Author Topic: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope  (Read 29419 times)

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Offline rx8pilot

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #50 on: February 12, 2015, 09:36:44 pm »
Shahriar.....

Kindly install a PCI bus connection on your head so I can download your brain.
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Offline w2aew

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #51 on: February 12, 2015, 10:08:09 pm »
The heterodyne conversion of the two lasers does not happen in the optical domain. It happens in the electrical domain. There are ways to mix light in a non-linear fashion directly in the optical domain, but that is not what is happening here.

The photo detector is only sensitive to the light signal intensity and it operates in square law detection mode. The two lasers illuminate the photo detector at the same time and the beat frequency is generated already in the electrical domain (constructive and destructive addition of light on the surface of the detector).

There are limitations however, for example the two lasers can't be orthogonal in polarization.

The beauty of square-law detection - mixing products for free (basically).
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Offline Hugoneus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #52 on: February 13, 2015, 12:32:57 am »
How many layers does ADC board have? I would guess at least 8-10.
Also, how did they produced that metal PCB frame? Casting or CNC only? Seems to be very big, but narrow part.

The board is 28 layers. The frame I think is CNC.

Offline vaualbus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #53 on: February 13, 2015, 01:15:08 am »
Ok so my comment on youtube about the price of the board have to be modify. This can cost a fortune (surly more than 5k) also why soo many layer? a lot of digital signals?
 I have never  hear  about 28 a layer board before! Amazing.
So do you know if keysighy is keysight is developing a scope for that range of frequency?
also at the beging the guy that explain the theory said that there are company made these oscilloscope. Keysight lecroy and tektronix right? Because the top model of tek scope go up to about 30ghz
 

Offline coppice

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #54 on: February 13, 2015, 05:53:50 am »
One thing I really like about such scope is that it is pushing the limits. It gets to 100 GHz, but just barely (almost all aspects are pushed to the limit, only extensive DSP corrections helps to keep it in one piece). I am sure a small amount of tweaking could bring another GHz or so for current model and future versions will be even better.

It is certainly not the case of having 200 GHz BW scope and configuring it via some jumpers to "entry range" 100 GHz BW version.
Why do you say "just barely"? It gets to 100GHz by old and well tried techniques, implemented with state of the art hardware. It will be a lot quirkier than a straightforward monolithic ADC. Anything large has thermal tracking issues, and anything that that many separate parts working in concert is going to have calibration issues. The calibration can be handled very well by modern approaches.

They make a 100GHz oscilloscope because that's what the optical people (who are the main market) want. If the optical people say they need 200GHz or 300GHz and have the budget, LeCroy should have no problems extending the current design to those bandwidths. Beyond 300GHz  or so life starts to get more interesting. :-)
 

Offline EEVblog

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #55 on: February 13, 2015, 06:05:40 am »
Ok so my comment on youtube about the price of the board have to be modify. This can cost a fortune (surly more than 5k) also why soo many layer? a lot of digital signals?
 I have never  hear  about 28 a layer board before! Amazing.

At these sorts of rates signal integrity is everything. That happens best with ground planes and lots of them.
Then you have the huge BGA parts that need fanning out.
You also have huge power requirements whcih also calls for many power planes, and there will be many power rails, 5 or 6 power rails in a high speed digital domain is not uncommon.
Fanning out a big arse BGA package usually takes 6-8 signal layers, and if you whack a ground plane between each one of them, that's 16 layers right there off the bat. Add another half dozen for big power rails and misc routing and you can start to see how you might need 28 layers.
 

Offline Wuerstchenhund

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #56 on: February 13, 2015, 06:15:59 am »
So do you know if keysighy is keysight is developing a scope for that range of frequency?

They are probably trying, but I doubt we will see anything like that from Keysight for the next 5 years or so.

And if they finally come out with their own 100GHz scope it probably will be a (non-expandable) 4 channel scope that only reaches 100GHz on one or two channels only.

LeCroy's LabMaster 10-100ZI can provide up to twenty 100GHz channels or up to eighty 36GHz channels. Even aside from the huge bandwidth, the LabMaster is a complete different beast than anything that is offered by Keysight or Tek.

