I Need Help With Choosing a Budget Oscilloscope! - Page 1
Forum section: electronics / testgear

author: ROFLCat
author_rank: Contributor
timestamp: October 17, 2020, 08:24:35 pm
content: Hi everyone!So I'm a 18 y/o EE who likes working with precision parts. I mostly design switchmode PSUs and precision low-noise voltage references for fun. Will be going to a university hopefully this year to study EE.I already have a pretty nice kinda hard-to-find GW Instek GDM 450A DMM which is a 20,000 count meter with very good accuracy (I believe around 0.05%).What my poor man's lab is missing is a low-end/mid-range oscilloscope. Now this being Iran with the awful inflations, it's super expensive for us to buy a $350 DS1054Z. Luckily, I was able to sell my graphics card to get around $270. But it's still not enough to buy and import a DS1054Z as it would cost north of $600 to do so. But I found a very reasonably priced Hantek DSO1062B for about $370 which is a 60MHz (lower than a hacked DS1054Z with 100MHz), 1GS/s sample rate (the same), and 2 channels (compared to Rigol's 4). It also has a built-in DMM with capacitance measurement which makes it pretty much a Chinese Fluke ScopeMeter. It's portable, affordable and an added bonus for a portable meter, FFT! I doubt it's powerful, but for my low frequency uses it should be just fine.There's also this Iwatsu SS-7635 350MHz, 4Ch analog/digital scope for about $470. Great value, but too expensive for me.I'm kinda stuck scratching my head honestly. Can anyone help me choose a decent scope for my purposes?Thank you! :3

author: ataradov
author_rank: Super Contributor
timestamp: October 17, 2020, 09:36:54 pm
content: I would do whatever I can to avoid those all-in-one button-only control portable things. They all universally terrible and frustrating to use. Their specs and performance are also questionable in many cases.I personally would take way lower speced ,but a real scope any time. Something like Hantek DSO5072P or DSO5102P. Their only real limitation is the memory depth.

author: bob91343
author_rank: Super Contributor
timestamp: October 17, 2020, 09:51:03 pm
content: Why not consider an older, used unit? You can get a good Tektronix 465 for instance, for very little money. I use one regularly and love it. I have others but that's my main one. Even my very old 453 is perfectly useful.My digital unit does FFT but not in such a way as to be useful for most purposes. I have spectrum analyers for that.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 17, 2020, 10:06:38 pm
content: I see a future member of the TEA group in the makingI also come from a country where buying test equipment is rather expensive, and there's not many options to acquire good gear without having to sell your organs to afford them.My first scope was a Rigol DS1052E (which I still think is an amazing entry level scope -especially if you hack it to unlock 100 Mhz bandwidth-) that I bought 10 years ago, and I kinda burned all the money I had at the time on that purchase.If you only want to see waveforms and do basic measurements, an analog scope is definitely an option (and I love them, they are beautiful things), but since you mentioned that you like working with precision and low-noise stuff, I guess it would be useful to you to be able to capture glitches, measure jitter, etc. With that in mind I think a digital scope would be a better option.I normally would advice against handheld scopes for a "main" scope (they are fine as a secondary or "field" tool) because they usually have pretty awkward controls, lack features (limited triggering options, limited storage capabilities, poor measurement capabilities, barely meet specs, etc) BUT that Hantek scope you mentioned seems to be fairly decent on paper (I went through the manual and looks fine, BUT I'm yet to see a review showing if it meets its specs, and all the features actually work, though).There's a recent review from Defpom on a budget scope that looked pretty promising:That instrument seems to be exactly the same as the OWON SDS1102, which is available even here in my country at a reasonable price (still higher than its standard price, but definitely cheaper than the Rigol I purchased as my first scope) Maybe it's also something you can get where you live?Aggressively stalking local auction sites is also recommended. Hopefully the second hand market in your country is bigger than here, though. Apparently VERY few people in my country worked on electronics in the past couple of decades, so it takes a miracle to find good used instruments at decent prices.

author: Fungus
author_rank: Super Contributor
timestamp: October 17, 2020, 10:30:53 pm
content: Quote from: ROFLCat on October 17, 2020, 08:24:35 pmHow much is a Rigol DS1052E there?

author: ROFLCat
author_rank: Contributor
timestamp: October 18, 2020, 02:58:16 am
content: Quote from: bob91343 on October 17, 2020, 09:51:03 pmYeah there were a few second hand 465s for sale but they were ridiculously priced TBH and actually Tek scopes are kinda rare. Common analogs in here are mostly Japanese stuff and mostly 20MHz, which I think is a bit too low.

author: ROFLCat
author_rank: Contributor
timestamp: October 18, 2020, 03:10:17 am
content: Quote from: battlecoder on October 17, 2020, 10:06:38 pmI honestly had not thought about the awkward controls of handheld scopes until you and ataradov mentioned it.I had seen these Owons and they're pretty common but I had doubts since I had only seen Dave's review of one and IIRC, it wasn't good. xDBut to be honest, at such a low budget there's not much choice to get a decent entry scope. I'll check out these Owons to see if there are any suitable models for me.Oh I'm always on a website similar to Ebay checking the test equipment section every single day. I'm OK with a second-hand scope even if it has cosmetic damage, just need it to perform well according to the specs.

author: james_s
author_rank: Super Contributor
timestamp: October 18, 2020, 05:28:36 am
content: Quote from: bob91343 on October 17, 2020, 09:51:03 pmIn Iran? I have no idea what the market is like there but I would not expect used instruments to be nearly as plentiful there, especially A-list American brands.

author: nctnico
author_rank: Super Contributor
timestamp: October 18, 2020, 10:45:53 am
content: Maybe the FNIRSI-1013D (tablet oscilloscope) is also an option. There is a long thread about it with comments from people who bought it:https://www.eevblog.com/forum/testgear/fnirsi-1013d-100mhz-tablet-oscilloscope/msg3022032/#msg3022032I think it is a better choice compared to a handheld 'automotive style' or analog oscilloscope because in the end it offers more features. Then again I wouldn't spend more than US $200 on it including shipping.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 18, 2020, 12:32:43 pm
content: Quote from: Fungus on October 17, 2020, 10:30:53 pmI second this recommendation. It's an "old scope" by now, but it's a pretty solid option; good performance, can be hacked to 100 Mhz, and it's simple to use but powerful, and with enough features for most use cases. As I mentioned, this was my first scope, and it took me nearly 10 years of tinkering with electronics to need something slightly more powerful and feature-rich.

author: ROFLCat
author_rank: Contributor
timestamp: October 18, 2020, 02:48:16 pm
content: Quote from: james_s on October 18, 2020, 05:28:36 amActually, I think there are lots of them and brands like Tek and HP are well-know, but the problem is that the owners would never let such good instruments go. That's why they only pop-up occasionally and at high prices.

author: ROFLCat
author_rank: Contributor
timestamp: October 18, 2020, 02:52:18 pm
content: Quote from: Fungus on October 17, 2020, 10:30:53 pmThere is a website that has it in stock and for about $300.

