Echelon Series 6000 Chip databook - Manual (Page 96)

EQUIPMENT
UNDER
TEST (EUT)
HP8656B
SIGNAL
GENERATOR
75W
POWER
AMP
GROUND PLANE
TEST
CONTROL
COMPUTER
FCC
CDN - M3
50 Ω
AUXILIARY
EQUIPMENT
(AE)
Dressler
Alpha 250 / 75W
-6dB
75W
PAD
EMCO
ATT 6 / 75
FCC
CDN - M3
EUT
POWER
AE
POWER
GPIB
50 Ω
FCC BCI - Fischer Custom Communications
Bulk Current Injection Probe P/N F-120-9A
FCC CDN M3 - Fischer Custom Communications
Coupling De-Coupling Network P/N FCC-801-M3-16A
UTP
FCC
BCI Termination
Figure 33. Typical EN 61000-4-6 Test Setup for Unshielded Twisted-Pair (UTP) Wires
For the EN 61000-4-6 tests, the EUT is placed on a 10 cm high, non-conducting support on
top of a metal ground plane. If the chassis of the EUT is connected to Earth ground in
typical installations, for the test it should be connected directly to the metal ground plane
with a short wire. If the EUT is left floating in normal use, there should be no connection
between the EUT and Earth ground for the EN 61000-4-6 tests.
Power connections for the auxiliary equipment and EUT should be routed through suitable
decoupling devices, such as non-driven M3 “coupling-decoupling” network (CDN) devices.
During the network immunity tests, any I/O lines that come out of the auxiliary equipment
or the EUT should also pass through a decoupling network. The objective of the BCI current
clamp is to drive the large common- mode noise signal into the network cable of the EUT.
The M3 CDNs ensure that the power supply inputs to the auxiliary equipment and EUT are
not an RF return path.
For shielded twisted-pair (STP) networks, the BCI current clamp injects common-mode noise
into the STP cable. The cable shield should be connected to Earth ground with a parallel
resistor and capacitor as shown in Figure 34. The resistor is generally 470 kΩ, 0.25 W, 5%.
The capacitor is generally 0.1 μF, 10%, metal polyester, with a voltage rating of 100 VDC or
higher.
84 Design and Test for Electromagnetic Compatibility