Quote
also at the beging the guy that explain the theory said that there are company made these oscilloscope. Keysight lecroy and tektronix right? Because the top model of tek scope go up to about 30ghz

He said that there are only three manufacturers of High Speed Oscilloscopes (i.e. oscilloscopes with high sample rates of 40GSa/s or more), which are LeCroy, Keysight and Tek.

Tek has been stuck at 33GHz for some time while LeCroy and later Agilent made the jump to 65GHz and (in case of LeCroy) now 100GHz, and it's unlikely that will change anytime soon.
« Last Edit: February 13, 2015, 06:20:21 am by Wuerstchenhund »
 

Offline rx8pilot

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #57 on: February 13, 2015, 06:39:25 am »
Ok so my comment on youtube about the price of the board have to be modify. This can cost a fortune (surly more than 5k) also why soo many layer? a lot of digital signals?
 I have never  hear  about 28 a layer board before! Amazing.

At these sorts of rates signal integrity is everything. That happens best with ground planes and lots of them.
Then you have the huge BGA parts that need fanning out.
You also have huge power requirements whcih also calls for many power planes, and there will be many power rails, 5 or 6 power rails in a high speed digital domain is not uncommon.
Fanning out a big arse BGA package usually takes 6-8 signal layers, and if you whack a ground plane between each one of them, that's 16 layers right there off the bat. Add another half dozen for big power rails and misc routing and you can start to see how you might need 28 layers.

I have never done a layer count like that but I remember talking to an engineering group doing some very high speed layout in the neighborhood of 28 layers. One interesting comment they made was that the PCB yield was rather low. The very fine traces mixed with blind and buried vias apparently get s very difficult to manufacture. It only takes one via (out of 10's of thousands) that does not make contact to make a rainy day. If the via is buried, or its a critical path, there may be no bodge wire option.
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Offline VK5RC

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #58 on: February 13, 2015, 07:56:47 am »
Thanks Shariar and Lecroy,  I liked the rf deck,  those connectors and lines are very special,  coax over 20GHz is pretty special, phase,  impedance matching,  was the figure below 50 fS? Light travels just ^0.1mm. Thanks
Whoah! Watch where that landed we might need it later.
 

Offline electr_peter

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #59 on: February 13, 2015, 11:51:14 am »
One thing I really like about such scope is that it is pushing the limits. It gets to 100 GHz, but just barely (almost all aspects are pushed to the limit, only extensive DSP corrections helps to keep it in one piece). I am sure a small amount of tweaking could bring another GHz or so for current model and future versions will be even better.
It is certainly not the case of having 200 GHz BW scope and configuring it via some jumpers to "entry range" 100 GHz BW version.
Why do you say "just barely"? It gets to 100GHz by old and well tried techniques, implemented with state of the art hardware. It will be a lot quirkier than a straightforward monolithic ADC. Anything large has thermal tracking issues, and anything that that many separate parts working in concert is going to have calibration issues. The calibration can be handled very well by modern approaches.
I mean to say that this scope is using many of components to the max specs while components are high speced to begin with. Not much headroom is left. Paper linked in this thread also shows that frequency response starts to roll of at higher frequencies. Triggering is harder to implement because of many steps involved in analog->digital path.

One of the main problems is a low BW and low sampling rate of ADCs. They solved it by interleaving multiple ADCs. BW limitations of ADC is solved by interleaving splitted and downconverted frequency bands. You can call this solution quicker than new high BW ADC but I think it is a bypass of current ADC limitations to get to full 100 GHz BW.

Quote
They make a 100GHz oscilloscope because that's what the optical people (who are the main market) want. If the optical people say they need 200GHz or 300GHz and have the budget, LeCroy should have no problems extending the current design to those bandwidths. Beyond 300GHz  or so life starts to get more interesting. :-)
100 GHz version is made because they can do it, they need to compete and innovate, it is needed for industry and research applications. I have no doubts that slightly higher BW version can be made with similar architecture, but it will be more and more difficult for them because of front end limitations.

Do you think they can make 200 GHz scope by using two 100 GHz scopes and using similar frequency splitting technique? I don't think it is possible now, more R&D is needed to boost front end BW.
 

Offline Hugoneus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #60 on: February 13, 2015, 06:57:57 pm »
There are some other practical problems in terms of getting signals into the instrument as well. 1mm connectors are rated to 110GHz, above that Anritsu has proprietary 0.9 ~ 0.8mm connectors up to 140GHz. After that, you are no longer in coax, you are in waveguide which of course is banded...

