Looking for opinions before buying Agilent MSOX2024A - Page 1
Forum section: electronics / testgear

author: Yaksaredabomb
author_rank: Regular Contributor
timestamp: May 10, 2013, 10:14:20 pm
content: Hi everyone. I posted back in October about trying to choose an oscilloscope in the $500 range. Some time has gone by, I've saved some more money, and I've re-evaluated what I'm looking for. I'm now thinking a 4-channel 200MHz scope could be better for me.Applications would include microcontroller work with up to 80MHz clocks and some switching power supply and power electronics work (for instance, a saltwater aquarium controller with several channels of dimmable LEDs).I was thinking of the Rigol DS1204B (~1400 USD). Then, however, I was surprised to have the opportunity to buy a used Agilent MSOX2024A for ~2000 USD (with warranty and calibration [and no options enabled]). It's quite more capable than the DS1204B, but leaves some things to be desired (for instance, 100k memory is standard). The Rigol DS4024 is much better than the Agilent in a few ways but is ~2900 USD. If I could find a DS4024 used with warranty and calibration maybe that would really be ideal.In the back of my head I'm thinking maybe I should just stick to the Rigol DS1102E I had nearly settled on back in October. I think the used MSOX2024A is well worth 5x a new DS1102E (~400 USD). Twice the bandwidth, 3x the channels (counting 8 digital as worth 2 analog), 100x the update rate, 5x the pixels, the Agilent name, etc. But does that mean I should buy it?I'll leave it at that to try keeping it brief for a change. I may buy the Agilent within the next week or so and I wanted to run it by people here first. Thanks for reading and anything anyone has to say!Jacob[Edit: Added clarification that no options would be enabled (though I could lobby them to include an option or two).]

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 10, 2013, 10:31:55 pm
content: I have the DSOX2002A, as written here:https://www.eevblog.com/forum/reviews/my-new-toy-%29-agilent-dsox2002a-sex-on-a-stick!/30/With Agilent you get a good after sale support. It's easy to download the new firmware... The scope is quite cold even after a few hours of running.On the other hand, there are only four automatic measurements. Not much for a 4 channel scope.The memory depth is 100kpoints per each channel. Not so much... You can buy optional 1Mpoints per channel.But the logic analyzer is not so good. It has only 50kpoints per channel and 12.5kpts memory per channel when the analog channels are ON. I don't know if it can be improved if you buy theDSOX2MEMUPoption.Rigol is better bang per buck but it has a few known problems and maybe it's not much ergonomic... And their DS4000 with digital channels is not in market yet.QuoteWill it have Wavegen and DVM included?? It's not certain.To sum up, this scope is easy to operate and pleasant to work with.But I probably wouldn't buy it if there wasn't a gratis DVM and WAVEGEN option.

author: EEVblog
author_rank: Unknown
timestamp: May 10, 2013, 10:36:03 pm
content: Rigol have a new 1000Z series just coming out, but I don't think it's 200MHz.Looked into Goodwill/Instek or Hameg perhaps?

author: jmole
author_rank: Regular Contributor
timestamp: May 10, 2013, 10:36:24 pm
content: I've got one. My second really, as my lab had one a few years before I did. Liked it so much I bought one myself.It's really the best scope you can get for $2000.My biggest beef is that the serial decode doesn't work on the digital channels. Bit of a bummer, but that's what the 30 day all-options trial is for. I honestly didn't find serial decode to be that useful.Also, the scope doesn't really go down to 10 mV/div, it's just a digitally scaled version of the 40 mV/div. Also a bit of a bummer. Single-bit 12 bit DAC transitions at 5 volts barely register on the scope (at least with the included 10:1 probes. You'll do much better with a 1:1 probe, but the included probes are non-switchable). At 1 mV/div in 1:1 mode, you could expect a maximum discernable resolution of about 250uV. Questionable if the signal trace is actually useful at those tiny levels.That said, the scope is a phenomenal piece of gear, and you won't find anything even coming close at the price they're going for now. Wait 2 years, and something new will come out. So that's the question, I guess. Do you need the $1500 NOW for something else, or do you need a great scope right now?

author: eevblogfan
author_rank: Frequent Contributor
timestamp: May 10, 2013, 10:52:43 pm
content: heyas user of DSOX2002 I can tell you that's awsome scope , are you sure you need all 4 channels ?if no , I'd go for the DSOX2002 , 1.2K$ , and please ask for student discount , they gave me that scope with wavegen and DVM for only 800$ , you must ask them , it worth it ,PS , 2 CH scope and decent 300$ logic analyzer is okay for you ?Cheers

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 10, 2013, 10:55:21 pm
content: Quote from: EEVblog on May 10, 2013, 10:36:03 pmIt is only 100MHz and no logic analyzer included. I would buy Rigol only after a year of production so they could eliminate all the bugs.

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 10, 2013, 10:58:59 pm
content: Another MSOX2024A with some upgrades here (memory upgrade, DVM, segmented memory, VGA/LAN card). I love it so far! Best scope for the money if you get one of the CertiPrime ones from AgilentUsed! Just get it, you wont regret it!

author: EEVblog
author_rank: Unknown
timestamp: May 10, 2013, 11:02:43 pm
content: Quote from: eevblogfan on May 10, 2013, 10:52:43 pmFor 2 channel I'd rather go with the Rigol DS2000. Just so much more capability for the same price or less.

author: EEVblog
author_rank: Unknown
timestamp: May 10, 2013, 11:05:19 pm
content: Quote from: Hydrawerk on May 10, 2013, 10:55:21 pmOk, fair call. That option is coming soon though. But soon ain't now. The 2000X is certainly a fine scope, and the firmware update and support is the best in the business. The 2000X had the market completely to itself 2 years ago, but now there is competition nipping at their heels.

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 01:26:42 am
content: Hi Jacob,I personally think, at this juncture, an Agilent MSOX2024A is a big mistake for a couple of reasons.First and foremost, it appears as if there is rather a big cock-up in the Agilent X-series regarding interpolation and waveform fidelity. No one is really talking about it, but it seems that Agilent's single-minded quest for waveform update rates in their MegaZoom ASICs causes some nasty artifacts at lower sampling speeds - including what might be either misaligned and/or missing sample points. You can read about itin this thread. Normally, to double-check sampling veracity, you would turn off interpolation and run some tests. Unfortunately, on the X-Series, youcan't turn offinterpolation - so you can never see where the actual sample points are. Since the most important thing a DSO must do is reproduce the waveform accurately, I wouldn't buy one suffering from this apparent defect - at least not before questioning Agilent about the cause of this problem.Secondly, even forgetting the above-mentioned problem, the best buy for a high-quality, fast, four channel DSO at the moment is the new GW-Instek GDS-2000A series.The GDS-2204A is $1962 brand new(before any dealer discounts - which are being offered heavily at the moment) - and it is, without a doubt (IMO), a MUCH better scope for the money then the Agilent X2024A. It has more memory, bigger screen with more waveform display real-estate, many more triggers, faster waveform update rate, real 1mV/div (not the digitally 'magnified' scales as on the Agilent), cheaper upgrade options, and many more features. This is what I would buy if getting a four-channel DSO at this time - grego (another member here)posted some video about the DSO here.Mark

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 11, 2013, 08:46:23 am
content: I have to agree with marmad here, the lack of a facility to disable interpolation in the DSO-X2000 is pathetic, and the apparent fidelity issues worrisome for a scope in this price range. Agilent can make good scopes (they don't always do, unfortunately) but just because of these two issues alone I would not touch a DSO-X2000/3000 with a bargepole, and albeit I'm still wary of Rigol I'd rather buy a Rigol DS2000 than an Agilent DSO-X2000. In addition, the DSO-X2000 seems to have very limited signal analysis capabilities, even for a scope in this class (entry level).

