Agilent Technologies E4418B Service Manual page 135

Worst case error on 15.8V maximum power setting
Error = ((10ppm x 15.8V) + (0.3ppm x 100.0V)) + (0.5ppm x 15.8V) + 5((0.15ppm x 15.8V) + (0.1ppm x 100V))
= 257.75uV
Voltage Error
257.75uV
The relationship between the applied voltage from the Universal Source to the
corresponding power is given from:
1mW = 0.14493mV
This is a linear relationship, for example, 0.1mW is equal to 0.014493volts. This
relationship is valid between 0dBm and –30dBm.
However, above 0dBm a look up table is used for voltage to mW conversion. This is
due to the sensors non linear behavior at higher power levels. The voltage correction
at the appropriate points is shown in Table A-2.
Power (mW)
1
10
100
Therefore to attain a power of 100mW as shown in the Table A-2, instead of applying
14.4493 Volts, the actual amount of voltage required from the Universal Source
would be:
14.4493 x 1.075533 = 15.6Volts
Agilent E4416A/E4417A Service Guide
Measurement Uncertainty Analysis – Instrument Accuracy Test
Percentage Error = 0.00163%
Distribution
Rectangular
Table A-2: Voltage Correction Multiplier
Standard Uncertainty
148.8uV
Voltage Correction Multiplier
1
1.006577
1.075533
Measurement Introduction
A-7