Rohde & Schwarz Oscilloscopes Review

The ability to have both the time domain and frequency domain, where the frequency domain is a very broad spectral plot, is extremely valuable

What is our primary use case?

I'm very much in the power integrity field. I spend a lot of time working for a major semi-conductor manufacturer doing silicon validation.

Our end product has to pass all the various FCC compliance tests, which is sort of the field of expertise that I have. For a customer to build a product with a switching mode power supply in it and be able to provide some degree of certification or comfort, they have to pass the compliance test which permits them to sell into the marketplace. That has always been an emphasis of mine, when I'm doing application engineering for a semiconductor company. They're selling to a company which integrates a switching mode device into their product. For them to sell that product, they have to jump through hoops, meeting a bunch of compliance tests that the FCC or European agencies establish. Once they pass, they are certified in their lab to sell. Then, I try and provide a lot of leading advice on how they can incorporate that noise generating device into a product with a high degree of likelihood that they will pass those tests.

We are doing an investigation of the interface between audio power amplifiers and loudspeakers, including the speaker wiring that provides the interconnect.

How has it helped my organization?

The Rohde & Schwarz gear that I use is because it's so sensitive. I'm always looking for things way down into the noise floor as part of the electromagnetic compliance work that I do.

What is most valuable?

In the case of Rohde & Schwarz, I have a power-oriented frequency display option which allows me to do spectral plots of the residual noise that I'm looking at and have that on a logarithmic frequency axis since I'm not using this in conventional communication applications. I'm looking for broadband noise and things that will stick up out of the spectrum. To be able to have both the time domain and frequency domain, where the frequency domain is a very broad spectral plot, it is extremely valuable. There are things which happen in the frequency domain, or you can see in the frequency domain, that you'd never see from a normal oscilloscope plot. You can try and get correlation between an oscilloscope and a spectrum analyzer as a separate instrument, but it is difficult. Only Rohde & Schwarz, at the time I was selecting this, had the logarithmic frequency axis to allow that plot.

What needs improvement?

There is certainly a learning curve. Finally, watching YouTube videos on using the instrument got me over the hump, as well as a sit down session with one of the oscilloscope experts. 

The Rohde & Schwarz user interface is very oriented towards drop and drag functions on the screen. Some of those are just not obvious how to use. You have to have somebody get you over the hump. My understanding is they have a newer user interface, but I haven't gotten around to upgrading the firmware on my scope in some time, so I'm not familiar with it yet. In comparison, I love the LeCroy interface.

Recently, I've learned that there are ways to adapt these instruments to become a Vector Network Analyzer (VNA), which is of interest to me. If I can use probes that are not in the 50 ohm domain, which is what you would have with a normal Vector Network Analyzer, then doing power applications for me, this would be a lot safer. Using a traditional communications type Vector Network Analyzer in the 50 ohm domain and having these high DC potentials (adding the DC blocks is adding air to the test method), then having an oscilloscope type front-end which is lot more tolerant of overload, it is a lot safer. The vector network analysis that I need to do is well under a gigahertz, and the other instruments that I have sort of stop at 40 megahertz. Trying to get past 40 megahertz into the mid-hundreds of megahertz and have high impedance probes that will tolerate DC, that is really of interest to me.

For how long have I used the solution?

One to three years.

What do I think about the scalability of the solution?

I have a 4 GHz scope, and the stuff that I am doing probably stops at around 500 MHz.

While there are options that they don't have, it's all field upgradable. With the hardware upgrades, they have little accessory bays in the back of the scope which I have been making inquiries about.

How are customer service and technical support?

The technical support is very good. It is just a phone call, and I always get a prompt response.

Which solution did I use previously and why did I switch?

The two LeCroy scopes that I owned were their 12-bit scopes. I had both a 4-channel and an 8-channel gigahertz scope, which ae a lot easier to run. However, they're lower in performance only from the standpoint that I ended up buying the highest performance Rohde & Schwarz unit, which I tend to use in automated setups under a LabVIEW Control.

This product would have been overkill for the previous project that I worked on, which is why I used LeCroy.

Where in reading Steve Sandler's book on power integrity, and in discussions with him, he pointed out how superior the the Rohde & Schwarz RTO's are

What's my experience with pricing, setup cost, and licensing?

In all cases, I have gotten demos of the products prior to purchase.

The pricing is expensive, but very fair when you look at the technology that you are getting. These are higher-end pieces which have a ton of engineering in them that is not evident on the package. However, you could imagine the amount of time that the vendor has spent on the firmware, optimizing the internal layout, developing custom ICs, etc. They're releasing a mass produced product, but these things are built to last.

Buying Rohde & Schwarz gear is like buying a Mercedes. It raises eyebrows when you're asking for that level of performance.

Which other solutions did I evaluate?

In the case of the Rohde & Schwarz scope, if you set it up side-by-side against the LeCroy 12-bit scopes, it has about a six time lower noise floor, even though it is an 8-bit scope. This allows me to dig deeper down into the noise floor and chase down some particular parasitic that might cause a compliance test failure. It has better sensitivity, aside from the better feature set, which is really important to me.

LeCroy tends to have some kind of either reliability issues or delays from their national service depot.

I haven't done anything lately with Keysight or Tektronix.

Anritsu also makes good gear too.

What other advice do I have?

It is a remarkable scope. It is hard to get used to compared to other oscilloscopes because of the cryptic user interface. However, once you get over that, it's got a lot of power.

We are not using this product to support connected devices, e.g., IoT development, nor are we planning to going forward.

Trial the models. Use them and see what the limits are that you can get away with using the highest-end gear, and also if you will need to step back to a lower-end product, like RIGOL.

In the case of the Rohde & Schwarz, with the number of equivalent screen updates that it does per second,you can find some really illusive glitch or failure to trigger. If you have another machine that runs substantially slower, you'll probably never find that little event, unless you're willing to wait a few weeks for the scope to finally trigger on a missed event. If you're trying to certify something to be rock solid, then you will to have to go with a scope which has much faster acquisitions, not just the sample rate, and has the ability to distill information looking for something that's out of the ordinary.

Which version of this solution are you currently using?

**Disclosure: I am a real user, and this review is based on my own experience and opinions.
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