Understanding Entry Level Scopes? (Limitations & Uses)

[Berni]

I would counter that there isn't a scope under $5000 that can even approach that kind of problem.

Hell, I design systems with PCIe, SATA and USB3 and it's *very* infrequent that I need a scope with that kind of capability. A recent contract had us scratching our heads trying to find out why a PCIe link would not come up. LeCroy dropped off one of their top-end MSOs. With all the bells and whistles on that demo unit the MSRP was almost $140k!

Was it a *damn* nice scope? Oh yes. It would directly decode PCIe transactions from looking at the TX/RX lanes. Is it something I'd ever buy for myself? Not a chance.

Well i bought a like new condition 2.5GHz Agilent DSO9000H for 6 grand on ebay that turned out to be a 4GHz scope after some software fiddling, and after some more unlocked all the options. It was because Keysight discontinued the H series and dumped like 10 or more of them on ebay for cheep, later i found that they are the same hardware as the A series that still sells today for high 5 digit dollars.

But beware that it doesn't stop here, you also need to spend another grand or more on fancy active probes to make use of it as the passive stuff stops at 500MHz and has so much capacitance that it screws up your signal under test.

[borjam]

borjam, do you happen to know which M-Audio interface your friend used?

I don't remember (I'll try to find out) but this classic Edirol interface (UA-25) states 20 Hz - 40 KHz +0 -2 dB @96 KHz.

https://www.roland.com/us/products/ua-25/specifications/

Although discontinued it's pretty easy to find second hand.

[cncjerry]

OK, here's a real world problem that the 1054Z can't solve:  Display a 1 GHz carrier with some high frequency modulation.

I would counter that there isn't a scope under $5000 that can even approach that kind of problem.

Hell, I design systems with PCIe, SATA and USB3 and it's *very* infrequent that I need a scope with that kind of capability. A recent contract had us scratching our heads trying to find out why a PCIe link would not come up. LeCroy dropped off one of their top-end MSOs. With all the bells and whistles on that demo unit the MSRP was almost $140k!

Was it a *damn* nice scope? Oh yes. It would directly decode PCIe transactions from looking at the TX/RX lanes. Is it something I'd ever buy for myself? Not a chance.

The 1054Z is an 'entry level' scope.  That means it is a good 'first' scope, probably not the 'last' scope.  Clearly, it would be out of place in a very high tech lab unless it was the designated 'beater' scope.  But it certainly meets my needs!

Couldn't agree more. I bought a Hantek MSO5074FG. It's got its warts but it's a decent scope for the price, and if I can ever get the time to hack on it, I can hack on it. Meanwhile I continue to scour ebay for a good used LeCroy, Tek or Agilent MSO with at least 2GHz bandwidth... *drools*

Sounds likes a challenge!  What would the objective be? Determine if there is HF modulation or not on a 1G signal using a scope that cost less than $500?   I can do it on my sub $500 SA, I wonder if a TDS784 can do it?  I paid $400 for mine with 6 probes.  I'm out of the country or would wire it up.  Let's put more parameters on the test, maybe 1G signal with 10Mhz FM modulation?

[Muxr]

Meanwhile I continue to scour ebay for a good used LeCroy, Tek or Agilent MSO with at least 2GHz bandwidth... *drools*

I sort of gave up on that idea mainly because those older multi Ghz scopes I could afford aren't really good day to day bench scopes. They tend to be huge, loud and take forever to boot. Also their inputs tend to be more fragile. Not to mention you need equally expensive probes for those frequencies as well.

I am pretty happy with my R&S RTM 1054.. it's plenty of scope for my needs and it didn't break the bank.

[Berni]

I sort of gave up on that idea mainly because those older multi Ghz scopes I could afford aren't really good day to day bench scopes. They tend to be huge, loud and take forever to boot. Also their inputs tend to be more fragile. Not to mention you need equally expensive probes for those frequencies as well.

I am pretty happy with my R&S RTM 1054.. it's plenty of scope for my needs and it didn't break the bank.

