LGE LG-KD3000, Service Manual

Page: 17 / 66

LG-KD3000
LGE
LG Electronics Inc.
15/21 LGE Internal Use
Only
[Figure 3-1] Block Diagram Of KD3000
1.2 Description of Receive Part Circuit
1.2.1 Duplexer (DP101)
The duplexer consists of the receive part bandpass filter (BPF) and the transmit part bandpass filter
(BPF) which have the function of separating transmit/receive signals in the full duplex system using
the transmit/receive common antenna. The transmit part BPF is used to suppress noises and spurious
waves entering the receive band among transmit signals in order to prevent the drop in receive
sensitivity characteristics. The receive part BPF blocks the signals sent out from entering the receive
end in order to improve sensitivity characteristics.
Insertion loss (IL) in the transmit band is 2.8dB (Max), whereas IL in the receive band is 3.5dB (Max).
The receive band attenuation amount of transmit filter is 45dB (Min) and the transmit band attenuation
TX
RX
DUP
ANT
BPF
DC 5V
Battery
19.2M OSC
Keypad
Backlight
MCP
32Mb X 16Mb
LCD
Backlight
Viblator
SPK/Earpiec
MIC
Keypad
User
Memory
Codec
SPK AMP
RF
Interface
Input
General
BB & PM
I/F
Output
Connectivity
UIM
UART
Quadrature
Quadrature
LN
RF Block
BPF
KD3000 Block Diagram
QSC6010
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