S3x-HB-1-11
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of these different configurations, the system is required to monitor the optical interface and compensate
the gain value.
The optical monitoring occurs at the input to the local receiver module, with the measured Receive Light
Level (RLL) being displayed on the receive module menu in the GUI. A coarse indication of the RLL is
also displayed on the receive module icon at the GUI top level display. Any losses that occur in the optical
domain over and above the factory calibrated level are then compensated for using the receive module’s
AGC. If the RLL is below the level required for the AGC to stabilise a warning is displayed on the GUI; to
clear this warning the cable routing and cleanliness of the fibre connectors will need to be checked. If the
AGC is unable to stabilise for more than 30 seconds the system stops trying to stabilise and displays a
notification. Disconnecting the fibre cable and reconnecting it will re-
start the receiver’s AGC stabilising
process.
If a user is concerned about continuous gain adjustments occurring during their measurement cycle, this
feature can be de-activated using the GUI. In this case no AGC is applied until the user re-activates the
feature.
An intermediate mode can be selected that restricts the application of AGC, only allowing it to occur when
the user manually changes the set gain value on the GUI or by remote command. This mode achieves a
reasonable degree of gain accuracy whilst preventing gain adjustments being made mid-measurement.
3.1.2.6
Factory calibration
Each remote transmitter and local receiver is calibrated to a factory standard, allowing any remote to be
used in combination with any receiver module; no permanent pairing of remote/receiver is required.
3.1.3
High impedance mode
If required, any of the remote transmitter inputs can be set to a high impedance mode. As the native
impedance of the system is 50Ω the high impedance performance is naturally constrained to ~500MHz.
For the Tx8 type of remoted head the high impedance mode can be set on a per input basis, allowing
each of the eight inputs to be set to a combinat
ion of high or 50Ω impedances depending on what probe
type is attached. Once the input configuration has been set up the user can freely switch between inputs
without needing to further update the input impedance.
3.1.4
Passive integrator mode
The Sentinel 3 remote heads support three user selectable passive integrator time constants as standard.
These can be remotely set to 0.1µs, 1µs, or 10µs using the systems GUI. When using the passive
integrator the user selectable gain is limited to 0dB or less.
3.1.5
Transmitter Power Modes
Sentinel 3 transmitters support two power modes, Sleep and On. In the former, only the transmitter’s
communication functions are enabled. In this mode, the battery life is increased significantly for periods
when the transmitters will be known to be idle. When switched on, the RF and optical functions are fully
enabled. The Sentinel 3 system controls the start-up state of each transmitter according to user
preference. Transmitters may always be started in sleep mode, always started in fully on mode or in the
power mode set explicitly by the user prior to shutting down the system or disconnecting the transmitter
battery.
When the optical connection to the transmitter is removed, either by disconnecting the optical cable or
shutting down the connected receiver, the transmitter automatically reverts to the power saving Sleep
mode. For long periods of inactivity, the battery should be physically disconnected.
3.2 Chassis
The Sentinel 3 chassis houses the integrated system controller, the battery charger, and up to six
receiver modules.
Содержание Sentinel 3
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