Video Review & Teardown of the Analog Arts SL987 USB Combo Instrument

[Hugoneus]

In this episode Shahriar takes a close look at the Analog Arts USB based mixed-domain instrument. The SL987 offers an oscilloscope, arbitrary waveform generator, FFT-based spectrum analyzer, pattern generator and logic analyzer in a compact form factor.
The teardown of the unit is presented along with the datasheet of every major component on the PCB. Some design limitations and concerns are presented along with basic performance verifications.

Watch the video here: [46 Minutes]
http://youtu.be/F-1uA4Iwce8

More videos at The Signal Path:
http://www.TheSignalPath.com

[photon]

Thanks for the post and teardown. The USB connector with host ports on each end is not possilble, AFAIK. I wonder what happened there? It could be that their circuit board had mistakenly put a host port connector instead of a device port connector. If someone thinks they can use such a connector with 2 host ports to connect 2 PC's via USB, then this would not work.

[Monkeh]

That.. is pretty horrific.

[photon]

I think it interesting that USB has spec'd a new connector, call TYPE-C, that will be universal, in the sense that there will be a single connector for both host and device. Also, it will have no up or down polarity in the plug, will support all versions of USB plus allow support for other bus protocols. It will negotiate all these issues, plus who is supplying power and how much, at plug-in time. The spec allows up to 100 watts of power!

[electr_peter]

Claimed "1GHz BW", wobbly BNC jacks, cross-talk all over the place, massive undersampling for BW, inadequate shielding, mysterious DC offsets, digital or analog modes only, ...
At least SW side is working without hiccups.

This device is well suited for lower (say 10-40 MHz) freq probing/logic probing/signal gen, but at this price point market is dense. Maybe manufacturer tried to amplify best possible scenario for specs to stand out. I think that built-in signal gen + scope is very useful for frequency response testing.
Comparison with bench scopes would be not be reasonable, because of different amount of processing/memory on main board. As mentioned in the video, DS1000Z series are hard to compete with.

As for USB connector, I think it is very reasonable choice. It is easy to connect, holds contacts well and gets good support from PCB. USB B is similar or a bit worse in some aspects, micro/mini are too weak in comparison. The only disadvantage - cable is harder to source.

[Hugoneus]

Unfortunately as you can imagine the company is not very happy with my review. As I mentioned I gave it the benefit of the doubt with regards to the board (assuming that it was a prototype). And I mentioned that for lower frequency inputs its performance is reasonable.

However, I would have betrayed my commitment to science and engineering if I didn't speak about its problems. 

[Monkeh]

As for USB connector, I think it is very reasonable choice. It is easy to connect, holds contacts well and gets good support from PCB. USB B is similar or a bit worse in some aspects, micro/mini are too weak in comparison. The only disadvantage - cable is harder to source.

It's a stupid choice, it's non-compliant and the cables are, as a result, not standard.

Unfortunately as you can imagine the company is not very happy with my review. As I mentioned I gave it the benefit of the doubt with regards to the board (assuming that it was a prototype). And I mentioned that for lower frequency inputs its performance is reasonable.

However, I would have betrayed my commitment to science and engineering if I didn't speak about its problems. 

You were very kind to it. Much kinder than it deserved. They should have known better than to send something like that to someone who actually knows what they're talking about.

[AF6LJ]

  Very Scary.

[mikeselectricstuff]

Unfortunately as you can imagine the company is not very happy with my review.

Well if they shipped you what looks like little more than a prototype what did they expect...?

I have seen USB A's abused like this on a couple of occasions, and USB A-A cables are fairly available, but it's an unnecessary annoyance.

[electr_peter]

As for USB connector, I think it is very reasonable choice. It is easy to connect, holds contacts well and gets good support from PCB. USB B is similar or a bit worse in some aspects, micro/mini are too weak in comparison. The only disadvantage - cable is harder to source.

It's a stupid choice, it's non-compliant and the cables are, as a result, not standard.

It is non-compliant (what will happen when two hosts are connected with such cable? ) and it should be marked with bright colors to inform general public about it. However, it is not that bad if only connector is concerned - one can do much worse. It is better than some non-standard connector for USB port or something crazy like plug/plug (male to male) IEC mains connector...

Thanks to Shahriar for such complete review of device as it is. Detailed explanations of schematics, comments on parts spec, fault finding, real performance testing and comparison to specs This is real journalism of technical topics.

[c4757p]

Damn you're a nice dude. This thing's a total heap of garbage, they're so lucky they got the kind review you gave it.

It needs to be reviewed with a hammer.

[EEVblog]

There isn't much Art inside that! Yuck!

[Hugoneus]

There isn't much Art inside that! Yuck!

It would have been interesting to hear what you thought about it. As I said, I feel bad about the review and I have given them a chance to address the issues and get back to me.

[EEVblog]

It needs to be reviewed with a hammer.

A Widlerizer  hammer!

[c4757p]

However, I would have betrayed my commitment to science and engineering if I didn't speak about its problems. 

I understand why it might disappoint you that they're Unimpressed, but dude, you scored a big one for integrity. You were honest about this thing, fair and balanced in every way - you gave it a chance when it deserved one, told the truth when the truth needed to be told, and as much as possible let the viewer reach his own decision. If they think the problem is your review and not their product, they have a serious disconnect with reality.

There's a reason your equipment reviews are my favorite of all of them. Analog Arts might not be happy, but I definitely thank you.

[Hugoneus]

However, I would have betrayed my commitment to science and engineering if I didn't speak about its problems. 

