Transmitter Part - LG L1100 Service Manual

Transmit modes should always use fø = 200kHz. The IF and RF output frequencies are set by
programming he N-Divider registers and also programmed via 3-wire interface with external system
controller.
X801
VC-TCXO
26MHz
XIN
XOUT
Baseband
Baseband XEN
(TI)
(TI)
PDN
U101
U101
IOTA
IOTA
+
+
SDI
U102
U102
SDO
Calypso
Calypso
SCLK
SEN

3.3 Transmitter Part

The Transmitter part contains the transmitter parts of Si4205-BM[U803], Power Amp Module[U804]
and Antenna switch[FL801]. The transmit section of Si4205-BM [U502] consists of an I/Q baseband
upconverter, an offset phase-locked loop(OPLL) and two output buffers that can drive external power
amplifiers(PA).
The RF GMSK outputs from the transmit VCO are fed directly to the RF power amplifiers.
The peak output power and the profile of the transmitted burst are controlled by means of
incorporated power control circuits inside of PA and DAC output from the Baseband Controller.
The PA outputs pass to the antenna connector via Antenna Switch.
Figure 2. Synthesizer Block
÷1,2 ÷65,130
÷1,2 ÷65,130
Power
PDIB
Power
control
PDRB
control
Serial
Serial
I/O
I/O
SDOSEL[4:0]
-15-
Φ
Φ
DET
DET
Self
Self
Tune
Tune
RF PLL
Self
Self
Tune
N
Tune
Φ
Φ
DET
DET
IF PLL
U803/Si4205
RF1
RF2
To Rx/Tx
N [15:0]
RF1
1/N
1/N
N [15:0]
RF2
1/N
1/N
[15:0]
IF
To Tx