sine wave of high frequency say 50K. it means 1 cycle in .00002 second. but the waveform chart allows the precision of only milliseconds how can i manage the things.
thanks again for replying