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Diplexer v.s. DuplexerDiplexer� Separates two different freq. bands in Rx path and combines them in Tx path.
� These freq. bands will be wide apart in freq. domain. Ex: separate EGSM, DCS or GSM, WCDMA.
� Tx-Rx isolation ~ 50-60 dB.
� One HPF and one LPF � HPF負責High-Band TRx, LPF負責Low-Band TRx.
� Smart phone always use the LC Diplexer.
� Use single antenna by both Tx and Rx at the same time.
� Both Tx and Rx paths have freq. bands very nearer, hence narrow BPF are used. Ex: DCS uplink and downlink.
� Two types of duplexer, one by using PIN diode switches and the other using circulators.
� Tx-Rx isolation very important ~ 90-95 dB.
� 兩個頻段不同的BPF �一個負責Tx,一個負責Rx.
� Smart phone always use the SAW Duplexer.
EGSM + DCS
EGSM 900
880-915 MHz
920-965 MHz
DCS 1800
1710-1785 MHz
1805-1880 MHz
DCS
1710-1785 MHz 1805-1880 MHz
Duplexer
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