The internal step calibrator of Boonton 4500B is traceable to NIST (National Institute for Standards and Technology) and it enhances the measurement accuracy. The output of the built-in programmable calibrator is available from a Type-N connector located on the front of the instrument. This calibrator is used to automatically calibrate sensor offset and linearity, and can also be used as an internal signal source. In order to maintain measurement accuracy, it is always recommended to calibrate the 4500B instrument once in a year.
Specifications of the Internal Calibration Source
Below is a brief specification of the internal calibrator of the Boonton 4500B power meter.
||CW, internal or external pulse|
||1.024 GHz ± 0.01%|
||-50 to +20 dBm|
||VSWR 1.20 maximum|
||±0.065 dB (±1.5%) at 0 dBm|
|Accuracy vs Level
||add ±0.03 dB per 5 dB increment from 0 dBm|
|Preset Internal Pulse Period
||0.1 or 1 or 10 msec|
|Preset Internal Pulse Duty Cycle
||10% to 90% in 10% increments|
|Variable Pulse On Time
||7 usec to 65.535 msec in 1 usec steps|
|Variable Pulse Period
||28 usec to 131.072 msec in 2 usec steps Off-time limits - within 7 usec to 65.535 msec|
||+ or -|
|RF Connector Precision
|External Pulse Input
||Rear panel BNC, TTL level compatible|
The calibrator is used to automatically generate linearity calibration data for peak power sensors.
The built-in 1 GHz internal calibrator provides a convenient means for calibrating the sensor. The internal calibrator is used to automatically generate linearity calibration data for peak power sensors. Before starting any measurement by using the 4500B power meter, the sensor must be connected to the built-in calibrator and need to be calibrated. The internal calibrator has a dynamic range from -50 dBm to +20 dBm. The user-selectable automatic calibration routine has a group of commands which is used to control automatic zero offset and linearity adjustment to the RF power sensor in steps over its full dynamic range.
Fig. 1: Screenshot of the automatic calibration menu selection for channel 1 on Boonton 4500B
Calibrator Report Information
There is a report information available about the installed calibrator in the Boonton 4500B power meter. The calibrator information can be retrieved by pressing "Calibrator" > "Extensions" > "Calibrator" menu keys. The report includes: Status, Serial Number, Software Version, Calibration Date and Internal Temperature.
Calibrator Output Modes
The internal calibrator of Boonton 4500B power meter has two selectable output modes - CW and Pulse. The calibrator output mode can be set as CW by selecting buttons "Spcl" > "Calibrator" > "Cal Mode" > "CW". For Pulse mode, the button selection should be as "Spcl" > "Calibrator" > "Cal Mode" > "Pulse". For each output mode, the calibrator output need to be enabled by selecting "Calibrator" > "Cal" > "Output" > "ON".