| 摘要 |
PURPOSE: A dual band front end module is provided to attain a small size and light weight by reducing the number of diodes and capacitors and extend call standby time by reducing battery consumption. CONSTITUTION: A PA(Power Amplifier) module(22) amplifies a signal transmitted from GSM and DCS sending terminals(Tx). The first and second phase shifters(24a,24b) change transmission and reception paths of the GSM signal. The third and fourth phase shifters(25a,25b) changes transmission and reception paths of the DCS signal. The first LPF(Low Pass Filter)(23a) cancels RF noise of a signal which has passed the first phase shifter(24a). The second LPF(23b) cancels RF noise of a signal which has passed the third phase shifter(25a). An antenna(27) transmits signals received from the DCS and GSM sending terminals to DCS and GSM receiving terminals. A diplexer(26) separates a signal received from the antenna(27) into an RF band(DCS) and a low frequency band(GSM) and determines which side it should be connected. The first SAW BPF(Band Pass Filter)(21a) passes only a signal of a certain range of frequency band desired by the GSM receiving end(Rx) and removes a signal that is not included in the range. The second SAW BPF(21b) passes only a signal of certain range of frequency band and removes a signal that is not included in the range.
|
