Tektronix MTM400 - Manual (Page 175)

Interface Configuration and Interpretation
MTM400 MPEG Transport Stream Monitor User Manual 3-131
Input Card Screen - 8PSK
The following LES indicators are available in the Readings section of the screen:
RF Lock Indicates when the RF reciver sections are in lock and receiving
normally.
FEC Lock Indicates when the Forward Error correction ( DVB or turbo
coded) is in lock and the data is being processed to give
Transport Streams.
The following graphs are available when the 8PSK interface card is installed:
Figure 3-49: Input card screen (example - 8PSK)
Constellation I and Q data are collected from the QAM front end and
displayed as a conventional constellation of 256 points by 256
points. The samples collected are not real time, so there is some
dwell (delay) before a complete constellation is displayed. The
persistence of the display can be varied using the Persist slider
control at the bottom of the graph.
MER and EVM calculations are performed on the constellation
data according to the formulas given in ETR290-101
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