Rigol DS1074Z or Rigol DS2072: which is the best choice? what SW upgrades? - Page 1
Forum section: electronics / testgear

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 01, 2014, 07:40:30 pm
content: I am going to buy a digital oscilloscope, but am doubting between the DS1074Z (4 channels) or the DS2072 (2 channels).Any recommendations or advice?Do you really need 4 channels, or are 2 channels enough?Are there SW patches for both models?Can the DS1074Z still be upgraded to DS1104Z? Max 100 MHz? or higher possible?Can the DS2072 still be upgraded to a DS2202 at 200MHz?Do these patches still work? What about the other SW options such as memory depth, protocol decoding?Is the ADC in both scopes overclocked? Or does the DS2000 series have an ADC that is not overclocked?

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 01, 2014, 09:11:25 pm
content: Actually I found out in the mean time that there is a DS2072 model, and DS2072A model.From what I can find is that the A model has 50 ohm input impedance.Can someone explain the exact difference and need for this update?It is not clear to me.Also it looks like DS2072A model can not be upgraded with SW patch.Is that correct?

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 01, 2014, 10:55:19 pm
content: BTW: If you would upgrade the DS1074Z from 70MHz to 100MHz (DS1104Z) or the DS2072A from 70MHz to 300 MHz (DS2302A), can you use the factory probes that came with the scope, or do you need better quality probes?

author: idpromnut
author_rank: Unknown
timestamp: January 02, 2014, 03:01:01 am
content: I am in the same position; I posted a similar question here:https://www.eevblog.com/forum/testgear/looking-for-ds1104z-s-impressionsopinions/msg354656/#msg354656I will probably be getting the DS2072(A). Just waiting for a quote to come in (I'm in Canada, otherwise I'd buy from TEquipment).Cheers!Chris

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 02, 2014, 05:19:51 am
content: Quote from: pascal_sweden on January 01, 2014, 10:55:19 pmWell, the DS1074Z comes with 150 MHz probes, and the DS2072A comes with 350 MHz probes. So what do you think?

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 05:37:19 am
content: Quote from: pascal_sweden on January 01, 2014, 09:11:25 pmThe model A has switchable inputs between 1 Meg / 50 Ohm - while the non-As just have 1 Meg inputs. The 50 Ohm capability is handy to have for direct connections in high-frequency applications, but it's not a critical feature. There isa good application note about probes and probing with DSOs here.

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 02, 2014, 06:57:53 am
content: Quote from: marmad on January 02, 2014, 05:37:19 amI'll second marmad's recommended reading on probes. LeCroy knows their stuff, having started out dealing with high-speed pulses in nuclear physics test labs. Plus they used screen shots in there of one of my (ancient) LeCroy scopes (a 9314L).However, the 50ohm option on the Rigol A-models isn't of much value, IMO. Primarily because even though it switches the resistive load internally from 1M to 50-ohms, it doesn't remove the internal capacitance. To get the best benefit from lo-Z probes (mine are all <1 pF), you need to remove the ~15 pF from the scope front-end. And the Rigols don't do that (though my Tek's and LeCroy's do). That means you can get essentially the same (degraded) results from using an inline 50-ohm terminator on the inputs, as the internal option.Secondly, with 50-ohm inputs, you can't inject as high a signal level. So it's possible to burn things up, if you're not being careful, or have just forgotten it's selected. And it's much easier to forget the mode you're in when it's a setting, than if you have an extra extension hanging off the input(s) on your scope.Since I have half a dozen 50-ohm inlines in my lab drawer, it's unlikely I'd use an internal 50-ohm option on a Rigol, even if it had one.

author: JDubU
author_rank: Frequent Contributor
timestamp: January 02, 2014, 07:10:26 am
content: Quote from: Mark_O on January 02, 2014, 06:57:53 amDo Rigol (or any) scopes with relay switched internal 50 ohm inputs attempt to protect the 50 ohm resistor by monitoring the input voltage and opening the relay if it reaches a dangerous threshold?

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 07:16:11 am
content: Quote from: Mark_O on January 02, 2014, 06:57:53 amAgreed. And considering:1) that the BW for the original DS2202 (or hacked DS2072) is already ~240MHz - and that the scope automatically does linear interpolation at sampling rates <=500MSa/s2) there is no evidence that anything other than minor changes to the front-end - plus the addition of added PCB layout space for the AWG - has been done to the A-models...I would say that if you're not interested in getting the DS2000A-S version, you might be better off getting the original DS2000 model, if available - knowing that the already published keygens will continue to work for your model indefinitely - so you will have all the options for free immediately and permanently.

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 02, 2014, 09:56:19 am
content: Quote from: marmad on January 02, 2014, 07:16:11 amYes. Now where did I put the keys to my time machine?

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 10:34:26 am
content: Quote from: Mark_O on January 02, 2014, 09:56:19 amThe OP wouldn't need one... he mentioned in the other thread that he could still get either non-A or A model DS2000s in Sweden.

