Measurement Uncertainty Analysis – Power Reference Level Test
Measurement Introduction
where,
Ps is the reflection coefficient of the source (i.e. the DUT) and Pd is the reflection coefficient of the 8478B detector.
Hence,
Pmeas = f(Vcomp,V1,V0,R,CF,Ms)
Consider the measurement setup that exists in Figure
POWER
REF
DUT
PS
8478B
Pd
432A Power Meter
Figure B-1: Measurement Setup
Po is the total power output from the DUT. Of this power a proportion related to Pd is reflected back towards the source. The power subjected on the 432 would be:
2 Po1 – Pd
But because a proportion of this total power related to Pd has been reflected Ps will again cause a reflection giving:
Po(1±PsPd)2
So the total power incident or measured by the 432 Power meter is given by:
Po1 – Pd2⁄ (1±PsPd)2
Note | In all cases Pd is extremely small therefore Pd² terms tend to zero leaving. |
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| Agilent E4416A/E4417A | Service | Guide | |
