choise of analog filter: system level design

hello all,

In big chain system level design where RF BPF, IF BPF, and LPF are required.
What is the choise of filter? which filter I should select for my design?
which on is good for Bluetooth and WLAN and WCDMA?
which is good choise butterworth or chebyshev?

Simple answer, you need to select filters that meet your requirements. You are thinking about filter response shapes, which are independent of the implementation technology.

To start with, you need to think about the frequency requirements of the filters. For an RF bandpass filter, the operating frequency is ~ 2 GHz, and a narrow BW is required. SAW filters seem to be the accepted, small size filter for the MS in systems that you mentioned, so the response isn't a traditional response.

IF FIlters generally are SAW/Crystals/Ceramics, so the bandpass response is, again, not a classical transfer function, but can work in 20 MHz to 200 MHz or so.

Baseband bandpass filters are where you finally get to things like chebyshev / butterworth etc, as they are implemented at baseband with Inductors and Capacitors.

Dave