Power Meter Operation
Zeroing and Calibrating the Power Meter
Agilent E4419B User’s Guide 2-7
Zeroing and Calibrating the Power Meter
This section describes how to zero and calibrate the power meter. You 
should always zero the power meter prior to calibrating it.
Zeroing the Power Meter
Zeroing adjusts the power meter for a zero power reading with no power 
applied to the power sensor. During zeroing, which takes approximately 
10 seconds, the wait symbol is displayed.
To zero the power meter:
1. Press .
2. To zero channel A or channel B use   or   
respectively. Alternatively, to zero both channel A and channel B 
sequentially, use  . During zeroing the wait symbol is 
displayed.
When to Zero?
Zeroing of the power meter is recommended:
• when a 5
0
C change in temperature occurs. 
• when you change the power sensor.
• every 24 hours.
• prior to measuring low level signals. For example, 10 dB above the 
lowest specified power for your power sensor.
Zero/Cal Lockout
The Zero/Cal Lockout facilty provides a means of ensuring that a 
measurement cannot be taken until the connected sensor has been zeroed 
and calibrated. If the Zero/Cal Lockout facilty is enabled and a sensor is 
connected which has not been zeroed and calibrated, then the display 
window for the sensor will display the message “Please Zero + Cal ChA” or 
“Please Zero + Cal ChB” depending on which channel the sensor is 
connected to.
If you zero the sensor before calibrating it, the message changes to “Please 
Cal ChA” or “Please Cal ChB” depending on which channel the sensor is 
connected to.
Zero A Zero B
Zero Both
HP4402.book  Page 7  Thursday, November 30, 2000  1:39 PM