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 02, 2014, 10:58:51 am
content: Stupid question: If the old DS2072 model only has 1M as internal impedance, can you make it 50 ohm by putting an external adapter?But then it is not switching between the two, but just added on top of the 1M? So how does that work out?

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 11:03:06 am
content: Quote from: pascal_sweden on January 02, 2014, 10:58:51 amYes. When you put on the inline 50 Ohm terminator, you're adding 50 Ohms in parallel to the 1M resistance - which equals 49.9975 Ohms.

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 02, 2014, 11:29:41 am
content: I would wait for the Siglent SDS2000. It may be as good as Rigol DS2000, but it can have four channels.

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 11:53:46 am
content: Quote from: Hydrawerk on January 02, 2014, 11:29:41 amMaybe he doesn't want to spend the money on 4 channels. Also:1) It depends on when he needs a DSO - no one knows (or has said) exactly when the Siglent will be released.2) We know nothing about it except what Siglent employees and dealers have posted. It looks good - but there may be flaws as well.3) The intensity-grading looks nice on the Siglent, but we've heard nothing about how it handles segmented memory. In this respect, so far the DS2000 crushes the competition.4) The D2000 is now a mature product; the Siglent is bound to have some problems in the early FW. As someone who decided not to buy a newer DS2000, and instead go for the older, safe Agilent, you must understand that feeling?5) According to preliminary pricing posted, the 200MHz 2-channel SDS2202 will be € 1250 excl. If he gets an original DS2000, he gets a ~240MHz DSO with all the options for € 700 excl.If he can afford to wait, all these questions will be answered eventually of course. But you do understand that the reason Siglent is posting info about the DSO on this forum (before the product is on the market) is exactly to get people to postpone purchases for an indefinite period of time, right?

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 02, 2014, 05:18:11 pm
content: Quote from: marmad on January 02, 2014, 11:53:46 amAccording to the official Siglent web site, it was released Nov/2013.According to my calendar, it's now Jan/2014.QuoteYes, and I'd say indefinite is pretty accurate. I can't say I'm fond of those tactics. It wasn't ready when they initially planned. It's not ready now. It's obviously still very much a work-in-progress. And there's no revised ETA. So it may be ready in a few months, or 6 months, or. At which point, it'll be a brand-new, untested product, ready for the beta-testers (err, guinea pigs... no, wait, I meant "lucky initial purchasers", yeah, that's the ticket!), to start making their lists of bugs. So perhaps by next fall this will be a real contender, and worthy of serious consideration. We don't know, and apparently, neither does Siglent.It looks like "someday" it will be quite nice, and provide something I'd really like to see: a scope in the class of a Rigol DS2074,that doesn't exist. I.e., the 4-channels of the 1000Z, combined with the performance of the DS2000. For much less $$$ than Rigol's only other 4-channel option, the DS4000. That's a significant hole in their current lineup, IMO.But unfortunately, today is not the time to be discussing it as a purchase choice, alongside options that actually exist. I really wish it were, because the 1000Z does not have the performance & feature set I need, the DS2000 doesn't have the channels I require, and the DS4000, which has both, isn't in a price class I can afford/justify.

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 05:39:11 pm
content: Quote from: Mark_O on January 02, 2014, 05:18:11 pmWell, it is possible that their strategy of getting it out to some dealers (and perhaps some enthusiastic early-adopters) for beta-testing will result in a more finished product than many other DSOs when first released. And itmighthappen soon. If the OP is in no hurry to purchase something, it might be worth waiting a couple of months to see what happens.QuoteAbsolutely. And from what I've seen so far, itmayhave the nicest intensity grading of anyone (under several thousand bucks) - a true 256 levels, at least at smaller memory depths - although it appears to reduce levels as the memory depth increases - it's not quite clear exactly what it's doing. The problem with the way information is being released about it in the other threads is if you ask the people posting about anything which is awkward or not-yet-finished in the firmware, they just don't respond.

author: nctnico
author_rank: Super Contributor
timestamp: January 02, 2014, 06:57:48 pm
content: I'm not sure whether 256 intensity levels is useful. A lot depends on the viewing angle of the TFT screen and so an. IMHO 8 levels is more than enough. I don't want a pretty picture, I want to see small pulses and 1 out of 256 is not going to make any visible difference on a screen.

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 02, 2014, 07:03:03 pm
content: It is funny that Siglent SDS2000 is already being sold in China, probably...Moreover...http://www.siglent.com/en/news/detail.aspx?id=100000065214624&nodecode=119002004QuoteWell, there seems to be a delay...

author: marmad
author_rank: Super Contributor
timestamp: January 02, 2014, 07:21:57 pm
content: Quote from: nctnico on January 02, 2014, 06:57:48 pmIf I was a cynic, I'd say the reason 8 is enough for you is because your DSO only has 16 levelsbut instead I'll just say I vehemently disagree and think 8/16 levels is crap.It's got nothing to do with pretty pictures, it has to do with encoding information for the screen. And using color/intensity to encode as much information as possible is just a no-brainer. Now one could argue that the eye can only distinguish about 100 discrete levels of brightness - but 100 isn't a power of 4, so it's generally either 64 or 256 - and from what I've seen, 256 seems to look more fluid and convey slightly more waveform detail, although you obviously can't see all of those levels of intensity (but you can see a lot more than 16).

