Page 6
2 Introduction
In order to validate electomagnetic compatibility (EMC) and operational electrostatic discharge (ESD)
tests, it is necessary to isolate the device under test (DUT) from other nodes within the MOST50 ePHY
network (see Figure 2-1). Isolation involves eliminating the influence of the other nodes as well as external
environmental factors from the DUT. In the case of EMC testing, environmental isolation is achieved
through the use of an anechoic chamber, which is a shielded room that is designed to attenuate environ-
mental noise sources. For operational ESD testing, the transient voltages induced on the ePHY network
need to be confined to the DUT. This is accomplished by electrically isolating the DUT ePHY network from
the other MOST50 devices.
The MOST50 E-O Converter assists in isolating the DUT during a functional network test by converting a
MOST50 ePHY network into an optical physical layer network interface. Figure 2-2 shows how this is
achieved by using two E-O Converter devices. One E-O Converter is connected electrically to the
MOST50 network devices outside of the test environment while the other E-O Converter is connected
electrically to the MOST50 DUT inside of the test environment. The MOST50 network is completed when
an optical connection is made between the two E-O Converters.
MOST50
Network
Device
#1
MOST50
Network
Device
(DUT)
MOST50
Network
Device
#2
MOST50
ePHY
Network
EMC/ESD measurements for
the DUT must be performed
while the device is operating
in an active system. Electrical
isolation is required to
minimize the influence of other
network devices and various
environmental factors.
Figure 2-1: MOST50 Network Implementation
