DSO life expectancy - Page 1
Forum section: electronics / testgear

author: Sylvi
author_rank: Regular Contributor
timestamp: September 12, 2018, 07:02:00 pm
content: HiThis could be called "DSO for linear use"...I work primarily with audio signals and analogue scopes have been the mainstay for decades. My first scope died after 30+ years and a new replacement died after just 18-months (one-year warranty plus some BONUS time - hehe)! The older one had through-hole components and leaded solder. I haven't opened up the new one yet, but I suspect it has a lot of surface-mounted parts and lead-free solder. In my experience, SM is not very good since it inherently has small solder connections, which might not be so bad were it not for the lead-free solder. The stuff is garbage!I'm at the point where I figure I should get a digital scope but there are a few issues I wonder about.First is reliability. The new scopes are made using new methods like SM and bad solder, so how long should one of these last? I can't afford to pay a few hundred dollars every year for a scope, let alone 500-1500 if I want better vertical resolution. Digital hardware does not seem to last very long even without the issues of software and planned obsolescence.Second is the latency between probing a signal and seeing a proper wave on the display. Digital audio equipment is notorious for this delay and it is a real problem in the recording studio. I'm used to the instant response of analogue scopes and I can see the latency issue driving me nuts.Third is vertical resolution. 8-bits is really a joke. 256 increments compared to whatever the phosphor-dot density of an 8x8cm analogue screen? I see people in your threads here wonder why someone wants 12-bit or more resolution? Well, I do but I don't need that resolution out to 100MHz; rather, for the audio band plus a bit more - 100kHz would be fine but you do need reasonable resolution into MHz to find certain noise and transients.Having a VGA output is a PLUS as it gives you an inexpensive way to have a much larger monitor than the tiny display. Most screen shots I see of DSO displays in action have all kinds of text and data around the perimeter and it would be nice for all of this AND the waves to be easily read even with my eyes.I saw the Keysight G-version scopes can do Bode plots, which is pretty nice.But you have to spend 300$ over the base model to get that and still it is an 8-bit 50MHz scope.I'm leaning towards an Owon scope since they seem to offer the best resolution at the lowest price.Does anyone know how long these things should really last?

author: metrologist
author_rank: Super Contributor
timestamp: September 12, 2018, 07:51:11 pm
content: They should have a three year warranty, maybe 5 for something expensive. Beyond that, use is luck of draw. Market is going to make it obsolete in 2 years probably as we progress.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 12, 2018, 08:04:33 pm
content: HiSome warranties are shorter, but even with a listed warranty of three years say, most have to be shipped back to China especially if you buy through Aliexpress (I see better deals there than at Amazon).You would hope the unit survives the warranty period but do you have to look at it as the manufacturer's claim of life expectancy? "It will last 3-years" then it dies a day later... My old scope probably only had a one-year warranty but it lasted 30-yrs - the second was 1-yr and lasted 1.5-yrs. I know it is the luck of the draw - you get a good one or you get a lemon.I don't use Amazon since they falsely accused me of taking payment for reviews. When I asked about this, I only got form letters and then they withdrew all my reviews. So, I'll never buy anything there gain.

author: nctnico
author_rank: Super Contributor
timestamp: September 12, 2018, 08:18:48 pm
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmI doubt you get much more resolution from a CRT screen. There are noise and non-linearities in the vertical amplifiers.The best warranty I'm aware of is offered by GW Instek. On (some of) their scopes the warranty ends 5 years after they stop producing the particular model.

author: Gyro
author_rank: Super Contributor
timestamp: September 12, 2018, 08:24:50 pm
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmYou'll normally find that it is the LCD resolution that actually limits the visible vertical display resolution rather than the ADC. Especially once you've got multiple channels displayed, on-screen options showing etc.