I have to agree on that. As soon as it is a scope that runs a desktop OS it tends to stop being a good every day scope. Sure there is all the performance in there but it boots slowly(not only the os, but often the scope app too), usually is noisy and uses a lot of power. Also often you can't set up all of the scope trough the front panel buttons, for some stuff you need a touchscreen or mouse to navigate extra menus.

I certainly had lots of cases where a high performance scope was incredibly helpful, but most often i use my 300MHz MSO6000 because it gets the job done faster.

So if you are looking to get a high end scope, you better also have some lowend lightweight scope for the case where you just want to quickly check if a 5MHz clock is running on a board or something. There is a reason they make hammers in different sizes, they are essentially the same tool but for different use cases.

[Wuerstchenhund]

I sort of gave up on that idea mainly because those older multi Ghz scopes I could afford aren't really good day to day bench scopes. They tend to be huge, loud and take forever to boot. Also their inputs tend to be more fragile. Not to mention you need equally expensive probes for those frequencies as well.

I am pretty happy with my R&S RTM 1054.. it's plenty of scope for my needs and it didn't break the bank.

I have to agree on that. As soon as it is a scope that runs a desktop OS it tends to stop being a good every day scope. Sure there is all the performance in there but it boots slowly(not only the os, but often the scope app too)

Not necessarily. Booting can be pretty fast once the standard slow low rpm hard drive that is commonly found in Windows based scopes has been replaced with a decent SSD.

And it's not that embedded platform scopes are necessarily fast, too. For example, my new Tek MDO3000 take around as long to boot as my old LeCroy WavePro 7300A running WindowsXP.

usually is noisy and uses a lot of power.

Yes, but that is mostly because Windows scopes tend to be mid-range or high-end scopes with very fast ADCs that produce a ton of heat, and if you replaced the PC processing backend with an embedded low-power backend as found in the typical low-end scope then it would still be noisy and suck a lot of power.

Also often you can't set up all of the scope trough the front panel buttons, for some stuff you need a touchscreen or mouse to navigate extra menus.

And touchscreen (which is used on an increasing number of entry-level scopes like the Keysight DSOX3kT) is bad because? How else would you want to control all the functions that can be found in a newer high-end scope? Buttons?

I do agree that an UI that requires a mouse isn't great for using on a bench, but it's mostly HP/Agilent that relied on it (although the UI on newer Keysight Infiniiums scopes has improved a lot over the old Infiniium 54800 UI). Tek had a somewhat decent touch UI on their Windows-based scopes, and LeCroy had their MAUI which is was designed for touch right from the start.

So if you are looking to get a high end scope, you better also have some lowend lightweight scope for the case where you just want to quickly check if a 5MHz clock is running on a board or something. There is a reason they make hammers in different sizes, they are essentially the same tool but for different use cases.

As someone who uses a high end scope pretty much every day (at work and at homeI have to disagree here. I find it's much easier to just do the measurement with the high-end scope than fetching a entry-level scope, powering it up and do the measurement with it. Plus quite often even simple problems turn out to be rather more complex, in which case the tools available on the high end scope make life so much easier, even if it's just a 50MHz signal.

However, I do have to admit that it very much depends on the scope in question. Newer Keysights like the DSO-S are great, they boot fast and have a decent an easy to use touch UI. LeCroy mid-range (WaveSurfer) and high-end (WaveRunner, WavePro) scopes also make great general purpose scopes. Older Infiniiums (especially pre-DSO9k models), not so much, simply because of their poor mouse-driven UI and various hardware limitations (i.e. sample memory size drop at higher sample rates) in some models. Tek Windows scopes, while having a somewhat decent UI, are generally slow like wading through molasses in pretty much everything, and tend to lock up when under load. They aren't exactly a joy to use but that is pretty independent of the complexity of the measurement.

Scope inputs aren't really a problem with scopes with a BW of up to 3-8 Ghz, which are usually equipped with BNC or BNC-compatible connectors and have switchable 50ohms/1M inputs. Only very high bandwidth scopes come with non-BNC low-Z (50ohms) inputs only, in which case you'd need an expensive high-z adapter to be able to use a standard passive probe.

So it really depends on what your scope is.

