David_
Advanced Member level 2
Hello.
I need to realize a couple of programmable filters as part of an lock-in amplifier design, I am sure that I need a programmable low-pass filter for the output of the phase sensitive detector(PSD) and I think that I should make a programmable band-pass filter for filtering the input to the PSD.
But researching this topic have turned out much harder than I had thought it would be, after a few hours of searching for information I am no wiser than I was when I began, if anything I am more confused.
All I seem to find is designs for people who are designing integrated circuits which is impossible for me to make sense out of and so I guess I'll look into active filters and using digital potentiometers to alter the the parameters.
I will read more about active filters but I am somewhat confused as to what I need to achieve.
While reading about lock-in amplifiers I have gotten the impression that a band-pass filter at the input isn't necessarily necessary but that it is a good idea.
The point if the lock-in design I am trying to develop has the ultimate goal of measuring complex impedance but it is also meant to allow me to experiential with that impedance measurement so it has to be able to manage excitation signals up to 1MHz, and below that frequency the adjustability should be as wide as possible.
I am actually not sure what I am asking and why but I cannot get further dealing with this stage and I don't know what I should do/try next in order to make any headway.
Does anyone have any suggestion?
Regards
I need to realize a couple of programmable filters as part of an lock-in amplifier design, I am sure that I need a programmable low-pass filter for the output of the phase sensitive detector(PSD) and I think that I should make a programmable band-pass filter for filtering the input to the PSD.
But researching this topic have turned out much harder than I had thought it would be, after a few hours of searching for information I am no wiser than I was when I began, if anything I am more confused.
All I seem to find is designs for people who are designing integrated circuits which is impossible for me to make sense out of and so I guess I'll look into active filters and using digital potentiometers to alter the the parameters.
I will read more about active filters but I am somewhat confused as to what I need to achieve.
While reading about lock-in amplifiers I have gotten the impression that a band-pass filter at the input isn't necessarily necessary but that it is a good idea.
The point if the lock-in design I am trying to develop has the ultimate goal of measuring complex impedance but it is also meant to allow me to experiential with that impedance measurement so it has to be able to manage excitation signals up to 1MHz, and below that frequency the adjustability should be as wide as possible.
I am actually not sure what I am asking and why but I cannot get further dealing with this stage and I don't know what I should do/try next in order to make any headway.
Does anyone have any suggestion?
Regards
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