Hi Christian,
There are probably tons of ways you can do this.
There are several VI's in the labview function palette that would be handy for this.
1. Under Analyze>Waveform Measurements there is a 'Pulse Measurements.vi' that accepts a periodic waveform or an array of periodic waveforms and returns the period, pulse duration (pulse width), duty cycle (duty factor)etc. Period returns the time between adjacent mid reference level crossings in the same direction in seconds. The reciprocal of this value would give you the signal frequency.
2. You can also use the Power Spectrum Vis and the power spike on the graph would match the signal frequency.(assuming you have a fairly constant frquency signal)
3. If you have TTL signals you can use the 'Measure Freque
ncy(DAQ-STC).vi' or 'Measure Frequency(NI-TIO).vi' examples (depending on the card you have) that are shipped with labview
I may have missed a few other easy ones but there are quite a few ways you can achieve this.
Hope this helps,
Pravin
