Rack-Mount RDMS
TM
Telemetry Receiver
100
Quasonix, Inc.
The DSP-based SNR estimator numerically measures received power relative to noise power at the demodulator
input, assuming the signal power is attributable to constant-envelope modulation and the noise power is attributable
to additive white Gaussian noise. This measurement is very accurate when the SNR is below 30 dB, but it will rarely
report a value above this (no matter how strong the signal). This selection is recommended for ARTM modulation
types (Tier 0, I, and II) or when an accurate AGC zeroing process is not feasible.
The AGC-based SNR estimator measures received power relative to the AGC zero point (i.e., noise floor). This
estimation is insensitive to modulation and does not distinguish between intended signal and interfering signal. This
selection is recommended for unknown signals or for signals with modulation that is not constant-envelope (for
example, unshaped PSK). This method is also recommended when the received signals may be more than 30 dB
above the noise floor. However, an accurate AGC zeroing process is required for accurate results.
4.2.4
Remote Monitoring Menu
The Remote Monitoring menu contains one option, Multiple RDMS Performance Monitor, as shown in Figure 175.
To access the Multiple RDMS Performance Monitor, navigate to the Main Menu, and then select Remote
Monitoring > Multiple RDMS Performance Monitor.
Figure 175: Multiple RDMS Performance Monitor
4.2.4.1
Multiple RDMS Performance Monitor
The Multiple RDMS Performance Monitor offers a quick snapshot of each rack-mount receiver, down to the channel
level. The monitor is comprised of a table with columns for RDMS IP address, RDMS alias, channel, mode, bit rate,
modulation scaling, modulation scale index, signal strength, signal quality, lock-detect status (as text and as a red or
green color block), and channel active status.
The Multiple RDMS Performance Monitor uses a numerical representation for signal strength and signal quality.
The range of signal strength readings is from -120 dBm to +10 dBm. For signal quality, the range is a unit-less 1 to
99, with 99 being the best possible quality. Also similarly, the status consists of a bar that is either green for a locked
signal or red for loss of lock.
At the bottom of the monitor window is a button that allows the user to show or hide inactive channels and a
checkbox for the All Devices Signal Lock Indicator, which tells the operator that all of the rack channels have signal
lock.
Figure 176 shows a single RDMS™ with two active channels. The Signal Lock field is highlighted in red to indicate
there is no signal lock.