Transmitter Part - Pantech G800 Service Manual

G800 Service Manual
Low-pass filters before the OPLL phase detector reduce the harmonic content of the quadrature
modulator and feedback mixer outputs. The cutoff frequency of the filters is programmable.

4.2.4.2 Transmitter Part

A. 6 dB attenuator : Z705, Z706
These passive components are adopted for PAM to operate in a stable output power.
B. ASM(Antenna Switch Module / built in LPF): Z701
These filters pass through the signals of which frequency band of 880MHz~915MHz,
1710MHz~1785MHz, and 1850MHz~1910MHz which is the transmit frequency of GSM, PCS
system terminal, and it suppresses other images and spurious frequencies when the terminal
transmits GMSK modulated frequencies.
C. Power AMP Module(PAM): Z710
This device amplifies signals ahead of transmiting them through the antenna to provide a sufficient RF power.
It has amplification factor of 28dB and efficiency of about 55% typically in GSM band and amplification of
27dB and efficiency of about 52% typically DCS / PCS band.
D. RF Switch connector: J701
RF Swithc connector used to test Mainboard's RF characteristics.
E. Antenna: Antenna Contact Plate J702
This device enables signals to be transmitted and received from BTS by Um interface.
External Antenna can be contacted with Mainboard through Antenna Contact Plate.
Antenna
Contact
Plate
ASM
PANTECH
PAM
Fig.4-9. Transmit part PCB Layout
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R&D CONFIDENTIAL
6dB
Attenuator