User Manual

SGD-SB2025NT-TUM, Part 2
Jan 12 Page 79 RECEIVER VOTING
As this process is undertaken for every packet, the voting response time is 20 ms. Since the IP
data packet contains both the RSSI information, the digitised audio and simultaneously conveys
the fact that a signal is present, no audio will be lost at the start of an incoming signal due to the
delay whilst the voter makes a signal assessment. The latter situation is common with
conventional analogue voting systems as the audio is already being presented before the voter has
made a selection.
10.4 V OTER C ONFIGURATION
The Firmware configuration table contains variable parameters that control the action of the Voting
process based on the Signal Quality information. These parameters have a range of movement
which may include the OFF state; they can be adjusted to give optimum performance to suit the
operational conditions.
10.4.1 Voting Parameters
The configuration table state is non-volatile and is accessed indirectly via the ET.
Table 4. Voter Adjustable Parameters.
Function Range
Level of difference in RSSI necessary before a selection
change is made.
1 to 13 in unity steps.
Deselect and ignore a site that has had mute open for x
(time). Return the site to voter availability when it’s mute
closes for a minimum of 10 seconds (not configurable).
Range OFF or x = 5 min to 30 min
in 5 min steps.
Voter Override – a means to force the selection of site x
irrespective of the incoming RSSI.
Range OFF or x = 1 to 32 – only
enabled slots may be selected.
10.5 B EST S IGNAL S ELECTION – P ARAMETERS
This relates to the measurement units used by the integrated Voting algorithm of the NI.
10.5.1 RSSI
An output is required from the base station Rx in the form of a varying voltage or a variable tone
that is input to the Station NI.
Table 5. RSSI Requirements.
Function Range
Voltage RSSI:
Voltage Input Range >0 V and <5 V DC
Conversion Resolution 14 steps
Conversion Settings
The minimum and maximum values of RSSI input are entered as
boundary values. A minimum value of zero will disable the function.
A value exceeding the maximum will not increase the RSSI further.
Tone RSSI:
Tone Input Range 2.6 kHz to 3.5 kHz – user definable.
Conversion Resolution 14 steps – equally spaced in tone range