[Q] noise separation from useful signal

[Nicholas]

I has a signal output from a RF module as below:

useful signal: 2.5Hz ~ 20Hz, several uV
noise: 50Hz, several mV

How can I extract the useful signal out of this mix-signal ????
Help!
Thanks.

 

[eng_Semi]

U can make a high order filter (may be active to have gain) of BW about 25 Hz, BUT also try to know what is the source of ur noise, i.e. an opened wire which act as an antenna or ur power supply may be noisy, so u may need to shield ur wires and device and make a good ground.

 

[artem]

But pay attention to following :

Do not put filter as first stage of your detection mean , because it can decrease signal to noice ratio (your signal is about few uV). But of course preamplifier with frequency correction will be good to make some reduction of 50 Hz signal. Try to amplify signal, but without saturation due to 50 HZ .
Then you can use high pass filter and for 50 HZ it will be better to use notch filter as well.

 

[mmohsen]

i think the main issue is to try to decrease the source of noise which is the ac line 50Hz so try to sheild your circuit and use diffrential structures in order to reject common-mode signals (noise) and then you should use the filtering technique discussed by artem it is really very good.

regards