X-Y components from analogue input to find max amplitude and frequency at that amplitude

[djnckln]

Dear all,

I could do with some help.

I am looking to extract the xy (frequency/amplitude) components from an analogue input to find the maximum amplitude and then the frequency when the signal is at max amplitude.

I am struggling to extract the xy components from my input signal. My thoughts are to get the xy components as clusters of xy pairs, one component of the cluster being the x value, the other the y, then unbundle the cluster and pass this to arry max min VI to find the max amplitude and then to find the frequency when amplitude is max. I am just struggling to implement this. I have attached the VI of my progress but I am struggling. 

Please could anyone offer some help and advice for this please? Many thanks in advance.

Kind regards

[Tom_Powers]

You need to acquire the data with a uniform time interval.  You are looking for a 1Signal, NSample acquisition.  That gives you a sample frequency and deltaT = 1 / (sample frequency) and an array of data taken at that uniform sample rate.

Put the data through a Hanning window function then a FFT function which is already combined in the function

Signal Processing -> Waveform Measure -> FFT Mag and Phase

An interesting experiment for the student is to acquire the data at a sample rate and number of samples  Run the data through a straight magnitude and phase output FFT.  Do one where one of the frequency bins lands exactly on that of the waveform and change the sample rate such that the frequency of the waveform lands exactly half way between two frequency bins. Then stick a Hanning window between the data and the FFT This fixes the magnitude issue. 

For frequency accuracy you need to acquire a lot of cycles of the waveform.