[Muxr]

However, I do have to admit that it very much depends on the scope in question. Newer Keysights like the DSO-S are great, they boot fast and have a decent an easy to use touch UI. LeCroy mid-range (WaveSurfer) and high-end (WaveRunner, WavePro) scopes also make great general purpose scopes. Older Infiniiums (especially pre-DSO9k models), not so much, simply because of their poor mouse-driven UI and various hardware limitations (i.e. sample memory size drop at higher sample rates) in some models. Tek Windows scopes, while having a somewhat decent UI, are generally slow like wading through molasses in pretty much everything, and tend to lock up when under load. They aren't exactly a joy to use but that is pretty independent of the complexity of the measurement.

Scope inputs aren't really a problem with scopes with a BW of up to 3-8 Ghz, which are usually equipped with BNC or BNC-compatible connectors and have switchable 50ohms/1M inputs. Only very high bandwidth scopes come with non-BNC low-Z (50ohms) inputs only, in which case you'd need an expensive high-z adapter to be able to use a standard passive probe.

So it really depends on what your scope is.

This is true. I was mostly thinking of the older Infiniums in my comment. I am sure newer 3-8Ghz scopes are sweet, but they also cost more than I am willing to spend. Everyone's needs and priorities are different. For me personally my next big item purchase is a pick and place machine.

[Wuerstchenhund]

This is true. I was mostly thinking of the older Infiniums in my comment. I am sure newer 3-8Ghz scopes are sweet, but they also cost more than I am willing to spend.

Yes, if you focus on Agilent/Keysight. It took a very long time until Agilent managed to do a Windows scope properly (the DSO9k is the first one that was decent, despite using the same poor UI as previous scopes), and only recent models have improved enough to make decent every-day scopes. The older Infiniiums also weren't particularly capable (limited options, mostly for some special purpose task like compliance testing).

The same isn't true for LeCroy scopes, though. Leaving the older non-Windows scopes out for now, all their Windows scopes (which are all either mid-range or high-end models) make great every-day scopes. Unlike the old Infiniiums, they do pretty much everything a good entry-level scope does, and a lot more. Every scope can do serial decode for a wide range of standards (which includes even niche standards like SpaceWire), there are a wide range of analysis options for pretty anything, and they don't suffer from silly architectural limitations like the drastic reduction of sample memory at higher sample rates as some of the older Infiniiums do. They are easy to use and even the first ones from 2001/2002 are still supported by the bi-yearly X-Stream software updates which makes them compatible with the latest probes which means you can pretty much use any ProBus probe that has been made since 1994 or so (Agilent/Keysight has not only artificially limited probe compatibility between InfiniiVision and Infiniium scopes, once a scope is out of support then software updates stop, and most often they have stopped long before that).

Fast ADCs still get very hot, and very hot stuff needs a lot of cooling, which means it more noise and more power draw. Unfoortunately for now there's no way around that. If you can live with the noise and higher power draw however, there are quite a few scopes, even on the 2nd hand market, that offer large BW and sophisticated analysis tools while making great every-day scopes.

Everyone's needs and priorities are different. For me personally my next big item purchase is a pick and place machine.

Nice

But you're right of course, individual needs and priorities do vary.

I just wanted to show that you don't really need a second every-day scope if you get yourself a more advanced scope.

[rstofer]

Meanwhile I continue to scour ebay for a good used LeCroy, Tek or Agilent MSO with at least 2GHz bandwidth... *drools*

I sort of gave up on that idea mainly because those older multi Ghz scopes I could afford aren't really good day to day bench scopes. They tend to be huge, loud and take forever to boot. Also their inputs tend to be more fragile. Not to mention you need equally expensive probes for those frequencies as well.

I am pretty happy with my R&S RTM 1054.. it's plenty of scope for my needs and it didn't break the bank.