author: DaJMasta
author_rank: Super Contributor
timestamp: September 12, 2018, 08:32:35 pm
content: Plenty of people will complain about the quality of Chinese made inexpensive scopes, but I don't see any reason why you'd expect them to fail in the near term. Perhaps the likelihood that they make it to a decade and are still going strong is not as good as from other makers or from eras when overengineering was more common (and the price reflected it), but I expect a good bit of my gear to last a decade with minimal maintenance, though my use case is far from 24/7/365.If you're looking for stuff with a brand name, like the Owons you mention, there are reputable test equipment vendors that sell them as well which can offer their own warranty policy or information. A company is only going to warranty what makes sense for the lifetime of the parts inside and what parts they want to have in storage, and with increasingly more integrated and less serviceable designs, it's harder to expect that distant support... so the warranty periods aren't that extensive, even if the parts have plenty of longevity.In terms of failure modes outside of improper use, a modern scope is probably dependent on electrolytic capacitor lifetime, screen backlight lifetime (if a CCFL, at least), fan lifetime, or maybe rotary encoder lifetime. Provided it's been designed well thermally, the reliability of construction is generally very good (and lead free solder is a VERY well understood process since it's used extensively in modern electronics, even if it's a pain to get right initially), and the lower power solid state parts used are probably more reliable than many of the solutions in equipment from the 80s or 90s... so there's really nothing making me expect that some of my newer gear won't be operational in 2025 or 2035.As for your particular use case, there are some 12, 14, and higher bit options around - some of the newest scope designs are 10+ bits, and picoscope (PC based, but also big screen friendly) has been offering high resolution converters for quite some time. You can also adjust your range switch and coupling to see very small details in most signals, so while the dynamic range of an 8 bit scope is quite limited, you can often still see very fine vertical detail. There's also the option of getting audio specific DAC/ADC gear and using a software suite to get the displays you want - there are many options for getting bode plots on 24 bit audio signals using mid to high end sound cards and software. There's also an increasing connectivity factor in some brands, where you can take a scope and plug a function gen into its USB port and have them coordinate automatically for bode plots and such. Siglent has some options like that, but I think R&S and Keysight in particular have made a move towards this kind of integration, though you certainly spend for it.If your tests aren't concerned with phase, you could also get your bode plot from a simple white noise generator and the FFT function on almost any modern scope. You'd have plenty of sample rate for enhanced resolution mode for such a low frequency signal range (usually 1-2 more effective bits), and the newest generation of scopes can manage a 1Mpoint FFT for very fine frequency detail.You shouldn't have delay issues using a scope. If you use a USB one and you have some application where you need to see the signal in realtime, you may run into issues, but generally speaking, the waveform updates per second of a current generation scope are high enough that the delay from measurement to the screen is less than the several ms delay a lot of DSP hardware has, and I can't think of an application where syncing the visual with the input is all that important. If you need to check alignment of very fast changes, there's always single shot mode, and if you're trying to coordinate a signal generator with what you see (for some reason), you can always just output a trigger signal from the sig gen to exactly align where the pulse was generated with what's being recorded on the scope. Since a scope isn't really a tool for processing and replaying signals in realtime, it's for visualizing continuous ones and capturing fast transient ones, I don't think you'll ever run into the sort of 'round trip delay' issues you'd have with a DSP based audio recording and playback system.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 13, 2018, 09:38:34 pm
content: HiThat's a lot of good information.I have no problem with buying stuff from China since their quality is whatever you are willing to pay for. The difference is their honour-system is a little different than in the west, but once you navigate that there are no issues. On the other hand, some of the US brands seem to charge a lot just because they are domestic and it props up their reputation to charge a lot. Keysight offers 3-yr warranty upgradable to 5-yr; maybe Techtronix does too. I had to look up Keysight's history to find out they were a spin-off of HP (Hewlett-Packard), so they are quite respectable, but...There's a colloquial thought about linear versus digital/switching gear, sort of related to heart-beats in animals. Animals with fast heart rates seem to live shorter lives than animals with slow heart-beats; one theory being that everything has 2-billion beats and then it is done. If the same is true about 60Hz transformers, say, versus switch-mode supplies, then the linear item lasts forever compared to the SMPS. This is true with inverter welders compared to transformer-based ones, and when you look at the life cycle of computer-based stuff there seems to be a similarity. maybe it is just the "fitting the observation to match the theory" syndrome? But it makes me a bit concerned about DSO life since most of the internals operates at high clock speeds.If I could count on 10-yrs from the OWON with its 3-yr warranty that would be great! If it were that I could only count on 3-years for the 3-yr warranty it is less great but acceptable considering the accelerated development for these products, i.e. there might be 16-bit or 20-bit units out by thenMilliseconds are noticeable on the human scale, but maybe it does not matter for the scope application as you suggest.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 13, 2018, 09:49:36 pm
content: The analogue scope that died six months after its warranty expired is a GW Instek. I have a function generator from them that is over 20-yrs old, so I expected better from the scope.It turns out the company I bought the scope from does free repair estimates although it still costs me $80 to send it there and $80 to get it back. I'll get it fixed but still think I'll get a DSO, too