author: ROFLCat
author_rank: Contributor
timestamp: October 18, 2020, 03:14:35 pm
content: From what I've seen, the other options compared to a DS1052E are, bad. xDThe desktop Hanteks and Owons probably have smoother UIs and more modern hardware, but their memory depths are really bad. Like a Hantek 100MHz or a 70Mhz model has 40kpts and an Owon 100MHz model has 10kpts, you kidding me?! Is it that hard to implement 1Mpts or something? Rigol did it over a decade ago LOL.Anyway, I'll probably save up a bit for the DS1052E and 100% put on a hacked firmware. Too bad I can't afford a DS1054Z, the 2 extra channels could be pretty damn useful.Thanks everyone for your input!

author: Fungus
author_rank: Super Contributor
timestamp: October 18, 2020, 04:12:57 pm
content: Quote from: ROFLCat on October 18, 2020, 03:14:35 pmMaybe it is. They could be using the RAM inside an FPGA which is usually very limited. Adding an external RAM chip could cost a lot more.

author: tautech
author_rank: Super Contributor
timestamp: October 18, 2020, 06:26:11 pm
content: Quote from: ROFLCat on October 18, 2020, 03:14:35 pmIf you can get by with just 2 channels maybe a SDS1202X-E can better suit your needs but might be at the top end of your budget.At least it has some reasonable memory depth (14 Mpts), 7" display, better sensitivity than most others in this class and a suite of decoders.

author: Fungus
author_rank: Super Contributor
timestamp: October 18, 2020, 06:38:09 pm
content: Quote from: tautech on October 18, 2020, 06:26:11 pmOr there's the new 2-channel Rigol DS1052Z, which is even cheaper.https://www.aliexpress.com/item/4001268857855.html

author: nctnico
author_rank: Super Contributor
timestamp: October 18, 2020, 07:16:14 pm
content: OP's biggest problem is his/her location. As stated there is a near 100% premium on top of importing something.

author: tv84
author_rank: Super Contributor
timestamp: October 18, 2020, 07:59:54 pm
content: What about a GW Instek GDS-1000B Series? Since the OP has a GW Instek DMM maybe that brand is easier to find...

author: Fungus
author_rank: Super Contributor
timestamp: October 18, 2020, 09:34:46 pm
content: Quote from: tv84 on October 18, 2020, 07:59:54 pmThey're not easy to find even here in Europe.

author: nctnico
author_rank: Super Contributor
timestamp: October 18, 2020, 10:19:23 pm
content: Quote from: Fungus on October 18, 2020, 09:34:46 pmNonsense. There are several webshops where you can buy them. Even RS sells these:https://nl.rs-online.com/web/p/oscilloscopes/1233540/(at an inflated price as you can expect from a distributor).

author: battlecoder
author_rank: Regular Contributor
timestamp: October 18, 2020, 11:02:04 pm
content: Quote from: ROFLCat on October 18, 2020, 03:14:35 pmThat's what I thought when I upgraded my oscilloscope a few years ago. Turns out I've only used channel 3 once. Channel 4 remains untouched. Bear in mind that enabling extra channels reduce your sampling rate and memory, so having more than 2 channels is not *that* great. For a bunch of logic signals (which is what I look at the most) a logic analyzer is more practical anyway. Even a cheap Saleae clone (which is what I have) works wonders.

author: Fungus
author_rank: Super Contributor
timestamp: October 18, 2020, 11:50:41 pm
content: Quote from: battlecoder on October 18, 2020, 11:02:04 pmI use mine for looking at Arduino pins. It's great to be able to put out pulses when you're debugging things.Quote from: battlecoder on October 18, 2020, 11:02:04 pmThe problem is that those don't have a real time display of the signals. You have to press "record" and then go back and analyze.(unless you have some software that I don't...)I just got an Analog Discovery 2 and thatdoeshave real time display (16 digital channels, 2 analog). Maybe a 2-channel 'scope would be OK for me now.

author: 0culus
author_rank: Super Contributor
timestamp: October 19, 2020, 12:02:30 am
content: Real time display of logic signals is often not wanted anyway...you want to record and go back to study what happened in detail. This is normal behavior for every logic analyzer I've used.

author: nctnico
author_rank: Super Contributor
timestamp: October 19, 2020, 12:02:54 am
content: @Fungus: please fix the quotation. I didn't write the text you attribute to me.@Oculus: A logic analyser is for different kinds of measurements. The ones where the signals in the analog domain are known to be good.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 19, 2020, 12:07:44 am
content: Quote from: nctnico on October 19, 2020, 12:02:54 amI guess we are now one and the same.

author: Fungus
author_rank: Super Contributor
timestamp: October 19, 2020, 12:21:01 am
content: Quote from: 0culus on October 19, 2020, 12:02:30 amImagine having to click record then stop then mouse around a bit every time you compile/run a program. It's a complete pain in the ass.Sometimes you just need to see the signals.

author: Fungus
author_rank: Super Contributor
timestamp: October 19, 2020, 12:21:37 am
content: Quote from: battlecoder on October 19, 2020, 12:07:44 amYeah, there's no going back after three people have quoted it.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 19, 2020, 12:26:58 am
content: Quote from: Fungus on October 18, 2020, 11:50:41 pmI do the same, but I've rarely needed to check more than 2 channels at once. For digital signals it's usually "something" vs the clock. And if there's any jitter/timing issue, it's "normally"** a problem only if it messes things up in the digital domain, in which case a logic analyzer should help you see quickly that something is off.** For most cases.Quote from: Fungus on October 18, 2020, 11:50:41 pm.Fair, but recording is normally a good thing when you are working with signals that change million times a second. Can't see myself debugging fast changing signals in realtime. I'd miss like half a million transitions just by blinking.Also, thanks for reminding me that I wanted an Analog Discovery board at one point. Now I'll probably spend the rest of the night watching video reviews and trying *not* to start saving for one. Maybe if I start a diet of cheap instant noodlesANDI can get everyone a cheaper Christmas present this year there might be a chance I can get one for myself before the year ends?

author: 0culus
author_rank: Super Contributor
timestamp: October 19, 2020, 12:30:36 am
content: Quote from: Fungus on October 19, 2020, 12:21:01 amSure, that's what the o-scope is for. The logic analyzer is a different instrument, and it works differently than an oscilloscope. Mine has a lot more memory depth available than most oscilloscopes too, as well as a fully configurable state machine trigger.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 19, 2020, 12:44:10 am
content: Quote from: 0culus on October 19, 2020, 12:30:36 amDefinitely a different instrument, but one "common" use of >2 channels is debugging communication/logic signal errors, in which case I was saying that a logic analyzer is better suited.There are definitely legitimate uses of 4 analog channels in an oscilloscope, but I don't think OP will miss having 4 channels as much as he/she thinks.

author: Fungus
author_rank: Super Contributor
timestamp: October 19, 2020, 01:24:41 am
content: Quote from: battlecoder on October 19, 2020, 12:26:58 amThere's a MASSIVE shortage of the chips at the moment so you'll be very lucky to get one this year. I only got mine by blagging my way through a special university education program.

