Giga-tronics 8003, Operation Manual

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Operation
Manual 20791, Rev. C, June 2001 2-95
2.12 Power Measurements
One of the unique capabilities of the 8003 Precision Scalar Analyzer is to accurately measure microwave
power. The analyzer is designed to always make as accurate power measurements as possible, but
squeezing the last bit of performance from the analyzer requires attention to a few simple guidelines
discussed later in section 2.14.
Accurate 8003 Analyzer power measurements always begin with the sensor calibration. Sensors should
be calibrated at least once daily, preferably after a 5-minute warmup period. See Section 2.8.1 for
calibration procedures.
The 8003 Analyzer is capable of making fully corrected power measurements during a sweep. It does this
by applying Cal Factors to each measurement point in the sweep. The sensor’s Cal Factor is a correction
for its frequency response. Cal Factors are precisely measured (typically at every 1 GHz) by the
manufacturer or your Cal Lab, and are traceable to the National Institute of Standards Technology
(NIST). All 803XXA series sensors used with the 8003 Analyzer have a table of Cal Factors stored in an
EEPROM in the sensor. You can examine each sensor’s Cal Factor table by pressing
[CONFIG]
followed by the [ SERVICE ] softkey. Then press [ SENSOR EEPROM ] followed by [ SENSR X EEPROM ],
where X is the sensor letter (A, B, or C). You will see a table similar to the one in Figure 2-52, giving
identification information for the sensor.
Figure 2-51: Sensor Calibration Screen
PERFORMING POWER SWEEP
-1V
-10 mV
-100 mV
CALIBRATOR OUTPUT POWER dBm
-25 -20
-15 -10 -5
0
5
ATTN 1 10dB ATTN 2 20dB
ATTN 3 30dB ATTN 4 40dB
Autoxero : Pass
ATTN 1 : Pass
ATTN 2 : Pass
ATTN 3 : Pass
ATTN 4 : Pass
+20 ~ +11 dBm: Pass
+10 ~
+1 dBm: Pass
0 ~ -9 dBm: Pass
-10 ~ -19 dBm: Pass
-20 ~ -30 dBm: Pass
CONT/
PAUSE
ABORT
CAL
SENSOR A
10 15
Balanced sensor limits