LG VX5400 Service Manual page 25

1.2 Description of Receive Part Circuit
1.2.1 Quintplexer (U101)
The Quintplexer consists of the Rx bandpass filter (BPF), the Tx BPF and the GPS filter(BPF) which has
the function of separating Tx, Rx and GPS signals in the full Triplex 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 VX5400 Quintplexer described below ;
PCS band
Pass Band 1850~1910 MHz
Insertion Loss
Return Loss
Attenuation 43 dB min (1930~1990MHz)
Cellular band
Pass Band 824~849MHz
Insertion Loss
Return Loss
43 dB min (869~894MHz)
Attenuation
GPS band
Pass Band
Insertion Loss
Return Loss
Isolation1
Copyright@2007 LG Electronics. Inc. All right reserved.
Only for training and serving purposes
Tx
3.9 dB max
9.0 dB min
Tx
2.4 dB max
9.0 min
55 dB min (824~849MHz)
1574.42~1576.42MHz
1.5 dB max
10 min
34 dB min(Cell Tx GPS)
- 25 -
Rx
1930~1990 MHz
4.2 dB max
9.0dB min
52dB min
(1850~1910MHz)
Rx
869~894 MHz
3.4 dB max
9.0 min
LGE Internal Use Only
Tx to Rx (min)
54 dB (1850~1910MHz)
45 dB (1930~1990MHz)
Tx to Rx (min)
55 dB (824~849MHz)
45 dB (869~894MHz)