author: roli_bark
author_rank: Regular Contributor
timestamp: May 11, 2013, 11:26:44 am
content: In an apples-to-apples comparison to Rigol's DS4024 - the GW GDS-2204A (without the Signal Generator/LA options) is cheaper by almost $900, however it has 'only' 2Mpts memory depth, 2G Sa/s, 80K wfm/s, & 250Mhz probes bundled, compared to 140Mpts, 4G Sa/s, 110K wfm/s, & 500Mhz probes.Whether these may/may-not be factored into the overall worth-for-buck is in the eyes of the beholder.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 11, 2013, 12:09:58 pm
content: Quote from: roli_bark on May 11, 2013, 11:26:44 amI wouldn't give too much on the bandwith of the probes, as passive probes are generally useless above 300MHz anyways.And as to 80k wfms/sec to 110k wfms/sec, oh well...

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 01:21:57 pm
content: Quote from: roli_bark on May 11, 2013, 11:26:44 amIt's true the Rigol beats the Instek hand-down in terms of memory, but that's about the only place it really leads. The 110k wfrm/s is a NON-interpolated speed (dots only); the DS4000 is closer to 80k wfrm/s with interpolation on - so I would say that's a wash between the two. Plus, IMO, the sample rate is rather a non-issue for the 200MHz BW we're discussing here.If you look through the manuals, the Instek has better analysis tools and memory search functions -andthe 800x600 screen - much better for 4-channels, IMO - is a big plus. Also, look at the price of the options:GDS-2000A: 8-channel logic analyzer module (hardware module which comes with triggers and decodes for I2C, SPI, UART, Parallel): $570DS4000:ONE SINGLEsoftware decode option (I2CorSPIorUART, etc): $500So, the question becomes - is it worth paying $900 more just for extra memory and more expensive options?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 11, 2013, 01:56:37 pm
content: Quote from: Wuerstchenhund on May 11, 2013, 08:46:23 amI can disable interpolation on my MSO6000 but have never seen any reason to do it. I really can't see why it is a big issue - the scope bandwidth means you're not going to see much more by looking at individual samples - there are far more important differencesbetween scopes than this.

author: roli_bark
author_rank: Regular Contributor
timestamp: May 11, 2013, 02:00:38 pm
content: Quote from: marmad on May 11, 2013, 01:21:57 pmYou forgot the probes. I assume that Rigol's 500M (4 of them) worth at least $400 more than the 250M included with the GW's. IMO the 800*480 vs. 800*600 screen resolution is not significant.So looking at the parameters mentioned - is a 140M pts memory worth the extra $500 spending.I have no idea...

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 02:12:48 pm
content: Quote from: mikeselectricstuff on May 11, 2013, 01:56:37 pmTrue, it's not something you'd use very often - but it's another level of abstraction layered on top of the original analog data. As mentioned above (and in the thread about the Agilent X-Series's interpolation), when trying to determine exactly what is going 'wrong' - either with sampling or, post-sampling, with interpolation, it can be kind of critical.

author: Unknown
author_rank: Unknown
timestamp: May 11, 2013, 02:18:00 pm
content: Quote from: roli_bark on May 11, 2013, 02:00:38 pmThe probes may be worth $400 extra. This assumes they are good quality: 500 MHz high-Z passive probes are not easy to design, and the old Rigol probes weren't exactly of stellar quality. Whether this extra $400 value is useful to you is another question. It could also have solid gold knobs worth $400, but are you willing to pay a $400 premium just for the solid gold knobs? Same for the 500 MHz probes, it's not like it makes much of a difference to the system bandwidth of the probe + scope.

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 02:23:29 pm
content: Quote from: roli_bark on May 11, 2013, 02:00:38 pmWell, the value you give them may be debatable, but in any case, as a prospective buyer looking to save money, I think I'd save the $400 initially and get higher BW probes if/when needed.QuoteSo, 25% more vertical space is NOT significant for a scope designed to display 4 waveforms above each other? Sorry - I strongly disagree; and the disparity will be even more apparent in the future when people are comparing the screen of the GDS-2000A series with LA module against the DS4000 with LA module.

author: EEVblog
author_rank: Unknown
timestamp: May 11, 2013, 02:23:55 pm
content: Quote from: Wuerstchenhund on May 11, 2013, 08:46:23 amWhy?Is there a common use case where disabling it would be advantageous?

author: roli_bark
author_rank: Regular Contributor
timestamp: May 11, 2013, 03:21:01 pm
content: Quote from: marmad on May 11, 2013, 02:23:29 pmSorry, but a 25% addition to vertical rez is insignificant for me.Not, as a sole reason. Yes, for saving $500.A different significant reason to opt for either (regardless of a $500 discrepancy) could have been a 1280 * 720 rez, 11" size screen. Especially for an LA.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 11, 2013, 04:04:27 pm
content: Quote from: EEVblog on May 11, 2013, 02:23:55 pmYes, as interpolation does introduce artificial signal deviations which are not in the actual input signal. Depending on the circumstances this can become a problem when the deviations become large enough so that the waveform displayed on the screen no longer resembles the signal you're measuring. The more complex the signal, then usually the larger the error introduced by interpolation. And it can get really bad with Peak Detect (which uses irregular sampling intervals).What's worse, the DSO-X2000/3000 seem to select the type of interpolation (linear or sin(x)/x) depending on the time base, when the interpolation should also be dependent on the type of signal (generally, sin(x)/x is more appropriate for sine-like signals than linear interpolation, and for square-ish waveforms it's the other way around). Many entry level scopes (i.e. Rigol DS2000) rely on such a table, but on most of them you can at least disable interpolation completely. Not so on the DSO-X.As mentioned in another thread, I have bought my first own low-end scope (Siglent SDS1102CNL, a really really cheap device), and even this cheap $350 scope not only lets me disable interpolation, I can also choose if I want linear or sin(x)/x (apparently independent on the time base setting).The weird thing is that Agilent believes its little entry level 4GSa/s scope doesn't require a facility to disable interpolation, yet on all larger models it's in there. Interpolation is still enabled by default on their scopes, but at least I can switch it off (which I usually do when I'm at work; my LeCroy Waverunner has interpolation off by default already which is how it should be).

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 05:00:09 pm
content: Quote from: roli_bark on May 11, 2013, 03:21:01 pmWell, I think if you had both scopes next to each other, with 4 (or 12) complex waveforms stacked on top of each other, I know which screen you'd be looking at.And extra vertical pixels require very little more from the DSO in terms of speed - while extra horizontal pixels will lower the wfrm/s rate unless you speed up the acquisition engine.And while I admire the DS4000 series, Rigol's in a spot of trouble at that price point (as is Agilent) with the introduction of the GDS-2000A - which is, as mentioned before, much better value for money in almost every way. Although it's possible their DS1000Z will mitigate part of that trouble for them.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 11, 2013, 05:14:58 pm
content: I am looking forward to the DS2000 with DDS generator. It would be nice if they made a four channel version of this scope, too.

author: roli_bark
author_rank: Regular Contributor
timestamp: May 11, 2013, 05:24:01 pm
content: Quote from: marmad on May 11, 2013, 05:00:09 pmSo, the "trouble" the Rigol's DS4024 has against the its GW counterpart is price ?What. then, would you recommend if both were at the same price ?e.g. - Regardless of the price, which has the better set of features/performance ?

