An innovative software-based radio system, the TB8100 provides two 5 or 50W channels or one 100W channel in a 4U subrack.

A two-channel TB8100 subrack contains two reciters and two power amplifiers. All subracks have their own power management unit.

This modular design makes replacement easy. Rugged construction with generous heatsinks and a front-to-rear fan-forced cooling system means that the base station can transmit continuously at full power with an air intake temperature from 30°C to 60°C (-22°F to 140°F).

Power Amplifier

The PA is available as 5W, 50W and 100W modules, and receives the RF signal from the reciter to amplify it to the required level.

The reciter controls the frequency based on its channel table and tells the PA what power level to use. The PA then waits for the key-up signal.

The TB8100 PA is available in 12VDC and 28V versions. TB8100 systems require a Power Management Unit to give complete monitoring and diagnostics including power monitoring and power supply alarms. A PMU is not required on the 12VDC system - hence the remote diagnostics features of the PMU are not available in this version.

Reciter

The reciter contains the receiver and the exciter, and has the following functions carried out via a state-of-the-art RISC processor and Digital Signal Processor:

• controlling base station operation
• storing the channel table and other configuration information
• holding licenses for optional features
• collecting faults from other modules and generating alarms
• running Task Manager.

The reciter communicates with other subrack modules over a control bus, with one reciter acting as the bus master to handle communications via the serial port on the front control panel.

A reciter covers one sub-band (see the TB8100 specifications for details). The receiver and exciter can be independently tuned to a switching range 2% of the centre frequency. Only two reciters are needed to receive on one sub-band and transmit on another.

System Interface

The System Interface provides line audio, digital inputs and outputs, and other interfaces such as a coaxial relay drive output, Tx Key and Rx Gate. Several options are available - you can choose the one most suited to the application.

Each system interface consists of a board fitted inside the reciter.  The reciter is generally supplied with the requested card already fitted.

Power Management Unit

The PMU is sized to provide sufficient power for one subrack (two 50W channels or one 100W channel). It offers the following features:

• power factor corrected
• can operate with mains supply from 88-264 VAC (no switching required)
• DC supplies have floating inputs, so that the supply can be negatively or positively earthed
• optional auxiliary power output (12V and 40W) for trickle charging battery or powering external equipment
• optional standby module for maximum power saving capability.

PMUs are available in several formats to suit customer requirements:

• For mains supply only, an AC-DC converter is used
• For DC power supply only, a DC-DC converter is used
• For AC/DC operation, a PMU with both converters is needed.

For power saving operation, a low current standby submodule is added, which provides just enough power for the receiver when the base station is in Deep Sleep mode and the main PMU is switched off.

The DC power supply and the auxiliary power output are available for 12V, 24V and 48V. Input and output voltages can be selected independently - for example, it is possible to have a 12VDC supply to the PMU and an auxiliary output of 24VDC, or a -48V supply and a 12V output.

Subrack, Front Panel, and Control Panel

The TB8100 is enclosed in a subrack with a front panel and control panel. The passivated steel subrack is very compact at 4U high, and is designed to fit into a standard 19 inch rack or cabinet.

The front panel incorporates the cooling fans for the PA and the PMU. The user can replace both the front panel and the individual fans if necessary.

The control panel is mounted onto the subrack independently of the front panel. Three versions are available:

• Power Save control panel: includes two LEDs to show power and alarms, plus a 9-way D-range connector.
• Standard single channel and dual channel control panels: these feature a serial port for TB8100 Service Kit connection, microphone socket, and other controls and channel displays.