Form factor of digital oscilloscopes which cost more than 5000 EUR - Page 1
Forum section: electronics / testgear

author: pascal_sweden
author_rank: Super Contributor
timestamp: December 08, 2015, 11:49:05 pm
content: Most digital oscilloscopes today come in a very small form factor.Everybody will agree that the small form factor, provides many advantages over the big form factor that traditional analog scopes used to have.Advantages of a smaller form factor:Bench space: the oscilloscope takes less space on your bench, leaving more room for your device under test.Portability: the oscilloscope weighs less, and it is easier to carry the scope with you, when you have to go out in the field for a measurement. Some oscilloscopes in this small form factor even come with an internal battery option, making them extremely portable.Cost factor: one integrated PCB board that contains the analog front-end, ADC chip, FPGA(s) for signal processing, display and other processing, not only leads to a reduced form factor, but also to a reduced cost.Shipping costs: smaller weight of the oscilloscope results in cheaper shipping costs, both when buying new from the factory, or when you have to return the oscilloscope for repair or calibration.However, a smaller form factor also has some disadvantages:Heat dissipation: when all the components are crammed close to each other, the air flow in the oscilloscope needs to be right, to avoid that the power supply does not build up too much heat, and that the FPGA and other computing intensive components on the PCB board don't run warm.No modularity: some older analog scope designs divided the different stages in the oscilloscope in different PCB boards. This concept made the design very modular, which increased the visibility towards the end user of the internal stages, making it easier for troubleshooting and an actual repair when needed.Less "value for money"-feeling: a small form factor with only one PCB board feels cheaper than a bigger form factor with several PCB boards.While I fully support this new trend of smaller form factor for low-end to mid-range digital oscilloscopes, I hereby want to question the form factor for digital oscilloscopes which have a price tag that is higher than 5000 EUR.I recognize that manufacturers are very cost sensitive, and that they constantly want to optimize the design process, improve the efficiency in production processes, and further reduce the overall product costs, but if the customer pays more than 5000 EUR for an oscilloscope, the customer wants to have a better "value for money"-feeling than a customer that buys a low-end oscilloscope starting at 399 EUR.The new trend today is that low-end, mid-range and high-end oscilloscopes all have the same form factor.I am not saying that all oscilloscopes have only 1 PCB board as a whole, but there are at least some high-end oscilloscopes who have only 1 PCB board.Of course those high-end oscilloscopes have better specs, such as higher bandwidth, higher sample rate, deeper memory, more decoding options, but essentially this comes down to more expensive parts on the main PCB board: a more expensive analog front-end (maybe an actual chip, instead of discrete components), a better ADC chip, more powerful FPGA, maybe some better shielding, etc.However the outer housing of the high-end scope, looks very similar to the outer housing of a mid-range scope, or even a low-end scope. I am not saying that this is the case for all high-end oscilloscopes, but at least it's a new trend, that we see more and more often.It is perfectly acceptable that the high-end scope costs much more than the low-end scope.The manufacturers don't only charge for these more expensive components. They also charge a very big margin on the sales price in order to amortize the highly expensive R&D costs. This is only normal, taking into account that it takes 2-4 years or more to develop some underlying technologies required in some high-end scopes. This fundamental research will contribute to innovation in the test & measurement industry, from which everybody can benefit eventually. Manufacturers have to protect their technologies through Intellectual Property, which contributes a significant amount to the overall R&D costs.Still I believe that there is room for making those high-end scopes more robust. Professional grade users, might prefer a more robust design and better modularity, even if that would mean that they have to compromise on bench space.Some practical examples: Suppose a customer owning a very expensive 12 bit oscilloscope, with a bandwidth of 2 Ghz and a high sample rate of 8 GSa/s is reaching the end of a critical design project.But then suddenly there is an issue with the analog front-end or with the memory in the scope.In case the oscilloscope would have been built in a modular fashion, the customer can just do an initial diagnosis on the oscilloscope, and request a replacement board for one more more stages in the oscilloscope. The customer would not have to send the whole scope back for repair. In fact, the customer maybe can still use some features on the scope that are still working, while waiting for the replacement boards. The scope can not get lost or damaged in transport. Moreover it will save a significant amount of shipping for both parties: the customer and the manufacturer (or the distributor). In fact, the distributor could stock some replacement cards in a "swap and replace" pool.A more traditional form factor for high-end scopes would also provide room for a more robust housing, using a metal housing and not a plastic housing. No matter whether the plastic is made from high quality or not, plastic is still plastic. And if the price tag of the oscilloscope is reaching 5000-1000 USD or even higher, I think there is definitely room left for a decent housing in something better than plasticSome high-end scopes today, come in the same form factor as a low-end scope. Both the low-end scope and the high-end scope look like a toy. While this is perfectly okey for the low-end scope, where the hobbyist only has spent 399 USD, I don't think that an expensive oscilloscope should look like a Speak & Spell toy.