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 05:55:50 pm
content: Quote from: roli_bark on May 11, 2013, 05:24:01 pmBTW, I had forgotten about the VGA out of the DS4000 - so that brings the two DSOs $280 closer in price, since that's what the VGA/LAN module costs for the Instek (assuming a potential buyer needs either feature).As for your question, it might hinge on whether the options were also similarly priced. If they were, then I'd probably go with the DS4000 - since you can't increase the memory size later on the Instek, but you can 'workaround' problems like a smaller screen using the VGA out. And I know (from my DS2000) that having large amounts of memory available for segments andlongsingle-shot captures is fantastic.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 11, 2013, 06:15:03 pm
content: Quote from: Wuerstchenhund on May 11, 2013, 04:04:27 pmDo you have an example that illustrates this?Quote

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 06:34:57 pm
content: Quote from: mikeselectricstuff on May 11, 2013, 06:15:03 pmWell, I'm not sure the following image is quite as extreme as Wuerstchenhund mentions, but I would say that if this is what Agilent's interpolation is doing to perfectly symmetrical, slightly under-sampled sine and square waves, I would definitely want the ability to turn it off.

author: Electro Fan
author_rank: Super Contributor
timestamp: May 11, 2013, 06:41:56 pm
content: Quote from: marmad on May 11, 2013, 01:26:42 amMarmad,I admire your objectivity. I know that you have been a major proponent and an excellent spokesperson for the Rigol 2000 series. I think it's especially admirable when a person can own a product and still acknowledge that other products have their merits. In my opinion the Rigol 2000 is a great product and at the same time, I'm sure I'd also enjoy owning an Agilent 2000 series DSO and especially one of their MSOs.After watching the development of the many page thread you initiated on the Rigol 2000 and now this thread on the Agilent along with other threads here I'm becoming more intrigued by the Instek 2000 series. My reason for this is that I thought you and Grego and others did a very nice job of vetting the Rigol and Instek in your Rigol posting (I think it's up to about 60+ pages) and in other posts.Long story short, after learning more about the Rigol and now the Agilent's capabilities (and in some cases lack thereof) in the LA area, I've spent more time seriously looking at the Instek.I realize my criteria are just mine and not anyone else's much less everyone else's, but when it comes to DSO+LA integration (ie, MSO capabilities) it looks like the Instek is out in front in functionality and price. It provides base DSO features and pricing that are competitive with Rigol and it provides both 8 and 16 channel LA capabilties that appear to be superior to Agilent's (and at a better price).After come up the learning curve on LAs it has become much more apparent to me just recently that there is no good way to make a DSO and an external LA play together as well as an integrated MSO. I realize not everyone wants to examine or manage digital signals, but it sure seems like it would be hard to remain in a realm with just analog signals. This is not to in any way negate the importance of analog. The analog realm is the foundation that digital rides on but digital is clearly the path to the future. So while pixels, and various types of memory, and math, and the many other important features are just that - important, the ability to have strong analog plus digital integration is the most desirable of all the possible features (again, admittedly, this is just one "use case" or "user case" so I'm sure that for some users no LA or limited digital signal functionality is A-OK.).With A+D integration in mind, when you look at the various entry level MSOs, it is starting to look like Instek currently has the best combination of analog+LA features and also the best price. Maybe Rigol will unleash something new shortly and I'm sure Agilent will keep improving it's LA (but probably also remain rightfully proud of it's price). In the meantime if you had to pull the trigger (kind of a pun) on a box that has great integrated analog and digital triggers (and decoders, etc.), Instek looks like it has jumped into the lead.(Having said all that, there are certain user interface and look and feel aspects of the Rigol and Agilent products that would be nice to have in the Instek products. The nice thing about this forum is the ability to get lots of input and new perspectives based on various interesting "use/user cases" - thanks again to everyone here for sharing a ton of cool info and thoughts.)

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 11, 2013, 08:51:40 pm
content: Well, if you need a large memory 28MB per channel (but with no search or mark function), you must buy Rigol DS2000. Agilent DSOX3000 has only 2MB per channel (probably), it might be enough for somebody, but the scope is much more expensive than DS2000... And it has only 1000 segments of segmented memory. Rigol DS2000 has 65000 segments.But I would buy Rigol only for hobby (=not 10 hours a day) usage.

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 08:59:37 pm
content: Quote from: Hydrawerk on May 11, 2013, 08:51:40 pmI keep seeing you post similar statements such as this. What data are you basing this opinion on? Are there any substantiated facts published somewhere which indicate either that Rigol DSO's are less reliable than others in the same price bracket - or that they can't stand up to long hours of use?

author: Unknown
author_rank: Unknown
timestamp: May 11, 2013, 09:11:49 pm
content: Few people outside Rigol/Agilent will have any data at this point, the DS2000 series is too new to make any definitive statements. Agilent certainly has a better reputation and a longer history of making reliable low-end scopes, although I don't recall major quality issues (except for some dodgy rotary encoders and knobs) with past Rigol equipment. The other thing you might argue is that Agilent support is better in most parts of the world, which is useful if you have a problem that's holding up a project.

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 09:27:16 pm
content: Quote from: Electro Fan on May 11, 2013, 06:41:56 pmThanks for your kind words - although I often fly off the 'objective' handle;but I do try to remain focused on the best deals in the lower end of the test equipment market. And I just have to say: wow, has the overall quality and bang-for-buck of what you can get taken huge leaps in the last 2 years - it's pretty amazing.As far as the Instek: it certainly seems the best deal for a quality MSO at the moment (with, IMO, an all-important decent vertical screen size) - although I'd like to see some video (and review) of the actual LA being used to decode. Hopefully that will come soon.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 11, 2013, 10:04:03 pm
content: Quote from: marmad on May 11, 2013, 08:59:37 pmWell, my friend from school bought DS1052E probably in 2008. I don't know who was the distributor. Maybe dealextreme.com. He had bad experiences with this scope. Problems with encoders and PSU fault due to bad capacitors. He is an advanced hobbyists who used the scope quite often. He told me: "Never buy any Rigol product, not even DS2000."He repaired his DS1052E and sold it about two months ago. Here are his bad experiences:I am not sure if this is actually a bug:He wanted to buy a DSOX2000 series but then he chose Tektronix DPO2002B.https://plus.google.com/photos/104378593109746079667/albums/5598108503973350065/5858246677982881490I don't know why. Maybe he thinks that the Wave Inspector feature is useful.You can write him, he visits this forum asDrirr.He even published a DPO2002B teardown.Galleryhttps://www.eevblog.com/forum/testgear/tektronix-dpo2000b-teardown/msg209264/#msg209264On the other hand, there is no doubt that the DS2000 is a much better bang per buck and if you want more than 10MB per channel memory, it's hard to chose something else than DS2000. Maybe Tek DPO4000 or WaveSurfer 24MXs-B, but they are bloody expensive.

