2 General Power Meter Functions
108 N1911A/1912A P-Series Power Meters User’s Guide
• Press ,
   and toggle the   to On.
The  Zeroing pop- up is displayed when a zero occurs.
Manual Zeroing
To manually zero the power meter and sensor:
• Press   and the channel   softkey. 
The  Zeroing pop- up is displayed. 
Calibration
Calibration sets the gain of each power meter channel and P- Series sensor 
combination. This is achieved without the need to connect it to the 
1.0 mW Power Reference. The power meter can be set to automatically 
calibrate  on- the- fly while you are using it. Alternatively, you can perform 
the calibration manually. The reference calibration factor is automatically 
set for all P- Series power sensors.
During calibration, the wait symbol is displayed. 
Figure 2-88 Calibration wait pop-up
When you are performing measurements, this may cause delays in obtaining results. 
During this time, it is recommended to disable the automatic zeroing.
On dual channel meters you can zero each channel independently or both channels 
sequentially by pressing the   softkey - choosing  ,   or