Rohde & Schwarz 1138.4000, Service Manual

Page: 76 / 213

Instrument Design and Function Description Radio Unit R&S CRTU-RU
1140.0050.82 3.2 E-4
Block diagram
FRONTMODULE
RFTX1
IF3RX1
RXTX BOARD 1
IF2 486.515MHZ IF3 10.7MHZ
IF1 843.085MHz
/1816.115 MHZ
IF2 487.52MHZ IF3 13.85MHZ
IF1 842.08MHz
/1817.12 MHZ
RFRX1
LO1 TX
LO1 RX LO2
RF
F
R
O
N
TE
N
D
RF
R
X
2
RFRX1
R
F
R
X
T
X
AU
X1
R
FTX
2
R
F
R
X
T
X
AU
X2
R
FTX
1
LO3
TX
LO3
RX
LC DISPLAY
POWER SUPPLY INTERFACES
O C X O
R E F E R E N C E
O S C .
C R T U - B 2
FA
N
REFERENCE BOARD
FRONT MODULE CONTROLER
HARDDISK
FA
N
R4
IN
RF
2
RF
1
RF
3
O
U
T
INTERFACES
FAN
TR-CORRECTION
MODULE
FA
N
R5
OCXO
T C X O
1 0 M H z
X T A L
1 1 0 . 8
M H z
D IV
3
DD
S
DD
S
VC
O
84
t
o
16
8M
H
z
VC
O
84
t
o
16
8M
H
z
DI
V
2/
4
DI
V
2/
4
N E T C L K 2
2 1 to 8 4 M H z
N E T C L K 1
2 1 to 8 4 M H z
1 1 0 . 8 M 2
R121
1 1 0 . 8 M 1
1 1 0 . 8 M 3
+5VR EF
R120
Option
Sandwich
Module
VAR/KEYBOARD
MAINS
RFTX2
RXTX BOARD 2
IF2 486.515MHZ IF3 10.7MHZ
IF1 843.085MHz
/1816.115 MHZ
IF2 487.52MHZ IF3 13.85MHZ
IF1 842.08MHz
/1817.12 MHZ
RFRX2
LO1 TX
LO1 RX LO2
LO3
TX
LO3
RX
TR-CORRECTION
MODULE
DIGITAL BOARD
VAR 03
IQ/IF INTERFACE BOARD
CRTU-B7
CLOCK DISTRIBUTION
IF-RX DISTRIBUTION
IF-TX DISTRIBUTION
IF <-> IQ CONVERSION
MOTHERBOARD
LINKHANDLER1
CRTU-B5
LINKHANDLER 2
CRTU-B5
M A C SP E E C H
C R T U -B 6
AUC
ADC ADC DDC Mod. DDC Mod.
AUC TX DSP TX DSP
R F - S p l i t t e r
Attenuator
Attenuator
Attenuator
Attenuator
Fig. 3-1 Block diagram of CRTU Radio Unit