author: marmad
author_rank: Super Contributor
timestamp: May 11, 2013, 10:58:33 pm
content: Quote from: Hydrawerk on May 11, 2013, 10:04:03 pmBut you can likely find an irate customer of every known brand of product on the planet - as well as a slew of videos detailing problems of virtually anything that is heavily sold. It doesn't really amount to any useful data unless it's repeated regularly. Also, your friend doesn't seem to know about the quality shift in Rigol's latest products, as mentioned below.QuoteIt's not just that. You just have to look at the teardowns of the newest Rigol gear by Dave, Mike, Connor Wolf, etc. - or use one of the new DSOs, AWGs, etc (compared to their older stuff) to realize that they have upped their game considerably in terms of design, build quality and manufacturing. My DS2000 is as similar (in quality level) to your friend's old DS1052E as his Tek DPO2000b is.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 12, 2013, 01:07:49 am
content: Well, it's difficult to decide... My friend has seen those teardowns.It's a matter of emotion. For example, i consider Volkswagen to be better than Hyundai, but I have no proof... I only know, that Volkswagen has produced good quality cars maybe since 1970, they have a long tradition. Hyundai must have been quite crap in 1970s. But in recent years they improved their quality a lot... Many people buy their cars nowadays and they are OK...Hard to consider a long term quality of a scope DS2000 that has been produced for one year now... I've never said that the scope internal design looked bad.

author: EEVblog
author_rank: Unknown
timestamp: May 12, 2013, 01:31:46 am
content: Quote from: marmad on May 11, 2013, 08:59:37 pmRemember, Agilent, as a huge OEM customer, helped Rigol set up their manufacturing lines, quality control, designs, and likely a whole host of other stuff. Agilent helped create the monster that is now taking away their low end market.Rigol stuff should be as good as or close to Agilent (low end) gear in terms of quality and reliability.

author: EEVblog
author_rank: Unknown
timestamp: May 12, 2013, 01:38:09 am
content: Quote from: Hydrawerk on May 11, 2013, 10:04:03 pmI've mentioned this before, but worth repeating.My DS1052E is a similar vintage, and it's now Sagans daily toy (he loves scopes). I'll leave it up to you to picture the abuse it getsSuffice it to say that it still works perfectly after 5 years and all that abuse.As someone else said, you will find bad examples of every product, it's not an indicator of anything. Betcha there is someone who think their Bently or Rolls is a lemon.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: May 12, 2013, 01:58:11 am
content: My 2cents,I have a refurbished MSOX2024a, my first digital scope and it's a pleasure to use, the UI is great, to the extent that I haven't actually bothered opening the user manual yet.Already having saved myself what would have been hours of mucking around on my analogue CROs.I really don't like the grabbers on the probes though. They still work as designed but they have stripped so much of the cost out of the probes that they 'seem' a bit cheap.Also I have had contact with Agilent service department in regards to my probes and if anything they overreacted, giving me an unnecessary level of service.I am sure if you do go with the Agilent that you will have a very useful tool.

author: Someone
author_rank: Super Contributor
timestamp: May 12, 2013, 04:34:44 am
content: Quote from: marmad on May 11, 2013, 06:34:57 pmYou like walking into corner cases and then proclaiming that a particular tool is so vastly superior to another, use any tool the wrong way and it seems bad. That screenshot you so dearly rely on has a few points that people may not realise:See that 50MSa/s, someone had 2 bonded channels enabled and halved the sample rate. But hang on what? 50MSa/a on a 2GSa/s scope, thats right whats shown on that screen was captured at 2ms/div per division and the zoomed in 20,000 times to 100ns/div. Hardly the way you'd be looking at waveforms where the shape was important.20,000 times zoomed!Agilent run the maximum memory depth at all times, which allows these amazing depths of zoom, and hides all the complexities away from the user. Anyone with a tek background will know the fun of constantly changing memory depths to try and balance the update and UI speed with the signal detail. For low/mid end Agilent scopes these settings are all eliminated and the usability is vastly improved for my taste.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 12, 2013, 08:51:32 am
content: Quote from: EEVblog on May 11, 2013, 02:23:55 pmI wouldn't go as far and saying that the need to disable interpolation is a common case, and I guess for many use cases where these scopes are used it probably doesn't make much difference if interpolation is on or off. But at work I often have to disable interpolation, because it introduces errors large enough to cause spurious signal content that isn't there which does cause us problems, even for deviations that are small enough that they are hardly noticeable on the screen.At the end of the day, we should not forget that a scope is based on maths. The waveform on a scope's display is a nothing else than an equation. The bad thing with interpolation is that it introduces data points which (unless you're using Sin(x)/x on a perfect sine wave or linear (x) interpolation on a perfect square wave, which most certainly will never be the case) aren't there. In most cases where a scope is used merely as a display to look at waveforms, this is probably not much of a problem. It can however quickly become a problem if the data points are used for further processing (i.e. maths), where small deviations can lead to large errors.In addition, wasn't one of the arguments why beginners should learn with an analog scope that they don't learn to rely on all the automatics of a digital scope? So what Agilent does is exactly that, forcing the user to rely on automatics. It's difficult for a beginner to learn about the effects of the common interpolation methods if they can't be disabled.So no, I don't think Agilent's blind trust in forced interpolation based on a simple time base setting schedule is a good thing. They should really provide the capability to switch off interpolation as an option.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 12, 2013, 08:58:59 am
content: Quote from: Hydrawerk on May 11, 2013, 08:51:40 pmThis statement doesn't make much sense. Leaving the general quality of Rigol scopes aside (as this has been addressed by others already), even for a crap scope it should not matter if it's used 2hrs or 10hrs a day. The biggest stress for the PSU (and electronics in general) is during the power on/off cycles), not when they are powered on. Even more, leaving it running for longer means less on/off cycles and generally much longer equipment life.

author: Unknown
author_rank: Unknown
timestamp: May 12, 2013, 10:54:35 am
content: Such sweeping statements are usually at best oversimplified and at worst completely false (yes, I notice the irony of this statement). A scope turned on and off every minute will probably last shorter than a scope turned on 24/7. A scope turned on once per month will probably last longer (depending on the exact failure mode). It depends on duty cycle and frequency.Leaking/dried out electrolytics are the most common failure mode of many switching power supplies. Electrolytics age much faster at higher temperatures. Unless the instrument lives in an oven, the temperature will be (much) higher when the instrument is turned on. A failure mode of the old DS1000E series was dodgy rotary encoders. Rotary encoders have a limited number of rotations until they go out of spec.An instrument that's used for ten hours per day may also be expected to be more critical than an instrument used for two hours every Sunday.

author: marmad
author_rank: Super Contributor
timestamp: May 12, 2013, 10:57:05 am
content: Quote from: Someone on May 12, 2013, 04:34:44 amWalking into corner cases? Is that some kind of Australian expression that loses it's meaning when translated into English?QuoteYes. All of that information isCLEARLY VISIBLEon the screen - for anyone who knows how to read and understand information on a DSO screen. In case they don't, I actually linked to the thread discussing this issue a couple of posts earlier - which, BTW, wasn't started by me but was started by a concerned Agilent X owner. And of course, this problem is confined to very specific circumstances - if it wasn't, every Agilent X owner would be clamoring for their money back - but that doesn't mean that a problem doesn't exist.QuoteYes, of course, that's precisely why I zoom in to look at detail in a waveform - because it's unimportant.QuoteI think you're slightly behind the curve-ball in terms of DSO technology if you think Agilent somehow offers levels of zoom unavailable on other DSOs. But just in case, I've re-posted the two images from the other thread, which compares the zoom being used on a similar waveform on both the Agilent and Rigol DS2000 (and note: the Rigol is actually sampling the sine wave at 100MSa/s - half the rate of the Agilent - and still reproducing it more accurately).As far as I can tell, there is nothing special about the X2000 series other than the fact that it can maintain an impressive sustained level of waveform captures per second - but at the expense, it seems, of user control and waveform fidelity at certain settings.But it's clear you prefer technology which is 'easier' to use, but that has less controllable and/or satisfactory output; I prefer the opposite. I like to decide what size sample length to use; whether to turn on anti-aliasing; whether to use interpolation or not; etc. You're probably an Apple owner as well, right?Edit:BTW, I would also argue that Agilent hasn't "eliminated settings" to improve usability on the X series - but instead, has done it in the chase for maximum sustained wfrm/s, which was the big advertised feature when released.

author: ben_r_
author_rank: Frequent Contributor
timestamp: May 12, 2013, 08:17:38 pm
content: Quote from: marmad on May 12, 2013, 10:57:05 amOh man... PLEASE do not bring up this analogy.

