Dsp 56301 Module; Option Iqif Board Crtu-B7 - Rohde & Schwarz CRTU-RU Service Manual

Radio Unit R&S
CRTU-RU

DSP 56301 Module

Option IQIF BOARD CRTU-B7

The IQIF BOARDs contains all circuit parts for generating IQ In and Out for 2 RX and TX channels.
Design
Cooling system
Control and supply
Complete function
Receiver functions
(x stands for first or second
channel)
1140.0050.82
Instrument Design and Function Description
The sandwich modules are directly plugged onto the LINKHANDLER via
multipoint connectors. They contain the DSPs including the memory.
The IQIF BOARD is designed as a plug-in module with a silver-coated
two-shell aluminum casing fixed with several screws.
This casing is equipped with cooling fins at the rear which are provided
with a cover sheet so that a special cooling duct is produced. These
cooling duct is evenly cooled by the air flow of the instrument fan
irrespective of neighboring modules. This efficient cooling is required
since a very high degree of integration is implemented on this board.
Control and voltage supply of the IQIF BOARD are effected via two 96-
pin FUTURE-bus connectors from MOTHERBOARD1.
The IQIF BOARD demodulates IQ-data from the IF for two RX and TX
channels. It also modulates external IQ-data onto an IF frequency. So
an external loop between IQ IN and IQ OUT is possible for each of the
two RX and TX channels (connectors IQ IN/OUT CH1 and IQ IN/OUT
CH2 on the rear panel).
The board is divided into 4 parts: RX1 IQ IN and OUT, RX2 IQ IN and
OUT, TX1 IQ IN and OUT and TX2 IQ IN and OUT. This strict
separation of the functions permits to achieve high decoupling between
the separate modules.
The module can also generate a reference signal at the internal MMCX
connector REF OUT3. The LO for this reference signal is synchronized
by the 110.8 MHz reference frequency from the REFERENCE BOARD
fed in via the MMCX connector IN110.8M3.
The buffered 110.8 MHz signal is fed out via a further MMCX connector.
On the receiver side an IF signal provided by the RXTX board is applied
to the internal MMCX connector IF3RXCHxIN of the IQIF BOARD. The
signal can be directly
IFWRXCHxOUT or fed through the inner path with additional monitoring
of the IQ OUT signal at pins RXxIOUT and RXxQOUT of the IQ IN/OUT
CHx connectors. Alternatively, it is possible to feed out the IQ data via
IQ IN/OUT CHx and to modulate the IF with IQ IN fed in via IQ IN/OUT
CHx.
The first RX (RX1) channel can be split to generate a second RX
channel.
The signal received from the RXTX-Board is fed out via the connector
EXTxIFRXOUT. An external IF signal can be fed in via EXTxIFRXIN.
The LO is synchronized to the 110.8 MHz reference frequency from the
REFERENCE BOARD applied to the MMCX connector IN110.8M3.
3.15
fed through to IF3RXCHxOUT and
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