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PSM-500/500L/500LT SCPC Satellite Modem
"2047" pattern or "2" for a "2^23-1" pattern. The "0" key will disable the BER test mode. BERT test
readings are displayed in the <Int'f: Status - BER> parameter and the 6 items below it.
Since there is no noise added in the IF Loop-back mode the BER results should show no errors.
This test is more useful once the modem is configured and a Loop-back over the satellite is
performed by setting the receive frequency to that output by the modulator.
The IF Loop-back state and the BERT state are both stored in EEPROM, therefore if the unit is
powered off during IF loop-back and/or BERT test it will return to this state when powered up
again.
More information on the BERT functions is given in Section 4.1.2 "Using the Built-in BERT".
2.9 Modem Configuration
Configuring the PSM-500 Modem operating parameters is essential before placing the unit into
service. The PSM-500 Modem operating parameters may be set up using the front panel, the
USB or the terminal command mode. The binary remote control input may also be used if the
remote interface parameters are already known and set.
2.9.0 Configuring the Modem for Operation
The following description assumes that the modem setup is to be done manually at a depot
location or in the field via the front panel. Alternately, the modem could be automatically set up
using a controller and the command interface. No software is provided for such an external
control application and therefore this task is the responsibility of the using organization.
2.9.1 Setting Essential Parameters
The setting of several basic parameters is essential to achieve proper operation and carrier lock
with the modem. Improper setting of any of these parameters will probably result in failure to
communicate with the far end of the link. These basic parameters are listed here to serve as a
minimum checklist for installation.
Modulator and Demodulator
1. Carrier Frequency (Note special procedures below available for L-Band interfaces.)
2. Modulation Mode (BPSK or QPSK)
3. Bit Rate
4. FEC Code Rate
5. Scrambler (Normally Enabled in IESS 308/309 mode – See "Using The Proper
Scramble" below)
6. Clock sources set per system requirements.
7. Reed-Solomon Codec settings if enabled
8. IBS Multiplexer settings if enabled
9. External reference set properly
10. Modulator and Demodulator functions enabled
Modulator
1. Output Level
2. Carrier Enable
3. The L-Band modem can also supply power and reference to a BUC.
Demodulator
1. Carrier Acquisition Mode and Acquisition Range
PSM-500/500L/500LT - Rev. 0.91
Installation
Page 2-15
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