Alcatel-Lucent 9500 MXC User Manual page 865

ODU 300
ODU 300, 6 to 15 GHz
Figure F-3.
ODU
IQ
311 MHz
DMD-
MOD
Ref
Osc
INU
N-PLXR
-48VDC
AGC
126 MHz
3DB 23063 ADAA - Rev 004 July 2007
ODU 300 platforms for 6 to 15 GHz, and 18 to 38 GHz, differ in respect of the
synthesizers used to derive the signal sources for the Tx and Rx mixer stages. For
the 6 to 15 GHz ODU, separate synthesizers are used. For 18 to 38 GHz, a
common synthesizer is used.
Figure F-3 shows a 6 to 15 GHz ODU 300ep block diagram.
TX Mixer
TX IF
TX-IF LO
Telemetry
uP
Multiple DC rails
DC-DC
Conv
RX-IF LO
AGC
IF Mixer
The quadrature modulated 311 MHz IF signal from the RAC is extracted at the
N-Plexer and passed via a cable AGC circuit to an IQ demodulator/modulator.
Here the 311 MHz IF is demodulated to derive the separate I and Q signals using
the 10 MHz synchronizing reference signal from the RAC.
These I and Q signals modulate a Tx IF, which has been set to a specific
frequency between 1700 and 2300 MHz, such that when mixed with the Tx local
oscillator signal (TXLO) in the subsequent mixer stage, provides the selected
transmit frequency. Both the IF and Tx local oscillators are synthesizer types.
Between the IQ modulator and the mixer, a variable attenuator provides software
adjustment of Tx power.
After the mixer, the transmit signal is amplified in the PA (Power Amplifier) and
passed via the diplexer to the antenna feed port.
A microprocessor in the ODU supports configuration of the synthesizers,
transmit power, and alarm and performance monitoring. The ODU
microprocessor is managed under the NCC microprocessor, with which it
communicates via the telemetry channel.
PA
TX LO
Diplexer
assembly
RX LO
LNA
Rx Mixer
9500 MXC User Manual
TX Power
Monitor
Vol. VI-F-9