NXU-2B Operations Manual
3-6
equipment other than radios may be used with the NXU-2B, so VOX and VMR options are
provided. The Application Notes provided with JPS Radio Interface Cables may also specify
what COR method must be used with that cable.
The options are:
•
Hardware COR – Active Low. A control signal that goes low when valid audio is present.
For a radio, this signal is low when the radio breaks squelch.
•
Hardware Core – Active High. A control signal that goes high when valid audio is present.
For a radio, this signal is high when the radio breaks squelch.
•
VOX. Stands for “Voice Operated Xmit” – an NXU-2B algorithm detects the level of
audio in the incoming signal and indicates “valid audio” when that level exceeds a
threshold. That threshold can be modified by the VOX/VMR Sensitivity setting.
•
VMR. Stands for “Voice Modulation Recognition” – an NXU-2B algorithm detects the
level of human speech content in the incoming signal and indicates “valid audio” when
that level exceeds a threshold. That threshold can be modified by the VOX/VMR
Sensitivity setting. VMR is a good choice for noisy audio signals.
3.3.13
VOX/VMR Sensitivity
This setting applies only if COR Sense is set to either VOX or VMR. Options are Low,
Medium, and High. A lower setting means that a smaller amount of audio (for VOX) or human
speech content (for VMR) will be required for the incoming audio to be considered valid and
transmitted over the IP network.
3.3.14
VOX/VMR Hangtime
This setting also applies only if COR Sense is set to either VOX or VMR. This is the amount of
time the VOX or VMR remains active after the valid audio detection falls below the set
threshold, and may be set to 500, 1000, 2000, 3000, or 4000 milliseconds. Hangtime prevents
the valid audio determination from being inappropriately halted during short pauses in speech
or between words.
3.3.15
RX Input Level
Use this setting to adjust the NXU-2B for proper operation with the amount of audio being
applied.
Selecting a value for RX input level means that the NXU-2B expects that level as its nominal
input. That is, if the NXU-2B RX Audio Input is set to 0, the unit expects, and operates best, with
an input of 0dBm.
With normal audio input applied at the Audio/Control connector, the RX input level setting
should be adjusted until the AUDIO INPUT indicator flashes on voice peaks (and only on the
peaks).
3.3.16
RX Boost Mode
The receive input level may optionally be boosted by +20db in order to accommodate low level
signal sources. Selections are “No Boost” and “Boost +20db”.
Summary of Contents for NXU-2B
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