author: bd139
author_rank: Super Contributor
timestamp: September 13, 2018, 10:04:17 pm
content: I've got a 1998 Tektronix TDS210 still going strong.If you want something good for audio it might be worth looking at a Digilent Analog Discovery 2 instead of a normal DSO. That'll give you 100MSPS but 14 bits, AWG, plus network and spectrum analyser with THD, noise measurement capabilityhttps://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/

author: DaJMasta
author_rank: Super Contributor
timestamp: September 13, 2018, 10:36:36 pm
content: Timing and speed are the strength of scopes, just as voltage precision is the strength of DMMs, so the advances in scope technology have been increased resolution (sample rate), increased storage, and increased processing to get that from the acquisition system into meaningful information to the user. Personally, I haven't seen any correlation between operating frequency and expected lifespan. There are some things that may superficially seem like that, but which end up being a different root cause than just frequency - a part being used on the edge of its thermal limits or at the edge of its drift parameters to maintain spec, an exotic material that's more sensitive to vibration, voltage fluctuations, etc. - it's basically never the signal frequency that causes damage, it's the tighter tolerances required for high speed devices requiring more sensitive devices, the heat associated with power requirements for operating fast, or other factors. Especially in these mainstream range scopes, the designs are very well understood because their features are no longer leading edge, but that means that it's a much more manageable task to put together a working system because the performance tolerances available in the parts are much broader. Some of this is eaten up by cost reduction, for sure, but a 200MHz frontend of today is going to fairly versatile and robust, whereas a 200MHz frontend 30 years ago was a specialty device made of exotic materials. What used to be large, hot running ADCs made on ceramic hybrids are now off the shelf chips in a 10mm square BGA that can be passively cooled, even when operating faster, even though the package is significantly easier to design around and is more durable in the long term. I guess my point is, just because it runs fast doesn't mean it's unreliable - we've gotten good at making fast stuff.Any usage lag you run into will likely be limited by LCD screen refresh rate at any time scale small enough to fill the screen quickly (100ms per division still takes a second for an update if you're 10 divisions wide), but if you zoom in all the way with full sample rate on a modern inexpensive scope, you can easily see single digit nanosecond level alignment precision. Enough so that if you had a 1m scope probe lead and a 2m scope probe lead, the timing difference between the two measuring the same source would be obvious.Also worth mentioning that bit depth probably won't jump a staggering amount. We've been stuck at 8 bits for a couple decades in the mainstream, and are only now seeing 10+ bit converters standard in regular scopes. There's also sort of a limit on how quiet a signal can be made - even 24 bit audio converters only get 19 or 20 effective bits with a bunch of noise because of the limits of thermal noise and other sources - these very high resolution converters are also much slower than the sorts used in scopes, so it's unlikely to see audio resolution ADCs running at 1GS/s+ any time soon, let alone having them be built into mainstream scopes. You can get better effective resolution out of averaging, oversampling, or other techniques, though, so you can get some very low noise signals from captures of a repetitive signal, even on an 8 bit converter.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 14, 2018, 12:20:59 am
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmi cant tell about other digital scope such as Owon, Keysight, Hantek, Siglent etc, even my own 3 years old Rigol DS1054Z, but i can tell about my DS1052E that it still works for 9 years now, next year it will be its 10th year anniversary (geez time is too short), and its with my brother now.Quote from: Sylvi on September 12, 2018, 07:02:00 pmyou clearly havent used a digital scope before. there is no such thing as latency or 256 steps joke. what you hear is hearsay or exaggeration from idealists, people want 12 bits scope because they are in multibillion dollar business building high end stuffs, so they want the best THD or FFT reading out of the scope, and they certainly can afford or easily justifying things like$9600 CS448 14 bits Isolated Oscilloscopeand they will buy another one if they have to.Quote from: Sylvi on September 12, 2018, 07:02:00 pmmeet$5500 Bode 100 Vector Network Analyzer. if you really care about $300, you may get a $400 scope like DS1054Z and a $100 PC controllable function generator, learn programming and make the bode plot on a 30" PC monitor.

