Recommendations for a fast (GHz) scope ?

[LeoUCDavis]

Hi all

I've been working on impulse radar designs and I've really felt the need for a high speed (>3 GHz) oscilloscope to look at the signals in time domain. We are sometimes dealing with one shot signals so a sub-sampling scope is out of the question.

We have a budget of about $7000 so I'm pretty sure we'll have to buy a second hand one.

Any recommendations?

Thanks!

[EEVblog]

First, you need to put what country you are from. US/California it seems.
It's a bit of squeeze for that budget, but possible:

http://www.ebay.com/itm/LeCroy-DDA-3000-XL-3Ghz-4-Channel-Digital-Oscilloscope-20GS-s-100Mpt-/301409747557?pt=LH_DefaultDomain_0&hash=item462d6bc265

http://www.ebay.com/itm/Tektronix-TDS694C-3Ghz-10Gs-s-5-in-stock-/231281969989?pt=LH_DefaultDomain_0&hash=item35d97acb45

Keysight Certiprime are usually good value, and stock comes up all the time, and you can bargain them down:
http://stores.ebay.com/keysight
This 6GHz one is hard to beat:
http://www.ebay.com/itm/Keysight-DSO80604B-Infiniium-High-Performance-Oscilloscope-Agilent-DSO80604B-/171363959684?pt=LH_DefaultDomain_0&hash=item27e6168384
Might get it for $8K?

[skipjackrc4]

I'll second the DSO80604.  I've seen them go for as low as $5k, though that's probably fairly rare.

[don]

Hi all

I've been working on impulse radar designs and I've really felt the need for a high speed (>3 GHz) oscilloscope to look at the signals in time domain. We are sometimes dealing with one shot signals so a sub-sampling scope is out of the question.

We have a budget of about $7000 so I'm pretty sure we'll have to buy a second hand one.

Any recommendations?

Thanks!

Are probes included in budget?   Probes can add up depending on what you need.

[HighVoltage]

Keysight Certiprime are usually good value, and stock comes up all the time, and you can bargain them down:

Very true.
I bought a few items from the Keygsight ebay store and sometimes the extra bargain was significant, to say the least!
They also have a Keysight DSO81204B listed
12 GHz, 4 channels

List price: $106,377
You save: $90,420.45 (85% off)
Now: US $15,956.55

You might even get that one in to your budget

I had an opportunity to play with one of these DSO81204B a few weeks ago on our local calibration lab.
And suddenly a MSO-X 3000A is a toy in comparison of all the stuff that can be done.

[Wuerstchenhund]

I've been working on impulse radar designs and I've really felt the need for a high speed (>3 GHz) oscilloscope to look at the signals in time domain. We are sometimes dealing with one shot signals so a sub-sampling scope is out of the question.

We have a budget of about $7000 so I'm pretty sure we'll have to buy a second hand one.

Any recommendations?

Yes. As someone who works in a similar field my recommendation would be go with a LeCroy. Not only because they make excellent high end scopes (probably the best ones) but also because they offer the longest support (7 years full support after a Series has ceased production, and on a best effort basis after that; they still repair scopes as old as the 9300 Series which stopped production in 1998). That means if your second hand purchase fails you're not left alone as with some of the other alternatives.

For scopes that are still inside the 7 year support period you can also buy manufacturer warranty when the scope is sent in for calibration and it passes, so you can get the same protection as with a brand new one.

Considering your requirements and budget I'd say go with a LeCroy WavePro 7300A. This is a 3Ghz 20GSa/s high end scope with up to 100Mpts sample memory and a massive list of supported software options (i.e. Jitter Analysis, Serial Decode of stuff like MIL-STD1553, ARINC429 and 8B/10B, Signal Data Analysis and so on) which can be invaluable.

Here's the full spec sheet:
http://www3.imperial.ac.uk/pls/portallive/docs/1/7293022.PDF

If you need more than 3GHz bandwidth then the next step up is the WaveMaster 8000A (which starts at 1GHz and goes up to 6GHz) which is essentially a WavePro with higher bandwidth and some additional features. Note that the WaveMaster has 50 ohms inputs only while the WavePro 7300A has 1M/50 ohms switchable.