Regardless, electro-optics don't have 100GHz bandwidth yet.

Offline rx8pilot

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #61 on: February 13, 2015, 07:32:46 pm »
What is the target audience or field for an instrument like this? What kind of advantage would it offer to justify the enormous effort/price. If someone had a 66Ghz scope and they stumble across this thing, how likely would they say - "I NEED that or a just cannot continue with this project"?



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Offline vaualbus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #62 on: February 13, 2015, 11:46:33 pm »
There are some other practical problems in terms of getting signals into the instrument as well. 1mm connectors are rated to 110GHz, above that Anritsu has proprietary 0.9 ~ 0.8mm connectors up to 140GHz. After that, you are no longer in coax, you are in waveguide which of course is banded...

Regardless, electro-optics don't have 100GHz bandwidth yet.

I have recently read a document from aritsu I think about connector and the feature.
http://downloadfile.anritsu.com/RefFiles/ja-JP/About-Anritsu/R_D/Technical/89/89_07.pdf
So they're developing a 0.8 connector able to reach 140Ghz. It is a interest reading by the way for someone that really haven't work and studied this type of rf stuff (rf? microwave would be a better term). 
 

Offline Terabyte2007

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #63 on: February 14, 2015, 12:26:59 am »
What is the target audience or field for an instrument like this? What kind of advantage would it offer to justify the enormous effort/price. If someone had a 66Ghz scope and they stumble across this thing, how likely would they say - "I NEED that or a just cannot continue with this project"?

I would have to agree with you. The first thing that came to mind was the niche market for a scope like this. Although the video was very cool and informative the practicality of a scope of this magnitude would be limited to very few corporations. I wonder what the calibration cycle is and how much they charge?  ;D

BTW, does anyone know what they are selling this beast for? I probably don't want to know.
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Offline Hugoneus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #64 on: February 14, 2015, 12:39:54 am »
What is the target audience or field for an instrument like this? What kind of advantage would it offer to justify the enormous effort/price. If someone had a 66Ghz scope and they stumble across this thing, how likely would they say - "I NEED that or a just cannot continue with this project"?
I would have to agree with you. The first thing that came to mind was the niche market for a scope like this. Although the video was very cool and informative the practicality of a scope of this magnitude would be limited to very few corporations. I wonder what the calibration cycle is and how much they charge?  ;D
BTW, does anyone know what they are selling this beast for? I probably don't want to know.

It is $1 million dollars.

Offline Terabyte2007

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #65 on: February 14, 2015, 12:48:20 am »
What is the target audience or field for an instrument like this? What kind of advantage would it offer to justify the enormous effort/price. If someone had a 66Ghz scope and they stumble across this thing, how likely would they say - "I NEED that or a just cannot continue with this project"?
I would have to agree with you. The first thing that came to mind was the niche market for a scope like this. Although the video was very cool and informative the practicality of a scope of this magnitude would be limited to very few corporations. I wonder what the calibration cycle is and how much they charge?  ;D
BTW, does anyone know what they are selling this beast for? I probably don't want to know.

It is $1 million dollars.

Doh!  :o
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Online IanB

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #66 on: February 14, 2015, 01:01:26 am »
It is $1 million dollars.

Which is not, relatively, a huge amount of money when considering the operating budget of a medium to large corporation.
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Offline rx8pilot

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #67 on: February 14, 2015, 01:08:44 am »
If that is the instrument that allows you to get more data over existing trans-ocean fiber or something similar - $1mil is chump change compared to laying a new pipe. Just better make sure the guy requesting the PO knows what to do with it. My first task would be making a post in the "Show Your Squarewave" thread. Probably not worth the money for that task.

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Offline Hugoneus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #68 on: February 14, 2015, 01:17:48 am »
« Last Edit: February 14, 2015, 01:23:21 am by Hugoneus »
 

Offline andrija

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #69 on: February 14, 2015, 02:11:58 am »
If that is the instrument that allows you to get more data over existing trans-ocean fiber or something similar - $1mil is chump change compared to laying a new pipe. Just better make sure the guy requesting the PO knows what to do with it. My first task would be making a post in the "Show Your Squarewave" thread. Probably not worth the money for that task.