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2018, 12:31:08 am
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmYes and no. DSOs do clever signal reconstruction and can average multiple waves together to improve those 8 bits. In reality, 8 bits is probably as good as your analogue 'scope when it comes to viewing a nice periodic wave on screen.Of course they have a limited number of pixels on screen, you might be able to see those.Quote from: Sylvi on September 12, 2018, 07:02:00 pmThere's not much data on that yet... because they simply aren't dying.

author: Bassman59
author_rank: Super Contributor
timestamp: September 14, 2018, 12:44:33 am
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmExcept, no, SMT stuff built with lead-free solder is not garbage.I have a Tek TDS2024 (original, not A, B or C) at home, bought it new in 1999 or whenever, and it's as good as new. No issues at all. I use it for audio work, and for microcontroller/digital work.An HP1661E logic analyzer is on my bench, again all stuffed full of SMT, works like a champ, except that it's kinda big and anyway everything I do is FPGAs so there's no call for a traditional benchtop logic analyzer any more.

author: james_s
author_rank: Super Contributor
timestamp: September 14, 2018, 04:01:16 am
content: I have several DSOs that are ~25 years old and they still work fine. I had to replace some power supply capacitors in a couple of them, attenuator relays in my TDS784 but that's about it. Overall they have been as reliable as my analog scopes.8 bits of vertical resolution is plenty unless you are doing something really specialized. I doubt you'd be able to see the difference side by side between 8 bits and 12 bits in most cases.

author: joeqsmith
author_rank: Super Contributor
timestamp: September 14, 2018, 04:32:57 am
content: Quote from: james_s on September 14, 2018, 04:01:16 amMy LeCroy 7200 is about that old. It still runs fine. I've had a few tant caps go bad in it but no other major problems.Looks like OP is asking about a specific scope. I don't have anything that new.OP, if you are happy with an analog scope, why not just stay with that technology?

author: tautech
author_rank: Super Contributor
timestamp: September 14, 2018, 05:24:58 am
content: Quote from: joeqsmith on September 14, 2018, 04:32:57 amThat's certainly the simplest instead of needing to teach one eyed old dogs new tricks !

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2018, 12:59:37 pm
content: Even low end DSOs need solid metal shielding and chassis inside. The first time you pick one up you'll be, like, "Damn, that feels solid". No twisting or creaking here.eg.This $350 model:Lead-free is horrible for use with soldering iron but they've got it figured out at an industrial level. It's all about temperature.

author: rstofer
author_rank: Super Contributor
timestamp: September 14, 2018, 02:37:09 pm
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmI'm pretty sure the PC you typed this on used SMT and lead-free solder. Nobody seems concerned.If you want real resolution and a really attractive price, consider the Analog Discovery 2. There's a dual channel 30 MHz scope with 14 bit resolution. More important, it will do Network Analysis directly using its internal signal generator (it has 2 arbitrary waveform generators capable of 12 MHz).https://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/For folks interested in Audio, this seems like an attractive tool. You would need the BNC adapter board in order to use scope probes. For vacuum tube technology, you would need 100:1 probes but that would be the case for any other scope.Don't overlook the advantage of a 27" display.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 14, 2018, 05:47:32 pm
content: I really appreciate all the good info and experience you guys have!I've only ever used analogue scopes, so I am used to seeing that smooth wave representation and instant response. Recording studio exposure to digital audio products and their time-lag pitfalls made me concerned about digital scope response inasmuch as being able to see things instantly when probing around a circuit. From what you say here, the sample rate and screen refresh times should be quick enough for that to be a nonissue.A friend has a Fluke handheld scope that he raves about, but he often works on ladders and other barely accessible places sussing out audio installation issues. he is happy to see a signal and maybe if it is clipped or not. part from that, i don't think he is looking for deviations from sine that interest me. Otherwise, the display on his scope looks dreadful to me, and he has an anolgue scope on his work bench.The USB scopes are interesting since modern computers are tiny and most packages like the Picoscope are built with proper BNCs in a box. That Digalent item seems like a toy in that regard. I'm not a programmer type and have some trepidation about navigating the software needed to use these and don't want using the thing to become a whole research project unto itself - my time is already amply filled - haha. Plus, scrolling through menus to make a basic measurement has no appeal at all - a unitised DSO seems like a better way to go for me.I don't have a lot of money to spend on a scope right now - or on anything - and that makes trying to pick one out a bit harder, especially after having my new-last-year scope die already. If there was a good way to know the real life expectancy of these things it would be worth stretching the budget to get something a bit better than something merely functional. I guess I'm trying to skip the "starter-DSO" step and go directly to what would suit me for a whilePart of the problem of a tight budget.My reference to the heart-beat analogy was not to say that the signal will damage the scope or wear it out; rather, the internal clock of the circuit is doing that on its own. Yes, I have computers here that are older. My 2012 Linux continues to lose functionality and because of its OS security level is denied access to more sites every month (the OS is not supported since a few years ago). Because of that, I am writing this on a Chrome desktop bought last year, but it too has already lost some functionality. Many of the problems with these things is the software but I do use them many hours a day - sometimes they are running all day. Surprisingly my offline computers are way more solid.