I understand why it might disappoint you that they're Unimpressed, but dude, you scored a big one for integrity. You were honest about this thing, fair and balanced in every way - you gave it a chance when it deserved one, told the truth when the truth needed to be told, and as much as possible let the viewer reach his own decision. If they think the problem is your review and not their product, they have a serious disconnect with reality.
There's a reason your equipment reviews are my favorite of all of them. Analog Arts might not be happy, but I definitely thank you.

I appreciate that.

[EEVblog]

It would have been interesting to hear what you thought about it. As I said, I feel bad about the review and I have given them a chance to address the issues and get back to me.

I only briefly watch the inside teardown bit, but that was enough. Seeing that I doubt I would have even bothered continuing with any review.
For a company that claims:

Analog Arts is a private high-technology company headquartered in Massachusetts, USA. Formerly known as Edge Technology, the company was founded in 1992. It specializes in high performance digital and analog signal processing and advanced test measurement systems. Analog Arts products range from custom board level solutions to complete stand-alone equipment. Throughout its history, Analog Arts has been committed to offer reliable and cost effective solutions to challenging ideas. Relying on a pool of highly experienced and motivated scientists and engineers, Analog Arts has become a world resource for outstanding engineering. As a recognized leader in signal processing and measurement equipment, Analog Arts has provided designs, products, and services to scientific, military, and commercial companies throughout the world. The company designs, develops, tests, purchases parts, manufactures, and packages all products in the United States.
We customize our technology for particular applications. With features like, 140 dB of dynamic performance, 100 GHz sampling rates, 28 bits of resolution, and super high bandwidths, our solutions have satisfied a wide range of applications including radar, communication, automotive, medical, and satellite.

You have to wonder how they could be this incompetent?
$1260 and the best and most expensive product in their range? Yikes.

[EEVblog]

I understand why it might disappoint you that they're Unimpressed, but dude, you scored a big one for integrity. You were honest about this thing, fair and balanced in every way - you gave it a chance when it deserved one, told the truth when the truth needed to be told, and as much as possible let the viewer reach his own decision.

The funny thing is I've been criticised for doing that 
I've found that people want a strong opinion one way or the other, Yay or Nay.
If I did anything less than toss it across the room, I'd get hate mail and accused of having sold out 

[c4757p]

I understand why it might disappoint you that they're Unimpressed, but dude, you scored a big one for integrity. You were honest about this thing, fair and balanced in every way - you gave it a chance when it deserved one, told the truth when the truth needed to be told, and as much as possible let the viewer reach his own decision.

The funny thing is I've been criticised for doing that 
I've found that people want a strong opinion one way or the other, Yay or Nay.
If I did anything less than toss it across the room, I'd get hate mail and accused of having sold out 

People expect you to be mean.

[EEVblog]

People expect you to be mean.

I suspect they confuse meanness with brutal untactful honesty 

Ok, I'm mean 

[Lukas]

1GHz with a 100MSa/s ADC is not completely impossible. You may use a comparator and a TDC to determine the exact triggering instant and then accumulate over multiple acquisitions. HP did that in the 54600 series and manged to get >100MHz bandwidth out of a 20MSa/s ADC.

[Hugoneus]

1GHz with a 100MSa/s ADC is not completely impossible. You may use a comparator and a TDC to determine the exact triggering instant and then accumulate over multiple acquisitions. HP did that in the 54600 series and manged to get >100MHz bandwidth out of a 20MSa/s ADC.

As I mentioned in the video, such a system requires either a coherent precision time-base signal or an entirely different architecture. The problem arises from the fact that the instrument makes mistakes on computing the actual frequency of the signal being applied once it is above Nyquist. And it can only do this on periodic signals (and if the period fits within the captured memory). It is essentially trying to reconstruct the aliased signal from multiple periods.

[photon]

As for USB connector, I think it is very reasonable choice. It is easy to connect, holds contacts well and gets good support from PCB. USB B is similar or a bit worse in some aspects, micro/mini are too weak in comparison. The only disadvantage - cable is harder to source.

It's a stupid choice, it's non-compliant and the cables are, as a result, not standard.

It is non-compliant (what will happen when two hosts are connected with such cable? )

Yes, it is indeed broke. Since a USB hosts supplies power on VBUS, having 2 hosts connected together, type-A to type-A, will short their supplies and can cause damage. On the other hand, I agree that if one of the 2 ports is a device, then this problem does not occur since a device does not supply power but rather consumes it. The only type-A to type-A connector that I would trust would be one where the cable contains a small circuit board that bridges the two ports. Such cables exist and are handy to network 2 PC's using USB, but they require a special driver and are more expensive.

[Lukas]

1GHz with a 100MSa/s ADC is not completely impossible. You may use a comparator and a TDC to determine the exact triggering instant and then accumulate over multiple acquisitions. HP did that in the 54600 series and manged to get >100MHz bandwidth out of a 20MSa/s ADC.

As I mentioned in the video, such a system requires either a coherent precision time-base signal or an entirely different architecture. The problem arises from the fact that the instrument makes mistakes on computing the actual frequency of the signal being applied once it is above Nyquist. And it can only do this on periodic signals (and if the period fits within the captured memory). It is essentially trying to reconstruct the aliased signal from multiple periods.

I guess you're thinking of sampling oscilloscopes like the DCA from Keysight? Random sampling oscilloscopes like the 54600 don't require a coherent clock/trigger, since they determine the clock-to-trigger relationship on each trigger event using a TDC.

[nfmax]

The Intronix LogicPort USB logic analyser also uses a type A connector, and they supply a typeA/typeA cable with it. I've never seen this done elsewhere before.