Design of a tunable filter!

Hi friends,
i am trying to design and implement a tunable bandpass filter in a receiver path.
the bandwidh would vary from 10 MHz to 100MHz.
i have porved its utility but now i am searching how to implement it and i am interested to prove its feasability since i did not yet fixed the process ( traditional CMOS porcess, or BICMOS or any other process).
that's why, i would appreciate any help to guide me if there some kind of bandpass filter that could comply with my specification.
thanks for your help


regards,

imar

At those frequencies, a Chebycheff or Cauer type bandpass filter within an amplifer will be very proper.You can change the capacitor values by switching CMOS transistors that are digitally controlled.For more information, see active filter design methodologies.For inductances, you can use bonding wires and so you get L-C components.

Can you provide a full spec?

Do you want to tune the the filter BW as well as centre frequency?

That could be difficult.

You want a Wadley loop receiver.

Thanks for your interest.
it is true !
i need to tune not only the filter BW but also its center frequency too.
in fact, i am trying to proove that it could possible to design such filter especially i didn't yet fixed the process because it is not the most critical point now.
So, i need to find a solution to prove its feasability since it is an idea that i want to justify it.
thanks for any suggestion or proposition of some kind of filter that could comply with my need. i know it is not so easy to find it. that's why i am waiting really your help my friends to help me.

thanks in advance

regards,
imar

Over what range would the centre frequency need to be tuned?

the center frequency would vary from 10MHz to 80 MHz and the BW from 6MHz to 50MHz.

I'd start by synthesising capacitor coupled filters similar to the one in this previous post

https://www.edaboard.com/ftopic305397.html

You should be able to keep the inductance constant and vary the BW, mainly, by the value of the top coupling capacitor. (odd numbers in the schematic)

Then vary the centre frequency, mainly, with the resonator capacitors. (Even numbers).

In practice you'd realise the capacitor values using varactor, and maybe pin, diodes

You'd generate a large look-up table to cover the required range and eventually hook it all up to a microcontroller.[/url]

http://televideo.ws/wadley.html