author: DaJMasta
author_rank: Super Contributor
timestamp: September 14, 2018, 06:28:42 pm
content: Not just on the front end, frequency specific aging does not happen in solid state devices.Take the same chip from the same batch and run one at 500MHz and run the other at 100MHz - provided the 500MHz is still within spec and the core temperature and other environmental aspects are the same, they should last for the same time. There's an analog with mechanical components, but solid state devices don't have the same base wear and tear from usage, so the comparison isn't really valid. If you're looking at bleeding edge vs. bleeding edge, then maybe the lifetime is comparable with that of 30 years ago, but if you're looking at the same frequency then vs. now, the now will be more reliable and less expensive to implement, and though the comparison is a strange one, you can certainly get more speed for your life expectancy out of a modern component over an old one when they're designed for the same thing. Semiconductor failures are almost always about heat - even ESD events are about localized spikes burning through tiny transistors.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 14, 2018, 06:29:05 pm
content: Quote from: Sylvi on September 14, 2018, 05:47:32 pmthats not your problem. your problem is you never used a digital scope before. dont worry, just get a Rigol DS1054Z and you'll never look back. everybody had their chance with analog scope as you do at some point in time. you may also get Siglent scope if bode plot is important to you, at a little bit pricey, and you need to buy their function generator as well, so combined may cost you near $1K i guess. Keysight? Rohde Scwarzh? more money you probably need to sell some part of your house for them leaving your house a big hole.DSO is not a digital audio instrument, DSO (same as CRO) just take the signal and display it at sub micro or nano second delay, you will not be able to notice even it is ms delay. digital audio instrument need some heavy math real time post processing or some delay filter before you can hear the output, so they are different function you cannot compare them.Quote from: Sylvi on September 14, 2018, 05:47:32 pmFluke famous because of safety feature, he doesnt want falling from ladder due to electric shock from short circuiting or sparking instrument. thats why probably they bought the Fluke. and yes, anything of that size and class will look terrible on monitor, even 5 digit price class i guess. there are cheaper version of handheld DSO and isolated input that looks nice on monitor, but they are not palm size so it will be awkward to bring up the ladder.Quote from: Sylvi on September 14, 2018, 05:47:32 pmprepare for laggy display on Picoscope, the reviews in youtube show not that great refresh rate signal. get rigol or siglent "unitized" DSO you wont look back. you can google the review in youtube to see how fast they are at showing signals.Quote from: Sylvi on September 14, 2018, 05:47:32 pmformat them and they will be as good as new, send to PC shop if you dont know how to do it yourself. the lagginess thats because modern OS are shit they want automatic internet update everytime. only few weeks or few times of use from newly installed, and they will be like shit slow, yes my Win10 machine is like that. i reformat my WinXP machine every 2-3 years and believe me WinXP is the lightest OS on the planet for the functionality and i still need to reformat it because performance (softwares) is deteriorating. my WinXP machine is 10 years old now after changing PSU twice, its not game grade machine is cheap to medium price hardwares.btw... how is Al-Sisi?

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 14, 2018, 07:11:14 pm
content: Quote from: Mechatrommer on September 14, 2018, 06:29:05 pmLaggy is relative. Some stuff that may make it laggy is outright impossible on most scopes. I made 2408B laggy (2Hz) running2x2Mpts FFTIt is "analytical" scope if you wish, not so much "DPO". So if no need for high frequency and want to learn about digital signal processing there is 2204A which is less than 100EUR w/o probes and has full blown sw with many decoders etc. I started with 25MHz 2205 and its still going strong after 8 years. If want just DPO (digital phosphor) and keep it more along analog lines then look GW Instek GDS-1054B, which is very properly done thing, if too expensive for 50MHz look Siglent SDS1104X-E. Rigol is more for Arduino/digital tinkerers since it works best with digital type of signal (analog ones may get bit distorted at times...), but its cheap

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2018, 08:15:01 pm
content: Quote from: MrW0lf on September 14, 2018, 07:11:14 pmWhat sort of analog signals will distort on a Rigol but no others?

author: nctnico
author_rank: Super Contributor
timestamp: September 14, 2018, 08:30:15 pm
content: Quote from: Fungus on September 14, 2018, 08:15:01 pmI guess MrW0lf is referring to the sin/x interpolation not being correct. This is a bit of a fail. BTW the GDS-1054B MrW0lf is referring to can be unlocked to 300MHz and have protocol decoding as well.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 14, 2018, 08:30:48 pm
content: Quote from: Fungus on September 14, 2018, 08:15:01 pmResponse is clearly not Gaussian (analog scope like) over 50-60MHz with all channels on. Coming from analog scope Gaussian response would be much preferred. If interests lie below 50MHz or are limited to max 1-2 channels over 50MHz no prob.

