Comtech EF Data SDM-650B - Manual (Page 145)

Rev. 6 6–1
Chapter 6.
MAINTENANCE
This chapter provides information on the following:
• System checkout
• Fault isolation
• Interface fault isolation
• Module
replacement
• Module identification
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.