Members:
Could someone familiar with the IEC 1000-4-6 standard give me
some guidence in interpreting the sections referring to the setting of
the test's common mode voltage (Ucom) levels for direct and Current
injection modes?
The difficulty I am having is understanding how the Ucom levels
presented at the EUT port are established with the two methods of
RF injection.
I will try to explain.
Under section 6.4.1 "Setting of output levels at the EUT port." with
direct injection test set up (CDN networks) the RF generator is
adjusted to give an Umr level which is -15.6dB down from, or 1/6 of,
the Uo (test level), say three volts. This would requires a Umr voltage
of 0.5 volts at the measuring device and would appear to set at the
EUT port of the calibration set-up, at a ( Ucom) of 1.5Volts.
With the current injection test jig method it is my understanding that
each side of the calibration test jig is terminated into 50 ohms, with
the one termination being the 50 ohm impedance of the measuring
device. For this test set-up we are instructed to set the Umr voltage
to be set at 1/2 or 6 dB down for the Uo level of 3 Volts, giving a Umr
of 1.5V.
Since the current clamp test jig has two 50 ohm termination and the
measuring device is seeing only half of the total, this would set the
current clamps inducted voltage or Ucom to 3V at the EUT port.
It would appear that with the direct injection method, the test set-up
has adjusted our generator for a 1.5 volt Ucom, where with the
current injection mode the Ucom is set to 3 volts.
What have I missed?
Has anyone else had the same difficulty interpreting this standard?
Any help would be appreciated.
Donald McElheran
Ross Video Ltd.
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
[email protected]
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: [email protected]
Michael Garretson: [email protected]
For policy questions, send mail to:
Richard Nute: [email protected]
