Rack-Mount RDMS
TM
Telemetry Receiver
18
Quasonix, Inc.
In addition to the eye pattern or constellation, the waveform graphics screen displays signal strength and signal
quality in vertical bar graph form, a red line AGC Zero On indicator in the Signal Strength bar, and signal lock
detect through a padlock icon, as shown in Figure 13.
Figure 13: Waveform Graphics LCD with Locked PCM/FM Signal
The signal strength bar, the left of the two with the letter “S” below it, is measured in dBm with an unspecified
range of -120 dBm to +10 dBm. When a signal -100 dBm or higher is detected, the bar turns green to signify “good”
signal strength.
The measurement of strength from an incoming telemetry signal by itself does not provide enough information
about the integrity of the received data. Therefore, the signal quality metric is displayed to the right of the signal
strength bar, with “Q” below the graph.
Signal quality is displayed as a unit-less metric with a range from 0 to 99. When the receiver locks onto a signal, the
signal quality bar turns green. Otherwise, the bar is displayed in red.
4.1.1.1
Signal Quality
The Signal Quality indicator is derived from an estimate of the Signal-to-Noise Ratio (SNR) of the received signal.
This estimate is calculated identically for all modes using one of two algorithms selected by the choice of SNR
Estimator (refer to sections 4.1.5.22 and 4.2.3.1.2.9.4 for further details).
4.1.2
Navigation
The Rack-Mount Receiver’s traditional hierarchical menu structure is navigated using the arrow and Enter keys on
the front panel keypad, as shown in Figure 14.