Mechatronics Eng
New Member
Hi mech_eng,
a short comment to your filter circuit.
It is an equal-component Sallen-Key topology with unity gain (the resistor in the feedback path has no effect) - and, thus, has a pole quality factor of only Qp=0.5.
This value is the lower limit for an active realization since this value can be realized also as a pure passive RC filter.
As a consequence, the magnitude response at the end of the passband (approx. 1 kHz) is not as "constant" as it could be.
Therefore, my suggestion: Increase the upper capacitor from 0.01uF to 0.02uF . This will give you a maximally flat response (Butterworth approximation) with Qp=0.707.
It is well known that such a lowpass response is a good trade-off between time and frequency domain. By the way: In this case, the 3-dB cut-off will be at 1.1 kHz.
Thank you for your details, but I am not in dire need for such electronic backgrounds. I just need to run the circuit ti fulfill my needs in Mechatronics projects. Warm greetings.