L3Harris NARDA PMM ER8000 User Manual page 16

1.11 Ultra fast
measurement: a
unique feature of
the PMM ER8000
1-8 General Information
In the CISPR bands A (9 kHz ÷ 150 kHz), B (150 kHz ÷ 30 MHz), C (30 ÷
300 MHz) and D (300 ÷ 1000 MHz) the standards requires the use of
specially shaped 200 Hz, 9 kHz, and 120 kHz RBW filters.
For example, in the CISPR band A (9 ÷ 150 kHz), the standards requires
the use of a 200 Hz filter that is, by nature, a filter that implies a long
measurement time: a complete scan may require even more than 10
minutes, depending on the detector in use.
Thanks to its architecture and to the large internal memory capability, the
PMM ER8000 can take a "snapshot" of the whole band in just one second
and, using a gap-less true built-in FFT capability, perfectly displays the
complete band in all its details. This feature is not only useful to greatly
increase the productivity of the test lab, but also to make better and more
comprehensive analysis in case the disturbance to be evaluated is
somehow intermittent and with an irregular repetition rate; its analysis with
a traditional receiver could be hardly made in a proper way (even if an FFT
capability is available: this feature needs a very comprehensive design), as
irregular pulses could be lost during a usual sweep.
To be noted that during the FFT analysis, the PMM ER8000 makes use of
internal filters mathematically modelled to the perfection using a FIR
technique.