Receive filter using frequency translation for or in cellular telephony base station

摘要: A device for filtering wide-band signals at radio frequencies is usable either in a base station cellular telephony system or separately. The signal occupies total frequency band comprising bands allocated to that and central extraneous signal. Within the device, mixed with heterodyne wave translate from RF IF. IF then filtered by two surface acoustic (SAW) band-pass filters which have respective pass correspond of signal, SAW effect passing low attenuation those while substantially attenuating and/or noise between bands. after being so remains when supplied or, subsequent stage again be restored back RF. may adjustable frequency.