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 12, 2013, 09:08:56 pm
content: Quote from: Someone on May 12, 2013, 04:34:44 amAlmost like that. My DSOX2002A uses 50kpoints per channel inRun/Stopmode and 100kpoints inSinglemode.If you buy (or turn on 30-day Trial of) theDSOX2MEMUP, it will be better. Then the scope uses 500kpoints per channel inRun/Stopmode and 1Mpoints inSinglemode.It doesn't matter how many channels are on.QuoteOK, Agilent looks a bit like Apple product, but I don't have any Apple gadget and I will never buy any.

author: marmad
author_rank: Super Contributor
timestamp: May 12, 2013, 09:55:41 pm
content: Quote from: ben_r_ on May 12, 2013, 08:17:38 pmThe winking smiley wasn't enough to indicate I was joking?

author: Yaksaredabomb
author_rank: Regular Contributor
timestamp: May 13, 2013, 06:06:07 am
content: Wow! Thank you to all for writing, even Dave himself! I'm so glad I decided to take a step back and write here before jumping on the scope.Quote from: Hydrawerk on May 10, 2013, 10:31:55 pmThanks Hydra! I'd started reading that thread actually and have to admit all the stuff about fuses and plug types had thrown me off before I got to your pro/con list. I hadn't thought about what the memory situation would for the LA, thanks. No WAVEGEN or DVM but I don't think I'd use either anyways, so that would only sweeten it for possible resale years down the road. The pro/con list was helpful. Several were interesting so people should read them; most notable cons I hadn't seen yet were 1:10 fixed probes and no alt trigger mode.Quote from: EEVblog on May 10, 2013, 10:36:03 pmI hadn't heard anything about the 1000Z yet and couldn't find any info in English, but with some guesswork and help from Google Translate the following was very interesting:http://cn.rigol.com/prodserv/DS1000Z/ > English.Data SheetAs Google puts it, "Reference price (yuan, including tax)" is 6,680 for 100MHz w/WAVEGEN and 4,980 without. About $1090USD and $810 respectively. About the WAVEGEN, Google reads its description as: "This option includes a built-in dual-channel function / arbitrary waveform generator, the sampling rate 200MSa / s, the highest frequency of the sine wave 25MHz."Though it's true the series only appears to reach 100MHz, if it really can be had for $810 or so then it could be an excellent option. At the end of the day this is for personal use and it's quite a leap to get 200MHz with the $1960 Instek GDS-2204A. $1100 is a big enough bribe to convince me to give up some BW, if the other specs are sufficient and competitive for the price. The only question is when will you get your hands on one, Dave, and when will it be available in the USA?Quote from: jmole on May 10, 2013, 10:36:24 pmThanks for the feedback! Glad you're so happy with it and it does indeed seem like a great scope. Interesting the decode doesn't work on the digital channels, very good to know. Also the 10mV and 40mV talk threw me off as I hadn't yet realized the included probes are 10:1 and not switchable! Thanks for highlighting that again.Yes, always something better and cheaper if you wait. Already options have improved quite a bit in the last year or two since I started "window shopping" and even the last 6 months since I really started looking to pull the trigger. Soon there might even be the Rigol 1000Z's! A fact of life. Sooner or later one must come to peace with it and make a choice for better or worse or all the projects piling up will never get done! Thanks for the sentiment.Quote from: eevblogfan on May 10, 2013, 10:52:43 pmThanks for your review! Pretty set on 4 channels, and would prefer that over a 2 channel with LA. Mostly due to pricing and spec creep.By the time I looked at $1100-$1600 for 2 channel 100-200MHz scopes, I felt I'd be missing good value and a very useful feature to not step up to 4 channels. The Rigol DS1204B seemed like a no-frills but capable scope and at 1400 USD it illustrated the channels and BW I wanted weren't too out of reach. Of course the used Agilent MSOX2024A I then found offers so much more than the DS1204B. I suppose I should be grateful for so many options in today's "hobby" market, for lack of better term."MSO" LA capability isn't too important to me but is sure a nice extra feature and may be a tie breaker when comparing against say the 4-channel Instek GDS-2204A w/o LA for about the same price.Quote from: Hydrawerk on May 10, 2013, 10:55:21 pmThanks for the extra info and good point on possible bugs. Rigol's reputation seems to be improving and a few members here defend them, but it must be factored in that it's only reasonable any 1000Z model would likely have more and worse bugs than the Agilent MSOX2024A I'm considering, or possibly even the Instek GDS-2204A. For hobby use I could tolerate that uncertainty but nice to go in expecting it.Quote from: ben_r_ on May 10, 2013, 10:58:59 pmThanks! I'm really getting the feeling that although the MSOX2024A may not necessarily be the "best" choice, it certainly would not be a bad one and would cause few (if any) regrets.Quote from: EEVblog on May 10, 2013, 11:02:43 pmThanks - I've been convinced this is true. Your reviews (and marmad's, among others) of the DS2000 series is what started my trouble by taking me off track from the DS1102E I'd almost decided on a few months ago, haha. It's been amazing to be able to get your impressions and see this equipment on your bench - the reviews and this forum are irreplaceable complements to the data sheets.Quote from: EEVblog on May 10, 2013, 11:05:19 pmSo "soon" then, I see. I suppose that could mean almost anything - though hopefully at least it will be this year. What I really need this scope in time for is a bunch of backlogged projects I'd like to do while my wife is away attending some training this June and July. My price on the MSOX is good for another couple weeks, assuming they don't sell out, but I'm willing to risk that.Glad you agree the 2000X is still a fine scope, even if it may not still be the clear winner in today's market.Quote from: marmad on May 11, 2013, 01:26:42 amHere I was starting to get a bit of a warm-fuzzy feeling of concurrence that the MSOX would be a good choice and then wham! Haha, it's okay. I appreciate it actually. You gave me quite a bit to read and catch up on and that was great. I think, for my purposes, I'd still be fine with the MSOX. It includes the digital channels for about 500 USD less than the Instek would. Of course, the LA upgrade on the Instek appears to include all decoding options which would be a nice treat, perhaps some months from now when I can afford the upgrade (~2k USD really *should* be my limit if my wife is to speak with me afterwards, haha).Nonetheless thank you so much for adding your input and the weight of your recommendation behind the Instek. It looks like a fantastic option and I'm really excited for more reviews to be posted! Hope grego is able to continue informing us all!***I really appreciate everyone's input so far and I've read all of it (and a lot from the links too, thanks!). That's all I can respond to at the moment though and I'll continue as soon as I get a chance.The really valuable thing is of course everyone's input and the discussion anyways, and I'm sure people are better off with fewer of my long posts. Figured as the OP I should say something though.Jacob

author: vk6zgo
author_rank: Super Contributor
timestamp: May 13, 2013, 07:17:21 am
content: Comment from an unreconstructed analog greybeard--------ZZZZZZZZZ!

