If the displayed values are unstable increase the Running Average from the default value of 1. Maximum value is 60. Increasing the running average is useful when measuring unstable sources or when measuring near the zero calibration level described below.
To monitor and record the maximum power level over time, set Max Hold to On. The needle and numeric values will display the maximum recorded value until Max Hold is turned off.
In Cont + Run mode (Figure: Limit Setting Display Changes), the power meter is continuously measuring and updating the power reading. In Cont + Hold mode, the readings are halted.
In Single + Run mode, the power meter performs the number of readings set in Running Average (default is 1) and then places the instrument in Hold mode. Changing the mode from Hold to Run will initiate another series of readings and then returns the instrument mode to Hold once again.
Calibration
The Calibration Zero function can be used to remove unwanted low-level interference signals from the power measurement. The interference signals must be below –20 dBm for the zero function to execute. When measuring the Device Under Test with CalibrationZeroOn, the unwanted interference power level is subtracted from the power reading in linear terms (i.e., milliwatts) and displayed.
To perform a Zero calibration:
1. Connect the Device Under Test to the Site Master’s InstaCal/Power Meter port.
2. Turn off the RF source of the Device Under Test, or disconnect the source from the test apparatus so only the noise/interference signals are present.
Note
If there is no interference signal detected by the instrument in Step 2, a “No Signal Detected” message appears on the screen and the Zero calibration is not necessary.
3. Press the Calibration main menu key and then set Zero to On.
4. Turn on the RF source of the Device Under Test or connect the source from the test apparatus. The power meter will now display the power level with the unwanted interference signal subtracted out.
Note
If there is excessive signal present at the port during the Zero Calibration (> –20 dBm), the following error message is displayed “Signal too high. Zeroing not allowed!”
