Figure 5-4. Loopback Modes - Comtech EF Data CDM-570 Installation And Operation Manual

CDM-570/570L Satellite Modem with Optional IP Module
Front Panel Operation
Selection Description
(Transmit an alternating 1,0,1,0 pattern) Used to check the carrier suppression of the Modulator.
This test mode forces the modulator to transmit a carrier modulated with an alternating 1,0,1,0
pattern, at the currently selected symbol rate. This causes two discrete spectral lines to appear,
spaced at +/- half the symbol rate, about the carrier frequency.
TX-1,0
If OQPSK is selected as the modulation type, the test produces a spectral pattern suitable for the
measurement of SSB rejection – useful in determining the phase and amplitude accuracy of the
modulator.

Figure 5-4. Loopback Modes

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Revision 12
MN/CDM570L.IOM