Oscilloscope manufacturers provide more functionality for less

4 min read

You might think that users at the lower end of the oscilloscope market were not interested in performance. But you would be wrong, as leading oscilloscope manufacturers are bringing technology to bear in an attempt to meet users' demands.

Peter Kasenbacher, Agilent's European product line manager for oscilloscopes, noted: "Even in the general purpose market, new technology is playing an important role." And the new technology to which Kasenbacher refers is a range of asics. "ASICs bring better performance to a new price point." Agilent's latest asic for oscilloscopes is MegaVision IV, a 90nm design featuring 6million gates and 40Mbit of embedded dram. The part, capable of supporting 1m updates per second, is performing tasks previously undertaken in software. Software based processing is now seen as something that slows performance. Agilent is not alone in looking to advanced technology to bring more functionality to its products; both Tektronix and LeCroy have made similar investments. Dave Ireland, European marketing manager with Tektronix, said: "Developing asics for these applications requires a substantial investment. Once that investment has been made, it will migrate over time down the product portfolio and allow us to get a return over the longer term." Why is this increase in functionality needed? Bill Driver, product marketing manager with LeCroy, noted: "There is a trend towards the use of analysis tools. A general purpose scope will only go so far to meeting their needs. Then, it's a case of what else we can offer. For example," he continued, "power supply designers need to know about things that aren't normally seen on a scope. They're asking 'how do I solve problems which aren't easy to see, but which are there?'." Ireland's view is: "It's because customers are having to take more work on board. Things like serial buses. If you look at USB3, you're talking about a high performance serial bus and that level of performance requires more from the scope, including an appropriate bandwidth. Nevertheless, while you might have the ability in the scope, the signal path is becoming the limiting factor." Driver said a combination of hardware and software tools was helping to bring different views of problems. "Then, designers can focus on one offs or rare events which cost time and money. Our focus is on making designers lives easier." Much like you can get your favourite burger 'super sized', there is an emerging trend towards the provision of 'super scopes'. Driver explained: "We have had the situation where our traditional 8bit products don't provide the accuracy which designers need. This can cause them to not carry on with their projects." But he also contended that scopes mean different things to different users. "Some believe scopes are good for dc measurement," he noted. "That requires good precision and that has driven development of the WaveRunner HRO 6 Zi, where we have tried to get accuracy down to 0.5% – a factor of four improvement. That's not specmanship, that's a necessity and we want our scopes to be as accurate as dmms and dvms, but we're not there yet." Ireland had a similar view: "We're giving engineers the opportunity to access more features at an affordable price and that's what's behind the DPO5000 series; taking high end technology and migrating it to a Windows based platform." Despite being 'super sized', scopes remain a design tool and live, in general, on the bench. "It's a key piece of equipment," Driver accepted, "but scopes have traditionally been used with other devices. As bench space shrinks and budgets decline, there is a move to one instrument – and that's generally a scope. The challenge for us is to squeeze more into a smaller box." Bandwidth is a figure of interest. "WavePro scopes now offer 3 to 6GHz, but are being used in the same market space," said Driver. "Similarly, WaveRunner devices offer 2 to 4GHz." He said that it is sometimes hard to believe the speed with which scopes are now being developed. "For LeCroy, the challenge is turn round time; integrating new ideas with the existing architecture. We're finding things can't always fit." What has enabled WavePro scopes to run up to 6GHz is a new chipset with a 40Gsample/s a/d converter. "That chip also allows WaveMaster scopes to push up to 45GHz," said Driver. "We're sharing technologies between platforms, but it takes a couple of years to develop products and bring them to market." But there's only so much 'shrinkage' that can be done. "We'd like to scale WaveMaster down and sell it as a lower end product," Driver admitted, "but you can only go so far before it doesn't make economic sense." The other way to approach that problem is to offer users an upgrade path; an approach driven by Agilent over the last few years. By offering upgrades, Agilent believes its customers investment is protected. Driver asserted: "Customers now demand this; they are more comfortable with a product that can be upgraded." Agilent's recently announced 2000 and 3000 series devices, in Kasenbacher's opinion, bring 'more scope' to the user. "They have the largest screens in their class, they have the deepest memory and the fastest waveform update rate." Kasenbacher recognises the increasing pressure on bench space. "Designers don't have enough bench space," he observed, "so putting things together makes sense. But the intrinsic performance must be good." He said those using mixed signal scopes generally have only a few comms lines, so providing 8 or 16 is fine. "If they need more than that, they really should be using a logic analyser," he commented. Yet even in a sector where products have been developed over decades, there is still room for innovation. In LeCroy's case, it's a pivoting display. Driver thinks the ability to look at signals in a portrait format will be important. "Now, users can look at up to 36 digital lines and see a lot more detail. We don't see this as a gimmick." Despite what a scope can do, how it's designed remains important, as recently retired Agilent engineer John Campbell notes. "In the InfiniiVision X-Series, there are 26 different models. These can be configured by combining three final assemblies. These assemblies draw from a total of 11 sub assemblies – four front panels, six acquisition and one rear end/supply assembly. The internal structure and assembly can represent real value to the end customer, but the designer must primarily satisfy those who have to produce the product." Ireland said there was more to mid range scopes than just providing the instrument itself. "We have to give support beyond the physical level, such as protocol support. Engineers want to use the scope to see what's going on. Trying to look at a USB3 design without the coding attached doesn't help very much; they need to know how data packets get from A to B," he concluded.