Boonton 4530 Peak Power Meter User Manual - Manual (Page 42)

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Chapter 3 Boonton Electronics
Operation 4530 Series RF Power Meter
Table 3-4. Zero/Cal Menu
Zero Chan (ALL SENSOR TYPES) Zero the sensor to remove the low-level power offsets of the sensor without
doing a complete AutoCal. This procedure is used to remove the effects of thermal drift. On non-
temperature compensated peak sensors, an advisory message will appear in the graphical and text
headers when the sensor's temperature changes more than 4 degrees Celsius from the calibration
temperature. This is not an error message. The need to zero is determined by the signal level
measured and the desired repeatability. It is recommended that a sensor be re-zeroed immediately
before performing any measurement in the lowest 10 dB of the sensor’s dynamic range.
When a sensor zero is performed, the sensor must be removed from any RF source, or connected to
the selected calibrator. Allow the sensor to settle for at least 30 seconds before zeroing if a high level
signal was previously applied.
GPIB Command Syntax: CALibration:{INTernal|EXTernal}:ZERO[?]
NOTE
The CALibrate commands ending with a question mark (?) are combined command/queries. At the
end of the calibration procedure, they return a zero character in the read buffer if successful, and
a one character if unsuccessful. This is in addition to any service request flags in use.
AutoCal (PEAK AND CW SENSORS) Performs a zero and complete step calibration of the sensor over its
specified dynamic range. This is required when the sensor is changed or when the temperature of the
environment has changed a significant amount. Peak sensor bandwidth is automatically set to low
and restored to its original setting at the end of the calibration process. This is the preferred method
of calibration for most CW sensors, and the required method for peak sensors. Frequency is auto-
matically set to the correct value during calibration and restored to the previous value afterward.
GPIB Command Syntax: CALibration:{INTernal|EXTernal}:AUTOcal[?]
FixedCal (CW SENSORS ONLY) Perform a fixed level calibration of the CW sensor. The calibration signal level
used depends upon the sensor's input attenuation. A Zero adjustment should always be performed
before a FixedCal. Frequency is automatically set to the correct value during calibration and restored
to the previous value afterwards. In most cases, AutoCal provides a more accurate calibration.
Attenuation Calibration Level Example
0 dB 0 dBm 51075
10 dB +10 dBm 51077
20 dB +20 dBm 51079
GPIB Command Syntax: CALibration:{INTernal|EXTernal}:FIXEDcal[?]
FreqCal (ALL POWER SENSORS) A single frequency, 0 dBm calibration with a user supplied reference
source of known accuracy. Set the channel's frequency parameter to the frequency of the external
power reference. On peak sensors, an AutoCal of the sensor must be completed before a FreqCal
may be performed.
GPIB Command Syntax: CALibration:USER:FREQcal[?]
NOTE
To change the calibration method of the sensor in use from the AutoCal to the FreqCal method,
perform a CancelCal to erase the AutoCal data.