L3 NARDA PMM 9010, User Manual

Page: 36 / 108

4-8 Sweep Mode Operating Instructions
4.6 Load Store
Pressing this key allows the User to have access to the memory of the
receiver and enables the storing up to a number of different
configurations/sweeps that depends on the parameters set on the receiver
(i.e. the number of measured points). For example, using standard CISPR
parameters it is possible to store up to 15 sweeps on the A+B band.
Each new scan will be stored in the first available memory position thanks to
the button
Store #x , where x is the first available position. When all positions
are occupied by a scan, this function is disabled until one of the previous
scan is erased.
To load a stored trace, press the
Load #x button until the proper scan is
displayed; to unload a trace select the Unload Trace button.
Please note that the Load function is scanning the memory in a circular way,
therefore all the occupied memory positions are shown in sequence. When
the key shows “Load #4”, it means the trace #3 is displayed and that the #4
will be loaded after the key is pressed, and so on and so forth.
To erase a trace, press the
Erase#x button .
Due to the structure of the memory, it is possible to erase only the latest
stored memory, with a sequence “LIFO” (Last In First Out), therefore after
having erased the #x, the #(x-1) will be the trace to be erased. With
reference to the example at the left, the last stored trace is the #4, and it is
the first that will be erased. After that, the key will show “Erase #3”, and so on
and so forth.
A more advanced trace management could be done using the PMM 9010
Software Utility.
Turn Off the tracking generator, if it is not used, while you are in Scan
Mode.
This prevents interferences and the measurements are more clean and
accurate.
4.7 Ultra Fast FFT scan
The Ultra Fast FFT (Fast Fourier Transform), as described at
§
1.11, provides
a “snapshot” of the whole band in just one second, what is useful for a more
comprehensive analysis in case the disturbance to be evaluated is somehow
intermittent and with an irregular repetition rate.
To activate this feature few settings have to be manually performed at first,
as per the following:
- Peak detector
- ≤ 50ms Hold Time
- Band A sweep.
Once all these conditions are satisfied, the Sweep is performed in really “one
second”, what is very useful to soon realize overall behaviour of EUTs in a
debugging phase, saving time and making it possible even in those cases
where the EUT cannot stay ON for a long time without getting damaged
(small electric motors, etc.)
Later on will be then possible to make the full-compliant Quasi-Peak
evaluation of all the frequencies of interest after the measurements will been
taken.
During such FFT analysis the PMM 9010 makes use of internal standard
Gaussian filters still in compliance with the norms.