3 Spectrum Analyzer Mode
3.11 Harmonics Measurement
If one of the above parameters is in “Sense”, the first sweep occurs when any of the
following happen:
1.
We first enter the measurement
2.
After a preset
3.
When a parameter change causes a measurement restart in continuous sweep
mode
4.
When the user initiates a sweep.
First Sweep Action
If Fundamental Frequency is set to “Sense”, the first sweep sets the fundamental
frequency to the largest amplitude signal between 10 MHz and half the bandwidth
of the spectrum analyzer. We should span zoom (or frequency count) to give us a
good measurement of the fundamental frequency.
If Resolution Bandwidth is set to “Sense”, the first sweep sets the resolution
bandwidth to the lowest available Resolution Bandwidth greater than the 3.5 times
the 99% occupied bandwidth of the signal, to a minimum of 30 Hz. By default, the
video bandwidth and sweep time are coupled to those parameters, and all harmonic
parameters are coupled to the fundamental parameters.
Note that, even though the automatic RBW is limited to a minimum of 30 Hz, the
actual value measured should be retained. When multiplying the RBW for the 2
nd
and subsequent harmonics, use the maximum of the calculated value and 30 Hz.
For example, assume that the occupied bandwidth calculation results in desired
RBW of 12 Hz. The fundamental RBW will use 30 Hz, the second harmonic RBW will
use 30 Hz. The calculated RBW for the third and subsequent harmonics exceeds 30
Hz, so we should use the calculated value when measuring those harmonics.
3.11.1 Views
There is only one predefined view for this measurement (Normal), which displays
zero-span traces corresponding to the fundamental and the measured harmonics.
Normal is a multiple-window View. When in a multiple-window View, you select a
window by touching it. The menu controls may sometimes change depending on
which window is selected.
Whenever the View changes, the default menu is Frequency, unless otherwise
specified in the view description.
The table below shows the View and Windows used for this Measurement:
1850 Spectrum Analyzer Mode User's &Programmer's Reference
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