author: tautech
author_rank: Super Contributor
timestamp: December 09, 2015, 12:35:10 am
content: Quote from: pascal_sweden on December 08, 2015, 11:49:05 pmYou overlook some important design advances in recent times:SMD componentry has vastly reduced the size and therefore weight of scopes, no longer do they "need" to be built like a brick dunny, couple this to the reduced cost of a smaller enclosure as well and you have just what we commonly see today. Compact high performance scopes.Despite being generally frowned upon "experienced" users do float their scopes and this dangerous practice is much safer with an entirely plastic case and the usually plastic shafted pots and knobs that are common today.

author: Fungus
author_rank: Super Contributor
timestamp: December 09, 2015, 07:37:09 am
content: Quote from: pascal_sweden on December 08, 2015, 11:49:05 pmAre there enough components in a modern scope for it to be split across several boards?

author: nctnico
author_rank: Super Contributor
timestamp: December 09, 2015, 09:22:30 am
content: more connectors and wires = less reliability

author: Wim_L
author_rank: Regular Contributor
timestamp: December 09, 2015, 10:22:21 am
content: Analog scope size is determined by two things: Front panel size (enough space for a screen and all necessary knobs to control it), and having enough length to be able to fit the display tube in it. Analog scope display tubes with electrostatic deflection always have a length that is much larger than the visible screen size, this reduces the angular beam deflection needed, which improves scan speed and reduces distortion. The rest of the oscilloscope might be packed full of electronics (early designs with through-hole construction often needed all the space they could get), or be mostly empty.Early generation digital oscilloscopes often used a compact computer monitor with magnetic deflection. These already were shorter than analog scopes, though the front panel could be bigger. Current DSOs have LCD screens, which allow even more compact form factors.Being built with a compact form factor, or having plastic on the outside, does not necessarily make the oscilloscope less robust. Much depends on the quality of construction and materials chosen, and a compact instrument may be easier to make robust than a long one.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: December 09, 2015, 10:48:11 am
content: Quote from: pascal_sweden on December 08, 2015, 11:49:05 pmThat depends, really. For a bench scope a small size is often benficial, but say for a rack-mounted scope there's no point in a super compact enclosure when the mounting frame dictates 19" width.QuoteYes, on your bench. But most labs I've seen use carts for their larger scopes, so bench space is left for the actual project.QuoteTrue, but this is a concern primarily for low end scopes as this is generally the category that is taken out in the field.QuoteNot just that. It also increases reliability (less connectors -> less potential points of failure), and reduces support costs (less different spares to keep on stock).QuoteThat's a non-issue, really, because for expensive scopes the transport insurance makes for a large part of the shipping costs.QuoteTrue.QuoteNot really, because believe it or not but the typical end user of scopes doesn't tend to open his scope to glance at the PCBs, and from the outside it doesn't make a yota of difference.Older designs are also not modular to "increase visibility", they are modular because the technology at that time didn't allow sufficient integration to put all required components on a single PCB.QuoteNot really, at least not with sufficient complex scopes. Even older scopes were pretty much repaired by board replacement, the difference was that back then you might had to swap multiple boards instead of one or two today. Overall repair complexity (from a manufacturer's point of view, not necessarily from the viewpoint of a hobbyist!) has decreased a lot with modern designs.QuoteNot really, as otherwise scopes would still be big like trunks and heavy as a coffin, which they obviously aren't.Such emotional considerations are pretty much petty issues of consumers, not professionals.QuoteWhy?QuoteAs a professional, value of money comes from what scope performance, reliability and usability I get for the money I put in. Simples. As I said, emotional factors play very little into this.And in my experience that is pretty common amongst professionals.QuoteNo, they don't. Really not.QuoteOK, name one!Pretty much all newer high end scopes run Windows, and there's always at least a PC board in a high end scope, plus the aquisition board(s), plus a PSU, which already makes three PCBs. Then there's the front panel (four), and most high end scopes have a separate front end module (five).QuoteOnly in very broad terms. Which, considering that scopes pretty much have well established controls and layouts, this isn't really surprising.QuoteNo, not really.QuoteAside from the fact that "modularity" is inversely congruent to "modularity", I can't see the point. Hardly anyone is going to take a sensitive $50k scope out in the field to do some probing. The typical applications for high end scopes pretty much demand a fixed lab environment, just because probing alone gets so complex that you can hardly do this out in the field.In addition, I can't see how robustness requires improevement, considering that the build quality of most high end scopes is pretty high, that they have handles, and that the only thing that really prevents them from being carried along is their weight and their value.QuoteThat doesn't exist yet.QuoteYeah, right, I'll have one of my engineers with a charge-out rate of say $300/hr doing some extended diagnostics on a piece of test equipment under warranty. That's money right down the drain.Also, if you're in a critical phase of a project and relying on a piece of equipment then you better make sure that replacement is available, either in form of a second scope (most labs working on high end stuff have more than one scope), or in form of a rental unit from a T&M rental provider.If time is not *that* critical then you just go and buy onsite support (i.e. the manufacturer sends a technician onsite to fix your scope). For some high end scopes that's standard anyways.The last thing I'm gonna do is waste more of my engineer's time to figure out a problem with a piece of test equipment.QuoteGreat, aside from the fact that the calibration of the scope has suddeny become invalid, which regularly is a problem, I still have my engineer sitting there and twiddling thumbs while he could have just get a rental/loaner unit and moved on.QuoteAnd on pretty much most high end scopes plastics is pretty much just the facade on a robust metal chassis.Or do you seriously believe a 40kg scope is build the same way as a Rigol DS1054z?QuoteWell, scopes look as they do because its practical, and most professionals don't give a crap if the scope looks like that $399 Rigol (plus, whatever you change the appearance of your expensive scopes to, the Chinese B-brands will eventually copy it anyways!)Please don't take this as an offence, but it's pretty obvious that you don't know a lot about expensive scopes. Most of your points are pretty much revolving about how stuff works in your imagination, which has little resemblence to reality.

