This article appeared inEvaluation Engineeringand has been published here with permission.
What you'll learn:
- Design challenges facing engineers today.
- An insider's look at the R&S RTO6 6-GHz class oscilloscope.
- How the instruments helps address those engineering challenges.
设计最新先进的产品more and more challenging, with many factors contributing to the difficulties. From advanced core technologies disrupting the marketplace, to the implementation and deployment of those technologies in an effective and optimum manner, having the right test and evaluation tools are an important part of the job.
最新的台式工程工具正在越来越强大，以满足不断增加的需求。一个示例可以在Rohde & Schwarz’s最新产品介绍，R＆S RTO6 6 GHz级示波器。完全集成的测试解决方案提供六种不同的带宽型号，从600 MHz到6 GHz，最高为20 Gsamples/s的样本率具有高波形更新速率，出色的信号保真度，强大的数字触发器和响应性的深度内存(see figure)。
功能包括15.6英寸。全高清屏幕，易于使用的触摸功能以及重新设计的前面板，以使测试工程师能够快速设置测量值。较大的屏幕可以显示最大的波形查看区域，并使用R＆S SmartGrid将信号拖放到屏幕的不同部分，并通过单个TAP访问所有示波器的应用程序。
An architecture with a dedicated ASIC for optimized signal processing delivers an acquisition rate of up to one million waveforms per second, and a low-noise front end and single-core analog-to-digital converters (ADCs) with extremely small linearity errors offer a spurious-free dynamic range (SFDR) of 65 dBc, and a 9.4 ENOB. A high-definition mode increases the vertical resolution of the R&S RTO6 oscilloscopes up to 16 bits with digital filtering, also used by the digital trigger system that gives the R&S RTO6 the capability to isolate even the smallest signal details.
More than 90 measurement functions are included in the R&S RTO6 series, organized into amplitude and time measurements, jitter, eye, histogram and spectral measurements. The R&S RTO6 is now available from Rohde & Schwarz as a four-channel base instrument with bandwidth options of 600 MHz, 1 GHz, 2 GHz, 3 GHz, 4 GHz, and 6 GHz. We caught up with Tim Paasch-Colberg, product manager for the RTO6 family, to get a handle on some of the important aspects of the new series.
EE:It’s amazing how oscilloscopes have come so far. Once upon a time, an oscilloscope could do only one basic thing, and that was display and capture information. So why don't you tell me a little bit about how you see the migration of the oscilloscope into the tool that is today?
Tim Paasch-Colberg:Well, back in the day, a scope was a tool where you would measure a signal varying over time, and could display that when it was still analog. Several years ago, digital oscilloscopes became available, and they are initially running on computers. Well, once a signal gets digitized, you can do much more than just display the signal over time. Of course you can still analyze relatively simple analog signals, and just voltage and/or current over time, but now you can do logic analysis, you can do protocol, you can do compliance tests. For example, you can measure the communication interface of your DUT and check if it's compliant with the standard you're using, or not.
例如，RTO内置了非常强大的频谱分析。因此，在此范围内，您基本上还获得了专用的频谱分析仪，但是对于许多许多应用程序来说已经足够了。因此，我认为使用当今示波器的频谱分析现在是一个非常广泛的应用领域。另外，在电力电子测试方面，您需要示波器。这取决于您实际要测量的内容。在某些情况下，您还需要随着时间的推移信号并对此进行分析。在某些情况下，您还将使用频谱分析，因为例如，如果您想进行EMI调试，通常还要查看信号的光谱部分。
EE:当今的设计师必须有一个多功能工具，因为否则他们将无法解决这些设计中的所有活动部件。因此，拥有一个合理地完成所有操作的工具对开发人员来说比三个数字精确的垂直设备更有价值。这里的重要性是它带给平均台式机的力量。我想听听您对这一方面的想法，关于将这种功能，以前无法访问的绩效水平的水平提升到该价格点的想法。
Paasch-Colberg:这是一个很好的点你在这儿提及。当厕所king at the EMI part, for example, every electronic device that goes on the market has to fulfill EMI standards. For that, it typically has to go to a test house where they have all this super-expensive equipment to run this EMI test. But the developer who is building a device, at some point before he or she has to run the EMI test in the test house, they can easily use an oscilloscope to already do some EMI debugging, to find out where sources of interference and EMI or emissions are on the board.
