beautypg.com

Scrambling types, Differential encoder, Transmit frequency (if) – Comtech EF Data SNM-1001L User Manual

Page 317: Frequency reference, Transmit frequency change time, C.2.3 scrambling types, C.2.4 differential encoder, C.2.5 transmit frequency (if), C.2.6 frequency reference, C.2.7 transmit frequency change time

background image

SNM-1001L Satellite Modem

Revision 1

Burst Mode Modulator Operation

MN/SNM1001L.OM

C–3

C.2.3 Scrambling

Types

One of the following scrambling types can be selected by the operator.

• A programmable seed 2^15 -1 Synchronous Scrambler.
• None

C.2.4 Differential

Encoder

The differential encoder is not needed as the data inversion ambiguity is resolved during
acquisition.

C.2.5 Transmit

Frequency

(IF)

The range of the output IF spectrum can be selected by the operator from 50 to 180 MHz, in 1
Hz steps.

C.2.6 Frequency

Reference

SCT, RX Bit Clock, and IF output are locked to the Frequency Reference.

Internal (Standard

Stability over the operating temperature range =

± 10 PPM.

Internal High Stability

(Optional)

Stability over the operating temperature range =

± 0.2 PPM.

External Reference

Input (Standard)

The External frequency reference connector is located on the back panel. This
allows Frequency Reference to be locked to an external reference frequency

standard.
Impedance 75

Frequency

1, 5, 10 or 20 MHz

Amplitude

≥ +0 dBm < +20 dBm

DC offset

Capacitively coupled

Connector BNC

Reference Frequency

Output (Optional)

The External frequency reference connector can be used as an output when the
High Stability option is installed. When selected from the front panel, this output

can be used to lock other equipment to the Internal High Stability Reference of the
selected modem. The output is 10 MHz, the level is +10 dBm

± 5 dBm.

C.2.7

Transmit Frequency Change Time

The time between the end of a remote command and the end of the modem reply for frequency
change and synthesizer lock will be < 200 mS.