Fig.3:The IF AMP and Demodulator
AGC Control
:-
PGSTR
SYGCCL
SYGCDT
8-9
PMB2410 (IC300)
RX_ON2
PUPLO2
36
31
TO W2013 (IC100)
(TX IF Modulator)
RINO
540MHz
Div2
Div2/3
RINO
RIPO
RQNO
RQPO
45
46
40
39
FL304
23-24
20-21
1st IF
270Mhz
270Mhz
First Mixer
Varactor Network
D303 (A,B)
LOOP FILTER
32-35
11,12,13
From (IC201#18) IF PLL (See Fig.4)
GSM_TX
Rx I&Q Demodulator
The modulated IF signal of 270Mhz is demodulated by mixing it with another
270Mhz signal, which is derived from an 540Mhz oscillator located inside IC300.
The 540Mhz is reduced by a pre-selectable divider, which can be set by the
control signal GSM_TX (from IC27#23). The output from the 540Mhz oscillator is
divided down by a factor of 2 or 3 to produce either a 180 or 270Mhz signal,
depending on whether the mobile is in TX or RX modes . It is this signal which is
mixed with that from the IF amplifier to produce the baseband I and Q signals. The
I and Q signals are then buffered and fed differentially to the Superchip (IC27) for
filtering and digitising.
The signal RX_ON2 (from IC27#28) enables both the demodulator and internal
buffers. The signal PUPLO2 which is supplied from IC27 #26, enables the
540Mhz internal oscillator.
Summary of Contents for DB2000
Page 1: ...DB2000 Service Manual Help ...
Page 3: ... ...
Page 5: ... 2 3 4 2 2 2 2 2 0 0 0 5 3 4 2 6 2 7 2 2 2 2 0 8 9 2 2 2 2 2 2 2 2 ...
Page 7: ... 2 6 2 2 2 2 2 3 4 2 2 0 2 ...
Page 8: ... 2 ...
Page 9: ... Previous Section Next Section Main Menu Section 2 Unit Specifications ...
Page 77: ... 1 2 ...
Page 83: ...Fit Antenna INSERT AND SCREW THE ANTENNA INTO THE ASSEMBLY ...
Page 107: ...Fig 3 7 GSM_LNA Pg 3 3I TP419 Fig 3 8 PCN_LNA Pg 3 3J TP420 Fig 4 9 TCXO Pg 2 H11 TP413 ...
Page 109: ...Fig 4 3 PCN_TX Pg 1 1J TP417 Fig 4 4 3V_G_TX Pg 1 4I TP100 Fig 4 5 3V_P_TX Pg 1 4J TP101 ...
Page 110: ...Fig 4 6 GSM_ON Pg 1 2K TP402 Fig 4 7 PCN_ON Pg 1 1K TP415 Fig 4 8 PRE_ON Pg 1 4J TP416 ...
Page 112: ... I Q ...
Page 113: ...Fig 4 14 V_ERROR PCN Pwr Lvl 7Pg 1 16I Fig 4 15 300khz Charge Pump Pg 1 Log 9G ...
Page 115: ... Previous Section Next Section Main Menu Section 6 Device Device Information Information ...
Page 172: ......
Page 173: ......
Page 174: ......
Page 175: ......
Page 176: ......
Page 177: ......
Page 178: ......
Page 179: ......
Page 180: ......
Page 181: ......
Page 182: ......
Page 183: ......
Page 184: ......
Page 185: ......
Page 186: ......
Page 187: ......
Page 188: ......
Page 189: ......
Page 190: ... Previous Section Next Section Main Menu Glossary of Terms ...