author: Fungus
author_rank: Super Contributor
timestamp: October 19, 2020, 01:26:20 am
content: Quote from: battlecoder on October 19, 2020, 12:44:10 amDepends on what you use it for. I use more than 2 channels very often, eg. for timing how long a function takes to execute, that sort of thing.

author: ROFLCat
author_rank: Contributor
timestamp: October 19, 2020, 02:07:51 pm
content: Quote from: Fungus on October 18, 2020, 06:38:09 pmIf you can get by with just 2 channels maybe a SDS1202X-E can better suit your needs but might be at the top end of your budget.At least it has some reasonable memory depth (14 Mpts), 7" display, better sensitivity than most others in this class and a suite of decoders.Or there's the new 2-channel Rigol DS1052Z, which is even cheaper.https://www.aliexpress.com/item/4001268857855.htmlI had never heard of this model. Is it new or something?

author: ROFLCat
author_rank: Contributor
timestamp: October 19, 2020, 02:10:08 pm
content: Quote from: tv84 on October 18, 2020, 07:59:54 pmActually, there is a GDS-1052U 50MHz, 2ch 'scope for about $340 second-hand, which I think is a bit too much.

author: ROFLCat
author_rank: Contributor
timestamp: October 19, 2020, 02:13:48 pm
content: Quote from: battlecoder on October 18, 2020, 11:02:04 pmThat's what I thought when I upgraded my oscilloscope a few years ago. Turns out I've only used channel 3 once. Channel 4 remains untouched. Bear in mind that enabling extra channels reduce your sampling rate and memory, so having more than 2 channels is not *that* great. For a bunch of logic signals (which is what I look at the most) a logic analyzer is more practical anyway. Even a cheap Saleae clone (which is what I have) works wonders.Yes I'm aware of the reduction in sample rate on these mid-range 'scopes. Well you'll never know when you'll need them so... .

author: ROFLCat
author_rank: Contributor
timestamp: October 19, 2020, 02:21:13 pm
content: There is this company that takes orders from China, especially TaoBao (Tmall.com). I'm a long-time customer of theirs and I have ordered some LR8 regulators through them; it was all fine, especially the price. The only problem was that they had told me it would take 3-4 months but my order took around 7 months to arrive. I think the major delay was because of the human malware that caused every shop and stuff to close down at the beginning of 2020, so I don't blame them.I'll ask them and get a quote on the price and time on a DS1054Z, provided that Tmall has some for a good price.

author: David Hess
author_rank: Super Contributor
timestamp: October 19, 2020, 05:12:27 pm
content: Quote from: ROFLCat on October 17, 2020, 08:24:35 pmNeither require anything special in an oscilloscope. Low noise would be nice for references however no modern oscilloscope is that low and a low noise amplifier allows the use of any oscilloscope. An oscilloscope which can perform low frequency network analysis would be nice but this is not available in anything except high end instruments.Storage is useful in general but not overwhelmingly so that I would exclude an old but working analog oscilloscope if it is inexpensive.100 MHz of bandwidth or even 50 MHz is sufficient except for the highest performance switching regulators.Do not underestimate the importance of probes. A lower bandwidth oscilloscope with better probes, differential, current, whatever, will be more useful than a higher bandwidth oscilloscope without them.

author: ROFLCat
author_rank: Contributor
timestamp: October 19, 2020, 07:26:03 pm
content: Quote from: David Hess on October 19, 2020, 05:12:27 pmQuite true. I've actually never used a proper oscilloscope so I don't know how much of a difference there is between 10kpts and 1Mpts of memory but I guess 10kpts would make waveforms look very inaccurate when measuring 0.1 to 10Hz noise.I'll still be waiting for that company's response. If the total cost comes out less than about $370, I'll order a DS1054Z.

author: David Hess
author_rank: Super Contributor
timestamp: October 19, 2020, 10:33:06 pm
content: Quote from: ROFLCat on October 19, 2020, 07:26:03 pmThe problem is that the impedance buffer stage at the input of the oscilloscope has quite poor low frequency noise with a high flicker noise corner frequency. It is just a compromise to be made for high bandwidth and fast recovery from overload. Oscilloscope front ends designed for low noise have a much more limited bandwidth.But noise is not a problem when you can easily build an external low noise amplifier.Limited record length creates more aliasing of high frequency noise to low. So for instance 10 kpoints from 0.1 to 10Hz has a sample rate of 1kHz so input bandwidth needs to be limited to below 500Hz. A 1 Mpoint record length considerably relaxes this requirement.I do not have any DSOs suitable for FFT noise measurement so I still rely on spot noise measurements using the oscilloscope to measure RMS noise. In practice spot noise is usually more relevant anyway, like measuring total noise from 0.1 to 10 Hz. You can bet that if I ever design a DSO, it will include this capability and network analysis as well.

author: james_s
author_rank: Super Contributor
timestamp: October 20, 2020, 12:58:13 am
content: It really depends on what you're trying to do. The scope I use the most is a TDS3000 with 10k points and in most cases I have not found that to be a major limitation. I have a TDS700 with the 8M points option and I very rarely make use of that extra memory depth because it just results in capturing a ton of excess waveform to scroll through and it slows down the interface when you have a really big capture. IMHO it's better to focus on setting up the triggering to capture what you want instead of using massive amounts of memory to capture everything.

author: tautech
author_rank: Super Contributor
timestamp: October 20, 2020, 01:25:56 am
content: Quote from: james_s on October 20, 2020, 12:58:13 amQuite so however it much depends on your use case as one channel might be triggered on to capture an event while other channels might be monitoring so to find what might have caused such an event.Of course success depends on how time correlated the channels and events actually are, timebase settings and the mem depth available.When working like this there is never too much mem depth.

author: nctnico
author_rank: Super Contributor
timestamp: October 20, 2020, 06:20:36 am
content: Quote from: james_s on October 20, 2020, 12:58:13 amNo. Use an oscilloscope with a faster hardware platform. Those TDS700 are rather slow to drive (been there, done that). Modern oscilloscopes have no problem dealing with tens of megapoints worth of data.

author: ROFLCat
author_rank: Contributor
timestamp: October 20, 2020, 03:13:56 pm
content: Quote from: David Hess on October 19, 2020, 10:33:06 pmInteresting. Didn't know about that. But then again, I want some rough measurements on the noise of precision parts and being able to debug my power supplies and take output ripple measurements is really good. One other reason I want a decent digital oscilloscope is the ability to decode I²C and SPI signals as I'm also into data acquisition.

author: ROFLCat
author_rank: Contributor
timestamp: October 20, 2020, 03:21:34 pm
content: Thankfully, there's a deflation happening and the Rials per US Dollars ratio dropped by about 10% today which is great. The chances of getting a DS1054Z increases.Also, if I there's a bit of money left in my pocket after an oscilloscope, I'll get this very unique and extremely rare frequency counter from a reputable and old manufacturer of test equipments. Stay tuned?Let's just say that it has a unique display with an affordable price.

