how to chnage a bandpass filter to a low pass filter

Started by taisa ahmad October 31, 2006
hello and good day !

A pass band receiver system will process modulated signal , i.e. there iz RF stage , then IF stage and Baseband (BB) stage.

I want to model LPF instead of BPF in RF and IF stage i.e. model a LPF from a BPF, which gives the same output as passband system gives.

I tackle this problem that i take hilbert transform to retain only positive frequencies and then multiply with exp(-jwct) to shift it to zero frequency......

Q 1) how to retrieve a time domain transfer function in 's' domain of bandpass filter....

Q 2 ) whether i have to made these operations to bandpass filter transfer function or to the output of a bandpass filter.