NARDA PMM 9010 Series, Руководство пользователя

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10-6 Click Mode Operating Instructions
10.4.1 Determination of
the click rate The first step of the measuring process is to determine the click rate N in
the minimum observation time. This is done measuring the time needed to
count up to 40 clicks or 40 switching operations; the maximum time
allowed is anyway 2 hours (120 minutes), unless the cycle is determined
by a program, which needs additional time to be terminated.
Therefore, if the equipment has a cycle and in this cycle less than 40 clicks
appear, then the cycle shall be repeated until 40 clicks are counted or until
the observation time is 2 hours.
If the equipment has a cycle and in this cycle more than 40 clicks appear,
the observation time is anyway determined by the cycle.
When the minimum observation time has been defined, it is possible to
calculate the click rate
N using the simple relationship:
T
n
N 1
=
where n
1
is the number of clicks measured and T is the minimum
observation time.
However, in certain conditions – see CISPR 14-1 for further reference –
the click rate
N must be calculated using a different approach:
T
f n
N
⋅
=
2
where n
2
is the number of switching operations and f is a factor dictated in
the standard. Such a factor can be taken into account for automatic
calculations if its value is properly set in the main setup page.
The click rate shall be determined at two frequencies: 150 kHz (Step 1)
and 500 kHz (Step 3).
10.4.2 Preliminary
Conformity and
Exceptions Once the number of clicks – or switching operations – has been
determined, then some preliminary controls can be made to verify if the
rate is greater than 30 (fail conditions); if the measured clicks are
conforming to the definition of the standard; if there are exceptions
applicable.
Thanks to its digital architecture, PMM 9010 can easily record and store all
the relevant parameters, keeping trace of all the events occurring during
the test and allowing the User to post-process all these data; PMM 9010
will also notify immediately the test results to the User.
10.4.2.1 Old and New
exceptions The “Click” test also requires verifying if exceptions E1 to E4 are
applicable. While E1 and E2 are “old” exceptions, easy to deal with, the
new E3 and, in particular, E4 are calling for a new hardware structure: an
old click analyzer is no longer compliant.
E3 is an additional counter, does not require additional memory and
implies only minor changes in the test flow, thus can be implemented in a
relatively easy way.
E4 is very demanding in terms of hardware requirements: a memory for
storing each disturbance duration and interval is required in order to post-
elaborate them, and it is mandatory to provide all the data in the test
report. Moreover, as the application of E4 is conditional to the final click
rate N - which in turn may prevent using E4 – the test flow significantly
changes.
Only new analysers specifically designed – like the PMM 9010 - can
successfully meet the requirements of the standard and be compliant with
the new Click test criteria.