Active Second-order low-pass Butterworth filter

[webhelp]

I need help in designing an active 2nd order low-pass Butterworth Filter that meets certain requirements.
The requiremetns are that it needs to be a minimum 2nd order coincident pole system design with a break frequency at 6kHz
and a minimum 40dB roll-off at the break frequency.

 

[Ouabache]

I am no expert on filter design, but I may have some helpful suggestions and there are others here who can assist you.
What have you done so far in your design? At what point are you getting stuck?

 

[ravenprp]

Designing an active second-order low-pass Butterworth filter requires a thorough understanding of filter design principles and techniques. To meet the given requirements of a minimum 2nd order coincident pole system design with a break frequency at 6kHz and a minimum 40dB roll-off at the break frequency, the following steps can be followed:

1. Determine the filter topology: The Butterworth filter is a popular choice for low-pass filters due to its maximally flat response in the passband. For an active implementation, the most commonly used topology is the Sallen-Key circuit.

2. Calculate the component values: The component values of the filter can be calculated using the standard Butterworth filter equations. These equations relate the component values to the desired cut-off frequency and the quality factor (Q) of the filter.

3. Choose the active components: In an active implementation, operational amplifiers (op-amps) are used as the active components. Select op-amps with high gain and bandwidth to ensure minimal distortion and good frequency response.

4. Simulate the filter response: Before building the physical circuit, it is recommended to simulate the filter response using a software tool such as LTSpice. This will help in verifying the design and making any necessary adjustments.

5. Build the circuit: Once the design is simulated and verified, the circuit can be built using the chosen op-amps and passive components. It is important to use high-quality components for optimal performance.

6. Test and tune: After the circuit is built, it is essential to test its response using a signal generator and an oscilloscope. Any discrepancies between the simulated and actual response can be corrected by tuning the component values.

In conclusion, designing an active second-order low-pass Butterworth filter requires a combination of theoretical knowledge and practical skills. By following the above steps, you should be able to design a filter that meets the given requirements.