Samsung Electronics
6-5
6-2 Receiver
(For PCS)
LOW NOISE AMPLIFIER (LNA)
The low noise amplifier featuring 1.6dB Noise
Figure and 16dB gain amplifier a weak signal
receiver from the base station to obtain the
optimum signal level.
DOWN CONVERTER (MIXER)
First local signal is applied to this down converter.
The down converter transfers the signal amplified
at the LNA into 210.38 MHz IF signal. 210.38MHz
IF signal is made by subtracting 1960 ±30 MHz RF
signal from 1750 ± 30 MHz first local signal. The
LAN is U401 and down converter is U407.
LOCAL BUFFER AMPLIFIER
Buffer (U408) amplifies signal to be applied to the
local input of the down converter (U407) when a
phase is locked between U616 and U640.
IF AUTOMATIC AGIN CONTROLLER (AGC)
AMP
210.38MHz IF signal is applied to IF AGC amplifier.
AGC output level is applied to BBA (Base Band
Analog). The AGC amp (U403) keep the signal at a
constant level by controlling the gain. Dynamic
range is 90dB, up gain +45dB, and down gain
-45dB.
RF BAND PASS FILTER (BPF)
The RF BPF (F401) passes only a specific frequency
(1960±30MHz) from the signal received from the
mobile station. The band width is 60MHz.
IF SAW BAND PASS FILTER
IF SAW BPF (F402) is used for CDMA system
having 1.23MHz wide band and ±630kHz
bandwidth. The filter also climinates spurious
signals generated at the mixer.
VOLTAGE CONTROLLED OSCILLATOR
The VCO (U616) generates the signal having
1750MHz center frequency and ±30MHz deviation
with voltage control. PLL IC (U640) controls this
signal.
PHASE LOCKED LOOP (PLL)
Input reference frequency is generated at VCTCXO
(U680) and the divider signal is generated at VCO.
PLL compares the two signals and generates the
desired signal with a preprogrammed counter
which controls voltage.
VOLTAGE CONTROLLED TEMPERATURE
COMPENSATED CRYSTAL OSCILLATOR
It provides 19.68MHz reference frequency to PLL
(U640) and BBA (U600). A correct frequency turning
is made by the voltage control.
TEMPERATURE TO VOLTAGE CONVERTER
The Temperature to Voltage Converter (U691)
detects temperature. It is used to compensate active
component characteristics due to the temperature
difference.
DUPLEXER
Duplexer (F406) controls to transmit through the
antenna only the signals within acceptable Tx
frequency range (1880 ±30MHz). It also matches
LNA (U401) input in receiving part and PA out in
transmitter part with the antenna.
Circuit Description
Summary of Contents for SCH-1500 series
Page 2: ...Samsung Electronics Co Ltd ELECTRONICS ...
Page 4: ...1 2 Samsung Electronics General Introduction Memo ...
Page 22: ...4 8 Samsung Electronics NAM Programming Memo ...
Page 46: ...Memo 7 4 Samsung Electronics Test Procedure ...
Page 81: ...10 1 DBDM Phone 10 1 1 Main Board PCB REV 2 1 10 PCB Diagrams Top View Bottom View ...
Page 82: ...10 1 2 Memory Board PCB REV 2 0 ...
Page 83: ...10 2 Desk Top Rapid Charger Board PCB ...
Page 84: ...10 3 Travel Charger Board PCB ...
Page 85: ...10 4 Cigarette Lighter Adaptor Board PCB ...
Page 86: ...10 5 Hands Free Kit Board PCB ...
Page 87: ...10 6 Cradle PCB ...
Page 88: ...Memo ...
Page 116: ...12 1 Main Block Diagram ...
Page 117: ...12 2 Desk Top Rapid Charger Block Diagram ...
Page 118: ...12 3 Travel Charger Block Diagram ...
Page 119: ...12 4 Cigarette Lighter Adaptor Block Diagram ...
Page 120: ...12 5 Hands Free Kit Block Diagram ...
Page 121: ...12 6 Logic Circuit Diagram REV 2 1 ...
Page 122: ......
Page 123: ...12 7 Memory Board Circuit Diagram REV 2 0 ...
Page 124: ...12 8 RF Circuit Diagram REV 2 1 ...
Page 125: ...12 9 Desk Top Rapid Charger Circuit Diagram ...
Page 126: ...12 10 Travel Charger Circuit Diagram ...
Page 127: ...12 11 Cigarette Lighter Adaptor Circuit Diagram ...
Page 128: ...12 12 Hands Free Circuit Diagram 12 12 1 Power Supply ...
Page 129: ...12 12 2 Audio Amp ...
Page 130: ...12 12 3 Comm Cont ...
Page 131: ...12 13 Cradle Circuit Diagram ...
Page 132: ...Memo ...