The WaveMaster 8kA spec sheet is here:
http://wiki.epfl.ch/carplat/documents/PDF/LC6800A_WaveMaster_Series_Brochure_in_PDF_format.pdf


As to the Agilent DSO80604 and DSO81204 that was suggested elsewhere: we had several of these Agilent DSO80k scopes when they were still current several years ago, and while there are various options available for them as well they are really no match for a WavePro 7kA or WaveMaster 8kA, neither in performance nor in its capabilities. For example, even if you have the max sample memory option for the DSO80604 it only works at up to 4GSa/s which is rather pathetic, as is the waveform update rate (4800 wfms/s at 64pts sample memory and up to 10GSa/s, up to 800 wfms/s with larger memory sizes and faster sample rates). The WavePro/WaveMaster is specified for up to 150k wfms/s. Or the DSO80k's smaller screen (8.4" 640x480 vs 10.4" 800x600) which is limited to displaying four grids only (WP/WM eight grids). Or the UI (designed for mouse UI on the Agilent, full touch UI on the LeCroy). Lots of things that make working with the LeCroy so much easier.

The DSO80k is also out of support since 2013 while the WavePro/WaveMaster are still supported (until end of 2016 if I remember correctly). This also shows in the software support (latest version for the Agilent is from April 2009, latest version for the WavePro/WaveMaster is from 2nd of March 2015, and it will get further updates).


There's an ebay seller called 'technosaurus' who regularly sells LeCroy scopes. He often has some WavePro 7300A ex-demo scopes with all software options and 48M memory for less than $5k which is a steal. I paid in the same region for mine. You could send him a message, maybe he has something available.

[Wuerstchenhund]

http://www.ebay.com/itm/LeCroy-DDA-3000-XL-3Ghz-4-Channel-Digital-Oscilloscope-20GS-s-100Mpt-/301409747557?pt=LH_DefaultDomain_0&hash=item462d6bc265

That's a Disk Drive Analyzer. It's essentially a WavePro 7300(A) with special software for hard drive analysis. It can be used as a normal scope but most of the advanced options aren't officially available for the DDA.

It's a good scope but almost $8k are a bit excessive considering that it lacks most of the interesting options.

http://www.ebay.com/itm/Tektronix-TDS694C-3Ghz-10Gs-s-5-in-stock-/231281969989?pt=LH_DefaultDomain_0&hash=item35d97acb45

Really, a 17 year old antique with CRT screen and a whooping 120kpts sample memory for $4700? I'm sorry but I'd say whoever sinks that amount of money into such an old banger needs his head examined.

Keysight Certiprime are usually good value, and stock comes up all the time, and you can bargain them down:
http://stores.ebay.com/keysight

Yes, CertiPrime stuff which is pretty new and comes with full warranty is indeed good value. Unfortunately the same can't be said about their older non-CertiPrime offerings.

This 6GHz one is hard to beat:
http://www.ebay.com/itm/Keysight-DSO80604B-Infiniium-High-Performance-Oscilloscope-Agilent-DSO80604B-/171363959684?pt=LH_DefaultDomain_0&hash=item27e6168384
Might get it for $8K?

The bandwidth is nice but the rest isn't, really. 512k sample memory is a joke, as is only 30 days of warranty for an $8k item. Especially when considering that this is the manufacturer's web shop, not a 3rd party seller. They obviously have very little trust in their stuff.

This scope has also been out of support since 2013.

I'm not sure that any of these are a sensible investment.

They also have a Keysight DSO81204B listed
12 GHz, 4 channels

List price: $106,377
You save: $90,420.45 (85% off)
Now: US $15,956.55

You might even get that one in to your budget

And still suffers from the same limitations (small sample memory, low waveform rate, slow processing and a very limited architecture).

I had an opportunity to play with one of these DSO81204B a few weeks ago on our local calibration lab.
And suddenly a MSO-X 3000A is a toy in comparison of all the stuff that can be done.

I'm sorry to have to say this but a MSOX3k *is* a toy in comparison to any newer highend scope.

[rolycat]

If you are based in the US then logistics may be tricky, but there is a DSO81204B (12 GHz, 40 GSa/s) currently for sale with a 30 day warranty on Craigslist London for £3550 (around $5300). Optional 2 Mpts memory (64 Mpts at 4 GSa/s).

[nctnico]

I would not buy the Tektronix TDS694C if I need to depend on it. One of the problems is that the chip which deals with the triggering can overheat and fail. Ofcourse this chip is made from unobtanium so if the trigger chip is dead you are left with a dud.

