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8 Spectrum Analysis Mode
170
IDA - 3106 Narda
8.4.1 Changing the time resolution (Time Resolution)
In total, 400 lines are available in the spectrogram for the display. The time
resolution corresponds to the representation of one line and therefore
determines the maximum time that can be displayed: t = 400 x Time Res. If
the measurement time needed for a spectrum is longer than the time
resolution setting, the average sweep time will be shown in the display as
Time Res.
When the maximum display time is reached, the oldest result is
overwritten in each case (rolling memory).
To change the Time Resolution:

Press the
Spectrogram / Time Resolution
softkey and select a value.
NOTE:
A new spectrogram line is generated with every new spectrum if you set
As
fast as possible
.
8.4.2 Selecting the detector
Since the data in the time axis as well as the frequency axis is compressed
to display each individual pixel in the spectrogram, you must select a
detector. The choice of a detector determines which values from the
spectrum are shown in the spectrogram. The following types can be
selected:
•
RMS:
The spectrogram shows the time characteristic of the RMS value
•
+Peak:
The spectrogram shows the time characteristic of the largest
value
• –
Peak:
The spectrogram shows the time characteristic of the smallest
value
NOTE:
The measurement is always performed for all three detectors at the same
time. You can therefore switch between the detector types at any time and
the results shown immediately, without the need for a new measurement.
To select a detector:
 Press the
Detector
softkey, select a type using the rotary control knob
and press
OK
to set it.