U2021XA Datasheet, PDF (8/20 Pages) Keysight Technologies – U2020 X-Series USB Peak and Average Power Sensors

08 | Keysight | U2020 X-Series USB Peak and Average Power Sensors – Data Sheet
Recorder Output and
Video Output
Characteristic Peak Flatness
The recorder output produces a voltage
proportional to the selected power
measurement and is updated at the
measurement rate. Scaling can be
selected with an output range of 0 to
1 V and impedance of 1 kΩ.
The peak flatness is the flatness of a peak-
to-average ratio measurement for various
tone separations for an equal magnitude
two- tone RF input. The figure below
refers to the relative error in peak-to-
average ratio measurements as the tone
separation is varied. The measurements
were performed at –10 dBm.
The video output is the direct signal output
detected by the sensor diode, with no
correction applied. The video output
provides a DC voltage proportional to the
measured input power. The DC voltage
can be displayed on an oscilloscope for
time measurement. The video output
impedance is 50 Ω and the level is approxi-
mately 500 mV at 20 dBm CW. The trigger
out and recorder/video out share the same
port, and the level is approximately 250 mV
at 20 dBm.
Figure 2. U2021XA/22XA error in peak-to-average measurements for a two-tone input
(High, Medium, Low and Off Filters)
Noise and drift
Mode
Zeroing
Normal
Average only
No RF on input
RF present
No RF on input
Measurement average setting
Normal mode Free run noise
multiplier
Average only
NORMal speed
noise multiplier
DOUBle speed
noise multiplier
Video bandwidth setting
Noise per sample
multiplier
Zero set
< 500 MHz ≥ 500 MHz
200 nW
200 nW
200 nW
10 nW
1
2
4
1.00 0.9
0.8
Zero drift ¹
100 nW
Noise per sample
< 500 MHz ≥ 500 MHz
3 μW
2.5 μW
6 nW
3 μW
8
16
32
0.7
0.6
0.5
2.5 μW
64
128
0.45 0.4
Measurement noise
100 nW ²
(Free run)
4 nW ³
256 512
0.3
0.25
1024
0.2
4.25 2.84 2.15 1.52 1.00 0.78 0.71 0.52 0.5
0.47 0.42
5.88 4.00 2.93 1.89 1.56 1.00 0.73 0.55 0.52 0.48 0.44
< 500 MHz
≥ 500 MHz
Low: 5 MHz
0.6
0.55
Medium: 15 MHz
1.3
0.65
High: 30 MHz
Off
2.7
1.00
0.8
1.00
For average only mode with aperture size of ≥ 12 ms and averaging set to 1, the measurement noise is calculated as follows:
Measurement noise = 120/√(aperture size in ms) nW
For average only mode with aperture size of <12 ms and averaging set to 1, the measurement noise is equal to 50 nW.
For example, if the aperture size is 50 ms and averaging set to 1, Measurement noise = 120/√(50) nW = 17 n
1.  Within 1 hour after zeroing, at a constant temperature, after a 24-hour warm-up of the U2020 X-Series. This component can be disregarded with the
auto-zeroing mode set to ON.
2.  Measured over a 1-minute interval, at NORMal speed, at a constant temperature, two standard deviations, with averaging set to 1.
3.  Tested with averaging set to 16 at NORMal speed and 32 at DOUBLE speed.