OM20 Universal Outdoor Modem
OM20 Theory of Operation
MN-OM20– Revision 5
4–2
4.1.1
OM20 L-Band Printed Circuit Card
The L-Band Printed Circuit Card consists of an analog modulation function, an analog complex
downconversion, and two wide-band digital synthesizers. The block diagram of the L-Band
Assembly is shown in Figure 4-2.
In the modulator, analog in-phase (I) and quadrature (Q) signals are generated on the Digital
Baseband Printed Circuit Card, routed to the L-Band/IF Printed Circuit Card, and modulated at
the desired frequency. The L-Band modulated signal is then passed through a microprocessor
controlled variable attenuator providing gain control of the output signal.
In the complex downconverter, the signal for demodulation is amplified and sent through a
variable wideband attenuator for AGC. The gain-controlled signal is then passed through a
complex downconverter to a low IF.
Quadrature
Demodulator
IF
B
oar
d
C
onn
ect
or
(
40
-P
in
H
eader
)
Demodulator I
Demodulator I Inv.
Demodulator Q
Demodulator Q Inv.
AGC
L-Band
Synthesizer
(950-1750)
PDA
Analog Q Inv.
Analog I Inv.
L-Band
Synthesizer
(950-1750)
Quadrature
Modulator
Analog Q
Analog I
Q AA
Filter
I AA
Filter
Switch
RxLB
TxLB
L-Band
C
oupl
er
DCSA
L-Band
Figure 4-2. L-Band Card Block Diagram
Summary of Contents for OM20
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Page 20: ...OM20 Universal Outdoor Modem Introduction MN OM20 Revision 5 1 4 Notes ...
Page 32: ...OM20 Universal Outdoor Modem Installation MN OM20 Revision 5 2 12 Notes ...
Page 38: ...OM20 Universal Outdoor Modem OM20 Initial Configuration MN OM20 Revision 5 3 6 Notes ...
Page 66: ...OM20 Universal Outdoor Modem OM20 Theory of Operation MN OM20 Revision 5 4 28 Notes ...
Page 138: ...OM20 Universal Outdoor Modem Web Browser Remote Protocol MN OM20 Revision 5 6 64 ...
Page 164: ...OM20 Universal Outdoor Modem Technical Specifications MN OM20 Revision 5 8 20 Notes ...
Page 198: ...OM20 Universal Outdoor Modem Appendix E MN OM20 Revision 5 E 16 Notes ...
Page 204: ...OM20 Universal Outdoor Modem Appendix F MN OM20 Revision 5 F 6 Notes ...
Page 214: ...OM20 Universal Outdoor Modem Appendix G MN OM20 Revision 5 G 10 Notes ...
Page 218: ...OM20 Universal Outdoor Modem Appendix G MN OM20 Revision 5 H 4 Notes ...
Page 220: ...2114 WEST 7TH STREET TEMPE ARIZONA 85281 USA 480 333 2200 PHONE 480 333 2161 FAX ...