Datasheet

Page 6
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1. US Patent #4943764, assigned to Hewlett-Packard Company.
2. November 1986 Hewlett-Packard Journal pages 14-2, “Diode Integrated Circuits for Millimeter-Wave Applications”.
3. Refer to “Maximum Power” on page 9 for maximum power handling specifications.
RF in
Low Sense
+
Low Sense
–
High Sense
+
High Sense
–
Built-in triggering port
for synchronization with
external instruments or
events
LED indicator for PC communication
Small and lightweight
build
Secure locking mechanism
USB 2.0-compliant cable for
connection to PC or other instruments
Diode-based sensors frequently rely on
the application of correction factors to
extend their dynamic range beyond their
square-law region, typically in the range
of –70 to –20 dBm. While this technique
achieves measurement of CW signals over
a wide dynamic range, it fails to do so for
modulated signals when the signal level is
above the square-law region. Modulated
signals must be padded down, with their
average and peak power levels within the
diode square-law region, for accurate
average power measurement.
The U2000 Series USB power sensors are
true-average, wide-dynamic-range RF/
microwave power sensors, based on a
dual-sensor diode pair/attenuator/diode
pair topology as proposed by Szente et.
al. in 1990
1
.
The simplified block diagram shown here
illustrates this technique.
This technique ensures diodes in the
selected signal path are kept in their
square law region—with output current
and voltage proportional to input power.
The diode pair/attenuator/diode pair
assembly can then yield the average of
complex modulation formats across a
wide dynamic range, irrespective of signal
bandwidth.
The dual-range Modified Barrier
Integrated Diode (MBID) 2 package
incorporates diode stacks in place of
single diodes. This further improves
measurement accuracy of high-level
signals with high crest factors without
incurring damage 3 to the sensor.
Implementation of both techniques in
the U2000 Series USB sensors enable
effective average power measurements
of a wide range of signals, including
multitone and spread spectrum signals
used in CDMA, W-CDMA and digital
television sytems.