Realtime data analysis and storage

Hello,

I am aquiring time domain data using matlab from a sound sensor connected to NI DAQ module. I want to analyse the fft and psd of a specific time length (like 10 seconds) at a time and do this continously and plot it for display the peaks. I also want store data in a table taking this fixed interval timing. How can i do this?

Thank you

JY

Answer 1

[Vidip]

I understand you want to analyze the FFT and PSD of a specific time length (like 10 seconds) at a time continuously and plot it for display the peaks along with this store data in a table, you can use the following steps:

1. Initialize MATLAB and DAQ Tools: Initialize MATLAB and use the Data Acquisition Toolbox to interface with your DAQ hardware. You can create a session and add an analog input channel for acquiring data from the sound sensor.
2. Continuous Data Acquisition: Configure your data acquisition session to acquire data in a continuous mode.
3. Data Processing: Continuously acquire data in chunks of 10 seconds. You can use a loop or a callback function to do this. For each chunk apply an FFT to the data to convert it from the time domain to the frequency domain then calculate the power spectral density (PSD) from the FFT results.
4. Plotting Peaks: Create plots to visualize the PSD and identify peaks. You can use functions like plot to create time-varying plots.
5. Data Storage: Create a table or a data structure to store the data from each 10-second interval. Append this data to the table in each iteration. Use function like table to store and manage the acquired data.

For further information, refer to the documentation links below:

• https://www.mathworks.com/help/matlab/ref/fft.html
• https://www.mathworks.com/help/signal/ug/power-spectral-density-estimates-using-fft.html
• https://www.mathworks.com/help/matlab/tables.html