doncarlosalbatros
Full Member level 2
Quick way for an adjustable low pass filter with roll-off frequency display
Hello,
I want to build an adjustable low-pass filter for 0 to 10 kHz range as general purpose but especially to be used as an anti-aliasing filter.
One should be able to adjust the cut-off frequency of the filter by turning a knob and be able to see the adjusted cut-off freq. on an LCD or any indicator(otherwise without an LCD he will never be able to know what the adjusted cut off is).
Here illustrates basic idea:
So a controller controlled by a human will adjust the cut-off frequency and simultaneously display that data on an LCD or something similar. I didn't draw the power supply inputs for simplicity.
Does anybody have any experience with such an adjustable filter? I would like to have a filter at least 4th order Chebyshev. What type and order of filter do you recommend for an anti-aliasing filter?
Is a micro-controller a must for such application for the control side? And most importantly what is the good or easy way to make an adjustable filter in this case? I was thinking using a digital potentiometer but are is there any other ad-hoc adjustable filter controlled by PWM or something like that?
I would appreciate your experience and suggestions.
Hello,
I want to build an adjustable low-pass filter for 0 to 10 kHz range as general purpose but especially to be used as an anti-aliasing filter.
One should be able to adjust the cut-off frequency of the filter by turning a knob and be able to see the adjusted cut-off freq. on an LCD or any indicator(otherwise without an LCD he will never be able to know what the adjusted cut off is).
Here illustrates basic idea:
So a controller controlled by a human will adjust the cut-off frequency and simultaneously display that data on an LCD or something similar. I didn't draw the power supply inputs for simplicity.
Does anybody have any experience with such an adjustable filter? I would like to have a filter at least 4th order Chebyshev. What type and order of filter do you recommend for an anti-aliasing filter?
Is a micro-controller a must for such application for the control side? And most importantly what is the good or easy way to make an adjustable filter in this case? I was thinking using a digital potentiometer but are is there any other ad-hoc adjustable filter controlled by PWM or something like that?
I would appreciate your experience and suggestions.