User manual

Audio Analyzer
AM700 Audio Measurement Set User Manual
4-71
Acquiring a Reference. Set up the Audio Analyzer and make a measurement that
provides a trace or single data point to use as a reference. On the front panel, press
the Set Ref button to save the acquired data (trace or point) as a reference. On the
display status line the AM700 displays a message that a reference trace is available.
To acquire a single data point as a reference, sweep detection must be disabled so
that a single point can be plotted. After acquiring the single data point, press Set Ref
to store the reference. You can then enable sweep detection if your measurement
needs to be able to detect a sweep start.
Displaying a Trace Relative to Reference. To display new trace data relative to the
reference you have just acquired, set the display units to one of the relative units
settings. You do this by touching the vertical axis and selecting delta V, delta mV, or
dBr, as appropriate for the measurement, using either the Units key or the Units
menu. The reference is positioned at the zero graticule line. Traces from following
measurements are displayed with respect to the reference. The plot of new trace data
is done relative to the reference and shows the differences between the new trace
and the reference.
Setting Up a Rel to Ref File. The reference can also be stored in a file for use at a later
time as shown in Figure 4-31 on page 4-73. To setup a Rel to Ref file, press the
Configure front-panel button, select Measurement Setup, and touch the Rel To Ref
soft key. This displays the Relative to Reference control panel as seen in
Figure 4-31. When a reference is stored in memory, a message is displayed to show
what type of reference it is (Level vs. Frequency is shown in Figure 4-31) and if the
reference is saved to a file.
Touch Save to a File to save the reference in the default reference file. If not saved
to a file, the reference will be lost if Set Ref is pressed a second time (if the acquired
trace or point has changed or has been cleared), since the reference memory is
overwritten every time the Set Ref button is pressed. You can clear the reference
from memory by touching the Clear Reference Memory Contents soft key.