Regarding the DSO8000 series: make sure you have a way to get the signal into the probe inputs!

[LabSpokane]

Some notes on the Keysight eBay store:

The Premium scopes come with all the accessories as new. They also offer full warranty typically. Haggling room is about 15% below listed price.

Plain used scopes are bare scope only.  I'm not sure about the bargaining room on these. Hopefully it's more than 15% otherwise these are pretty poor values.

I'd write to them via eBay and make sure they know you're academic, because they might swing a super deal. Software upgrades are usually negotiable with the sale. You'd quite likely get them to toss in the 2M point upgrade on the Infinium.

[G0HZU]

Hi all

I've been working on impulse radar designs and I've really felt the need for a high speed (>3 GHz) oscilloscope to look at the signals in time domain. We are sometimes dealing with one shot signals so a sub-sampling scope is out of the question.

We have a budget of about $7000 so I'm pretty sure we'll have to buy a second hand one.

Any recommendations?

Thanks!

The classic workhorse for stuff like this is the old Tek TDS7404 and these can be purchased within your budget. I'm pretty sure this is the model we have at work for capturing data for stuff like this. 

So I would suggest that you should consider the TDS7404 as the initial benchmark for performance for your task as it is (was) a proven tool in this field. I'm sure there will be better suited scopes available today but maybe not within your price budget.

[tggzzz]

If you only need it for a short time, have you considered hiring a scope.

The last time I looked, decades ago, hiring cost was around 10% of purchase price per month.

[codeboy2k]

I would not buy the Tektronix TDS694C if I need to depend on it. One of the problems is that the chip which deals with the triggering can overheat and fail. Ofcourse this chip is made from unobtanium so if the trigger chip is dead you are left with a dud.

Would that be the problem with this TDS694C? $1299

http://www.ebay.com/itm/Tektronix-TDS694C-Digital-Oscilloscope-4Ch-3Ghz-10Gs-s-Option-13-1F-HD-1M-2F/301550127879?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20131003132420%26meid%3D2499533c123b4100b11d4e0c1c558b71%26pid%3D100005%26rk%3D5%26rkt%3D6%26sd%3D231281969989&rt=nc

The seller says selling for parts/not working, but it powers on and passes self-tests.  Seller says it has an overheat failure shortly after power-on.
If it's not completely failed yet, is it repairable before it fails completely?

[Wuerstchenhund]

The classic workhorse for stuff like this is the old Tek TDS7404 and these can be purchased within your budget. I'm pretty sure this is the model we have at work for capturing data for stuff like this. 

So I would suggest that you should consider the TDS7404 as the initial benchmark for performance for your task as it is (was) a proven tool in this field. I'm sure there will be better suited scopes available today but maybe not within your price budget.

The TDS7404 is certainly a better choice than the mentioned Agilent DSO80604, as the Tek at least offers a better UI and doesn't suffer from the silly sample rate limitations when using long memory or the abysmally low waveform update rate of the Agilent.

The negatives I see is that it only can do 20GSa/s in single channel mode (10GSa/s in dual channel, and only 5GSa/s in four channel mode), which is quite poor for such a scope. Software options are also very limited (both in number and capabilities), and whenever I had to use a TDS7k I found they got pretty sluggish when using some of the advanced functionality.

Also, both TDS7404 and TDS7404B are out of support for quite a while now, and even for the B variant the last software update is from 2005 (2004 for the non-B) which isn't great either.

[G0HZU]

I suggested the TDS7404 because the task appears to be radar related. At work we are always interested in through wall radar technology and in recent years the Tek TDS7xxx seemed to be a popular tool for capture of UWB radar signals.

I think we have the TDS7404 model at work and it is very good in terms of being able to capture and dump out data for post processing. For UWB radar research this is probably the main feature that it needs to be good at.

[rolycat]

Some notes on the Keysight eBay store:

The Premium scopes come with all the accessories as new. They also offer full warranty typically. Haggling room is about 15% below listed price.

Plain used scopes are bare scope only.  I'm not sure about the bargaining room on these. Hopefully it's more than 15% otherwise these are pretty poor values.

I'd write to them via eBay and make sure they know you're academic, because they might swing a super deal. Software upgrades are usually negotiable with the sale. You'd quite likely get them to toss in the 2M point upgrade on the Infinium.

As I understand it, the OP will still need additional budget for probes with sufficient bandwidth.