I believe that is exactly what you have at the end of the video. It is showing a femtosecond pulse generator output. Although I have no idea if the pulse itself if square, of course.
 

Offline coppice

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #70 on: February 14, 2015, 05:42:38 pm »
Quote
They make a 100GHz oscilloscope because that's what the optical people (who are the main market) want. If the optical people say they need 200GHz or 300GHz and have the budget, LeCroy should have no problems extending the current design to those bandwidths. Beyond 300GHz  or so life starts to get more interesting. :-)
100 GHz version is made because they can do it, they need to compete and innovate, it is needed for industry and research applications. I have no doubts that slightly higher BW version can be made with similar architecture, but it will be more and more difficult for them because of front end limitations.

Do you think they can make 200 GHz scope by using two 100 GHz scopes and using similar frequency splitting technique? I don't think it is possible now, more R&D is needed to boost front end BW.
Making these things is not an intellectual game. Its a business. You make what people want. If you can't make enough of them to cover costs you don't go ahead. Many research prototypes don't move on to full development because the market is too small. If enough people with enough money have a strong need you make them an instrument. If you can't make exactly what they want you get the result they need by a more circuitous route. Right now the market and the development cost of a 200GHz aren't matching up or LeCroy would have a 200GHz instrument. External connections are certainly going to be tough, and the approach they use now isn't rated for 200GHz , but they'd find something if the market were there. From work we did in the 80s, I suspect 300GHz is about where you'd start scratching your head.
 

Offline vaualbus

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #71 on: February 15, 2015, 12:28:10 am »
Quote
They make a 100GHz oscilloscope because that's what the optical people (who are the main market) want. If the optical people say they need 200GHz or 300GHz and have the budget, LeCroy should have no problems extending the current design to those bandwidths. Beyond 300GHz  or so life starts to get more interesting. :-)
100 GHz version is made because they can do it, they need to compete and innovate, it is needed for industry and research applications. I have no doubts that slightly higher BW version can be made with similar architecture, but it will be more and more difficult for them because of front end limitations.

Do you think they can make 200 GHz scope by using two 100 GHz scopes and using similar frequency splitting technique? I don't think it is possible now, more R&D is needed to boost front end BW.
Making these things is not an intellectual game. Its a business. You make what people want. If you can't make enough of them to cover costs you don't go ahead. Many research prototypes don't move on to full development because the market is too small. If enough people with enough money have a strong need you make them an instrument. If you can't make exactly what they want you get the result they need by a more circuitous route. Right now the market and the development cost of a 200GHz aren't matching up or LeCroy would have a 200GHz instrument. External connections are certainly going to be tough, and the approach they use now isn't rated for 200GHz , but they'd find something if the market were there. From work we did in the 80s, I suspect 300GHz is about where you'd start scratching your head.

There is also physics problem. You can't build a such frequency scope becuase there are no connectors type for that frequency and also there no use for them. I think personally that the end for scope is near I think that a 200ghz will never released.
 

Offline Lukas

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #72 on: February 15, 2015, 12:59:40 am »
I'm wondering when you really need 100GHz real time bandwidth. All in the experiments in the video could have been done using a sampling scope. Although not has convenient since you'd have to provide a trigger source.
 

Offline w2aew

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #73 on: February 15, 2015, 02:38:15 am »
I'm wondering when you really need 100GHz real time bandwidth. All in the experiments in the video could have been done using a sampling scope. Although not has convenient since you'd have to provide a trigger source.

One key application would be coherent optical signal analysis, where the quadrature components of multiple optical polarizations need to be simultaneously captured and analyzed. Another potential application is vector signal analysis of Wideband RF signals in the 60/70/90Ghz bands.
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Offline mikeselectricstuff

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Re: Video Teardown & Experiements with LeCroy's 100GHz, 240GS/s Scope
« Reply #74 on: February 15, 2015, 10:36:17 am »
i have a suggestion ... not sure if it will breach secrets of making PCB ...  :-//

i saw youtube 4 layer PCB how they make it (eurocircuits) ...

any chance of a factory tour that takes us to see these 28 layer PCB fabs ? and some kind of similar narrative about how they do it?  :-+ ... maybe some PCB fab will offer to show on EEVblog ?
Just watch the 4 layer video 7 times  ;D
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