$3500 for a 'seller refurbished' unit?  That's not my idea of an 'entry level' scope.  Looks pretty nice though...

http://www.ebay.com/itm/Rohde-Schwarz-RTM-1054-4-Ch-500-MHz-5-GSa-s-Digital-Oscilloscope-w-Accys-/271835203486

List price over $10k?  Clearly not an 'entry level' scope:

https://www.conres.com/test-equipment/product/rohde-schwarz-rtm1054-500mhz-4-channel-digital-oscilloscope/

We're talking $400 scopes, maybe $1000 scopes - 'entry level'

[Muxr]

Meanwhile I continue to scour ebay for a good used LeCroy, Tek or Agilent MSO with at least 2GHz bandwidth... *drools*

I sort of gave up on that idea mainly because those older multi Ghz scopes I could afford aren't really good day to day bench scopes. They tend to be huge, loud and take forever to boot. Also their inputs tend to be more fragile. Not to mention you need equally expensive probes for those frequencies as well.

I am pretty happy with my R&S RTM 1054.. it's plenty of scope for my needs and it didn't break the bank.

$3500 for a 'seller refurbished' unit?  That's not my idea of an 'entry level' scope.  Looks pretty nice though...

http://www.ebay.com/itm/Rohde-Schwarz-RTM-1054-4-Ch-500-MHz-5-GSa-s-Digital-Oscilloscope-w-Accys-/271835203486

List price over $10k?  Clearly not an 'entry level' scope:

https://www.conres.com/test-equipment/product/rohde-schwarz-rtm1054-500mhz-4-channel-digital-oscilloscope/

We're talking $400 scopes, maybe $1000 scopes - 'entry level'

I got lucky. Thanks to Wuerstchenhund in fact.. he mentioned them being available on ebay for $2000 in one of his posts while back. Someone was liquidating a lot of 10 or so. So I snatched one. They were used but looked in brand new condition, mine came with all the probes and accesories looking brand new.

But you're right not exactly entry level, although close in price.

[Wuerstchenhund]

$3500 for a 'seller refurbished' unit?  That's not my idea of an 'entry level' scope.  Looks pretty nice though...

http://www.ebay.com/itm/Rohde-Schwarz-RTM-1054-4-Ch-500-MHz-5-GSa-s-Digital-Oscilloscope-w-Accys-/271835203486

List price over $10k?  Clearly not an 'entry level' scope:

https://www.conres.com/test-equipment/product/rohde-schwarz-rtm1054-500mhz-4-channel-digital-oscilloscope/

You are right, the RTM1000 isn't entry-level, it's actually R&S' lower mid-range scope series (the R&S entry level is made up of Hameg devices).

And yes, $3.5k for a "seller refurbished" (whatever that should mean) unit is ludicrous, but as Mux said a while ago there was a dealer who sold ten or so for below $2k, all in pretty much pristine condition and with all accessories and probes (still sealed) included.

And for $2k it's a really nice scope and one of the only few that can actually do X/Y/Z operation (i.e. brightness modulation, something that's usually limited to analog scopes) 

We're talking $400 scopes, maybe $1000 scopes - 'entry level'

The Entry Level segment goes much further than $1000 (i.e. the Keysight DSOX3000T which is an upper entry-level scope that starts at some $3k or so) and can easily exceed $5k.

What you probably mean are bottom-of-the-barrel scopes, which is an appropriate term for scopes in the sub-$1k price class.

[Jwalling]

What you probably mean are bottom-of-the-barrel scopes, which is an appropriate term for scopes in the sub-$1k price class.

 

Yep.

Jay

[Fungus]

What you probably mean are bottom-of-the-barrel scopes, which is an appropriate term for scopes in the sub-$1k price class.

 

Don't complain: They'd have been "mid-range" not too long ago.

[Wuerstchenhund]

What you probably mean are bottom-of-the-barrel scopes, which is an appropriate term for scopes in the sub-$1k price class.

 

Don't complain: They'd have been "mid-range" not too long ago.

Actually, they would have been mid-range in the mid '90s. Which only counts as "not too long ago" in glacial terms 

[marmad]

Actually, they would have been mid-range in the mid '90s. Which only counts as "not too long ago" in glacial terms 

Actually, similar to the fact that light-year is a term of distance, not time, glacial (at least in English) is a term used to denote speed, not time 

[Fungus]

What you probably mean are bottom-of-the-barrel scopes, which is an appropriate term for scopes in the sub-$1k price class.

 

Don't complain: They'd have been "mid-range" not too long ago.

Actually, they would have been mid-range in the mid '90s. Which only counts as "not too long ago" in glacial terms 

I guess it depends on what you class as "mid-range".

