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Design Languages >> Verilog-AMS >> laplace transform
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Message started by Tommy on Feb 15^th, 2007, 7:00am

Title: laplace transform
Post by Tommy on Feb 15^th, 2007, 7:00am

Hi,
How to implement a function like H(s) = 1 + as + bs^2 ?
laplace_nd in cadence spectre exits complaining that the order of denominator is not same as numerator order.

Thanks
Tom

Title: Re: laplace transform
Post by Geoffrey_Coram on Feb 15^th, 2007, 11:51am

Are you sure you don't want H(s) = 1/ (1 + as + bs^2) ?

Title: Re: laplace transform
Post by Ken Kundert on Feb 15^th, 2007, 1:25pm

In case you want your original transfer function rather than Geoffrey's, you can get it by using the laplace function to implement a voltage-to-current converter with Geoffrey's, and then place it in the feedback path of an ideal opamp configured as an inverting amplifier. That will act to invert the transfer function.

-Ken

Title: Re: laplace transform
Post by mg777 on Feb 18^th, 2007, 10:52pm

To continue on the denominator theme, add a D(s) such that H'(s) = H(s)/D(s) has a bandwidth 3X larger than the signal you're emphasizing. A good choice for D(s) would be a 3rd order Bessel.

M.G.Rajan
www.eecalc.com