Grace,
It is possible to overload the input of your analyzer/receiver without damage,
normally this just causes signals to clip. However strong signals outside your
normal range of measurement can be a concern.
If you are concerned about spikes caused by click sources, it is possible to
Dear Members,
Happy New Year!!!
I need your advice to prevent RS ESU receiver from damage. A service
report (as a result of annual calibration) indicates frequency response
out of specification below 10MHz. Adjusted frequency response. Adjusted
the reference oscillator to optimize frequency
Happy new year to all, and hope you had a great Christmas !
Every receiver or spectrum analyzer used for conducted
measurements on a LISN or AMN to mains voltage
ABSOLUTELY NEEDS a dedicated surge/spike suppressor.
They are easy to purchase, but you can build one yourself
using a fast
Here is one example:
RS®ESH3-Z2 Pulse Limiter
High RF input levels and high-energy interfering pulses generated on artificial
mains networks when the DUT is switched on and off can damage the RF input
circuits of test receivers. The RS®ESH3-Z2 pulse limiter limits and reduces
the interference
Ken,
Having worked power electronics for years, I have on occasion seen conducted
emissions far exceed 107 dBuV. Of course I have routinely measured emissions
on mains of up to 100 amps and more recently up to 700 amps. Caution is
warranted. Also some of these products use AC large
HP/Agilent sells a spike limiter especially for CE measurements. Before we
installed that, I was always taught to disconnect the spectrum analyzer prior
to switching the LISN from one phase to the other. Apparently, this can cause
major spikes which will zap the front-end preamp of the spec an.
Yes, an excellent post.
There is a problem sometimes when using a LISN for 400 Hz power. I
remember a manager at a former employer who didn't want to add a high
pass filter between his LISN and receiver when the limit was too low for
an attenuator. He ended up buying a new a receiver
I believe the limiter mentioned below also included a 60 Hz (high pass) filter
to reduce the fundamental.
___
Kenneth Wyatt
Wyatt Technical Services LLC
Woodland Park, CO
Email Me! | Web Site | Blog
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On Dec 27, 2011, at 11:33
Gert provided an excellent post, but I am puzzled by the need for all this
protection. Granted I work in a screen room with either dedicated power or
filtered power, but here is the question, nonetheless.
The conducted emission limit above 150 kHz is at or above 60 dBuV these
days, correct? So
Because EUT may contain inductors and switches
that generate spike when intentional or unintentional switching
or switching ON/OFF during the test.
Invariably the day comes that a BIG transient blows BIG money without
such a protector.
Gert
Van: emc-p...@ieee.org
Clearly, under the conditions of hundreds of Amperes (what LISN was
employed?) and large contactors, special attention is required. But the
original post seemed to address more mundane, everyday situations, and that
was the focus of my question.
Ken Javor
Phone: (256) 650-5261
From:
Once again, 400 cycles is a special case that does not apply to the original
post. But in my experience, if testing a 400 cycle load, one is either
testing to MIL-STD-461, or RTCA/DO-160, or an international equivalent. In
461, the test method requires a 20 dB pad between LISN EMI port and EMI
The CISPR 16, 5 uH LISN.
Doug Powell
Sent from my Verizon Wireless BlackBerry
-Original Message-
From: Ken Javor ken.ja...@emccompliance.com
Date: Tue, 27 Dec 2011 13:40:13
To: EMC-PSTC@LISTSERV.IEEE.ORG
Reply-To: Ken Javor ken.ja...@emccompliance.com
Subject: Re: [PSES]
In my many visits to high altitude, I have never noticed an abrupt change in
pressure from 80 kPa to 70 kPa at 2001 meters altitude.
Hi Doug:
Indeed, nature seldom has abrupt changes.
However, standards committees tend to use tables rather
than graphs. Tables depict step-functions,
In message
CAJq2vaiFyrB6kE3BkVn33=tTm1XhfWUXNw3Oe8cmmjknrobK=g...@mail.gmail.com,
dated Tue, 27 Dec 2011, Grace Lin graceli...@gmail.com writes:
Hi, Grace.
I need your advice to prevent RS ESU receiver from damage. A service
report (as a result of annual calibration) indicates frequency
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I am curious what means people are using to exercise Ethernet telecom ports
when testing for conducted emissions according to CISPR 22 and conducted
immunity according to CISPR 24?
Do you use an external piece of equipment (AE) to send Ethernet traffic? If
so, what do you use and do you like
I'm not sure if someone has covered this, but my biggest concern with
damaging a receiver/SA is during the application of, or removal of power.
Specifically, if power is applied at the peak of a line cycle, a pulse
almost equal to the peak line voltage couples through the internal LISN
cap
Back in the early 1990s, Tegam supplied a LISN that had a switch which could
be depressed while connecting the EMI receiver to the LISN EMI port.
Without that switch, the open-circuit potential at the EMI port is the line
potential. When the switch is depressed, it shorts out the bleed resistor
Hi Jim,
Just be careful with the exercising equipment you use. I have seen a
lot of Ethernet equipment that did not have very good balance and
potentially cause a failure of either emissions or immunity unless
you isolate it from the test electrically. For an
Not entirely correct. The 1 kOhm bleeder working against the 0.25 uF
blocking cap yields a 10:1 voltage divider, open-circuit. Still too much
for an EMI receiver absent adequate attenuation and/or filtering. At 400
cycles (per one post, not the original concern) the problem is greatly
At minimum, usually the case in development, continuous pings. Later, xmit a
file, read the file compare, in a fashion that is quick, as in single digit
seconds. Emissions, look for 125 MHz and harmonics. Immunity, look for missed
or slow pings, or mis-copied files.
Sent from my MetroPCS
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