Could anyone help me find the transfer function of the 2nd order low pass filter and prove the variables are true as shown in the question?
Any help is appreciated
Any help is appreciated
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Would you mind explaining what a unity gain is, and if that applies to the circuit I posted.Here is a link to a derivation of the unity gain version. Non-unity gain is discussed at the end.
http://en.wikipedia.org/wiki/Sallen_key
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Unity Gain is Gain=1=Av.Would you mind explaining what a unity gain is, and if that applies to the circuit I posted.
What does s stand for in the equation?Unity Gain is Gain=1=Av.
Since your Av is Av=Rb/Ra, make Rb=Ra, then Av=1 and you meet the unity gain definition of Gain=1=Av.
s=jwWhat does s stand for in the equation?
Do you just write the transfer function in terms of the variables since they don't have any values given in the question or am I missing something?s=jw
From wiki:
"The transfer function can also be shown using the Fourier transform which is only a special case of the bilateral Laplace transform for the case where s = j\(\omega\)."
http://en.wikipedia.org/wiki/Transfer_function
No, you are not missing anything. For Part a you just write transfer function in terms of R1, R2, C1, C2, Ra, Rb. That is exactly what Part a asks you to do.Do you just write the transfer function in terms of the variables since they don't have any values given in the question or am I missing something?
Yes, for exampleDo you just write the transfer function in terms of the variables since they don't have any values given in the question or am I missing something?
The design given on the wikipedia article does not have Ra and Rb, would you happen to have an example similar to my design circuitNo, you are not missing anything. For Part a you just write transfer function in terms of R1, R2, C1, C2, Ra, Rb. That is exactly what Part a asks you to do.
Found this example:Yes, for example
(Vs - Va)/R1 = (Va - Vp)/R2 + (Va - Vout)*s*C1
(Va - Vp)/R2 = Va*s*C2
Vout = Vp * Av
Where Av = 1 + Rb/Ra
And you solve this for Vout/Vs