author: David Hess
author_rank: Super Contributor
timestamp: October 20, 2020, 07:25:23 pm
content: Quote from: ROFLCat on October 20, 2020, 03:13:56 pmIt is not a big deal; it just means do not look to oscilloscopes for low noise measurements unless you want to deal with something like a Tektronix 7A22. Designing and building a low noise preamplifier to test reference and regulator noise is not difficult and then any oscilloscope can be used.'

author: tautech
author_rank: Super Contributor
timestamp: October 20, 2020, 08:53:08 pm
content: Quote from: ROFLCat on October 20, 2020, 03:13:56 pmHow good will you require ?As we mainly use a scope with 10x probes a scopes max sensitivity can limit how far down we can go without switching to a 1x probe.Study of scope datasheets and marketing blurb might reveal some brands are better suited down in the mV/div region due to high sensitivity and lower noise inputs.

author: ROFLCat
author_rank: Contributor
timestamp: October 21, 2020, 05:01:07 am
content: Quote from: David Hess on October 20, 2020, 07:25:23 pmOh yeah I'm trying to build a cascaded Sallen-Key low-pass filter based on two LTC2055s (the lowest noise op amps that I can find and purchase). I might buy more in the future and connect them in parallel to achieve even lower noise?

author: ROFLCat
author_rank: Contributor
timestamp: October 21, 2020, 05:09:57 am
content: Quote from: tautech on October 20, 2020, 08:53:08 pmWell, power supply noise and ripples are usually taken with a 20MHz bandwidth limit so that's completely fine on the 1x setting. Decoding I²C and SPI buses is fine with a 10x too since they're logic level and 3.3Vpp or 5Vpp.And about the low-noise references, I'll be using a low-noise amplifier to boost up the signal by a factor of 10 or 100 as reading microvolts isn't too easily with any oscilloscope.Bandwidth on these measurements is irrelevant to be honest as it will mostly likely be low-frequency stuff (0.1 to 10Hz).

author: Fungus
author_rank: Super Contributor
timestamp: October 21, 2020, 05:43:18 am
content: Quote from: ROFLCat on October 21, 2020, 05:09:57 amYep.There's people here who'll go on and on about how their brand of oscilloscope can do 0.5mV instead of 1mV but is that really a make/break difference when a cheapo amplifier can let you see 1uV noise onanyoscilloscope?

author: David Hess
author_rank: Super Contributor
timestamp: October 21, 2020, 09:10:04 am
content: Quote from: ROFLCat on October 21, 2020, 05:01:07 amUsually the problem is removing the DC component while passing frequencies down to 0.1 Hz. Low noise and low drift with a 0.1 Hz low frequency cutoff is somewhat contradictory because of the impedances required to get such a long time constant with a reasonable value of capacitance. Check out Linear Technology application notes 83 and 124 for example circuits.Another method is to use an "offset probe" or differential comparator which subtracts the DC voltage. This is essentially a differential probe with one input connected to the source to measure and the other connected to a low noise reference of the same voltage.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 21, 2020, 08:07:23 pm
content: Quote from: David Hess on October 21, 2020, 09:10:04 am^This. Application notes are gold mines of good advise and practical uses of different components and technologies. On the topic of low-noise amplifiers for instance there's this guy who built a reasonable amplifier circuit based on a couple of application notes:AND he builds the device to characterize low-noise regulators and power supplies, so it might be well in line with OP's request.Even more, the guy is actually using a 70Mhz Hantek DSO5072P scope (which is a model someone here already suggested) and seems to work just fine for the job.I think brands like Hantek/Mustool/Owon/whoever-the-original-oem-of-those-devices-is are doing a pretty good job at making decent entry-level oscilloscopes that are WAY beyond the specs of what hobbyist had access to even 10 years ago. They are definitely not state of the art, but I would have killed for one of those scopes when I started. Some of them are terrible, sure, but we are starting to see some models that definitely meet the specs, have a reasonable range of features, and don't have that many UX glitches as previous "budget" scopes.Now, sure, if you can afford a Rigol or a Siglent ( or if you happen to find a good deal for a second hand <reputable brand>) by all means go for it. Just don't overlook the few little gems that are coming from "generic" manufacturers. I've seen a lot of people doing amazing stuff with them already.

author: Fungus
author_rank: Super Contributor
timestamp: October 22, 2020, 11:52:14 am
content: You can buy a pre-built signal amplifier on Aliexpress for $5 and add a battery and biscuit tin.

author: ROFLCat
author_rank: Contributor
timestamp: October 25, 2020, 08:11:11 am
content: Quote from: David Hess on October 21, 2020, 09:10:04 amThanks for the tip! I'll definitely check them out.

author: ROFLCat
author_rank: Contributor
timestamp: October 25, 2020, 08:17:05 am
content: Quote from: battlecoder on October 21, 2020, 08:07:23 pmI'll check it out. ThanksYeah some of these are making a comeback.I'm still waiting for the prices to drop down and seeing if there are going to be any good second-hand models for sale.

author: ROFLCat
author_rank: Contributor
timestamp: October 25, 2020, 08:18:04 am
content: Quote from: Fungus on October 22, 2020, 11:52:14 amOh I don't know about that. I wouldn't wanna count on a low-noise reference with fake chips.

author: Fungus
author_rank: Super Contributor
timestamp: October 25, 2020, 11:27:43 am
content: Quote from: ROFLCat on October 25, 2020, 08:18:04 amNot everything is "fake" on there.The point is that no oscilloscope magically solves the problem of measuring noise.

author: mawyatt
author_rank: Super Contributor
timestamp: October 25, 2020, 01:30:29 pm
content: Quote from: Fungus on October 25, 2020, 11:27:43 amNope, Tektronix did this 50 years ago with the 7A22 Differential plug-in. Quite good actually at measuring low frequency noise, even had selectable built-in separate LP and HP filters for setting the BW as well as variable offset introduced near the front end to help with post-amplifier saturation. We had a number of these for use with our sub-nanovolt/root Hz amplifiers/systems and other ultra-low noise endeavors.The amplifier you mentioned is worthless for the low noise low frequency reference measurements, the LT app notes mentioned by D Hess is what's required, especially in front of a really noisy low-resolution scopeIf you want to learn about low noise scope measurements, study the 7A22 design/notes, the mentioned LT App notes, and the video.BTW the old Tektronix Main Frame scopes allowed various "plug-ins" for both vertical and horizontal, these were the workhorse analog scopes which could be tailored by plug-ins for covering a large range of measurements, including the mentioned low noise references.Best,

author: ROFLCat
author_rank: Contributor
timestamp: October 31, 2020, 10:18:38 am
content: Hello again!So today a new ad popped up, it's a Philips PM3315 125MHz, 2 channel 'scope with 3 waveform memories and good amounts of trigger options for less than $90. The tube seems bright and consistent, the chassis looks extra clean but the seller says that some volts/divs need calibration and they're a bit off and he says the main power button sometimes doesn't turn it on and it can probably be fixed with some cleaning. It doesn't have any probes though. I don't know, do you guys think I should just go for it and buy separate probes? (Most probes available are Chinese with crappy plastic) I can see a 60MHz Taiwanese probe for about $20 and from the same company but 250MHz is $50, more than half the price of the scope LOL.

