Design World – Power Transmission Reference Guide June 2019

(^38) DESIGN WORLD — EE NETWORK 6 • 2019 eeworldonline.com | designworldonline.com
TEST & MEASUREMENT HANDBOOK
Protocol-level testing:
Validate functionality with a known-good
signal
Test how protocol defects affect the receiver
performance
Digital receiver margin testing:
Inter-channel skew margin performance
Jitter and SSC margin performance
Data-rate margin performance
Amplitude margin performance
Offset margin performance
Duty cycle margin performance
Analog receiver margin testing
Characterize receiver performance across
a wide range of analog pulses
In addition, an AWG-based test set
up is useful for performing environmental
margin testing on an ASIC or other device
that incorporates LVDS. In this case, the
AWG generates a known-clean signal that
is sent to the device under test (DUT) sitting
in a temperature chamber. The impact of
temperature variations is then evaluated
using an oscilloscope.
For testing applications that involve
large numbers of channels, pattern
generation software makes it possible to use
both analog and digital outputs for as many
as 40 channels on a single AWG. This is
accomplished by assigning bit sequences to
both analog and digital outputs.
For complex test requirements, pattern
generation tools make it possible to create
digital pattern waveforms with a variety of
custom-defined impairments and distortions.
In the case of imported text files with
predefined bit patterns, these patterns can
be edited and modified within the tool after
importing. Periodic and sinusoidal jitter with
different amplitudes, frequencies and phases
can be added to a base pattern, and skew
can be applied between both analog and
digital channels. And for LVDS applications,
both inter-channel and intra-channel skew
can be applied, and LVDS pairs can be
created from a single bit pattern by copying
and inverting bits.
By assigning bit sequences to both analog and digital
outputs, both analog and digital outputs are available,
important when high channel counts are required.
Margin testing take place through
selecting low and high data rates.
Tektronix — Test and Measurement HB 06-19.indd 38 6/10/19 8:32 AM