i think u r looking for a broad band reciever.. is it true? I also assume that the frequency signals are analog. Dear, broad band filters can help u in this regard, but still their response is different for different frequencies. One prefered method is to use 3 seperate filetrs, one for low frequencies, second for medium frequencies and the third for high frequencies. Then amplify the 3 outputs seperately to an equal amplitude.
the same can be applied when the signals are digital.
- Ali Sajjad