Hello I am successful in reading the analog signal using the MCP3008 ( analog to digital converter) along with Raspberry Pi to LabVIEW using the BCM2835 library. The signal acquired is a Double (64 bit). Then I converted it into 1D array and then I build a waveform using the array. After getting the waveform, I tried using the tone measurement to measure the quantities. But using tone measurement in the same while loop is making the loop to run slow, where I am missing the samples. So I am using the Producer Consumer loop concept. Data is acquired in producer loop and analyzed in consumer loop. I am using the enqueue and dequeue to pass the data between two loops. When I am using the tone measurement in consumer loop it outputs are showing as zero ( I found the possible reason as tone measurement block require certain number of cycles to measure the data, but dequeue is passing one element at a time, but I am not able to resolve the issue). Can any one please let know how to measure the frequency, amplitude and phase of the data acquired. I also used Buneman frequency estimator with the generated waveform, but the frequency I am measuring is slightly higher (+0.2 to +8) than the analog source signal. Thank you in advance Ram

LabVIEW

Data Acquisition using Raspberry pi and processing the signal to measure the frequency, amplitude and phase.

Hi Ram,

I am able to generate the same wavefrom in the array form,

I don't think so.

You are creating a waveform in the consumer loop, but with some arbitrary dt and t0 values. (Surely not the "same" as in the producer loop.)

but the frequency is varying. Even when I measure frequency from 1D array it is showing 67Hz, but when I measure frequency after converting the array to dynamic data I am getting 0.067HZ.

Because all your conversions from array to waveform (or DDT) are missing the correct dt/t0 values!

I am not able to figure whats the issue.

Do you see all those coercion dots? They are part of that conversion problem!

A quick&dirty way to use the same dt in the producer and consumer loop:

Best regards,
GerdW

using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019

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LabVIEW

Data Acquisition using Raspberry pi and processing the signal to measure the frequency, amplitude and phase.

Re: Data Acquisition using Raspberry pi and processing the signal to measure the frequency, amplitude and phase.