Technical data

5
The U2000 Series is based on the
powerful RF/icrowave diode sensing
technologies which have been
exploited by Agilent for over 30 years.
Introduced as the HP 8484A sensor in
1975, it utilized the then-new LBS
diode technology, which featured
metal to semiconductor junctions.
Such diode junctions are rugged,
highly consistent and repeatable from
diode to diode, and reliable in long
term measurement. [Ref: 1.2, page 19]
Over the years, the diode power
sensors have been improved to include
balanced (back-to-back) diode
confi gurations and also the addition of
two channel adaptations that extended
the power dynamic (square-law) range
signifi cantly.
Balanced diodes reduce the effect of
signal harmonics on the measurement.
In addition, later improvements
included super-integration of diodes
onto a single micro-substrate. A
functional block which provides for
on-board zeroing is also included on
the same substrate, thus removing the
need for any operators to unscrew the
RF sensor connector from test power
signal or to turn off the the test power.
In the U2000 Series, 5-diode stacks are
used for the high power range which
extends the dynamic range square-law
detection, and 2-diode stacks for the
low power range.
These stack technologies have
already been used in previous sensor
product lines. By basing the U2000
Series diodes on the popular E9300
Series sensor technology and the
on-board zeroing of the P-series
(N1921/22A) sensor technology, the
new sensors include all the signal
conditioning and analog-to-digital
formatting functions that have been in
use for several years. Thus, users can
be assured that the new USB power
sensor will deliver highly predictable
results.
[Ref: 2, pages 24–30] [Ref: 5]
Figure 6 shows an abbreviated block
diagram.
Figure 6 U2000 Series block diagram, showing the internal processing of power data. The diode stacks are shown
abbreviated graphically, the actual low power path has 2-diode balanced stacks and the high power path
has 5-diode stacks.
U2000 Series Product Concepts and Capabilities
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