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2018, 08:54:45 pm
content: Quote from: Sylvi on September 14, 2018, 05:47:32 pmNobody will argue the analog 'scopes aren't pretty.DSOs can do so much more though.Quote from: Sylvi on September 14, 2018, 05:47:32 pmYou have to spend a lot of money to get a "good" picoscope (one that's worth having).Quote from: Sylvi on September 14, 2018, 05:47:32 pmTrue, but better boxes can be made and it's a really powerful device.Signal generator and 14-bit oscilloscope in one unit and really nice software. The only downside is that you need to be connected to a PC to be able to use it.(that's true of Picoscopes, too)

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2018, 09:02:17 pm
content: Quote from: nctnico on September 14, 2018, 08:30:15 pmThis was discussed in the other thread over the last few days. The real problem is that an unlocked DS1054Z can have an analog bandwidth too high for the 250MSa/s you get with four channels turned on.250MSa/s gives a Nyquist limit of 125MHz and a DS1054Z caneasilygo past that (we were seeing one 'scope with a response close to 200Mhz in that thread).The non-gaussian response came from the analog circuitry being too good!For audio work you'd probably want the 20Mhz bandwidth limiter on most of the time anyway (or just don't unlock all the extra bandwidth, stick with factory supplied 50Mhz).

author: nctnico
author_rank: Super Contributor
timestamp: September 14, 2018, 09:16:07 pm
content: Quote from: Fungus on September 14, 2018, 09:02:17 pmWith the hack you have the choice to lower the bandwidth or not. Besides that the GDS-1054B can do input filtering so the input signal can be filtered further to get rid of unwanted noise.

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2018, 10:19:28 pm
content: Quote from: nctnico on September 14, 2018, 09:16:07 pmYep. The bandwidth can be unlocked/relocked very easily (I mention this for the newbies, I knowyouknow that).Quote from: nctnico on September 14, 2018, 09:16:07 pmThe recent GW-Instek hacking is quite interesting. 300Mhz front-end with only a single 1Gs ADC is a bit much though. Even in 2-channel mode you're well above Nyquist.Maybe 70MHz would be a good unlock option on these 1GSa/sec scopes. The analog front-end have way more than advertised bandwidth so a 70Mhz unlock would actually give them something close to 100Mhz. This would keep the input signal below Nyquist and avoid Wolfie's concerns.Then again: With 1 or 2 channels enabled the problem vanishes so why limit the device? When I have four channels on I'm usually looking at digital stuff so I don't really care how Gaussian it is. YMMV but a 70Mhz unlock might suit analog guys who want to look at 4 fast signals simultaneously.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 15, 2018, 04:27:41 am
content: I was trying to find out what the "resolution" of an oscilloscope CRT is but could only find a reference to the front face having a phosphor coating. "Coating" suggests an evenly applied film rather than a pixellated application, like the dots for a TV with specific beam positioning. A scope can have a randomly positioned dot on the face, as far as I can tell, which contributes to the smooth wave presentation. I don't believe you can ever get this with the modern monitor resolutions unless it is a high number of pixels and a smallish screen?

author: DaJMasta
author_rank: Super Contributor
timestamp: September 15, 2018, 04:44:35 am
content: Small dot pitch does it, but you can map a dot to multiple pixels, using reduced levels at adjacent pixels. This is effectively how a CRO display works, since while you have analog positioning, you have a finite minimum trace thickness and on a smaller scale a finite positional accuracy given the noise level. Let's say your CRO trace dot is only half a millimeter wide, which may be smaller than a pixel on some equivalent digital display, it's still going to slightly illuminate the phosphors around it, giving a little hotspot of light. The dot can be mapped the same way to a panel of pixels, and it would look fairly equivalent.This isn't a hugely important facet, though, as if you want to see that very fine detail of the height or contour of something, you just go to a lower voltage or time scale to see the detail. Modern digital scope screens definitely do a better job, being higher resolution and actually blending the pixel to represent its place instead of a direct mapping to whatever pixel it falls in, as older digital scopes often did. Take a look at the older DS1052E screen for the unblended screen style has a bit of a more noticeable issue that you're describing, but looking at the newer DS1054Z screen looks a lot smoother because of the increased resolution and better blending, as does something like the SDS1204X-E, which has some very analog-looking persistence display modes in a lot of their promotional pictures (and it does look like that in use).

