Tait TB8100 User Manual

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TB8100 Calibration Kit User’s Manual Calibrating the PA Power 28■ If the Low Pass Filter (LPF)/directional coupler PCB module is replaced■ After servicing of any components in the detector circuitry (such as thedetector diodes) on the LPF/ directional coupler PCBTo calibrate the forward and reverse detector bias voltages1. Ensure that the Calibration Kit PC is connected to the base station.2. Select the PA Calibration tab, and double-click Calibrate Fwd/RevDetector Bias Voltages.3. Ensure that the PA is not transmitting and that there is no RF source presentat the PA RF input or output by disconnecting the input SMA connectoron the PA front panel and the ‘N’ type output connector from the rear ofthe PA. Click Calibrate.When you have finished, the icon on the PA Calibration tab indicates thatthis task is complete.Calibrating the PA PowerThe power amplifier (PA) receives the RF signal from the reciter and amplifiesit to the required level, in watts, as requested by the reciter. The desired outputpower is determined by the reference voltage for the power control loop.The PA power control loop is calibrated at a single frequency, generally in thecenter of the operating band.You perform the calibration procedure to define – for each power level – thereference DAC (Digital-to-Analogue Converter) value and forward detectorvoltage.You should only need to re-calibrate the PA power if:■ The Low Pass Filter (LPF)/directional coupler PCB module is replaced■ Any repairs are carried out on the forward and reverse detector circuitry onthe Low Pass Filter/directional coupler PCB module■ You require a more accurate power calibration on a specific frequencyEquipment■ Either an inline power meter and 50 ohm load with a high power rating, or■ A terminating power meter and appropriate 50 ohm attenuator with a highpower ratingSetup for InlinePower MeterNote: Cables and connectors can easily cause a power loss of severalwatts if either too long or poorly terminated. Always use theshortest possible leads (or connectors instead of leads) between thePA and power meter set-up.1 32451 Reciter 3 PA 5 Load2 16-way cable 4 RF Power Meter