author: battlecoder
author_rank: Regular Contributor
timestamp: October 31, 2020, 05:04:54 pm
content: Quote from: ROFLCat on October 31, 2020, 10:18:38 amFirst, that's a REALLY good price in my opinion. HOWEVER...From my experience I can tell you that calibrating a scope normally requires pretty precise function generator and other gear. This is especially an issue when it comes to >20 Mhz scopes, because you start getting into the terrain of reasonably high-frequency signals where no cheap instrument will dare tread.In fact, this is something I struggled A LOT with, when I had to calibrate a 100Mhz analog scope. The HF circuitry was reasonable complex and required gear I didn't have. I ended up cobbling together a high-frequency square-wave generator myself, and verifying the readings against a 100Mhz digital scope, which is definitely NOT the way the service manual recommended. At most I can say it ended up "more or less as poorly or well calibrated as the other guy"So buying that scope might end up buying yourself a week (or more) of quality time with the scope partially disassembled over your dining table while you desperately try to come up with the signals and measurements you need to verify that it's performing as expected trhough its full bandwidth.Regarding Chinese probes, some are pretty decent, to be fair. I have bought a couple sets for different scopes, and I'm yet to find a reason to complain about them. In fact, I'd say the last set I bought seems to work better than the probes that came with my Rigol scope (that doesn't make them good probes, but at least makes them better than what Rigol considers a good probe set for their entry-level scopes). Just make sure they are reasonably above the scope's bandwidth to avoid problems with the conversion ratio between "real Mhz" and "$20 with free shipping Mhz".

author: ROFLCat
author_rank: Contributor
timestamp: October 31, 2020, 05:59:13 pm
content: You're right, the calibration does need good equipment that I don't have either. The price/performance is amazing but the calibration thing... Oof.I found a set of two 100MHz probes for $12 LOL.

author: Fungus
author_rank: Super Contributor
timestamp: October 31, 2020, 06:16:51 pm
content: Quote from: ROFLCat on October 31, 2020, 05:59:13 pmIt doesn't have to be very precise for you to be able to use the 'scope. Most usage of an oscilloscope is looking at theshapeof waves together with anapproximatevoltage measurement, eg. many DSOs are only specified to about 5% accuracy on the voltage readings.So... if you can generate an accurate 5V square wave thena) You can calibrate the most common scales directly from that.b) For the mV voltage scales you can feed your 5V though a 10 turn potentiometer, adjust it to output the voltage you need by measuring with a multimeter, now feed your square wave through that to calibrate the 'scope.Quote from: ROFLCat on October 31, 2020, 05:59:13 pmFinding probes for a 125MHz 'scope shouldn't be a problem.

author: ROFLCat
author_rank: Contributor
timestamp: October 31, 2020, 06:24:28 pm
content: Quote from: Fungus on October 31, 2020, 06:16:51 pmAh true. An "issue" that has come up is that the seller has made the 'scope private for an individual who may be buying. If they don't,thenI can maybe buy it.Probes are easy to find, just a bit expensive.

author: Fungus
author_rank: Super Contributor
timestamp: October 31, 2020, 06:36:17 pm
content: Quote from: ROFLCat on October 31, 2020, 06:24:28 pmCheap probes:https://www.eevblog.com/forum/reviews/cheapest-100mhz-oscilloscope-probes-hands-on-review/

author: battlecoder
author_rank: Regular Contributor
timestamp: October 31, 2020, 08:00:58 pm
content: Quote from: Fungus on October 31, 2020, 06:16:51 pmWell yes and no.Yes; It doesn't need to be precise to be useful for watching shapes (unless you want to look into high-frequency ringing and artifacts). But from what I remember OP was interested in measuring ripple, noise, and whathaveyou. For that I think he'd need the device to be as precise as possible, so a quick basic calibration with a breadboard square gen might not be enough.Of course buying it now, and solving the calibration aspect later is an option. I'm sure there's a lot of people here who can MacGyver a calibration procedure for a 125Mhz scope with readily-available parts and gear, and would be happy to chime in.

author: Fungus
author_rank: Super Contributor
timestamp: October 31, 2020, 08:49:32 pm
content: Quote from: battlecoder on October 31, 2020, 08:00:58 pmyes and no.You want to be able to see it. You want to know how it changes when you do things to the circuit. Absolute accuracy? Maybe not as important as you might think. A bigger problem would be if there was a huge jump between ranges.I'm sure something reasonably accurate can be done without spending a lot of money. The "square wave and pot" was just a starting point.Itmightjust be a dirty switch and the problem will go away with a can of contact cleaner.The best thing is to find a place where people know that model and ask their opinion.

author: nctnico
author_rank: Super Contributor
timestamp: October 31, 2020, 08:55:56 pm
content: Quote from: Fungus on October 31, 2020, 08:49:32 pmPlease no contact cleaner! Makes things work for a week or two and then everything is fubar due to corrosion. A better approach would be to get a service manual first to see what can be adjusted and perhaps clean switches and potmeters gently with alcohol. Not sure whether that will improve things because once a switch or potmeter is worn it simply needs to be replaced in order to get a piece of equipment back to work properly.Given the problems the OP describes I'm not sure whether the scope was a really good purchase but then again it was cheap. I would have gone for any reasonable modern DSO.

author: rf-loop
author_rank: Super Contributor
timestamp: November 01, 2020, 05:15:38 am
content: Quote from: nctnico on October 31, 2020, 08:55:56 pmThere are many many alcohols.I do not recommend ethyl alcohol for this kind of work. Ethanol need keep away until very special known reason for use it in some specially named place.Mostly, right alcohol is isopropyl alcohol (isopropanol) Aka IPA.

author: ROFLCat
author_rank: Contributor
timestamp: November 01, 2020, 09:51:03 am
content: So... Anymore ideas and reasons to buy it?

author: ROFLCat
author_rank: Contributor
timestamp: November 01, 2020, 10:01:29 am
content: The seller just messaged me that the other person didn't buy it and they've re-posted the ad. He says he wants to sell it outside of the website and "you'd better get it soon", probably trying to trigger me LOL.I still haven't decided because even though I probably could fix it, I don't like the chance of blowing off the money I can't restore on something that's half working.Update: I told the guy that I'm not interested and that he shouldn't wait for me.

author: nctnico
author_rank: Super Contributor
timestamp: November 01, 2020, 10:39:36 am
content: Quote from: ROFLCat on November 01, 2020, 10:01:29 amGood choice. BTW don't worry about probes. Used probes that come with oscilloscopes are usually crap and need replacing anyway.

author: Fungus
author_rank: Super Contributor
timestamp: November 01, 2020, 11:13:29 am
content: Quote from: ROFLCat on November 01, 2020, 10:01:29 amWhat's the plan now? Rigol DS1052E?

