Question

Two computers are transferring digital data on a single wire at a rate of 1500 bits/s. The digital voltage waveform, is a sequence of bits alternating between “high” and “low” values. Also present in the environment is a source of 150 kHz (942 krad/s) noise, which is corrupting the data. Design a second-order Low Pass active filter to filter out the high-frequency noise without destroying the data waveform. Discuss the choice of your location of poles and zeros. Prove the correctness of your design using any software package available to you??

Answer 1

I will choose the butterworth filter for this application as its pass band is almost flat. And slope is -20dB/decade

For butterworth 2nd order low pass filter

If R1 =R2 AND C1 = C2 then

fc = 1/(2piRC)

taking fc = 10kHz because I want 1.5kHz to be minimum distorted and 150kHz noise to be distorted I took fc= 10kHz

Form that I got R =6.2Kohm and C = 0.1uF

Circuit is as in the picture

If you have any query ask in the comments