Suppress noise and gain signal in FPGA

[danieletime]

Hi all,

I'm in trouble with a signal processing in fpga. I'm reading a pressure signal from trasducer (0-100 mbar | 4-20mA with 500 ohm shunt resistor) with a NI9205 module and cRIO9063.

Sampling at 1kHz.

Take a look the png to view the acquisition chart, the Y are in Volt.

The question is: how to suppress the noise and amplify the signal? I need the peaks more amplified.

These are the tests I've done:

1) moving average: good for noise but cut the peaks;

2) butterworth filter varing a lot of parameters: I found improvements with second order filter and 100 Hz cut off frequency, but not enough;

Any solutions?

Thanks

[Henrik_Volkers]

Know your enemy 🙂

Sample with 10k and do a FFT.

(your timescale is missing  .. or a raw data snipped (vi with copied graph and saved with current values default)

If (as I expect) your major noise is line noise a notch filter as a software solution is worth a try.

[danieletime]

Thanks Henrik,

Take a look. The FFT show a small peak at 1800Hz. I think this does not affect the result, because I do a filter over 100Hz.

[Lysandros]

Yes applying a low-pass filter will reduce the noise at higher frequencies and the peaks will probably be more prominent. But if there is noise in the signal, there is probably a reason for it. By supressing the noise & amplifying the signal one only loses information which will not be available later, at post processing.