Confused with all the feature updates and new specifications you see on oscilloscopes? This interview takes a look at the broad trends affecting oscilloscopes and how they help engineers.
Trevor J. Smith, manager, test & measurement, Pico Technology, speaks with Dilin Anand from EFY.
Q. What one feature defines newer oscilloscopes?
A. Newer test equipment and oscilloscopes have much deeper memory. The best among the latest scopes have 512 mega samples or more of capture or buffer memory. Looking at the trend, scopes had up to 500Mhz with one gigasample of buffer memory in 2013. Today, it has doubled. For an example of memory increase, oscilloscopes with 250MHz to 500MHz bandwidth come with a two GS buffer that can hold two 200 m captures at a rate of up to five gigasamples per second!
Q. What drives the need for additional memory on oscilloscopes and other test equipment?
A. Test engineers today need to do some really deep analysis. This creates the need for really high sampling speed, which also increases the need for more memory. Additional memory is also good for analysing strings of data. If design engineers are working on serial standards like I2C and Flexray, then analysing those communications channels along with the collected data would require additional memory.
Q. Apart from specification upgrades like memory, what else defines new oscilloscope hardware?
A. At the ports side, scopes have now upgraded to use USB3.0 instead of USB 2.0 for the interface. While the new interface is obviously faster, the real difference is that integrating USB 3.0 allows users to stream gap-free continuous data from oscilloscopes onto the user’s computer. This means that users can now graph frequency and duty cycle against time thus enabling them to capture waveforms in the modulation domain rather than the frequency and time domain.
Q. Now that we have a good idea about hardware developments, could you give an idea of the software side of things?
A. Software upgrades to scopes are also a big part of their feature set. Vendors are constantly releasing new versions of software. Sometimes you even see software updates deliver support for newer protocols that the original equipment did not ship with. In January 2016, some oscilloscopes saw feature updates that increased the number of serial decoders to 16 from the seven or eight protocols that they previously had. Sometimes, customers request support for specific protocols like Flexray and we add those to their test equipment through software updates.
Q. Any changes in new scopes relating to how engineers today use these equipment?
A. Yes, on the user interface front, it has been designed to be more usable for touch-based zooming and panning. One interesting feature here is an age counter, so that people counting long data streams to count the positive edges so that they don’t really have to manually add them. Another small but significant change was with simplifying visuals. If you look at the CAN bus package, there are different fields. What we did was we colour coded them. The beauty of that for end customers is they are able to visually understand the results of the decoder.
Q. Any Interesting insights noticed in engineers’ preferences for various features or oscilloscopes?
A. What we have seen is that while older engineers prefer bench-top instruments, younger engineers prefer USB-based scopes. Some customers pick up USB-based scopes and use it as a component as an OEM. These guys do not use plain software, but use SDKs to develop their own software. Power analysis, monitoring, medical and all sorts of other applications are implemented using USB-based scopes as a component integrated inside.
Q. Any broad trend that you see for oscilloscopes as a whole?
A. High bandwidth is definitely a trend. Today, we see oscilloscopes for inspecting cables and transmission lines to look at their characteristics. In a car-wiring loom, we never used to worry about the bandwidth going around the car. Today, if you need a rear-view camera or other high performance signals, the wiring cable needs to have high quality cables. Traditional loom manufacturers tend to not deliver the quality that is now needed for vehicle manufacturers. As a result we find a lot of need for TDR (time domain reflectometer) measurements in automotive. The same happens in robotics and factory automation, where people look at high bandwidth signals.
