Chapter 6. Maintenance; System Checkout; Modulator - Comtech EF Data SDM-650B Installation And Operation Manual

This chapter provides information on the following:
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6.1 System Checkout

This section should be used as an aid in setting up a modem within an earth station.

6.1.1 Modulator

The modem supplies a QPSK modulated result of the DATA I/O connector to the IF
output connector (CP1).
A typical output spectrum is shown in Figure 6-1. If the output does not resemble this
picture, refer to the fault isolation in Section 6.2 to help find the problem.
Rev. 6
System checkout
Fault isolation
Interface fault isolation
Module replacement
Module identification
Chapter 6.
MAINTENANCE
6–1