Tektronix MTM400 Manuel d'utilisateur télécharger pdf (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

Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - FAX 781.665.0780 - TestEquipmentDepot.com

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Tektronix MTM400 Manuel d'utilisateur Page 175