Keysight Technologies FieldFox A Series, User Manual

Page: 589 / 756

Keysight N9927-90001 User’s Guide 589
Noise Figure Mode (Option 356 – CPU2 Only)
How to use Auto-Integration
these cases, since the jitter goal has not been reached, a jitter warning marker
will appear on the data trace (unless disabled by the user), indicating that the
jitter goal could not be achieved within the selected time constraint.
Due to the stability of the FieldFox receiver with its internal reference switch
and the design of the auto integration feature, it is possible to achieve a stable,
accurate, low jitter measurement results even under challenging measurement
conditions, such as when measuring low noise power output devices at high
frequencies with no pre-amplifier, by setting very long maximum integration
times. For example, stable measurements with 0.1 dB jitter and no discernible
drift have been demonstrated measuring a low gain, low noise amplifier at
50 GHz using maximum integration times of 5000 seconds per point, in spite of
ambient temperature drift of several degrees Centigrade over the course of the
measurement.
While auto integration can achieve very low jitter measurements, it is a good
practice to consider the contribution of the jitter uncertainty to the total
measurement uncertainty when selecting a jitter goal. If the measurement
uncertainty from other contributors is known to be 0.5 dB, for example, it
would make little sense to set a jitter goal of 0.1 dB. Setting a jitter goal of
0.3 dB in this case would only increase the RSS uncertainty to 0.58 dB, and
would potentially speed up the measurement by a factor of 9 relative to a jitter
goal of 0.1 dB. Auto integration makes it possible to select the jitter level with
confidence, and is therefore a valuable tool in obtaining the required level of
accuracy with the fastest possible measurement time.
Auto-Integration Procedure
No user cal was performed for this measurement, because no external preamp
was used.
Set the equipment up in an area where it will remain undisturbed for the
determined amount of measurement time. Refer to Figure 29-13 on page 591
and Figure 29-14 on page 592 . See also, Figure 28-1 on page 548 and Figure
28-1 on page 548 .
1. Enter the Measurement type:
Select
Measure > Noise Figure (default)
2. Enter the Noise Source ENR information into a table:
Select Measure Setup
Then choose:
— Noise Source then
— ENR Mode Table (default)
If you have previously saved your noise source’s ENR information into a
table, skip this step and proceed to step 4 .