For example, a Keysight Premium Used MSO9404A 4 GHz scope is supplied with 4 N2873A passive probes which are rated at just 500MHz.

[Wuerstchenhund]

As I understand it, the OP will still need additional budget for probes with sufficient bandwidth.

For example, a Keysight Premium Used MSO9404A 4 GHz scope is supplied with 4 N2873A passive probes which are rated at just 500MHz.

All scopes only come with low bandwidth passive probes, but yes, probing needs to be considered, especially since it can take up a large part of the budget.

[Wuerstchenhund]

I suggested the TDS7404 because the task appears to be radar related. At work we are always interested in through wall radar technology and in recent years the Tek TDS7xxx seemed to be a popular tool for capture of UWB radar signals.

I think we have the TDS7404 model at work and it is very good in terms of being able to capture and dump out data for post processing. For UWB radar research this is probably the main feature that it needs to be good at.

Well, any better scope can dump out data for post processing, that's not a special feature (even Rigol scopes can do that).

It's only becoming interesting if you can do the processing on the scope, and even better if it happens directly after the acquisition and not after a blob of data has been transferred to a PC. That's where a good high end scope shines, and in my experience the TDS7k(B) is just the wrong tool for that, not only because of the old/limited set of functionality but also because it's pretty slow.

There's really nothing in the TDS7k which makes it special or particularly well suited for RADAR related work. And you'll find that for UWB development the predominant tools come from Agilent/Keysight and especially LeCroy, simply because their toolsets are so much better than Tek's.

[G0HZU]

Well, any better scope can dump out data for post processing, that's not a special feature (even Rigol scopes can do that).

But that's my point... I assume that for UWB radar analysis it just needs to be able to capture and dump data efficiently. You sold the LeCroy in your first post because it offers 'invaluable' tool options like serial decode. What has serial decode got to do with UWB radar? 

I mentioned the TDS7404 because it has been used and proven in this field in the past. The TDS7404 also has decent quality input connectors (i.e. not BNC) and I assume this is one feature that would be good for UWB technology. But I'm just guessing. I've read quite a few papers on radar design over the years and the Tek TDS7404 was a popular choice as a research tool.

It's an old scope so there will be better choices available today but maybe not for $7k. I merely suggested it as a basic (and field proven) benchmark against which other scopes can be compared.

[Wuerstchenhund]

But that's my point... I assume that for UWB radar analysis it just needs to be able to capture and dump data efficiently. You sold the LeCroy in your first post because it offers 'invaluable' tool options like serial decode. What has serial decode got to do with UWB radar? 

I didn't say serial decode is 'invaluable' for UWB (and the OP never mentioned UWB, he just wrote RADAR). But depending on what type of RADARs one works being able to decode MIL-1553 or ARINC can be crucial.

Also what does certainly help for UWB RADAR development are tools like Jitter Analysis, Power Measurements or Signal Data Analysis. It also helps if you can write your own tools that run on the scope and directly pull out data from the acquisition system (before it reaches the scope processing), do some processing, and then feed it back into the scope system for further processing/analysis, which is great if you work on localization algorithms. You simply can't do that on the TDS7k, too slow and limited.

I mentioned the TDS7404 because it has been used and proven in this field in the past. The TDS7404 also has decent quality input connectors (i.e. not BNC) and I assume this is one feature that would be good for UWB technology.

Every high end scope has decent quality input connectors. Agilent has them, LeCroy has them (the older WavePro use BNC for up to 3GHz which is fine, the WaveMaster use some SMB style input connectors which are rated for higher frequencies), and Tek has them as well. There's nothing particular special on the TDS7404 connectors for a 4GHz scope.

And the only thing relevant for the type of connector on a scope is the required bandwidth, not the application.

But I'm just guessing. I've read quite a few papers on radar design over the years and the Tek TDS7404 was a popular choice as a research tool.

That must have been pretty old papers I guess.

Don't get me wrong, the TDS7k is a good scope (and better than some of the other alternatives suggested here) but a lot of stuff needed for modern UWB RADAR development simply isn't possible with it, and most of the more demanding UWB RADAR work these days is done with either a LeCroy's SDAs (which are WavePro/WaveMaster running the SDA/SDA2 package) or with something like an Agilent/Keysight DSOX90k plus some EDA software, simply because of their toolsets.

[G0HZU]

That must have been pretty old papers I guess.

