3
rd
Generation Rack-
Mount RDMS™
119
Quasonix, Inc.
4.5.2.1
Signal Graph and Signal Indicators
The Signal Graph, shown in Figure 201
, provides a separate window for monitoring the receiver’s constellation or
eye pattern. The graphical display, included for each channel, mimics the graphical display on the front panel of the
rack-mount receiver. Depending on the modulation chosen, the monitor will either display an eye pattern for
PCM/FM, or a signal constellation for the other modes.
To the right of the Signal Graph is the Signal Indicators window, also shown in Figure 201.
The Signal Indicators window includes the following indicators for each receiver channel:
•
Signal Lock detection
•
Signal Strength
•
Data Quality Metric (DQM)
Figure 201: Signal Graph and Signal Indicators Windows
A signal lock indicator provides a visual representation of the demodulator’s current lock
-detect state. If the
demodulator has locked onto a downconverted signal, a locked (closed) padlock displays. Conversely, if the receiver
has not locked onto a signal or has recently lost lock, the indicator turns red and displays as an unlocked padlock
icon.
The demodulator measures signal strength in dBm and there is no limit to what the signal strength might be. Signal
strength is displayed on a dynamic bar graph and spans from -127 dBm to +50 dBm on the Browser Interface. In
addition to the visual representation of signal strength, the current measurement, in dBm, is numerically displayed
directly above the bar graph. When a signal of -
100 dBm or higher is detected, the bar turns green to signify “good”
signal strength. The Strength bar is red if the signal level is below -100 dBm.
The standard signal strength (RSSI) information is set on the Configuration screen via the Advanced > RSSI Display
drop down menu (next to the Zero AGC button). Refer to section 4.5.3.9.
If “Absolute” was the RSSI Display selection, the actual signal strength is displayed.
If “Relative” was selected, the RSSI displayed is relative to AGC Zero. The following bullets apply to RSSI
Relative:
