Specifications

3-62 888-2857-001 5/9/13
WARNING: Disconnect primary power prior to servicing.
Section 3 Operation
Platinum VAX-C Series
Figure 3-40 DVB-T Setup Screen 8
.
Table 3-35 Xmtr Home>Exciter Home>Setup>DVB-T Modulator>Next x7
(screen 8)
Fields Explanation
These special test modes will cause errors and should not be used in normal operation.
Special Test Flag Choices are None, Test Sync, and Test Spectrum. None: No special tests are
selected. Test Sync: One OFDM packet at the beginning of each Mega-Frame
is deleted. This helps to measure alignment of VAX-C output in SFN mode.
Test Spectrum: Sub-carriers in center of band are deleted to create a spectral
null. This is used to evaluate spectral regrowth due to transmitter or other non-
linear distortion.
PRBS Test Choices are On or Off. PRBS (Pseudo Random Binary Sequence) On generates
a test pattern instead of processing an input stream. It is only used by for
testing. On is selected when transmitter RF output is desired but a valid transmission
stream is not available. When On is selected the PRBS Test box will turn yellow on the
GUI display. Since this is a test mode it will show up in the fault log upon activation. It
will also cause an amber flashing output light on the front of the VAX-C and the system
fault LED will also light on the VAX-C.
The PRBS test function should not be enabled during normal operation with a valid
transport stream. If a power interruption occurs with the PRBS test mode enabled it will
be automatically disabled when system power is restored.
PRBS Bits 20 is default value.
Test Pattern Single Tone: Test mode.
Offset Tone: Test mode.
Stop Test: Stops test patterns.
Softkeys
Setup Displays Setup screen.
Exciter Home Displays Exciter Home screen.