author: EEVblog
author_rank: Unknown
timestamp: May 13, 2013, 07:38:08 am
content: Quote from: jneumann on May 13, 2013, 06:06:07 amRigol have not approached me. First I heard about it was on the forum.Quote from: eevblogfan on May 10, 2013, 10:52:43 pmFor those pinching pennies, the wavegen in the Agilent is not worth the $800. For the same money you can get a kickarse Rigol 60MHz 4000 series ARB.Quote2 years ago when it wad released, it was the clear winner, you have been crazy to buy anything else. But now the competition have matched and beat it almost feature for feature. It's still a great scope, but no, not the obvious stand out it once was.QuoteFor 99.9% of uses, that is not a problem at all. You are making far too much over this.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 13, 2013, 08:10:01 am
content: Quote from: Hydrawerk on May 12, 2013, 09:08:56 pmWith any scope you need to understand how t uses memory. The above is due to double-buffering - acquiring into one buffer while displaying the other.Peak detect also reduces memory available as it stores the min & max for each sample. On 4-channel scopes, The permutation of channels usually also has an effect - e.g. using channels 1+3 will typically give you more samples than 1+2

author: jpb
author_rank: Super Contributor
timestamp: May 13, 2013, 09:31:51 am
content: Quote from: EEVblog on May 13, 2013, 07:38:08 amI think the $800 included the scope which does seem a good deal. Though the normal list price for the 20MHz fungen option on the 2000 series is £344+VAT in the UK which is pretty pricey but not quite the price of the Rigol (£670+VAT).

author: Hydrawerk
author_rank: Super Contributor
timestamp: May 13, 2013, 02:34:03 pm
content: Quote from: EEVblog on May 13, 2013, 07:38:08 amSo Agilent guys will have to release a new firmware with more functions.I am looking forward to that...I am looking forward to the DS2000-S with 1Gs/s per channel and DDS 25MHz generator. But I would never buy the DS1000Z-S because it has only 250Ms/s per channel...

author: Yaksaredabomb
author_rank: Regular Contributor
timestamp: May 13, 2013, 05:51:58 pm
content: Quote from: Hydrawerk on May 13, 2013, 02:34:03 pmWow, how did I overlook that. It was right there next to the pricing: 1GSa/s (single), 500MSa/s (dual-channel), 250MSa/s (four-channel). Thanks for highlighting that. Could be a much bigger issue for me than the lower BW. For reference theInstek announcementandAgilentspecs both say 2 GSa/s half-channel interleaved or 1 GSa/s per channel. So it seems their max sample rate when using all 4 channels is halved as expected, not quartered.

author: rbola35618
author_rank: Frequent Contributor
timestamp: May 14, 2013, 03:37:10 pm
content: Dave,When you get around to reviewing the Instek scope, I would like to see a comparision of the Rigol DS2000 and the Instek showing a video signal from a camera. The video signal is a very good test of the grading of a scope and you should see a difference. I compared the video signal on a DS4054 against the Agilent 3054 and the Agilent showed more detail. I am interested to see how the Instek stacks up.RB

author: vk6zgo
author_rank: Super Contributor
timestamp: May 15, 2013, 01:04:29 am
content: Quote from: rbola35618 on May 14, 2013, 03:37:10 pmEven better,look at the video signal at field rate.(not looking at individual lines within the field,just the whole field real time).Some DSOs have problems with this.

author: Yaksaredabomb
author_rank: Regular Contributor
timestamp: May 30, 2013, 01:11:12 pm
content: Okay, so just today I came across this in Buy/Sell/Wanted:Equipment For Sale: Power Supplies, Oscilloscopes, ProbesOne of the items in the post is:Tektronix TDS754D with options 13/1F/1M/2F (Calibrated)It's currently going for a $1400 USD bid or about $1800 "buy it now". I've asked the seller about probes but they haven't had a chance to reply yet.In the meantime, I found another listingTektronix TDS754D 500MHz 2GSa/s oscilloscope w/options 13 1F 2M 2Ffor $1850 "buy it now". Same story on the probes.The options referenced are:13: RS-232-C and Centronics interface ports.1F: 1.44MB Floppy drive.1M: Extends standard acquisition length from 50,000 points per channel to 500,000 samples on one channel, 250,000 on two channels, and 130,000 samples on three or four channels2M: Extends standard acquisition length from 50,000 points per channel to 2 million samples on three or four channels, 4 million samples on two channels, and 8 million samples on one channel.2F: Advanced DSP math features such as FFT, integration, and differentiation.1CH or 2CH 2GS/s, 4CH 1GS/s is a little slow for 500MHz BW - but in reality I'll probably settle for 200-300MHz probes anyways if they're not included. Maybe I'd splurg on 1 proper probe for special cases.Sure it's old, no usb, about 3x the depth, 7x the weight, and uses FDD instead of USB. No MSO capability. But 8 MS memory ("2M" option on second link), 200k waveforms/s, and as much BW as I want to buy probes for isn't available in a modern 4-channel scope for anywhere near $1800. And the downsides are only annoyances - not issues that will really get in my way (I'm "only" 26 but still no stranger to floppies haha).It seems I'm determined to never be able to make a decision on a scope. Just when I'm a week from pulling the trigger on an MSOX2024A the GDS-2204A becomes of great interest. Then, the Instek doesn't quite live up to the hype (at least in Dave's informal "first look"). Both are great scopes, but neither seem to really hit the nail on the head. Along comes the TDS754D as an option that has its own annoyances but seems to really have it where it counts (BW, Memory Depth, Channels, Wf/s) for negligibly different cost.I'm seriously considering buying a Hantek DSO5000B as one of the least expensive stop-gap options available, possibly followed by something later when/IF I can ever make my mind up. I've made a post in the Buy/Sell/Wanted forum even:LFS / WTB (USA) Hantek DSO5102B oscilloscope new or like new. I got a lead on where to buy one new (thanks!), but only 1 PM so far about getting one used (not sure if it will lead to anything). I'm hoping maybe I can help someone out who upgraded to the Rigol DS2000 series and can't stand to even look at their Hantek anymore- or anyone else looking to unload theirs for whatever reason. Feel free to post in that thread or PM me if you've got any interest.I'm tired of waiting to buy a scope!!! Haha. I should be grateful there are so many fantastic options on the market today compared to only 5 years ago. It's truly amazing - but maybe not such a good thing for people like me lol.(Btw, if these Tek scopes are fantastic bargains and someone buys them out from under me - that's fine. I accepted that risk when I called attention to them. The info from everyone on this forum has been invaluable so well worth it.)