author: marber
author_rank: Regular Contributor
timestamp: December 09, 2015, 02:52:58 pm
content: Quote from: Wuerstchenhund on December 09, 2015, 10:48:11 amOn the Rigol DS1054z, the plastics are pretty much just the facade on a robust metal chassis.It may be cheap, it may be lightweight, it may have a few bugs, but it's built pretty well.Quote...and your recent references to the Rigol DS1054z in particular haven't exactly supported your claims about cheap Chinese scopes that you've been making in various threads, either.

author: pascal_sweden
author_rank: Super Contributor
timestamp: December 09, 2015, 03:30:25 pm
content: Maybe I should have given a specific example of a digital oscilloscope, which costs more than 5000 EUR, and which looks like a toy.Here is an example: Rigol DS6104This example justifies my whole story! Okey, it's not a grade-A scope, but it costs more than 5000 EUR, and fulfills the criteria my story was built on.I am sure that there are other examples of actual grade-A scopes, that look the same.My story was not targeting ultra high-end scopes that cost more than 15.000 EUR, and which come in a 19 inch rack space.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: December 09, 2015, 04:05:59 pm
content: Quote from: pascal_sweden on December 09, 2015, 03:30:25 pmProbably.QuoteI see.QuoteI guess this is true, (and it really does look a bit like a toy), although the last thing I'd complain with a DS6000 is the build quality, which is actually OK. And I'm pretty sure that the looks are very far down the list of things thatmanythe few DS6000 owners would like to have changed on this scopeBut the points re. build quality (i.e. plastics not necessarily being inferior) and modular vs reliability still stand.QuoteIn this case it might have been better to specify some price bracket, i.e. €3000 to €6000 or something like that. "More than €5000" covers actually a very large segment of the overall scope market.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: December 09, 2015, 04:14:45 pm
content: Quote from: marber on December 09, 2015, 02:52:58 pmFine (but then I didn't say otherwise, did I?). But that was not the point, unless you want to claim that the DS1054z is built in a similar way and to similar strength as a 40kg high end scope (which would be silly).QuoteNot sure what you're talking about, there are lengthy threads about the various issues I mentioned, aside from the fact (which you obviously missed in your fanboi rant) that I stated many times that the DS1054z is a great deal at that price and that it's cheap enough for its bugs to be forgiven to some extend. I also said repeatedly (being the owner of a not that cheap Siglent SDS2204 myself), that it'sthe more expensive B-brand scopes which I believe are poor value for money, not the cheap bottom-of-the-barrel scopes like the DS1054z.But of course, feel free to continue selective reading or to ignore the facts that lie in front of you. To say it with Big Donald's words: I. Don't. Care.