Problems with relating Transfer Function to filter

[tok47]

Filter Transfer Function

Hi ALL,

I have some problem to relate the transfer function of my filter with the working frequency of my filter design.

The transfer function of my filter (active) block was like below
D
H(s) =---------------------
AS³+BS²+CS+1
where A,B,C,D are in term of gm (transconductance of the OTA in th ecircuit),R and C.

The filter is design as a 3 pole Butterworth LPF. And passband frequency is 500KHz.

So, my question is how can I related the frequency with the transfer function that I have with the passband frequency and determine the value of R and C?

Thanks

rdgs
tok

 

[v_c]

Re: Filter Transfer Function

Please take a look at the attached figure and the web page below, I think it is what you are looking for.

**broken link removed**

Best regards,
v_c

 

[tok47]

Filter Transfer Function

I am looking for the manual way to solve the equation H(S).

The formulas that I get is almost same with above. BUt my circuit is working with 3 OTA,3 C and 2R.

I hope some 1 can show me how to related it with pass band frequency.

Thanks