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2. Circuit Description
2-1. SGH-T809 RF Circuit Description
2-1-1. RX PART
- FRONT END MODULE(ANTENNA SWITCH MODULE + RX SAW FILTER) (F101)
It performs to switch Tx & Rx paths for GSM850, GSM900, DCS1800 and PCS1900 with logic controls below.
- FEM Control Logic Table
Tx Mode (GSM850/900)
Tx Mode (DCS1800/1900)
Rx Mode (GSM900/850)
Rx Mode (DCS1800)
Rx Mode (PCS1900)
- VC-TCXO (TCX100)
This module generates the 26MHz reference clock to drive the logic and RF systems.
It is turned on when the supply voltage (+VCC_SYN_2V8) is applied.
After buffering, the 26MHz reference clock is supplied to the other parts of the system through the transceiver pin
CLKOUT.
- Transceiver (U102)
This chip is fully integrated GSM & GPRS quad-band transceiver with RF VCO, loop filters and most of the
passive components required in it.
It 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 E-GSM900(GSM850), DCS1800 and PCS1900 aerial signal, convert the chosen
channel
down to a low IF of 100kHz.
In IF section, further amplifies the wanted channel, performs gain control to tune the 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.
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SAMSUNG Proprietary-Contents may change without notice
This Document can not be used with out Samsung ' s authorization
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