Since I did not get much response on this subject (I presume the bandwidth
of my question was too wide), I'll narrow down my question.
Referring to Annex A Measurement method 2 (page 17) of EN55024:1998.
" The following shall be fulfilled during a sweep in the whole of the
specified frequency range (80 to 1000 MHz).
Performance Criteria A (This is the pass criteria for radiated and conducted
immunity tests)
--for supporting telephony service, the following applies :
with the audio channel open and active, the demodulated differential mode
noise on the telecommunications port measured at the TTE nominal impedence
(as specified by the manufacturer), shall not be greater than the values
given in table A.1 (for radiated immunity it is -30 dBm). The measurement
bandwidth shall be 100 Hz maximum at 1 kHz. "
What is the best way of measuring the 1 kHz (induced noise from the test)
signal noise on an active phone line. Asuuming the TTE nominal impedence to
600 Ohms and the measuring instrument, if a spectrum Analyser, being 50
Ohms. This low impedence measuring instrument can affect the call on the
line and hence the results.
Apart from the fact that the test setup itself can influence the results in
a big way.
Hope to get some responses this time !!!
Regards,
Praveen
Dear Members,
For immunity tests in accordance with EN 55024 : 1998, 'Telecommunications
terminal equipment' (analogue and digital), have particulat test conditions
in Annex A of the standard. It is highlighted in the standard (section 7.2)
that the criteria given in Annex takes precedence over the general
performance criteria.
There are two methods of measurement in Annex A for radiated and conducted
immunity tests.
Anyone familiar with these measurements ? comments please.
What will be criteria for other immunity tests like the ESD, EFT, etc. ?
Criteria B and C are clear but criteria A is only for radiated and conducted
immunity tests.
Thanks for your responses.
Praveen
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