Now all of this initial finding of sources and so on, and learning about their power-off emission, can easily be done with a relatively cheap oscilloscope. So at the end, for them, it's critical to be fast on the market for a relatively reasonable amount of money, and this scope is exactly what helps them there. Especially if you have an oscilloscope with a very rich toolbox, like the RTO6, for example.
EE:我们已经讨论了示波器的迁移以及它如何成为强大的工具。因此，现在我希望您谈论这如何代表这一趋势。
Paasch-Colberg:RTO6具有针对不同应用程序的非常非常宽的工具箱。因此，这不仅是随时间测量工具的电压，而且还不是。就像我之前提到的那样，我们在那里进行了逻辑分析，我们进行了协议分析，其中有合规性测试。我们拥有非常强大的频谱分析，并具有功率和分析选项。最重要的是，我们有非常高速接口测试所需的东西。
在某些情况下，您需要去除，这意味着您基本上补偿了测量链的效果。因此，此范围可以实时补偿您的设置，电缆，所有连接器等。它具有时间域反射仪，时域的传输，并且内置了地图集。因此，您可以分析板上的痕迹。
With everything getting faster, and signals getting quicker, and lanes on your board getting smaller, it really matters how long they are, compared to other traces. So you need to analyze all that on your board. On top of that, the RTO has jitter analysis built-in. With everything going digital and going faster and faster, jitter is becoming a very important topic.
EE:Well, the more powerful the circuits, and the more powerful the systems, you've got to be faster than that, because in order to measure something, you have to be more precise than what you're measuring.
Paasch-Colberg:That's right, you can only get the signal as precisely as your measurement device can measure. And we addressed this topic with the RTO oscilloscope in general. We started this journey 11 years ago with this first scope, and already the RTO class oscilloscope had extremely good signal integrity. Over the years, we launched the second generation, which is the RTO2000, which is still in the market, and already had some improvements regarding signal integrity and some other things as well. And now the RTO6 is the third generation of RTO oscilloscopes, and it's getting better over the years.
One thing that is important for oscilloscopes is how fast you can measure. So, of course, the bandwidth is telling you how fast your signal can get, and you can still resolve it. But another very critical topic is how fast you can acquire that signal, and then the next signal. So let's say you take one trace off your signal now. Now the question is, how long does it take the oscilloscope to measure the next trace, that waveform? So, let's say you have a sine wave and it's from the left to right, how often does it fit on your screen? Now the question is, how long does it take before you can capture the next waveform?
This translates into the update rate of the scope, the refresh or acquisition rate, however you call that, it's all the same. The RTO6 reaches up to 1 million waveforms per second. It's extremely fast. This is one of the major points of the RTO, that it's very, very fast. So how does that help the customer?
假设他们有一个信号,这个信号是英航sically always the same, or very, very similar, like in a communication protocol, for example. But it has a glitch every other time it comes. But you don't know how often. Is it once per second? Is it once every 10 seconds? Is it maybe 10 times per second, or even more than that? Well, if you want to find that out, you would typically run a mask test. If it's a repetitive signal, you can put your mask anywhere, and that the mask is not violated, as long as your signal is correct.
现在，您可以在一定时间内运行此掩码测试以拥有一些统计信息。假设您想记录1000万波形。那是什么意思？如果您的示波器运行速度非常非常慢，并且更新速度较慢，则需要很长时间进行此测试，直到拥有这1000万个波形为止。相比之下，如果您的示波器运行得更快，则需要慢得多的测试，是的。这是简单的数学。
If you have a fast scope, you can measure more waveforms. This, in return, gives you more statistics. I talked about the signal fault that you want to find, and how often it appears. Now, let's say you measure a higher number of waveforms, and with the better statistics you have the much better you learn, how often does my signal interfere or violate with this mask test? That's one very critical thing for an oscilloscope nowadays is how fast can they run these types of tests. Because these tests are getting much, much more important when it comes to communication and interface testing.
