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Active Filter for 1200 Hz
I sort of know how an active filter works but I cannot select the components.


I haven't posted here for ages, i had to re-join as my e-mail address and computer have changed.

I need to come up with an active filter to pass a 1200 Hz signal. I have no idea how to select the capacitor and resistors for this frequency.

I would really appreciate if someone could give me some direction.

Thanks in advance
Roy Matson
Instrumentation Consultant (retired)


Just buy a tunable one like MFJ-752D Signal Enhancer II, at least for audio signals, not Ac power lines.

Sorry, I should have provided some more information the MFJ-752D would be way overkill. I am trying to detect a 1200 Hz signal from a light beam.

The signal I am trying to detect is a light beam modulated at 1200 Hz. Unfortunately, the detector is also subjected to natural sunlight which has the effect of swamping the signal. It needs to be a simple one or two stage filter entering on 1200.

I was thinking of an active filter based on a thru hole Op amp.


1 out of 1 members thought this post was helpful...

a simple split-tee filter will impress you, as it surprised me in a lab class I supervised.

For example

1 out of 1 members thought this post was helpful...


I am new member of this forum.
Would suggest you to read and take some notes from the document and the link herebelow:

Chapter 16
Active Filter Design Techniques

Its a well documented file for designing a filter.

Hope it can be an help ...