Premier Mounts CDM-600 specifications Hardware Options

CDM-600 Satellite Modem	Revision 7
Introduction	MN/CDM600.IOM

1.3.4Hardware Options

There are four hardware options available:

1)Low Rate (1st Generation) Turbo Product Codec - a plug-in daughter card (SIMM module). This is capable of data rates up to 5 Mbps, and code rates limited to Rate 5/16 (BPSK, Rate 21/44 (BPSK) and Rate 3/4 (QPSK, OQPSK, 8-PSK and 16- QAM).

2)High Rate (2st Generation) Turbo Product Codec - a plug-in daughter card (SIMM module). This is capable of data rates up to 20 Mbps, and adds Rate 7/8 and Rate 0.95 capability.

3)Combination Low-density Parity Check (LDPC) and TPC Codec - a plug-in daughter card (SIMM module). This is capable of data rates up to 20 Mbps, and provides Rate 1/2, Rate 2/3 and Rate 3/4 code rates across the range of modulation types.

4)Internal/External High Stability Reference that provides a frequency stability of 2 x 10-8 . This may be fitted in the factory at the time of order, or fitted in the field as an upgrade (provided the CDM-600 was manufactured after a certain date - consult the factory for further information).

* The option provides an additional connector on the rear panel to permit the connection of a high-stability external reference signal, which in turn will phase-lock all of the internal frequency generation circuits of the CDM-600, including the IF synthesizers.

* The new connector is an SMA female type, located at the extreme right of the rear panel (when looking at the rear panel). This connector accepts signals at 1, 2, 5, 10 or 20MHz, over the range -5 dBm to +15 dBm, and is matched for both 50 and 75 Ω systems. The frequency is selected from either the front panel, or over the remote control interface.

* If the user selects external reference operation, the unit expects to see an appropriate signal at this connector. If the monitor circuit does not sense a signal at the connector, a Traffic Alarm is generated, and the High-Stability Internal Reference (stability of 5 x 10-8) is automatically substituted.

* If the user selects Internal Reference, the user may then adjust the exact frequency of the reference using the front panel, or the remote control interface.

* In External mode the High-Stability Internal/External Reference Module works by phase-locking the Internal Reference to the externally applied signal. If for some reason (perhaps an incorrect frequency being applied) the PLL circuit senses a loss of lock, a Unit Alarm is generated, and the TX carrier will be muted.

* Because the High-Stability Internal Reference is comprised of an Ovenized Crystal Oscillator (OCXO) there is a warm up period associated with this scheme. The user

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