If the "high-end" includes things like this:


Then yes, they'd still be "low-end" not too long ago. 

The point is: Go back 5-10 years and not many people would have paid for a brand new, 100MHz, 4-channel DSO for home use and with their own money.

[Wuerstchenhund]

Actually, they would have been mid-range in the mid '90s. Which only counts as "not too long ago" in glacial terms 

Actually, similar to the fact that light-year is a term of distance, not time, glacial (at least in English) is a term used to denote speed, not time 

I'm sorry but that is wrong. 'Glacial' can refer to both speed (i.e. Glacial Speed) and time (Glacial Period).

https://en.wikipedia.org/wiki/Glacial_period

A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances.

Knowing is half the battle 

[Wuerstchenhund]

I guess it depends on what you class as "mid-range".


If the "high-end" includes things like this:



    [...]

Then yes, they'd still be "low-end" not too long ago.

  No, it does not "depend" on 'if' or 'when' or what you feel like should be included or what not, the T&M market is and has been for a long time pretty solidly categorized. And by that standard today's bottom-of-the-barrel scopes would have been mid-range in the mid-'90s. Don't forget that the progress in these scopes wasn't in capabilities, the real progress in that category is the low price.

BTW: that scope in the video, while being a high-end scope, is hardly the most expensive. In fact, the DSA91304A (which is a variant of the Infiniium 90k, which until a while ago was my day to day work scope, sold as signal analyzer) isn't (and wasn't) really far up the ladder in terms of high end scopes.

Point is: Go back 5-10 years and not many people would have paid for a brand new, 100MHz, 4-channel DSO with their own money.

Who knows, maybe that's true, maybe not. I don't know (I have no sales figures for sales to consumers or B-brand in general) and you don't know either. Fact is that many hobbyists have bought scopes in the past. Back in the old days the Rigol equivalent would have been something like that:



But it doesn't make current bottom-of-the-barrel scopes any more "mid-range". They still are what they are, the cheapest (reasonable) scopes money can buy.

[marmad]

I'm sorry but that is wrong. 'Glacial' can refer to both speed (i.e. Glacial Speed) and time (Glacial Period).

https://en.wikipedia.org/wiki/Glacial_period

A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances.

Knowing is half the battle 

Ahh... you want to quibble about whether it was technically correct, after a native English speaker tells you it reads as silly-sounding awkward*.  Fair enough; that's typical engineer-behavior - especially on this forum 

In any case, IMO, 20 years ago is "not too long ago" by human standards - so there's that as well.

*EDIT: You used the word in the context of an adjective (i.e. denoting speed [or temperature or produced or caused by glaciers]), not as a noun (i.e. denoting a period of time). For example, it's not "...in day terms" - it would be either "...in daily terms" or "in terms of days...", etc.

[Wuerstchenhund]

I'm sorry but that is wrong. 'Glacial' can refer to both speed (i.e. Glacial Speed) and time (Glacial Period).

https://en.wikipedia.org/wiki/Glacial_period

A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances.

Knowing is half the battle 

Ahh... you want to quibble about whether it was technically correct, after a native English speaker tells you it reads as silly-sounding awkward*.  Fair enough; that's typical engineer-behavior - especially on this forum 

Don't take this the wrong way, but frankly, I don't really care if you're a "native English speaker" (what English? British, American, Canadian, Aussie, NZ? What region? I have no idea what variant of English is spoken in Antarctica; besides I've met my fair share of "native speakers" in various languages that didn't exactly demonstrate a stellar command of their mother tongue), or if you think it "sounds silly". It might well be that in your part of the world "glacial" is only used in regard to speed. But it isn't in the parts of the world I move around, and clearly isn't in a scientific context, so here you go.

And it obviously wasn't beyond your intellect to understand the meaning.

In any case, IMO, 20 years ago is "not too long ago" by human standards - so there's that as well.

That, again, is merely your opinion, to which you're certainly entitled to. But it's just that, your opinion.

*EDIT: You used the word in the context of an adjective (i.e. denoting speed [or temperature or produced or caused by glaciers]), not as a noun (i.e. denoting a period of time). For example, it's not "...in day terms" - it would be either "...in daily terms" or "in terms of days...", etc.