Don't get me wrong, the TDS7k is a good scope (and better than some of the other alternatives suggested here) but a lot of stuff needed for modern UWB RADAR development simply isn't possible with it, and most of the more demanding UWB RADAR work these days is done with either a LeCroy's SDAs (which are WavePro/WaveMaster running the SDA/SDA2 package) or with something like an Agilent/Keysight DSOX90k plus some EDA software, simply because of their toolsets.

There's only a $7000 budget available...

[Wuerstchenhund]

That must have been pretty old papers I guess.

Don't get me wrong, the TDS7k is a good scope (and better than some of the other alternatives suggested here) but a lot of stuff needed for modern UWB RADAR development simply isn't possible with it, and most of the more demanding UWB RADAR work these days is done with either a LeCroy's SDAs (which are WavePro/WaveMaster running the SDA/SDA2 package) or with something like an Agilent/Keysight DSOX90k plus some EDA software, simply because of their toolsets.

There's only a $7000 budget available...

A 3GHz WavePro 7300A with all these options often goes for around $5k (I'm not the only one who got one at around that price, although sometimes a bit of patience is required). A loaded 5GHz WaveMaster 8500A sometimes goes for only little more (i.e. around $6k).

Most people only think "Tektronix" and "Agilent" when thinking about big brand scopes, which keeps prices of their 2nd hand gear high, often way beyond reason.

[nctnico]

As I understand it, the OP will still need additional budget for probes with sufficient bandwidth.

Not really. There is not much to probe at several GHz. The best thing is to hook up a circuit is using 50 Ohm coax; this is already tricky enough.

[G0HZU]

That must have been pretty old papers I guess.

Don't get me wrong, the TDS7k is a good scope (and better than some of the other alternatives suggested here) but a lot of stuff needed for modern UWB RADAR development simply isn't possible with it, and most of the more demanding UWB RADAR work these days is done with either a LeCroy's SDAs (which are WavePro/WaveMaster running the SDA/SDA2 package) or with something like an Agilent/Keysight DSOX90k plus some EDA software, simply because of their toolsets.

There's only a $7000 budget available...

A 3GHz WavePro 7300A with all these options often goes for around $5k (I'm not the only one who got one at around that price, although sometimes a bit of patience is required). A loaded 5GHz WaveMaster 8500A sometimes goes for only little more (i.e. around $6k).

Most people only think "Tektronix" and "Agilent" when thinking about big brand scopes, which keeps prices of their 2nd hand gear high, often way beyond reason.

You aren't being consistent here...

The 'more demanding' UWB work 'today' would typically require very high scope bandwidths. You mentioned the 90000 Agilent scopes above but they cost a fortune and offer bandwidths that are ten times higher than your used $5k LeCroy with its BW of just a few GHz.

or are you suggesting the OP can buy a 90000 series Agilent for $7k? If so I think I'd like one too

[Wuerstchenhund]

You aren't being consistent here...

The 'more demanding' UWB work 'today' would typically require very high scope bandwidths. You mentioned the 90000 Agilent scopes above but they cost a fortune and offer bandwidths that are ten times higher than your used $5k LeCroy with its BW of just a few GHz.

It's you who isn't consistent here. Didn't you just state that a 4GHz TDS7404 would be a good choice for UWB development even though there's absolutely nothing special on that scope aside from the fact that you read about it in some papers?

As to modern UWB development, you don't really need "bandwidths that are ten times higher". In fact, even for UWB developments in frequency ranges in excess of 20GHz you rarely see scopes over 6-10GHz. In fact, you'd be surprised how many of the older WavePro 7000A, WaveMaster 8000A and their SDA counterparts are still in use for UWB RADAR development. Simply because they still offer sufficient performance, offer (almost) the same toolsets as the latest LeCroy highend scopes, and are still fully supported by its manufacturer.

The same can't be said about any of the listed alternatives.

Which goes back to the OP's original question, which was a good 3GHz or better scope suitable for RADAR development work for up to $7k. And fact is that nothing that falls into that price bracket offers even close the performance, capabilities and support of a WavePro 7kA or WaveMaster 8kA. If you know something better then I'm sure the OP would appreciate it, but a TDS7404 simply isn't.

or are you suggesting the OP can buy a 90000 series Agilent for $7k? If so I think I'd like one too

No, I don't. My point was simply that you'll hardly see any simpler scopes like a TDS7404 used for complex tasks in UWB RADAR development.

