Agc output, Interface specifications, Transmit clock source – Comtech EF Data SDM-300A User Manual

Page 380: Send clock timing source

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SDM-300A Satellite Modem

Revision 6

Specifications

MN/SDM300A.IOM

19–24

19.7.3 AGC

Output

A programmable DC output, proportional to the receive signal level, is located on the rear
panel at 10 mA maximum (0 to 10 volts).

Default Level

0 volts for –60 dBm
10 volts for –25 dBm

Low Level (0V)

Programmed from 0 to 10V in 0.5V increments.

High Level (10V)

Programmed from 0 to 10V in 0.5V increments.

19.8 Interface

Specifications

19.8.1 Transmit

Clock

Source

Select the TX clock from the following sources.

• Terrestrial:

± 100 PPM of the programmed rate, ≤ 5% jitter.

• SCT (internal):

± 10 PPM or SCT (with high stability option). ± 0.2 PPM.

19.8.2

Send Clock Timing Source

The send clock timing output can be generated from the Frequency Reference (either via the
front panel or remotely).

• If loop timing is selected the send clock timing output can be:

• The external clock input must be ± 100 PPM of the selected data rate.

• The RX satellite clock, RX data rate must be ± 100 PPM of the TX data rate.


• If the Asymmetrical Loop Timing (ASLT) option is selected, either via the front panel or

remotely, the send clock timing output can be referenced from:

• The external clock input, (Master Clock), which can be any multiple of 8 kHz as

long as it is

≥ 64 kHz ≤ 4.376 MHz or any multiple of 600 Hz as long as it is

≥ 2.4 kHz ≤ 64 kHz.


• The RX clock which can be any multiple of 8 kHz as long as it is ≥ 64 kHz ≤ 4.376

MHz or any multiple of 600 Hz as long as it is

≥ 2.4 kHz ≤ 64 kHz.



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