另一件事基本上是整体信号完整性。什么是信号完整性？对我来说，当我从示波器开始时，这是一些流行语。我想，“好吧。这实际上是什么意思？”我认为这确实取决于您正在与谁交谈，每个人都说了其他话。因此，我可以告诉您这对我意味着什么。老实说，我没有查找信号完整性的官方定义。但是，对我而言，信号完整性意味着当我有一个信号时，我用示波器测量它，然后使用示波器显示此类信号。与原始信号相比，使用我的示波器的信号表示该信号的表现如何准确？现在，这就是我对信号完整性实际含义的解释。
EE:一个人可以过度专注，并说：“捕获的清晰度的程度”。您想捕获100％的信号。而且，如果您成功捕获信号的100％，则具有100％的信号完整性。因此，这只是用不同的话说同样的话。
Paasch-Colberg:Absolutely. I think engineers or users of oscilloscopes like numbers. They like numbers a lot, and in principle, you can shout out some numbers when it comes to signal integrity. We have things like noise levels. Noise levels of course are important. Well, there's going to be a certain baseline noise in any system. You try to reduce it as much as humanly possible.
Probes are important as well. But you can also just look at the shielding between channels, so you don't have noise coming from one channel to the next channel. On the other hand, you have to use very high-quality components that have inherently lower noise levels now. That's like moving from the city to the countryside where there are no cars. There are many ways to reduce noise.
With the RTO instruments, and especially now with the RTO6, we have a design with low-noise components on the front end. With this, we can achieve very good signal integrity. When you have components in the front end that are noisy, and you send that to your DAC, it basically digitizes the noise. And this is some trash in your signal that you actually don't want. It's like sitting in your flat, and you cannot filter out the noise from the street to listen to your music.
The front-end components are one important part for the signal integrity, but also the analog-to-digital conversion itself. With the RTO6, we have a very good ADC and very good ADC components inside that have a very, very wide spurious-free dynamic range. So when it comes to ADC technology, it's a very broad field on its own. I don't want to go too deep into that, but in principle, there are many ways to digitize signals. And while you do that, you have to take care of a large number of effects. Linearity matters. Then you have distortion effects.
您会出现错误，有偏移错误，线性错误。然后，有一些ADC具有多个核心，可以在原理上获得更高的位。但是，当您这样做时，您会出现定时错误，从而导致信号质量的降低。但是，使用RTO或RTO6，系统中有一个非常高的ADC。从我们的角度来看，一个数值是有效的位或应附数。使用RTO6，我们达到了最多9.4的钩针。
If you look at the datasheet values of oscilloscopes, you will find its bit depth. For example, the ADC of the RTO6 is an 8-bit ADC. If you look at other scopes, they have nowadays either 10 or 12 bits. So you might say, well, but this is bad, the RTO has only eight bits, and this other scope has 10 or even 12 bits. What we want to communicate and to get to our friends and customers is that the bit depth of the ADC is just one number in the datasheet of the overall scope.
In principle, they need to look at the overall signal integrity, which is measured with the ENOB. The ENOB in itself is super-complex, but in the end, from our point of view, it's the best value to compare oscilloscopes to each other. If you look at that with the RTO6, we reach an extent and outstanding ENOB of up to 9.4. ENOB on the other hand is very dependent on what bandwidth you have, what vertical settings you have, what input frequency you have, and also to measure ENOB, different people use different methods, and sometimes it's a bit unclear or also questionable.
However, we are very open with the way we measure ENOB, and with this 8-bit ADC, we reached ENOB of up to 9.4. So you might ask how's that even possible? The answer is the digital nature of this oscilloscope, we can use very clever filtering techniques that increase the vertical resolution of the scope and reach this overall system bit depth of 9.4 ENOB. So even with other scopes that have 10-bit or 12-bit ADCs, they do not reach a higher overall system ENOB.
EE:Excellent. Do you have a final thought for our audience about the device?
Paasch-Colberg:Well, we talked a lot about update rates and signal integrity. I think those are basically the most important things that we want to highlight with the RTO6 oscilloscope. In principle, what we really think about the RTO, since the story started 11 years ago, there's a lot of customer input that we learned from. Over the years and due to this, we were able to make this oscilloscope even better than the two generations before. So we really think that in oscilloscopes up to 6 GHz, the RTO6 is the best scope you can get.