author: ROFLCat
author_rank: Contributor
timestamp: November 01, 2020, 04:13:20 pm
content: Quote from: nctnico on November 01, 2020, 10:39:36 amYeah that's not an issue. I can get two 100MHz probes for $12 which I think is a pretty good deal.

author: ROFLCat
author_rank: Contributor
timestamp: November 01, 2020, 04:16:30 pm
content: Quote from: Fungus on November 01, 2020, 11:13:29 amYes and no. I'm still waiting for that company to give me a quote on the price to order a DS1054Z from China. I'm also waiting for other ads for 'scopes to pop up.They do from time to time but most of them are crappy 20MHz broken ones which are also way overpriced.

author: ROFLCat
author_rank: Contributor
timestamp: November 05, 2020, 10:16:17 pm
content: *Sigh*The company I was hoping to be able to import from TaoBao for cheap just told me it would be about $900 to import a DS1054Z which is just stupid frankly.I guess I'll just wait for the economy to get better or until I find a good second-hand one.Meanwhile, I got into a great university with amazing labs and stuff (haven't seen the EE lab but the labs for other fields are just chocked full of equipment worth tens of thousands of Dollars). The problem is that the human malware won't let me go into the building and use the equipment. Great.

author: ROFLCat
author_rank: Contributor
timestamp: November 07, 2020, 12:44:55 pm
content: Wow! An ad for a Tektronix TDS 220 popped up. 100MHz, 1GS/s, and 2 channels. It's a bit of an old model but I think it's pretty sweet, listed for about $330 and I can buy it in less than a day. The seller says it's fully functional and clean. I don't know if he would include the probes or not so I just asked and I'm waiting for an answer.Should I go for it? An alternative to this would be a DS1052E which is more expensive or a GW Instek 'scope with very low specs (like 40MHz or something).Update: They replied and told me it has 1 probe.

author: ROFLCat
author_rank: Contributor
timestamp: November 07, 2020, 01:27:23 pm
content: I don't think it's a good 'scope after seeing the reviews and stuff. Commonly BNCs break, slow UI, slow updating, no advanced math features, dim and slow LCD, they all make me go "meh".

author: smaultre
author_rank: Regular Contributor
timestamp: November 07, 2020, 03:21:49 pm
content: I think Tek TDS3000(b) series is the most preferred for 1-st osc.0) Small.1) Can be upgraded (FOR~FREE) to 500(600)MHz@5Gs its a very good for its price.2) Can be upgraded (FOR~FREE) with universal module to support advanced triggering modes.3) Have professional 50Ohm inputs, that supported the ultra wide range of active probes (High frequency, differential, mA current, high voltage dif, e.t.c).4) Active probes REALLY CHEAP (compared with other brands) and its so much on stock.5) (B) series can be easy connected to PC by LAN.6) Noisy fan can be replaced with quiet "hydra-bearing" from the PC store.7) Really cheap for its pros.The next-one goes TDS5000B series its cheapand provides a big screen and huge of functionality.

author: nctnico
author_rank: Super Contributor
timestamp: November 07, 2020, 03:28:23 pm
content: Quote from: ROFLCat on November 07, 2020, 01:27:23 pmAnd terribly noise too. Tek made a lot of nice DSOs but the TDS200 series isn't one of them.

author: battlecoder
author_rank: Regular Contributor
timestamp: November 07, 2020, 05:33:57 pm
content: I still think a Rigol DS1052 makes a really good first scope, even if it's "old". I used one for 10 years and I kinda regret selling it when I "upgraded". Sometimes I still wish I had it here.

author: ROFLCat
author_rank: Contributor
timestamp: November 07, 2020, 06:06:01 pm
content: Quote from: smaultre on November 07, 2020, 03:21:49 pmThanks for your reply.Well, there are lots of good oscilloscopes for decent prices, but my country makes everything absurdly expensive for no reason and I have a very limited budget of about $350.

author: ROFLCat
author_rank: Contributor
timestamp: November 07, 2020, 06:09:16 pm
content: Quote from: battlecoder on November 07, 2020, 05:33:57 pmYeah, I still have that on my list. A bit expensive for me but I'll get one if I can't find anything within a month or something.Thankfully, there has been a huge drop on the exchange rate of US Dollars to Rials so, I might be able to get something good if it keeps dropping?

author: Fungus
author_rank: Super Contributor
timestamp: November 07, 2020, 07:36:44 pm
content: Quote from: battlecoder on November 07, 2020, 05:33:57 pmYep. I played with one of those older Rigols the other day when I was visiting a factory and I was, like, "Hey, this is really fun/cute to use".Simplicity can be good. I'd be perfectly happy to own one of those.The only thing that would be missing (for me) would be serial decoders but you can get really cheap devices for that.Edit: And I'm not sure if it does FFT.

author: battlecoder
author_rank: Regular Contributor
timestamp: November 07, 2020, 09:33:01 pm
content: Quote from: Fungus on November 07, 2020, 07:36:44 pmIndeed. Modern scopes with more features can be overwhelming or cumbersome to use, especially for quick measurements. Having a bunch of features and settings is great, but if you don't have the right combination of options selected you can easily sabotage your measurements. Funny that you mention serial decoding; one of the reasons I upgraded to a more modern scope was actually serial decoding. Turns out I've rarely used that feature. I have a dirt cheap logic analyzer that works great for that, and it's way easier to explore and dump serial data with it, than it is to do it with the scope.

author: uski
author_rank: Frequent Contributor
timestamp: November 09, 2020, 03:51:50 am
content: Quote from: ROFLCat on November 07, 2020, 12:44:55 pmBe aware it has very limited memory, absolutely no decode feature, and unless it has the TDS2MM or TDS2CM module, no communication capabilities at all, which is annoying since you can't do screenshots or anything. It seems like a very steep price given the age of the instrument. But it's good quality, I liked it. I owned it for years, more than a decade, but I sold it.A DS1054Z from Rigol would be a thousand times better in my opinion.

author: Electro Fan
author_rank: Super Contributor
timestamp: November 09, 2020, 04:17:01 am
content: Find a way to go for this:http://www.saelig.com/product/sds1202x-e.htmIt will be 200 MHz and have two probes, and will be new and will have a 7” 800x480 color screen instead of a 5.7” 320x240 monochrome screen plus a bunch of additional useful and enjoyable features including color intensity gradingIt is a no brainer.

author: Fungus
author_rank: Super Contributor
timestamp: November 09, 2020, 04:26:04 am
content: Quote from: Electro Fan on November 09, 2020, 04:17:01 amIt might be if OP didn't live where he lives.

author: Electro Fan
author_rank: Super Contributor
timestamp: November 09, 2020, 04:29:15 am
content: Quote from: Fungus on November 09, 2020, 04:26:04 amOP is resourceful and if he can maybe find a Rigol he can maybe find a Siglent. First step is to know what he is looking for.

author: David Hess
author_rank: Super Contributor
timestamp: November 09, 2020, 12:35:29 pm
content: Quote from: battlecoder on November 07, 2020, 05:33:57 pmMy first encounter with Rigol was the DS1052D/E and it made a very bad impression on me. It lacks peak detection which I consider essential on any DSO but you would not immediately know it because the documentation lies by referring to envelope detection as peak detection. I only knew because I had tested one. Rigol's customer service was less than helpful and tried to convince me that they were the same thing.I bought and refurbished Tektronix 2230 instead. I would never recommend the Rigol DS1000D/E series.

