Mocomtech CDM-QX Config„Rx„Descram Descrambler, Config„Rx„Buf RX Buffer Clock Source, Ent

CDM-Qx Satellite Modem	Revision 5
Front Panel Operation	MN/CDMQx.IOM

(Config„Rx„Descram) - DESCRAMBLER

Descrambling: Default-On			ENT)
IESS-315-On Off		(◄ ►
Options are:
	the appropriate descrambler type is automatically selected.
Default-On

IESS-315-Onthis only applies when Turbo is installed and has been selected as the FEC type.

Off no descrambling.

As before, the options are displayed all of the time, but the ◄ ► arrow keys will force the cursor to skip past an unavailable choice.

The default descrambler types are:

IMPORTANT Viterbi, no framing: Viterbi, EDMAC frame: Viterbi + RS or TCM/RS: TPC:

ITU V.35 (Intelsat variant)

Comtech proprietary, frame synchronized Per IESS-308, frame synchronized Comtech proprietary, frame synchronized

(Config„Rx„Buf) – RX BUFFER CLOCK SOURCE

Rx Buffer: Internal Rx-Sat

Tx-Terrestrial Ins (◄ ►, ENT)

User will select which Rx buffer clock source. Note that Tx-Terrestrialwill only be selected if the cards are grouped as modem. Also, note that External will only be selected if QDI interface type is selected. Selecting either one will allow the user to select th e buffer size as shown below:

Rx Buffer Size:

Disabled (▲ ▼, ENT)

Edit the size, in bits, of the Plesiochronous/Doppler Buffer. The value is changed using the S T arrow keys. The user should then press ENT. Values of Disabled, ± 512, 1024, 2048, 4096, 8192, and 16384 bits are possible.

When Disabled is selected, the Plesiochronous/Doppler buffer is disabled. The receive clock will then be derived from the satellite signal, and will therefore be subject to clock offsets relative to the local transmit clock, This is due in part to the originating clock

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