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VX8350
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3.1.2 Description of RX Part Circuit
3.1.2.1 Triplexer (F105)
The main function of Triplexer is to prohibit the other band signals from flowing into the one band circuit and vice
versa. RF designer can use common tri-band antenna regardless of frequency band (800, 1575 and 1900 MHz). The
specification of VX8350 Triplexer is described below:
3.1.2.2 Duplexer (DP100, DP101)
The duplexer consists of the RX bandpass filter (BPF) and the TX BPF which has the function of separating TX and
RX signals in the full duplex system for using the common antenna. The TX part BPF is used to suppress noises and
spurious out of the TX frequency band. The RX BPF is used to receive only RX signal coming from the antenna,
which is usually called preselector. It’s main function is to limit the bandwidth of spectrum reaching the LNA and
mixer, attenuate receiver spurious response and suppress local oscillator energy. As a result frequency sensitivity and
selectivity of mobile phone increase. The specification of VX8350 duplexer described below ;
z PCS duplexer
TX RX TX to RX (min)
Pass Band 1850~1910 MHz 1930~1990 MHz
Insertion Loss 3.5dB max 3.0dB max
Return Loss 9.5dB min 9.5dB min
Attenuation 43dB min (1930~1990MHz)
52dB min
(1850~1910MHz)
54dB (1850~1910MHz)
45dB (1930~1990MHz)
Cellular GPS PCS
Frequency Range 824 – 894 MHz 1575.42 MHz 1850 – 1990 MHz
Insertion Loss to
Common
0.8 dB Max (at +25 deg) 1.8 dB Max. (at +25 deg) 0.85 dB Max (at +25 deg)
Isolation
42dB(GPS),20dB(PCS) 42dB(DCN),42dB(PCS) 42dB(GPS),15dB(DCN)
Temperature
Range
-30 to +85 deg
z Cellular duplexer
TX RX TX to RX (min)
Pass Band 824~849 MHz 869~894 MHz
Insertion Loss 2.3B max 3.5dB max
Return Loss 9dB min 8dB min
Attenuation 45dB min (869~894MHz) 54dB min (824~849MHz)
55dB (824~849MHz)
47dB (869~894MHz)
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