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Trace/Detector
Where:
Trace 1D is the measured value of trace 1, as it comes from the SENSe subsystem.
Normalized Trace is Trace 3, in which you have previously stored a reference trace
All values are in decibel units.
This Trace 1 contains the values that are returned form a trace query, or if the marker is placed on the
trace.
For example, let's say bucket 1 on Trace 1 is at 0 dBm, and bucket 1 on Trace 3 is at 10 dBm. The
resultant bucket is at 0 dBm – 10 dBm = –10 dB (just like with a delta marker).
You are also given the ability to define what (dB) value to use for Ref Level, and to define where on the
screen the Ref Lvl line will appear using Normalized Reference Position. This flexibility in displaying
the result allows a wide range of devices, including amplifiers, to be tested using Normalize.
In the example above, bucket 1 has the value of –10 dB. Let us assume you have set Norm Ref Lvl to 5
dB. Thus bucket 1 will display 1.5 divisions below the Reference Level line (assuming 10 dB per
division).
The Reference Level line is normally the top line of the graticule. If Norm Ref Posn is set to 10, this is
the case. If it is set to 9, it is the next line down. If it is set to 5, it is the middle line of the graticule. If set
to 0 it is the bottom line.
So in the example above, if Norm Ref Posn is set to 9, then bucket 1 will display 2.5 divisions below the
top line of the graticule.
None of the manipulations of Norm Ref Posn and Norm Ref Lvl affect the data in the trace.
As Normalize displays a ratio between two traces (a difference, in dB) the Y-Axis Unit while in
Normalize is dB in Log Amplitude and dimensionless in Linear. The Y-axis unit chosen in the Y-axis
unit menu is unaffected by Normalize. When you leave Normalize the Y-axis unit returns to the value set
in the Y-axis unit menu. While in Normalize, all amplitude functions, such as Marker Y and the values in
other traces, should be always in db unit, and so should the returned trace query results. In other words,
both trace query result and marker Y become independent of the Y-axis unit chosen in the Y-axis unit
menu when normalize is on.
(In Linear, the equivalent calculation is performed but it yields a dimensionless ratio, so the normalized
reference level is unitless, presetting to 1, just as in Log it presets to 0 dB).
Y-axis annotation is blanked while in Normalize. Any other traces on the display are plotted in dB, where
the dB value used is equivalent to the dBm value of the trace. For example, if bucket 1 in trace 2 is at –40
dBm, that bucket is plotted at –40 dB. All traces use Norm Ref Lvl and Norm Ref Posn for positioning
on the display. When Normalize exits, the normal Ref Lvl is restored. This normal Ref Level is
unaffected by Normalize.
Normalize Block Diagram
A block diagram showing how Normalize works is presented below: