Rack-Mount RDMS
TM
Telemetry Receiver
87
Quasonix, Inc.
4.2.3.1.1.4 Filter Settings Window
Directly below the Channel number is the Filter Settings window, shown in Figure 154.
Figure 154: Filter Settings Window, PCM/FM Mode
Based on the receiver’s high level of integration, the proper IF filter is automatically selected based on the current
mode and bit rate settings of the demodulator. Although manual filter selection is available through the Advanced
Terminal window in the RDMS™ client, or via the IF Filter Menu on the front panel LCD, as shown in Figure 110,
manual selection is not recommended. In the case of a receiver with diversity combining enabled, the two channels
must have the same IF filter selected for proper operation.
The basic premise of trellis demodulation relies on the precise phase modulation of the transmitted signal. Some
older analog transmitters have an inordinate amount of phase noise, reducing the effectiveness of the trellis
demodulator. In Tier 0 (PCM/FM), enabling the Phase Noise Compensation option (box checked) relaxes the
requirements of the trellis demodulator, allowing better receive performance for transmitters with a high degree of
phase noise.
When the modulation is set to PCM/FM, the Filter Settings window includes settings for IF and Phase Noise
Compensation. In any other mode, only the IF Filter option is available, as shown in Figure 155.
Figure 155: Filter Settings Window, Non-PCM/FM Mode
4.2.3.1.1.5 Signal Graph and Signal Indicators
The Signal Graph, shown in Figure 156, 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. The monitor also features a Persistence selection (adjustable