author: maginnovision
author_rank: Super Contributor
timestamp: September 15, 2018, 04:52:09 am
content: Not to mention an 8 bit adc is an 8 bit adc regardless of your display. If you like how it looks fine, but even if you assume infinite resolution it's still displaying the same 8bit data.

author: tautech
author_rank: Super Contributor
timestamp: September 15, 2018, 05:16:19 am
content: Quote from: maginnovision on September 15, 2018, 04:52:09 amWhich at the normal scope+3% accuracy can be better than parallax errors introduced by etched or overlaid graticules on a CRO.There's NO parallax graticle error in the modern LCD DSO.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 15, 2018, 06:22:38 am
content: Quote from: Sylvi on September 15, 2018, 04:27:41 amit doesnt have any practical implication/improvement if you have analog/continuous moving electrons on the screen, relatively speaking. yes yeas we can argue untill the world ends that people built spacecraft using CRO, but but we forgot, people also built better spacecraft using DSO. load the attached picture below to your screen, make it (zoom) 15.6cm wide exactly by the ruler, thats how you are going to see our DS1054Z screen, its 800 pixels wide hence 156mm / 800 = 0.2mm per pixel give or take, you need a magnifying lens to see those pixels. does it matter? you should mourn about the PC monitor you are using right now it has a lot bigger pitch than that and start looking for phosphor tv which i believe is totally extinct by now. but i think you still can make tv out of the analog scope, search member w2aew for consultancy on how to do that and you may enjoy continuous phospor stream of greenish monochrome youtube play. its all about visual perception, and nothing wrong with digital monitor in that respect. and then btw, try to configure analog scope to show single line (pixel or 0.2mm) of signal trace with good visibility, good luck!

author: Andreas
author_rank: Super Contributor
timestamp: September 15, 2018, 06:58:12 am
content: Quote from: Sylvi on September 12, 2018, 07:02:00 pmHello,a PicoScope 4262 has 16 bits and low noise ideal for audio applications.Higher bandwidth (and noise) is possible with the PicoScope 5000 series (14-16 Bits).Bode plots work at least on my PicoScope 5444A with the FRA-Tool.https://www.picotech.com/library/picoapp/frequency-response-analyzer-with-bode-plotswith best regardsAndreas

author: iMo
author_rank: Super Contributor
timestamp: September 15, 2018, 08:20:55 am
content: https://en.wikipedia.org/wiki/Planned_obsolescence

author: 2N3055
author_rank: Super Contributor
timestamp: September 15, 2018, 09:28:40 am
content: What Andreas said..And if you have decent PC, Picoscope is fast enough to be interactive... Combined with a huge screen, easy to see.. It has many measurements and features from high end scopes that cost 20000€ +.As for planned obsolescence, i still have my first Picoscope from 2003, 12 bit ADC212/100. They kept providing software updates for it until February 2016, and then they stopped because it is parallel port product. All software updates are free, and in those years, that little thing gained many new features, like decoding of dozens protocols, persistence mode etc etc...If you only want to see wiggly lines on the screen, for general troubleshooting purposes, ANY scope will do.If you want to measure things, you need more than 8 bits. And you need software to measure it.For audio work cheapest thing that is VERY useful is Analog Discovery II. If you want to have really good results, go with one of the Pico high bit devices. PicoScope 4262 is good enough that you don't need separate audio analyser. ADII is probably too for general work.Ideally, you would need something like Rigol DS1054Z (or equivalent) for "scoping" and AD II or PicoScope 4262 (or one of those audio analysers ) for measurements.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 15, 2018, 09:45:43 am
content: Quote from: Fungus on September 14, 2018, 09:02:17 pmThink if you tried similar scenario on GWI or Siglent results would be somewhat different, seems it has to do with trigger circuit and how it fights with jitter. So dont be shy your scope is sort of special it has mind of its own so to speak.

