Circuit Description - Samsung SGH-D600 Service Manual

2. Circuit Description

2-1. SGH-D600 RF Circuit Description
2-1-1. RX PART
- FEM(F100 SWICHPLEXER)
Switching Tx, Rx path for GSM850, GSM900, DCS1800 and PCS1900 by logic controlling.
- ANTENNA SWITCH Control Logic (F100) ¡ æ
GSM850/900 Rx Mode
DCS Rx Mode
PCS Rx Mode
GSM Tx Mode (GSM850/900)
DCS/PCS Tx Mode
- FILTER
To convert Electromagnetic Field Wave to Acoustic Wave and then pass the specific frequency band.
- GSM850 FILTER (L113,C133,C134,C135) ¡ æ
- GSM900 FILTER (L106,C122,C123,C124) ¡ æ
- DCS FILTER (L108,L109,C129,C130) ¡ æ
- PCS FILTER (L110,L111,C131,C132) ¡ æ
- VC-TCXO (U102)
To generate the 26MHz reference clock to drive the logic and RF.
After additional process, the reference clock applies to the U100 Rx IQ demodulator and Tx IQ modulator.
The oscillator for RX IQ demodulator and Tx modulator are controlled by serial data to select channel and use fast lock
mode for GPRS high class operation.
- TRANSCEIVER (U100)
This chip fully integrated GSM GPRS quad-band transceiver with transmit baluns, loop filters and most of the passive
component in it.
And also fully integrated fractional N RF synthesizer with AFC control possibility, RF VCO with integrated supply
regulator. semi integrated reference oscillator with integrated supply regulator.
RF Receiver front-end amplifies the GSM850, E-GSM900, DCS1800 and PCS1900 aerial signal, convert the chosen
channel down to a low IF of 100kHz.
In IF section, further amplifies the wanted channel output level to the desired value and rejects DC.
2-1-2. TX PART
The transmitter is fully differential using a direct up conversion architecture. It consists of a signal side band
power up mixer. Gain is controlled by 6 dB via 3-wire serial bus programing. The fully integrated VCO and power
mixer achieve LO suppression, quadrature phase error, quadrature amplitude balance and low noise floor specification.
Output matching/balun components drive a standard 50 ohms single ended load.
Truth Table
VC_1
L
L
L
H
L
For filtering the frequency band between 869 ~ 894 MHz.
For filtering the frequency band between 925 ~ 960 MHz.
For filtering the frequency band 1805 and 1880 MHz.
For filtering the frequency band 1930 and 1990 MHz.
SAMSUNG Proprietary-Contents may change without notice
This Document can not be used with out Samsung' s authorization
VC_2
L
L
L
L
H
2-1
VC_3
L
L
H
L
L