author: ROFLCat
author_rank: Contributor
timestamp: November 09, 2020, 10:03:41 pm
content: Quote from: Electro Fan on November 09, 2020, 04:17:01 amOh I doubt I could get one. The companies that import stuff only purchase from websites like Amazon and TaoBao, I don't think they would purchase from that website.The specs are impressive and well, it's from Siglent.

author: tautech
author_rank: Super Contributor
timestamp: November 10, 2020, 06:08:46 am
content: Dubai is your closest Siglent dealer:https://www.anaum.ae/

author: Fungus
author_rank: Super Contributor
timestamp: November 10, 2020, 01:48:19 pm
content: Quote from: David Hess on November 09, 2020, 12:35:29 pmYou're special.

author: David Hess
author_rank: Super Contributor
timestamp: November 10, 2020, 05:09:18 pm
content: Quote from: Fungus on November 10, 2020, 01:48:19 pmIs that your only reply? Don't you have some better personal insults to make? Don't hold back; tell us what you really think.What part of what I said about the DS1052D/E series was wrong?

author: nctnico
author_rank: Super Contributor
timestamp: November 10, 2020, 06:35:13 pm
content: Actually I don't think the DS1052 lacks peak detect. One of my customers has one (without digital channels) and I recall it being able to do peak detect. The problem is that Asian oscilloscope brands (most notably the Japanese) mis-label peak detect as envelope mode.

author: Fungus
author_rank: Super Contributor
timestamp: November 10, 2020, 07:41:01 pm
content: Quote from: David Hess on November 10, 2020, 05:09:18 pmThe part that was incorrect was telling somebody with limited budget in a country where test gear cost a fortune that they can't possibly buy a DS1052E because it doesn't have a feature they might never need.Edit: I don't have a DS1052E in front of me but the manual says it has it, in section 2-56:https://cdn-shop.adafruit.com/datasheets/Users+Guide+DS1000E.pdfQuote

author: battlecoder
author_rank: Regular Contributor
timestamp: November 10, 2020, 08:44:34 pm
content: I really don't quite remember if the DS1052 had Peak Detect or not. I vaguely remember using it, but wouldn't trust my memory on that one.Having said that, I managed to find a video review (in Spanish, though. Was hard to find a video where they would actually get into the Acquisition Mode menu. Most reviewers just ignore it) that shows that the feature is indeed there, and it's properly called "Peak Detect". It's not under a different name (as already shown in the manual shared by @Fungus)) or anything.https://youtu.be/htBXEjGV5CY?t=461Maybe you are thinking of a different scope, @David Hess?

author: dave j
author_rank: Regular Contributor
timestamp: November 10, 2020, 08:51:35 pm
content: My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events then it won't work in single shot mode.Attached are two images of my DS1102E's probe compensation waveform captured in single shot mode and zoomed in. Displayed as dots and vectors.Admittedly the way it's presented might not match other scopes. Having the two lines, one that links the max values and the other that links the min values, might be better than having one line that alternates between max/min values but that's a presentation issue.Tektronix's definitionQuote

author: David Hess
author_rank: Super Contributor
timestamp: November 11, 2020, 04:10:40 am
content: Quote from: battlecoder on November 10, 2020, 08:44:34 pmThe point is that the DS1052D/E series has a feature called peak detection, which on other DSOs going back decades is called envelope detection. Envelope detection is as easy as averaging to implement during processing but peak detection requires hardware and happens during decimation.And then when you get to the DS1000Z series, peak detection as described in the manual is different since they actually implemented it.Quote from: dave j on November 10, 2020, 08:51:35 pmAnd that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.QuoteThat does not show anything. A common test is to use a slow time/div and short record length to deliberately cause aliasing, and then switch to peak detection. On the DS1052D/E series this would have to be done with a single shot acquisition to prevent envelope detection since there is no way to limit the number of envelopes to 1 as on the Tektronix 2440 series. Other Tektronix DSOs had separate peak detection and envelope detection modes but for some reason they were combined on the 2440 series. The lack of a way to set that is another clue that the DS1052D/E series does not implement peak detection.If you have a pulse generator which can produce narrow variable width pulses, then you can quantitatively test how peak detection is occurring although DSOs now tend to have high enough sample rates that this is not practical beyond existence. When I ran this test on the Tektronis 2230 which only has peak detection to 100 nanoseconds, it really did detect every pulse of 100 nanoseconds or longer, and miss shorter pulses, which was doubly interesting because the 2230 uses an analog channel switch.Quote from: nctnico on November 10, 2020, 06:35:13 pmThe DS1052D/E series mislabels envelope mode as peak detection.If peak detection is supported, then envelope mode should use it, but not the reverse.Quote from: Fungus on November 10, 2020, 07:41:01 pmThen that is all you had to say rather than starting in with the personal insults.QuoteI am aware of the manual. It lies. Rigol lied, and did so repeatedly when I contacted them. Is that so surprising?Quote"over many acquisitions" should tell you something.

author: Shiv
author_rank: Regular Contributor
timestamp: November 11, 2020, 09:10:55 am
content: I went through analogs.Thats fun, because you can repair it almost eternally...468 was my first one... get it for free and sell it for 400 euros 3 months ago... but is toooo big for home.I would recomend something about 50-100 MHz, analog/digital... (Philips PM3375, Tek TDS310, Iwatsu oldies,...)468 in digital is only 10 MHz, but that works well for audio signals.There are too many of them and are usually cheap and repairable (try to find one with 1 functional channel and repair the others) ,but the problem is your country, don´t take it badly, simply I doubt there are too many tek or Philips equipment (fck politics...)For cheap new equipment, I saw UNI-T UTD2102e but I don´t know nothing about the brand (only that I like his mini function generator), but it´s only 179 bucks for 100 MHz

author: nctnico
author_rank: Super Contributor
timestamp: November 11, 2020, 07:13:17 pm
content: Quote from: David Hess on November 11, 2020, 04:10:40 amToday I had a chance to test with a DS1102E myself and peak-detect is definitely doing peak detect and not envelope mode. However I'm not ruling out that firmware for this oscilloscope has changed over the years.

author: TurboTom
author_rank: Super Contributor
timestamp: November 11, 2020, 09:18:37 pm
content: Quote from: ROFLCat on November 09, 2020, 10:03:41 pmHow much hassle would it be for you to import the scope yourself? I don't know how burocracy works in your country and if you need to pay a lot of import tax / customs duty, but just for fun I checked shipping from my country to Iran of a 5kg package -- it would be round about 45 Euros. And I don't think there would be any legal difficulty to send a "second hand entry level" DSO your way, maybe even declared as a "present". I'm pretty sure many members of this forum (myself included) wouldn't have much problem parting with one of their "toys" for a compensation that would fit within your financial frame, including postage. And you can be pretty sure that noone around here would cheat you.So if a second hand instrument would be okay for you, why don't you try it that way. I guess a Rigol DS1000Z should be within reach. Of course, it will only work that way if the import procedure until you finally can take it home, isn't too troublesome and expensive.