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 02, 2014, 09:00:38 pm
content: Quote from: marmad on January 02, 2014, 05:39:11 pmYeah, or get defensive, because they think you're attacking them, or casting aspersions. When you're really just genuinely interested and curious. That's why I only read there, and don't post queries.IMO, they could benefit a lot from getting a unit into the hands of an outsider or two. With a pre-release NDA, if they felt it necessary. Some knowledgeable, experienced, and unbiased testers, without any axes to grind, who'd agree not to post negative commentary while development was proceeding. But could extensively test & evaluate the unit, providing them with feedback, and making note of: a) cool new capabilities that represent competitive advantages, b) a list of things to be fixed (shared only with Siglent for now), and c) a list of known missing capabilities they could cross things off from as things progressed. And get private answers to the kinds of questions you've been asking, in the interim. That way, they'd hit the ground running a lot faster once they got things finished, and ready to ship. With a higher-quality product as a result.

author: pascal_sweden
author_rank: Super Contributor
timestamp: January 04, 2014, 03:25:22 pm
content: Quote from: Mark_O on January 02, 2014, 06:57:53 amDoes anybody know if this is better on Siglent SDS2000 series? Is it there the same as in the more expensive scopes?

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 04, 2014, 10:42:40 pm
content: Quote from: pascal_sweden on January 04, 2014, 03:25:22 pmWe don't know for sure, unless someone at Siglent can chime in, butthere's reason to be optimistic... Unlike Rigol, Siglent both documents the 2nd input impedance in the data sheet,andlabels it on the front panel:1 Mohm//18 pF, 400Vpkor50ohm <= 5VrmsThis is standard practice for scope manufacturers with independent switched input circuits. Based on that, the capacitanceshouldbe removed on the 50ohm load.EDITED: to correct erroneous information.

author: marmad
author_rank: Super Contributor
timestamp: January 04, 2014, 11:06:31 pm
content: Quote from: Mark_O on January 04, 2014, 10:42:40 pmOk, Mark, I was with you up until a point - but now I'm afraid you're grasping at straws.The DS2000A DOES label it on the front panel (1 Mohm//15 pF, 300V RMS CAT I -- 50ohm <= 5V RMS) - and here is how the 2 DSOs list it in their respective datasheets:Rigol has been building decent quality goods much longer than Siglent - if either DSO is likely to have switched impedance, I'd bet on the Rigol.

author: nctnico
author_rank: Super Contributor
timestamp: January 04, 2014, 11:21:00 pm
content: OTOH Siglent has been building Lecroy's low end gear for a while now.

author: marmad
author_rank: Super Contributor
timestamp: January 04, 2014, 11:33:21 pm
content: One thing I'd like to point out to those who are thinking of waiting and getting one of Siglent's new SDS2000 series:Rigol has been producing DPOs (the UltraVision line) for ~3.5 years - starting with the DS6000, then the DS4000, DS2000, and now the DS1000Z. I'm sure A LOT of bugs and problems have been worked out along the way. This is Siglent's FIRST DPO - so you might expect some problems.

author: Mark_O
author_rank: Frequent Contributor
timestamp: January 04, 2014, 11:41:33 pm
content: Quote from: marmad on January 04, 2014, 11:06:31 pmDagnabit! I was positive I had seen both a specsheet, or specs in a User's Guide for the 2000A, that were missing that tidbit. But the copies I have access to here from Sep/Oct both DO have it. And I must have seen an early front panel pic with an A mockup, because the shiny yellow highlighted info on input impedance does clearly indicate both, right on the 2000A front panel. I made note of these discrepancies at the time (months ago), specifically because they suggested Rigol may not have fully thought out the ramifications of their switching circuit. I was hoping the A-models would have corrected the HW.2 oversight.[One problem I have is when I find info on the web, I toss it in a folder. But I work from 3 separate systems, in 3 distant locations, and all I can say is the folder of Rigol data I havehere nowfully confirms your correction of my misstatement.]QuoteNo argument there.My apologies for adding nothing to the discussion. I actually thought I was on to something.Thanks for catching my mistake.~~And, back to pascal_sweden's initial question:No, no one seems to know... yet. Like many important questions about the SDS2000, that remains TBD (To Be Determined).

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 05, 2014, 05:00:06 pm
content: By the way, GW Instek introduced their expensive DPO GDS-3000 in early 2011. So I expected that their newer DPO GDS-2000A from end of 2012 might be OK. And it is not. Dave was unhappy with this scope and the DPO feature is badly implemented.

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 05, 2014, 05:04:37 pm
content: Quote from: nctnico on January 04, 2014, 11:21:00 pmWhat is the origin of Siglent SDS1000 series? Is it inspired by Rigol DS1000? Or was it developed in some cooperation with LeCroy? Who was the first? Rigol or Siglent?