I have a project in university where my professor gave us the following problem:
There is a transducer generating an AC signal with amplitude of 7.5mV and a frequency range from 50Hz to 150Hz.
This signal is subject to a noise of the following pattern:
The noise with frequency from 0 to 50Hz has -0.1dB of intensity (compared with the signal)
The noise with frequency of 60Hz has 1dB of intensity (this is due to the fact that power supply in my country works at 60Hz)
The noise with frequency from 50Hz upwards has a growth of 0.3dB/decade in intensity.
He asked us to remove this noise. He told us to discuss, use the internet, and try to find good solutions. I have a solution here, but honestly I don't know if it is good enough or if it is something a professional would do. Here is my approach.
- The first thing I do is using a band-stop filter to stop every signal from around 60Hz. I will be losing some of the original signal but a lot of the noise will be lost as well.
- Then I will apply a band-pass filter to collect all the signal that goes from 50Hz to 150Hz.
- The next thing I do is to apply a low pass filter that will start filtering at about 75Hz of frequency (I am thinking of a Bode's chart here).
Is this a good solution?
I am not sure because it seems that I will be losing a lot of the original signal with frequency around 150Hz, for example, due to the low pass filter.
Is there a better way to remove this noise?
Some additional information:
He didn't say the nature of the noise, just saying that this wasn't important.
We are supposed to remove this noise only using electronic circuits. Capacitors, inductors, operational amplifiers, diodes, etc.