Samsung SCH-3500 series Service Manual page 26

6-4 Transmitter Section
POWER AMP
Power Amp module (U412) amplifier signal to be
sent out to the base station through the antenna.
DRIVER AMP
The driver amp (U409) allows the signal input to
the Power Amp module (U412) to be within a
specified level.
UP CONVERTER (MIXER)
The up converter (U406) receives the first local
signal to generate 1880±30 MHz. 1880 ±30 MHz
signal comes out from the mixer output by adding
130MHz IF signal to 1750±30 MHz first local signal.
Up converter's reference number is U406.
ANTENNA
Antenna allows signal to send to receive from the
base station.
6-5 Transmitter Section
POWER AMP MODULE
Power Amp module (U411) amplifier signal to be
sent out to the base station through the antenna.
UP CONVERTER (MIXER)
The up converter (U407) receives the first local
signal to generate 836±12.5 MHz. 836 ±12.5 MHz
signal comes out from the mixer output by adding
130MHz IF signal to 966±12.5 MHz first local signal.
ANTENNA
Antenna allows signal to send to receive from the
base station.
(For PCS)
(For AMPS)
SAMSUNG Proprietary-Contents may change without notice
RF BAND PASS FILTER (BPF)
The RF BPF (F403, F404) accepts only specific
frequency (1880±30 MHz) to send it out to power
and Power Amp module. The band width is 60
MHz.
ISOLATOR
Isolator (U413) is used to reduce a reflected signal to
protect the power amp module from being
damaged.
POWER SUPPLY REGULATOR
The power supply regulator (U344) supplies a
regulated power to each part of transmitter. VBatt is
connected to power Amp Module (U412) directly.
U344 supplies 3.0 V to the others.
RF BAND PASS FILTER (BPF)
The RF BPF (F402, F405) accepts only specific
frequency (836±12.5 MHz) to send it out to base
station module. The band width is 25 MHz.
POWER SUPPLY REGULATOR
The power supply regulator (U343) supply a
regulated power to each part of transmitter. U343
supplies 3.0V to TX driver (U408), mixer (U407) and
VBatt is connected to Power Amp Module (U411)
directly.
6-8
Circuit Description