[G0HZU]

Didn't you just state that a 4GHz TDS7404 would be a good choice for UWB development even though there's absolutely nothing special on that scope aside from the fact that you read about it in some papers?

I offered it as a performance benchmark to compare against newer scopes (budget permitting). i.e. as an old scope that has been used for UWB research work that had the BW the OP desired and was within the budget limit. I'm pretty sure this is the model we have at work. We have newer and better scopes but these aren't worth mentioning as they are beyond the OPs budget.

[G0HZU]

OP, not sure what requirements you have.   I would be interested in hearing more about what processing you would need to do for this application.

Agreed. I assumed the OP would just use the scope for single shot or low PRF applications to do some verification etc. The Tek TDS7404 offers 20GHz sample rate on single shot or single channel.

I dug out an old paper on UWB pulsed radar that used this scope and they achieved a 50ps timeslot with this scope. This is directly related to the 20GHz sample rate on a single channel. Presumably this rate offers a decent range resolution. This performance is pretty good although this old school scope obviously uses interleaved ADCs to get this high sample rate. The processing was done externally in this case.

The TDS7404 was useful for stuff like this because it offers this fast timeslot that gives good range resolution. But I'm beginning to feel like I shouldn't have bothered mentioning the TDS7404 as a benchmark 

I'm not familiar with the LeCroy scopes so I'll leave it to Wuerstchenhund to show the single shot performance and  timeslot (and therefore range resolution?) the LeCroy model(s) can expect to achieve for a similar cost budget.

[LeoUCDavis]

Wow I'm surprised by this many responses. Thank you all. Seems to be a good amount of stuff for me to study ...

I'm in the US btw.

[LeoUCDavis]

Are probes included in budget?   Probes can add up depending on what you need.

No we normally just use RF cables.

[Wuerstchenhund]

I dug out an old paper on UWB pulsed radar that used this scope and they achieved a 50ps timeslot with this scope. This is directly related to the 20GHz sample rate on a single channel. Presumably this rate offers a decent range resolution. This performance is pretty good although this old school scope obviously uses interleaved ADCs to get this high sample rate. The processing was done externally in this case.

Yes, 50ps because as you say that is the timeslot resolution of the TD7404.

I'm not familiar with the LeCroy scopes so I'll leave it to Wuerstchenhund to show the single shot performance and  timeslot (and therefore range resolution?) the LeCroy model(s) can expect to achieve for a similar cost budget.

I couldn't be bothered to check for the WaveMaster but even my 3GHz WavePro 7300A can do timeslots down to 20ps 50ps and that on two channels simultaneously.

Also, the higher Time Interval Accuracy (+0.15/Sample Rate + (10 ppm * Reading) for the TDS7404, <0.06/Sample Rate + (10 ppm * Reading) for the LeCroy), Sample Rate and Delay Time Accuracy (±10 ppm for the Tek vs ±5ppm for the WavePro) and lower Trigger jitter (7ps TDS7404, 2.5ps WavePro) certainly helps. As does being able to do a lot of the processing on the scope directly.

All for approx $5k.

Although I admit that the comparison isn't really fair. The TDS7404 is a pretty old-fashioned scope, and the successor DPO7000 would actually be closer to the WavePro's/WaveMaster's performance class. However I haven't seen one going for less than $10k, not even the 500MHz models.


Edit: apologies, I was a bit in a hurry and picked up the wrong time slot, which of course is 50ps for the WP7kA as well (1/20 GSa/s.)

[G0HZU]

Just to clarify, I'm referring to the time interval at the real time sampling limit of the scope. So are you saying the $5k used Lecroy can sample at 50GHz on one channel (and in single slot) in real time to get that 20ps?

I'm not familiar with the LeCroy range so I don't know the age/cost/specs of them because they all have similar names.

I also don't know that much about UWB radar but it's usually used for short range high resolution operation and I assumed that the scope would be used to sample a channel at 20GHz and store maybe 5000 samples and then export this for processing. Then step and repeat for each Tx pulse.

Normally, in a radar range equation, the range resolution is a function of the real time sampling rate because the sampling sets the range bin size. So what real time sampling rate can the LeCroy deliver on a single channel and in single shot mode?

[Wuerstchenhund]

Just to clarify, I'm referring to the time interval at the real time sampling limit of the scope. So are you saying the $5k used Lecroy can sample at 50GHz on one channel (and in single slot) in real time to get that 20ps?

