3
rd
Generation Dual Channel
Compact RDMS
TM
Telemetry Receiver-Combiner
61
Quasonix, Inc.
With Mod Scaling turned Off, the Mod Index is set to the optimal 0.700. Mod Scaling should be turned off when a
new generation, digitally synthesized transmitter is the source. Digitally synthesized transmitters do not have a
variable deviation sensitivity adjustment, and as such are not subject to inaccurate modulation index settings
5.4.12.1.4 Modulation Scaling
– Acquire
When the RDMS™ is powered on, the default setting is Acquire, unless the unit was powered off from a preset
condition. Acquire mode has two states: Armed and Triggered. When Modulation Scaling is set to Acquire, in the
absence of signal, the Mod Scaling indicator on the Monitor screen shows Acquire, as shown in Figure 79, the state
is set to Armed. In Armed state, modulation scaling operates continuously.
Figure 78: Advanced PCMFM Settings Menu, Modulation Scaling
– Acquire
Figure 79: Monitor Screen, Mod Scaling Set to Acquire
If the receiver is locked and the delta h (the change in modulation index) has settled below the delta h threshold for
the specified settling time, the state changes to Triggered, and in Triggered mode, the estimated h (modulation
index) is monitored but the scale is not updated.
If delta h goes above the delta h threshold and settles again, the receiver is still locked, and the Eb/N0 at the settling
point is higher than the last settling point, the current scaling is updated with the new estimate. There is no transition
from Triggered back to Armed except for setting the mode to Acquire again.
5.4.12.2 Modulation Persistence
Modulation Persistence allows the current state of the Modulation Scaling setting to be retained following a power-
off cycle. The default value is Off (not checked), as shown in Figure 80.