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2013, 02:13:50 pm
content: Quote from: jneumann on May 30, 2013, 01:11:12 pmBig name 4 channels 500MHz, deep memory and fast for sub $2K is always good value, if that's what you are after.You have to weight up old vs new of course.There is this very nice Agilent 54642D mixed signal for $1700 if no one bids.http://www.ebay.com/itm/HP54642D-Mixed-Signal-500MHz-2GSa-s-Oscilloscope-Digital-MegaZoom-Agilent-/121116805354?pt=BI_Oscilloscopes&hash=item1c331fc8ea500MHz, 2GS/s, 8M, only 2 channels, but you get the nice 16ch MSO and probes.An excellent scope, and a bargain if you can get it at $1700 IMO.Heck, even this 500MHz Agilent Infiniium can be had for under $2K:http://www.ebay.com/itm/HP-Agilent-Infinium-54825A-oscilloscope-2GS-s-500-MHz-/221214312736?pt=BI_Oscilloscopes&hash=item3381668920No shortage of options in that sort of price range.

author: Yaksaredabomb
author_rank: Regular Contributor
timestamp: May 30, 2013, 06:25:58 pm
content: Quote from: EEVblog on May 30, 2013, 02:13:50 pmThank you for the input! The 8 MS Tek now presents yet another option but I'm glad to hear it's a good value.Quote from: EEVblog on May 30, 2013, 02:13:50 pmThis is a good scope and brings me back to my college days with the green CRT, but the listing is hilarious! "GOOD WORKING CONDITION, ACTUAL PHOTOS AND VIDEOS, INCLUDE HIDDEN GAME ! BUYER WILL HAVE THE ACCESS CODE TO GAME." - the seller boldly proclaims! The seller makes such a fuss about the "Hidden Space Game", in big colored caps - you'd think it was worth $1700 just for the game alone! Nevermind anything *else* the scope might be good for. Thanks for the laugh and I hope other people check it out too. Seriously though I appreciate the link to a good scope.Quote from: EEVblog on May 30, 2013, 02:13:50 pmThis was even more interesting than the first link. The comment "It works perfectly, and has at some point beenupgraded with Option E2633A(faster cpu, more memory and a LS120 drive)" stood out. Naturally I was curious about the details, and I came across this:Installation Instructions for Infiniium Oscilloscope Performance Upgrade Kits E2633-68701/3 and VoiceControl Upgrade Kit E2633-68704. Now that's what I call an upgrade! 16 pictures showing how to mess with the scopes internals - what cards, components, cables to add/remove, in what order, etc. And that's before you get to the "BIOS Setup Proceedure". Oh, and what was that? "VoiceControl"?! Yes, around 15 years ago you could talk to your 'scope. Maybe that's common knowledge for some but it was new to me! Unfortunately the scope only has32k memory depthand I can't figure out if the upgrade affects that or not (assuming not). In any case though, what an interesting scope to find!If anything I may jump on the 8 MS Tek - I'm partial to its extra analog channels and color traces over the Agilent 54642D (though I'm sure the 16-channel LA would be a winning feature for many). Also still hoping more people will contact me about having aused Hantek DSO5000B to sell.Thanks again for responding with your opinion and couple other ideas, Dave! Even for a "full time job" you sure put in your hours!

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 30, 2013, 09:34:07 pm
content: Quote from: EEVblog on May 30, 2013, 02:13:50 pmWith some luck there are even some 1GHz scopes available:http://www.ebay.com/itm/LeCroy-LC534L-Oscilloscope-Digital-1GHz-2GSa-s-4ch-/390179678584?pt=BI_Oscilloscopes&hash=item5ad8856978http://www.ebay.com/itm/LECROY-LC564A-1GHz-digital-OSCILLOSCOPE-4chl-/310354064694?pt=BI_Oscilloscopes&hash=item48428b3536or this:1GHz, 8GSa/s and 4M per channel:http://www.ebay.com/itm/LeCroy-LC374A-4-Ch-500-MHz-2-GSa-s-Oscilloscope-/270721316725?pt=LH_DefaultDomain_0&hash=item3f083f7775

author: nctnico
author_rank: Super Contributor
timestamp: May 30, 2013, 10:20:28 pm
content: Quote from: jneumann on May 30, 2013, 01:11:12 pmDon't bother with used probes. You can buy a pair of new probes for $80 or so. Don't expect to measure any signals over 100MHz with a high impedance probe anyway no matter whether it says 300MHz. It will load the circuit way too much due to the high capacitance. When going over 100MHz you need HF probes or a direct 50 OHm connection. Don't get scared though. You can build your own HF passive divider probes for a couple of dollars and some patience:http://www.emcesd.com/1ghzprob.htm.About the Lecroys: do proper research and see if they have peak detect.

author: Unknown
author_rank: Unknown
timestamp: May 30, 2013, 10:37:44 pm
content: The over 100 MHz you need something else than a passive high-Z probe statement is too strong in my opinion. Things definitely get harder, and 500 MHz is pushing it, but can still work for low-impedance nodes in the circuit. The bandwidth is specified when driven from a 25 Ohm source, so as long as your source impedance is under 25 Ohm, you should be OK.If you can't tolerate the high DC loading and attenuation of resistive divider probes (1kOhm/40x for the Doug Smith version), the other option is active FET probes. Finding these for $80 might be harder, although used Tektronix FET probes appear to be the more common than Agilent and Lecroy probes.Note that you need four probes to use all channels.

author: dfmischler
author_rank: Frequent Contributor
timestamp: May 30, 2013, 11:27:00 pm
content: Quote from: jneumann on May 10, 2013, 10:14:20 pmI know I came late to this party, but at 200 MHz bandwidth your 80 MHz clock is almost going to look like a sine wave. An ideal square wave consists of the primary and odd harmonics, and 3 x 80 = 240, 5 x 80 = 400, 7 x 80 = 560 and 9 x 80 = 720. So to see a good 80 MHz square wave you would probably need on the order of 700+ MHz bandwidth, with at least 5 gigasamples per second (more would be better if you want to see ringing). So the used 1 GHz scope you talked about in a later post is probably about right.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 30, 2013, 11:31:34 pm
content: Quote from: nctnico on May 30, 2013, 10:20:28 pmThey do. Peak Detect has been available from LeCroy at least since the old 9300 Series (which is much older than the LC Series models I listed, which should have Peak Detect as standard).

author: EEVblog
author_rank: Unknown
timestamp: May 30, 2013, 11:36:11 pm
content: Quote from: nctnico on May 30, 2013, 10:20:28 pmI disagree, 300MHz x10 passive probes are pretty cheap and good performers.e.g.http://au.element14.com/testec/tt-mf312-2-6-10020-2-6/probe-oscilloscope-double-mid-freq/dp/4308104AU$77 for a pair of quality 250MHz probes is great value. Probably cheaper in the US.

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2013, 12:13:22 pm
content: Quote from: EEVblog on May 30, 2013, 11:36:11 pmIn that case you've never probed around in high speed or RF circuits. A generic (high impedance) probe is utterly useless even if it says 300, 400 or 500MHz. Ofcourse you see a signal but its awfully distorted due to the capacitive loading.

author: EEVblog
author_rank: Unknown
timestamp: May 31, 2013, 12:45:38 pm
content: Quote from: nctnico on May 31, 2013, 12:13:22 pmSo every single passive probe that Tek, Agilent, Lecroy et.al make is utterly useless over 100MHz?If so it must have been stupid and pointless of them to push all that passive probe technology beyond 100MHz huh?

author: dfmischler
author_rank: Frequent Contributor
timestamp: May 31, 2013, 01:23:52 pm
content: There is some truth on both sides of the probe debate. A 500 MHz probe will work better than a 100 MHz probe on a 100 MHz square wave. But a low impedance probe is better for some applications:Praise for the Lo-Z ProbeIf you have a fast scope, make one yourself and see.

author: grenert
author_rank: Frequent Contributor
timestamp: May 31, 2013, 02:14:40 pm
content: Quote from: dfmischler on May 31, 2013, 01:23:52 pmOscilloscopes have always been rated for sine wave input, so of course a 100 MHz probe will not work well with a 100 MHz square wave. A 100 MHz scope can't "see" a 100 MHz square wave anyway.

