Multiple Feedback Filter Using Differential Low Pass Filter Circuit

Multiple Feedback Filter Using Differential Low Pass Filter Circuit

This is a circuit for low pass filter that can be used for multiple feedback filter. The filter is a two pole filter topology used to implement an electronic filter by adding two poles to the transfer function. This is available in a low pass, high pass, band pass, and notch versions, although the band pass and notch versions are not recommended because of the low resistor values. Some Feedback filters are useful for distribution, analysis and other tasks such as the Sound to light converter or a fully functional Vocoder. This is the figure of the circuit.


The circuit above shows an example of Multiple Feedback Filter with Differential Low Pass Filter Circuit Schematic Diagram. The table below contains details of the transfer functions (Bessel, Butterworth, and Chebyshev 3 dB).
Bessel
For = 1 / (2pRC)
R1 = R2 = 0.625R
R3 = 0.36R
C1 = C
C2 = 2.67C
Butterworth
For = 1 / (2pRC)
R1 = R2 = 0.65R
R3 = 0.375R
C1 = C
C2 = 4C
Chebyshev 3 dB
For = 1 / (2pRC)
R1 = 0.644R
R2 = 0.456R
R3 = 0.267R
C1 = 12C
C2 = C