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Design >> Mixed-Signal Design >> QAM versus filter type (receiver)
https://designers-guide.org/forum/YaBB.pl?num=1154004601

Message started by Visjnoe on Jul 27^th, 2006, 5:50am

Title: QAM versus filter type (receiver)
Post by Visjnoe on Jul 27^th, 2006, 5:50am

Hello,

is there anybody who has experience with the design of receiver filters for QAM-modulated communication systems?
More specifically, which is the best suited filter type (Butterworth, Chebyshev).

I was considering to use inverse Chebyshev (trade-off amplitude/phase accuracy OK versus sharp attenuation).

Kind Regards

Peter

Title: Re: QAM versus filter type (receiver)
Post by ACWWong on Jul 27^th, 2006, 8:32am

hi peter,

i guess butterworth should be good because of maximally flat passband with reasonable phase response/groupdelay. If attenuation is adequate i would definately use it as they are much easier to design on ICs (unit circle poles makes for easy choice of well matched components R,gm,C etc,)

the thing that would make me thing abit more about inverse cheby is that it has transmission zeros which can make the design a bit tougher. i guess if you are doing bandpass, this doesn;t matter, but for low pass, i think its easier to do a slightly higher order butterworth than an inv cheby.

cheers.
aw

Title: Re: QAM versus filter type (receiver)
Post by ACWWong on Jul 27^th, 2006, 8:34am

opps, of course i am talking continuous time analog filtering... maybe not relevant to you..