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Design a 2nd order Butterworth HPF with f​=ω/2π​​=1000 Hz and a gain of 1. What is the transfer function?

User Vsekhar
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Final answer:

The transfer function of the 2nd order Butterworth HPF with a cutoff frequency of 1000 Hz and a gain of 1 is H(s) = (4π²√10⁶s²) / (s² + 2√2π√1000s + 4π²√10⁶).

Step-by-step explanation:

Designing a 2nd Order Butterworth High-Pass Filter (HPF)

To design a 2nd order Butterworth HPF with a cutoff frequency (ƒc) of 1000 Hz and a gain of 1, we would first need to find the standard form of the 2nd order Butterworth filter transfer function. A 2nd order Butterworth filter has a squared magnitude response that is flat at low frequencies and falls off at -40 dB/decade beyond the cutoff frequency. The normalized transfer function H(s) for such a filter is given by:

H(s) = s^2 / (s^2 + √2*s + 1)

To convert this to a high-pass filter, we replace s with ƒc/s, where s is the complex frequency (jω). For our case, ƒc is 1000 Hz:

H(s) = (ƒc^2*s^2) / (s^2 + √2*ƒc*s + ƒc^2)

Substituting ƒc = 2π*1000 rad/s, the transfer function becomes:

H(s) = ((2π*1000)^2*s^2) / (s^2 + √2*2π*1000*s + (2π*1000)^2)

Therefore, the transfer function of the 2nd order Butterworth HPF with a cutoff frequency of 1000 Hz and a gain of 1 is:

H(s) = (4π^2*10^6*s^2) / (s^2 + 2√2π*1000*s + 4π^2*10^6)

User Tyrannas
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