Freedom R8100 SERIES, Руководство оператора

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Figure 2.2.7.9.1.3-6 Power Profile Slot with Markers
2.2.7.9.1.4 Meter Zone
See 2.2.5 Meter Zone for standard selections.
Constellation (Display Zone selection)
The Constellation display provides a visual representation of overall transmitter operation. This selection
displays a graph showing the distribution of symbol deviations of the received signal. Each plot consists
of one slot of the most current data available. Symbols (containing 2 data bits) are transmitted with phase
changes than can be represented as deviations of the carrier. Red tick marks on the display represent the
nominal locations for the deviation states when the radio is transmitting data using the modulation. White
bars show the actual deviation measurement. A tighter grouping around the red tick marks indicates more
accurate transmitter performance.
Be sure that the Modulation Type in the P25 II test zone is set for the expected receive signal in order to
establish the appropriate horizontal range and symbol timing used to sample the deviation appropriately.
Sampling is at symbol times for HDQPSK but halfway between symbol times for HCPM. ISI inherent in
the modulations causes some overshoot exhibited by groups being a little further from center.
Figure 2.2.7.9.1.4-1 HDQPSK Frequency Constellation