The Preferred Method
for Electronic Test
With oscilloscope technology developing at a fast pace,
vendors try to keep up with the common trends.
Oscilloscope technology is developing at a fast pace with more features packed into smaller and less expensive packages, pro- viding engineers with more choices in the
expanding marketplace. Recent market analysis
from TechNavio notes the global oscilloscope
market will grow at a 20% CAGR through 2016.
Engineers see the advantage in working with
companies, such as Rigol Technologies, Pico
Technology, Teledyne LeCroy and Keysight
Technologies, that can quickly adapt to new
standards and requirements they face more frequently in completing their projects. With the
advancements in field-programmable gate arrays
(FPGA) technology and power over the past five
years, users no longer have to wait for new ASIC
designs or repackaged products. Development of
new oscilloscope capabilities and value can now
quickly leverage the newest available hardware
components and the refinements of a multi-gen-erational user interface faster.
Once digital oscilloscopes became established
as the tool of choice for electronics system
designers, manufacturers raced to deliver oscil-
loscopes with increasing bandwidth and higher
timing resolution. “These products enabled the
first phase of the ‘digital revolution’,” says Trevor
Smith, business development manager, Pico
Technology Cambridgeshire, U.K.
Today’s digital oscilloscopes are pushing
the envelope in terms of bandwidth. In serial
data applications, a rule of thumb is oscillo-
scope bandwidth should be at least five times
the fundamental frequency of the signal being
measured. “A PCIe Gen 1 signal at 2. 5 Gb/sec
has a fundamental frequency of 1.25 GHz,” says
David Maliniak, technical marketing commu-
nications specialist, Teledyne LeCroy, Chestnut
Ridge, N. Y. “Thus, a 6-GHz oscilloscope would
Early digital scopes had 6-bit analog-to-dig-
ital converters (ADCs) in the data acquisition
front end. After a few years, 6-bit ADCs gave
way to 8-bit ADCs. ADCs have resolution of 2N
bits. “So for a 6-bit scope, that meant
64 discrete levels of vertical quantization,” says Maliniak. “When they
moved up to 8-bit ADCs, users got a
four times boost in vertical precision
with 256 discrete levels.” Most oscilloscopes have relied on 8-bit ADCs for
decades now.
In the interim, oscilloscope vendors have tried to mimic higher
levels of vertical resolution with soft-ware-based workarounds, including
averaging of multiple acquisition and
what they’ve called “enhanced resolution” or “high resolution” modes.
Both of these techniques have their
places and come with limitations
and/or tradeoffs. However, ADC technology has
advanced. In Teledyne LeCroy’s HDO Series of
12-bit high-definition oscilloscopes, the 12-bit
front end means 4,096 discrete levels of vertical
quantization. This is about 16 times better than
the standard 8-bit instruments.
Debugging and troubleshooting requires fast
update rates, which is how fast the scope can
trigger, process the information and plot it to
the display. The faster the scope can do that, the
more likely users can find infrequent problems
that are keeping a design from working prop-
erly. Having a scope with an uncompromised
update rate is important, as scopes that vary
their update rate based on what other features
are turned on can hide issues.
The way customers interact with oscilloscopes
has become more important. Vendors are leveraging advancements in touchscreens and the
increasing adoption of tablets and smartphones
by users. “There are some capabilities (like zone
triggers) where touch naturally lends itself to that
a traditional knob and button don’t,” says Richard Markley, product manager, Keysight Technologies, Santa Clara, Calif. “But just putting
a touchscreen in isn’t the answer, you need the
graphical user interface to be designed for touch
to make it truly useful.” In additional, implementing a technology like voice control can take
a frustrating experience and simplify it.
From analog to digital, or mixed
Analog oscilloscopes were known for their
ability to see things early digital oscilloscopes
hid due to their slow update rate, or dead time.
Creating oscilloscopes with uncompromised
update rates and hundreds of levels of intensity
grading helps bridge the gap between the ben-
efits of analog scopes and the benefits of digital
scopes. The same is true with high-resolution
ADCs. “Having an ADC that runs at 40 GS/sec
and 10 bits allows much better measurements
across a broad set of bandwidth points assuming
the entire signal path has been designed to take
advantage of the extra resolution,” says Markley.
The increasing embedded capability of dig-
ital storage scopes is bringing opportunities
for engineers to learn more about their devices
without constantly offloading data for analysis.
Higher-resolution screens mean ADCs can
be combined with advanced averaging and
filtering techniques to show more detail and
signal fidelity. “Color depth on the displays also
enables scopes to show additional information,
Advancements in high-sensitivity current probes,
like Keysight’s N2820A, allow designers to see
both a zoomed in and out view of the devices.