I used 'glacial' as an adjective because it is. That doesn't mean it's wrong. It's quite commonly used in scientific literature, i.e. in 'Up in Smoke? Latin America and the Caribbean' by Andrew Simms and Hannah Reid, p 18: "In glacial terms, 60 years is normally a blink in time.[..]". Or in 'Finding Time For The Old Age - A History Of Paleolithic Archaeology and Quaternary Geology in Britain, 1860-1960' by Anne O'Connor, p. 270: "... a distinctive stone tool might decide the age (in glacial terms) of a boulder clay...". And these are just two examples where the expression 'glacial terms' is used in regard to time, not speed.

As I said, knowledge is half the battle

So, can we go back to topic? 

[marmad]

It's quite commonly used...

I guess that depends on how one defines "quite commonly". When I Google the phrase "in glacial terms", 9 out of 10 of the hits on the first page (aside from, surprise, one of the quotes you posted) are the correct use of the adjective, 'glacial'. I'm guessing the percentage of the rest of the hits would be roughly equivalent, and thus "occasionally" would be, in my "part of the world", a more accurate way to describe it's usage. Nonetheless, even occasional usage in scientific literature does not mean the usage is correct. Can you post a link to any reference that describes "glacial" (the adjective - not the noun) as meaning time-related?

But honestly, the original response was done mainly in jest as a response to your typically pedantic response to Fungus' use of the phrase "not long ago". Merely your opinion, of course, to which you're certainly entitled. But it's just that, your opinion.

Your responses, of course, have not deviated from the norm.

As I said, knowledge is half the battle.

Clearly it's not.

So, can we go back to topic?

Which was what? How wonderful high end scopes are?

 

[nfmax]

Reverting to the original topic for a moment (sorry!) it is astonishing to me just how much scope you can get for a hobby budget today. I ceased to be professionally involved 'hands on' with electronics about 2005, and up to that time I had never regularly used a scope with as much capability as the Rigol DS1054Z, with the sole exception of bandwidth. Assuming it is reliable enough, and the firmware is solid enough, it should provide everything you need for years of experimentation and learning. Treat it's limitations a challenge to your ingenuity - search for a non-obvious way of making the measurement. You have the luxury of time to ponder different approaches, which the professional doesn't. That's one reason why we are so demanding of our tools.

While the Rigol looks to be the current best buy, there are plenty of alternatives around, so keep an eye open for bargains! Almost the only thing I wouldn't compromise on is the number of channels - 4 is much better than 2. And don't neglect the usefulness of an external trigger input. Bandwidth needs to be 50MHz at least, the more the better. Serial decoding, while very handy, is not essential IMHO unless you are trying to debug someone else's software. Measurements are also very handy and they all have them these days. A big screen is better than a small screen, even with the same number of pixels. Ensure it's not too big for the space you have available, and that you can live with the fan noise.

Finally, take care of your scope probes, and keep them properly calibrated! 

[David Hess]

Almost the only thing I wouldn't compromise on is the number of channels - 4 is much better than 2. And don't neglect the usefulness of an external trigger input.

Um, which is it?  4 channel oscilloscopes with external trigger inputs are very rare.  If you look for one with both, your options will be very limited.

[nctnico]

Almost the only thing I wouldn't compromise on is the number of channels - 4 is much better than 2. And don't neglect the usefulness of an external trigger input.

Um, which is it?  4 channel oscilloscopes with external trigger inputs are very rare.  If you look for one with both, your options will be very limited.

An MSO has 8 to 16 external trigger inputs!

[tautech]

Almost the only thing I wouldn't compromise on is the number of channels - 4 is much better than 2. And don't neglect the usefulness of an external trigger input.

Um, which is it?  4 channel oscilloscopes with external trigger inputs are very rare.  If you look for one with both, your options will be very limited.

An MSO has 8 to 16 external trigger inputs!

Following on....
SDS1000X+ series.....2 ch + Ext Trig + 16 Ch LA = 19 channels.
As previously linked:
http://www.siglentamerica.com/pdxx.aspx?id=4688&T=2&tid=1