Configuring The Allan Deviation Plot; Scaling The Allan Deviation Plot - Symmetricom 5120A Operation And Maintenance Manual

For general information about markers, see

5.2 Configuring the Allan Deviation Plot

The PNTS can display the Allan deviation of the input signals. This data shows how much
deviation there is over time between the Input signal and the Reference signal. All measurements
are referenced to the Input signal.
The Allan deviation screen shows the following:
Allan deviation plot of the collected data.
Current τ
Noise Equivalent Bandwidth of the input filter, NEQBW, is displayed in the upper right
corner. NEQBW describes the equivalent bandwidth of a filter for broadband (white)
noise and is the bandwidth of a rectangular characteristic filter having the same power
transfer function as the selection filter (same area under the curve).
The 5120A and 5120A-01 perform cross-correlation. They are able to compute the noise
floor and shade the region below the measurement noise floor in gray.
The 5115A does not perform cross-correlation, and cannot shade the measurement noise
floor region. Instead it computes error estimates and presents those estimates using red
vertical bars along with each measurement.
The following can be configured:
Plot scale (see
τ
setting (see
0
Test mask (see

5.2.1 Scaling the Allan Deviation Plot

The Allan deviation plot can be scaled automatically or manually.
To scale the plot:
1. Press Allan Deviation Plot (see
2. Press Config Allan Deviation.
3. Press Scale Plot.
The highlighted softkeys show the current settings.
Press Auto Scale X Axis or Auto Scale Y Axis to auto scale either axis.
To scale the plot manually, press one of the following:
•
•
5120A/5115A Operations and Maintenance Manual
value displays in the upper-left corner.
0
page 43)
page 44)
page 44)
Fixed Scale Y Axis
-
Use Inc Min or Dec Min to increase or decrease the minimum scale value.
-
Use Inc Max or Dec Max to increase or decrease the maximum scale value.
Fixed Scale X Axis
"5.1.2 Setting Data Markers"
"3.1.1 Navigation" on page 12 for details).
on page 35.
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