Tait TB8100 User Manual

Also see for TB8100: Installation and operation manual Operation manual User manual Installation guide User manual

Tait TB8100 User Manual Manual pdf 29 page image

TB8100 Calibration Kit User’s Manual Calibrating the Forward and Reverse Detector Bias Voltages 27Note: You must perform the calibration in sequence from the lowestto the highest step. The DAC setting must be greater than theprevious one otherwise the value will not be stored in the PA, andyou cannot move to the next line.6. When you have completed adjusting the DAC settings, click Finish.When you have finished, the icon on the PA Calibration tab indicates thatthis task is complete.Troubleshooting TipsDAC Settings When you adjust the DAC settings, the values for the DAC Setting, CouplerFwd Voltage, and Control Voltage should always increase as the power levelincreases. If these values do not increase, there is either a fault with the PA orthe previous step was not calibrated correctly. If you make a mistake in thecalibration table, you must start again from step 1.Control Voltage The Control Voltage is shown in the table to indicate the operation pointwithin the power control loop. The range of the control voltage is from 0 V to7.5 V. If the control voltage reaches its limit before achieving maximum powerin the table, this indicates either a faulty gain stage in the PA or low RF inputpower to the PA.VSWR The VSWR (Voltage Standing Wave Ratio) is monitored at the RF output ofthe PA during calibration. The software will not allow calibration into a loadVSWR > 1.3:1. If a calibration step cannot be stored, check that the loadVSWR is <1.3:1. It is recommended that the load should have an input VSWR<1.2:1.Calibrating the Forward and Reverse Detector Bias VoltagesThe RF detectors, used for measuring the forward and reverse power, operatewith a small bias current. The resulting bias voltage from each detector (withno RF present) is read and stored inside the PA. These voltages are used whencalculating the Antenna VSWR (Voltage Standing Wave Ratio).You should calibrate the forward and reverse detector bias voltages: 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 you are already 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 Finish.When you have finished, the icon on the PA Calibration tab indicates thatthis task is complete.