author: David Hess
author_rank: Super Contributor
timestamp: November 13, 2020, 01:51:48 am
content: Quote from: nctnico on November 11, 2020, 07:13:17 pmIf it does do peak detection when set to envelope mode, that would sure be annoying for routine use when you really wanted peak detection on individual acquisitions.I distinctly remember trying to do that when I tested it and having no luck. It operated like it had envelope mode, which is what the manual shows and describes, and single shot acquisitions in envelope mode were identical to single shot acquisitions in normal mode which was the only way to test it.

author: rf-loop
author_rank: Super Contributor
timestamp: November 13, 2020, 03:51:22 am
content: Quote from: David Hess on November 13, 2020, 01:51:48 amAs you can see, and many others who know, there is always peoples and even manufactures who do not even know or care what is digital oscilloscope peak detect mode and how it work and how it need work. Sad.

author: Fungus
author_rank: Super Contributor
timestamp: November 13, 2020, 05:14:31 am
content: Quote from: nctnico on November 11, 2020, 07:13:17 pmSo it seems a safe bet that it has it.Quote from: nctnico on November 11, 2020, 07:13:17 pmOccam's razor would suggest it hasn't.

author: Shiv
author_rank: Regular Contributor
timestamp: November 13, 2020, 08:27:42 am
content: Quote from: ROFLCat on October 31, 2020, 10:18:38 amWARNINGPM3315 is a good thing amd good price BUT I doubt it reaches 125MHz, I don´t find it, but if I´m correct, it will be 125MHz SAMPLING RATE, thats 60MHz on sines and crappy squares.The calibration of v/div can be done at home with a well known DMM, a DC generator and pacience, but the frequency response is quite dificult without equipment, same as timebase (you need a good reference)EDIT: Yeah, I was late, I didn´t see it has been discarded.Same with TDS200, I have a 220 at work and is a BAD scope.Everything of it breaks appart.I mean: screen backlight, CH1 connector dead and irreparable, plastics broken,...I think is the worse tek scope by far.

author: tautech
author_rank: Super Contributor
timestamp: November 13, 2020, 08:51:10 am
content: Quote from: Shiv on November 13, 2020, 08:27:42 amEasy fixes both of them and there's plenty of info on the forum of how to.

author: nctnico
author_rank: Super Contributor
timestamp: November 13, 2020, 09:34:25 am
content: Quote from: David Hess on November 13, 2020, 01:51:48 amOn the DS1102E I used it is called 'peak detect'; not envelope mode.Quote from: tautech on November 13, 2020, 08:51:10 amBut you still end up with a poor oscilloscope. Fine if you pay $40 (or less) for it but not more.

author: tautech
author_rank: Super Contributor
timestamp: November 13, 2020, 09:41:15 am
content: Quote from: nctnico on November 13, 2020, 09:34:25 amOf course, by today's standards they're a POS but still better than no scope.Broken BNC's were common in these as Tek only used a 2 prong fitting and zero chassis fixing.They were built to break !

author: Shiv
author_rank: Regular Contributor
timestamp: November 13, 2020, 10:11:43 am
content: Quote from: tautech on November 13, 2020, 08:51:10 amWhy?Oscilloscopes here (only my lab):DPO4104TDS3064TDS3054TDS784DTDS520D2465B (x2)2445BPM3375 (x2)CSA804 (40GHz)TDS8200 (50GHz)Oh, I forget the "trash":465468TDS320TDS310And failing/mules :2465´sPM33´sTDS7000TDS3xxxTDS5xxAnd that crappy 220 used as signal/config checker before plug the test leads on measurement system.Basically is used as a fuseIs the only Tek Scope that I don´t like.Is better than nothing? yesBut the question is... is better than something?For me, I prefeer that shitty boards of aliexpress and play for 10 bucks audio frecuencies while wait to get 100-200 bucks more and get something useful and durable.

author: dave j
author_rank: Regular Contributor
timestamp: November 13, 2020, 02:46:19 pm
content: Quote from: David Hess on November 11, 2020, 04:10:40 amCan you explain why the screenshots in my previous post have differing high/low values? My understanding of envelope mode with a single shot capture is that it will only have one sample to update each high/low pair with so they should be the same. The screenshots clearly show differing values.Quote from: David Hess on November 13, 2020, 01:51:48 amAttached are two screenshots showing single shot captures in normal acquisition mode and what the scope calls peak detect acquisition mode. As you can see, they are different which implies the latter is not envelope mode.My scope is on the latest firmware and I believe it's the latest hardware (version 58). I don't know which hardware/firmware combination you used but there does seem to be some difference in the behaviour between the two scopes.

author: David Hess
author_rank: Super Contributor
timestamp: November 14, 2020, 08:54:41 pm
content: Quote from: nctnico on November 13, 2020, 09:34:25 amThat is right, the DS1102E calls it peak detect mode. But what the manual describes and how it operated when I tested it was what other manufacturers and DSOs, including later Rigol DSOs, called envelope mode.Quote from: dave j on November 13, 2020, 02:46:19 pmThat might be what it should look like, but how exactly did you force a single shot acquisition for the second screenshot?The screenshows do not show but what is the record length in the two modes? Peak detection almost always halves the record length but envelope detection may not depending on the implementation.QuoteWhen I tested the DS1000D/E series it was a couple years before the DS1000Z series was released. It seems odd that they would update the hardware or firmware without fixing the user interface leaving peak detection crippled and also not update the manual.

author: dave j
author_rank: Regular Contributor
timestamp: November 14, 2020, 09:49:08 pm
content: Quote from: David Hess on November 14, 2020, 08:54:41 pmTrigger menu->Sweep->Single for both.QuoteRecord length Normal for both (you only get a choice of Normal or Long Mem on this scope). Zooming in, the samples are displayed at 200ns intervals for both traces. The 'peak detect' one has the same high/low zigzag pattern shown in my earlier screenshots so a high/low pair is over 400ns. That doubling of the sample time fits with the record length being halved as you suggest since it has to store high/low pairs instead of single samples. If the zigzag display is just a presentation thing because the hardware can't display two separate lines for high and low values it seems a reasonable compromise to make - you have to zoom in over 10x in order to see individual dots so it won't normally be an issue.QuoteWhen I first looked at 'peak detect' I noticed the discrepancy between what the scope appears to do and the manual. I'd just assumed they hadn't updated the manual.I freely admit I'm largely a novice at electronics, I'm really a software guy who's recently started looking at electronics as a hobby. I'd like to understand what the scope is actually doing but discrepancies between what the scope does and the manual says together with more experienced people saying it does peak detect/it's really envelope mode leave me a bit puzzled. What I can see the scope doing seems to fit with peak detect rather than envelope mode so I'm going with that for now but I'm open to hearing an explanation for what I'm seeing that fits envelope mode.