No. I just didn't pay attention as I was in a hurry and picked the wrong figure  while my mind was somewhere else 50ps it is for the WavePro of course. Apologies for the confusion.

So what real time sampling rate can the LeCroy deliver on a single channel and in single shot mode?

20GSa/s in single and dual channel mode, 10GSa/s in triple and quad channel mode.

[G0HZU]

It would be interesting and helpful to hear some system info from the OP what the sampling and range requirements are. It could be that the requirements demand a modern scope with a better sampling system. Or the opposite could be true.

My interpretation of the scope requirements are really basic. I would see it as little more than an ADC in a big box that takes maybe 5000 samples after each Tx pulse and sends this small packet of info to an external processing system. Because the pulse repetition frequency is probably going to be quite low (just a few kHz?) then the overall data transfer should be easy. But this is just my interpretation of a basic concept demonstrator system.

I think the upper limit of the old TDS7404 is 400,000 triggers (or radar Tx pulses?) a second but I'd expect that a typical dev system wouldn't operate a PRF this fast.

So I'm not sure that the slow old UI and other aspects of the (very dated) TDS7404 will matter that much. Obviously, if it was used for other tasks it would be a bit of a dog compared to a modern scope.

I think our 7404 at work is mainly a dust collector these days because the engineers reach for the faster/better/£££ modern stuff instead. I've seen it in use and it was very big and made lots of fan noise so it was not popular in the labs with anyone sitting nearby

Someone mentioned hiring a scope and maybe this would be a wise thing to do even if it just meant hiring a one of the >10 year old scopes like the TDS7404 or LeCroy models for a week.

I'd be tempted to also blag a brand new £££ modern scope on trial/approval/demo and see what things the older scope can't do.

[Wuerstchenhund]

It would be interesting and helpful to hear some system info from the OP what the sampling and range requirements are. It could be that the requirements demand a modern scope with a better sampling system. Or the opposite could be true.

Indeed. It may well be that even a lower bandwidth scope does fine. Without getting some more details from the OP this really boils down to "some 3GHz+ scope for <$7k".

[G0HZU]

Hi Joe
I found the single shot sample rate info vs model type on a google search so I deleted my question above as you were probably typing your answer!
Sorry for any confusion caused...

 

[Wuerstchenhund]

Nothing from the OP on what they need other than >3GHz? 

It looks like we won't hear much more from the OP.

[rfbroadband]

go with the R&S RTO series or the Keysight S-Series.

The RTO has the best hardware based FFT in any scope on the market, you get a low end usable spectrum analyzer for free.

The S  series scope has lower jitter than the RTO, but FFT is software based and rather slow.

[Wuerstchenhund]

go with the R&S RTO series or the Keysight S-Series.

You're joking, right? A basic 600MHz RTO starts at roughly $14k, and the 4GHz variant starts at $37k:
http://shop.rohde-schwarz.com/us/test-measurement/oscilloscopes/oscilloscopes.html

The Keysight DSO-S is in the same ballpark ($17k for the 500MHz variant, $37k for the 4GHz version):
http://www.keysight.com/en/pd-2396122-pn-DSOS054A/high-definition-oscilloscope-500-mhz-4-analog-channels?nid=-32877.1087978&cc=US&lc=eng
http://www.keysight.com/en/pd-2396465-pn-DSOS404A/high-definition-oscilloscope-4-ghz-4-analog-channels?nid=-32877.1087982&cc=US&lc=eng

So how do these scopes fit into the OP's budget of $7k then?

The RTO has the best hardware based FFT in any scope on the market, you get a low end usable spectrum analyzer for free.

It's true that FFT is pretty fast on the RTO (and that it's faster than on the Keysight DSO-S), but it still leaves you with the narrow (up to 4GHz, as that's the top end R&S offers) bandwidth of the scope, and it's no replacement for a proper spectrum analyzer. The RTO are good scopes (and it's nice that there is an OCXO option available for them) but for what they offer they are quite expensive (as are the options, accessories and R&S support), they offers limited analysis capabilities (and most of them are aimed at the telecoms market) and have a pretty convoluted UI. Price-wise it's also very close to LeCroy WavePro 7zi(-A), which is a 40GSa/s high end scope with tons of advanced analysis options.

However, all that is pretty irrelevant considering that the $7k of the OP will neither buy him a R&S RTO nor a Keysight DSO-S.