author: Unknown
author_rank: Unknown
timestamp: May 31, 2013, 02:42:21 pm
content: If you look at the impedance-frequency plot (or calculate it using the R//C model they specify), you'll see that the impedance of a 500 MHz passive probe is very low at 500 MHz, even compared to a 500 ohm 10x resistive divider probe. About 6 orders of magnitude lower than its DC resistance. This can cause roll-off of high frequencies well below 500 MHz if your test point is not very low impedance.Quote from: grenert on May 31, 2013, 02:14:40 pmYou're missing the point and are essentially repeating dfmischler's earlier post. ntcnico argued that 500 MHz passive probes are useless. This example illustrates that 500 MHz probes perform better than 100 MHz probes.

author: Yaksaredabomb
author_rank: Regular Contributor
timestamp: May 31, 2013, 06:05:27 pm
content: This has been very interesting discussion and I've learned something new, looking at those two sites (one,two). Thanks!A clarification on my first post - the 80MHz clock is an internal in the particular example I was thinking about, multiplied up from a 16MHz crystal. I don't want to buy a scope based specifically and only on this one application, so I hesitated to mention too many project specifics. Maybe it could do more good than harm at this point though, so here goes:*********************The project would heavily utilize the Stellaris Launchpad (now the "Tiva C Series"). Other micros may be involved as slaves (low-end MSP430s probably, if anything). There will be an LCD, possibly a simple 20-40 charactor one but more likely a 320x240 one such asthis.Stellaris Launchpad Eval Board User Manual:http://www.ti.com/lit/ug/spmu289a/spmu289a.pdfMicrocontroller data sheet (note it's a different device name but is identical):http://www.ti.com/lit/ds/spms351/spms351.pdfThe fastest clock I can get out of it on a pin is 40MHz, and only in a certain mode (I think). More likely the fastest actual signal I'd want to work with is around 20MHz, for driving some serial to parallel converters, DACs, or whatnot. I want 256-4096 levels of current control over several channels (12-36) of high-power LEDs (3W to 10W). I want this level of control because I think it would be really sweet to be able to do things like simulate clouds, storms, etc and tweak the wavelength mix just how I want it, without noticable "steps" or jerks in the transitions. Light perception is logrithmic, so that adds a facet.I plan to take 1 to 4 DC voltages into my circuit and do all the downstream power circuitry for the variable current control. With so many channels, I'm not going to buy off-the-shelf variable supplies from Meanwell or another brand at $15-$35 a pop. I'm hoping I can get by for $2-$5/channel in parts. Much less demanding, the circuit's other tasks will be to monitor several float switches and turn pumps on and off according to logic. I'd like to put it on a custom PCB in the end, and that may even be a requirement depending on the frequencies/part count/complexity/etc. Even if not required I'd like to do a PCB for better reliability and "fun".It's an interesting project, I think, with a few parts and at least a dozen viable ways to implement each one (probably 2 or 3 of which are equally defendable after cancelling out pros and cons). I've done a fair amount of planning and really only scratched the surface here.*********************I don't intend to derail this into that project at all. And as I said, I don't want to base my scope decision on this project alone (though this may be the most complex project I do in awhile) - I'm looking to get general use out of the scope for several years. I just thought it might help focus the issues to give this extra info though.I chose 200MHz since it was 5x 40MHz. Not sure I'll need to see a very defined square wave and be able to measure rise times - but I will probably need to see 2, 3, and 4-wire signals passing between chips at these speeds and check for signals or glitches I'm not expecting (maybe induced from a pump switching on or off nearby? etc). I'll want to know, is a signal loaded down by more than one device fighting over a bus and that's why it's unreliable? I'll want to see cause and effect and timing of multiple things - say a control signal, its effect on a DAC or programmable resistor output, and the output or inner workings of some sort of current-control circuit it drives. I've had a 4-channel scope at school and at work so perhaps I've been spoiled - that could be biasing me towards 4 analog channels versus 2 and a logic analyzer.Anyhow, if I got an older 500MHz+ scope I'd probably want 1 "legit" probe that can really not limit the scope's front end. Guessing this would be $100-$300 USD. I'm too cheap to get all 4 and I'm guessing I'd probably only need the full BW in special cases, where even then I could get by with looking at one signal at a time. I'd also have 4 less expensive 200MHz - 300MHz probes. They might affect the signals and not be capable of measuring acurate rise times etc (thanks for the head's up to not blindly trust the label!) but I'm guessing that won't bother me too much. If I really need a spot-on, full 500MHz measurement I can use the pricy probe.Though a 1GHz scope would be cool to have, I just don't think I'd be able to use anywhere near the full BW. If I really have to be concerned about +500MHz stuff then whatever the project is, I've bit off more than I can chew haha. At least for a home project.Thanks again for all the interesting discussion and insight - never would've thought a working 1 GHz scope would sell for less than $2k. Or, that these higher frequencies (100MHz, 300MHz, 500MHz+, whatever you believe) could be so hard to get an acurate look at with passive probes.

author: mike1305
author_rank: Contributor
timestamp: May 31, 2013, 06:07:48 pm
content: Quote from: Wuerstchenhund on May 12, 2013, 08:51:32 amTwo quick things here.If sinc interpolation is giving you large amounts of ringing or other affects, you may be pushing the boundaries of (or violating) nyquist's theorem.Additionally, the only real reason scopes had dot mode in the first place was to act as a crutch. Ten years ago, digital scopes didn't have the sample rate or memory depth to avoid aliasing fast edges, so they would go into equivalent time mode in order to satisfy nyquist.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: May 31, 2013, 06:37:45 pm
content: Quote from: mike1305 on May 31, 2013, 06:07:48 pmNope. Sin(x)/x is, by nature, only a valid interpolation for sine waveforms. It's 'good enough' for non-sine waveforms in most cases if the sampling rate is high enough, but the simple reason why every high end scope has a button or setting to switch off interpolation is that it does introduce errors which, in some circumstances, can be substantial.I agree that, for an entry level scope, this is probably of minor concern, but on the other hand there is no sane reason why a scope should not allow to switch off interpolation at least optionally.

author: mike1305
author_rank: Contributor
timestamp: May 31, 2013, 06:49:18 pm
content: Quote from: Wuerstchenhund on May 31, 2013, 06:37:45 pmAnything of use you'd look at on a scope is either analog (sine) or digital (square-ish), the latter can be roughly deconstructed with a fourier series. Perhaps there are other signals I'm not considering?

author: Bored@Work
author_rank: Super Contributor
timestamp: May 31, 2013, 07:30:48 pm
content: sin(x)/x is the right interpolation for every set of samples of a continuous-time, band-limited signal, not just a single sinus. It happens to be the impulse response of the ideal reconstruction filter. Which is an ideal rectangular filter.But here is where theory and practice divert a bit. The sampling system an oscilloscope represents, in fact, any real-world sampling system, is not ideal. And that is why sin(x)/x can sometimes do more harm than good. If you feed "garbage" into sin(x)/x you get garbage out. "garbage in" in the sense that your sampling system is not ideal so the numbers you have aren't exactly right.

author: nctnico
author_rank: Super Contributor
timestamp: May 31, 2013, 08:31:16 pm
content: Quote from: EEVblog on May 31, 2013, 12:45:38 pm<Drum roll> YES!Just do the math: a generic passive probe (and I'm not talking about HF passive divider probes here) has a capacitance at the tip around 10pf. At 200MHz this results in an impedance of 80 Ohms. Another problem is that the additional capacitance will delay edges in high speed digital circuits so you won't see what is actually there. The whole point of a probe is to disturb a signal as little as possible and make a scope show the signal as it would be without a probe connected. A generic passive probe won't do that for high frequencies in any real world circuit unless there is a really low impedance measuring point.