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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