author: Gyro
author_rank: Super Contributor
timestamp: September 15, 2018, 09:57:22 am
content: Quote from: 2N3055 on September 15, 2018, 09:28:40 amLikewise, I still have, and use my old 16 bit ADC216, the SA mode is perfect for low distortion audio measurements. Luckily I also have the sought-after Pico USB-Parallel converter - actually provided to me for free when I complained that it would only work on LPT1Later they updated the S/W to work with PCI parallel ports.The USB-Parallel port converter was only discontinued when they could no longer source the 52 pin Cypress CY7C64613, very simple circuit otherwise.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 19, 2018, 02:14:35 pm
content: HiThanks for the advice and info!After a lot of looking at manufacturers' sites and at stores on Aliexpress, and Mouser, I decided to get the OWON XDS2102A which is 12-bit 100MHz and has a VGA output. It can connect to a pictbridge printer, too, and LAN, although I don't think I'll need the latter except to update the firmware? Some vendors show pics of the scope with or without jacks or features contradicting the product description, and then either never answer emails or are really slow to answer. The particular one I bought was on sale at about 35% off the store's regular price. Whether that is list price who knows?OWON's little videos were helpful, especially since they have the dialogue on-screen since my computer doesn't have sound. They show the difference between 8-bit and 12-bit resolution, and between software-enhanced to 12-bits versus hardware 12-bits. I looked at the Sigilant site which is awful and decided against those - really, I was already leaning towards OWON anywayI also got some x100 probes for looking at tube circuits.I thought the unitised oscilloscope would be better for me at the moment given the comments about scrolling through menus and latency of USB scopes. I know their are menus to deal with in the stand-alone DSOs, but I only have to get used to one machine. I won't really know if another brand is "totally superior and easy" compared to this until maybe a few years down the road if I get another one.It's pretty exciting to be getting some new test equipment and to move into the 21st centuryOne note about the 8,12,14 bit mention on some of the stores selling OWON:If you look first at OWON's site and see the list of the benchtop oscilloscopes, the bit resolution is listed beside all the scopes except in the model ranges where they are all 8-bit. So, in the XDS-E range, there are some models that are 8-bit and some that are 14-bit; then in the XDS-N-in-1 range there are 8,12,14 bit models. Some of the stores selling these just rip all the data without putting it in a chart, so the main product description might say that the model being presented is 8-bits or whatever applies, but then the broad description below says 8,12,14 - which can be a bit confusing.

author: james_s
author_rank: Super Contributor
timestamp: September 19, 2018, 08:58:19 pm
content: Quote from: Sylvi on September 15, 2018, 04:27:41 amIt's true that you'll probably get a smoother "prettier" waveform on an analog CRO than you will on just about any DSO, but is that really useful? If I asked you to tell me the frequency, peak amplitude, RMS voltage and duty cycle, etc of a waveform could you really give me a more accurate answer using a CRO with infinitely high resolution when you still have to count ticks on a graticule? If I give you a black box that randomly produces one of 256 voltage levels can you look at it with a CRO and tell me which of those 256 levels it is outputting at the time?A CRO is a thing of beauty and I'm still fond of the "real" feel you get when using one, watching the beam paint the waveform in real time, zero lag, nice clean sharp trace, it looks great, but after using a DSO for a couple years I'd have a hard time going back to analog full time. I mostly keep my 465B around for the XY mode which really is far better than my DSO has but that's an edge case.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 20, 2018, 02:02:03 am
content: James-s: The thing that bothers me about the "pixelly" (but not Pixley) look of DSO waves is that if I saw the same wave on a CRT I would think there is a high frequency riding on top of the low frequency. So, the smoothness of the wave tells you something about the purity of the signal, and that is something relevant to what i do with a scope and the type of equipment I work on.So, I chose the 12-bit OWON to have 16-times the resolution of an 8-bit scope; the jagged look is suppressed as the videos show.I will still have to get used to whatever menus and such like it takes to get to just seeing waves, let alone capturing them (and teaching them to do tricks?), printing them, doing math, etc., but at the moment I'm excited having it ordered. They still have up to seven days to ship it and then 9-16 days transit. As soon as it gets here I expect to be cursing it for being so darn complicated - haha - but once you get over the hump it will be great again. I'm sure i'll be back with Qs when I'm trying to do the basic things you guys probably take for granted nowI can't believe I spelt "their" instead of "there"!

author: james_s
author_rank: Super Contributor
timestamp: September 20, 2018, 03:43:23 pm
content: In many cases you would be right to assume there is high frequency riding on the waveform giving the DSO trace a fuzzy look. You should watch Dave's video on why DSO traces look noisy. The CRO is hiding things from you due to limitations of the way it works. The end result is a nicer cleaner looking waveform.

author: Fungus
author_rank: Super Contributor
timestamp: September 20, 2018, 03:49:55 pm
content: Quote from: Sylvi on September 20, 2018, 02:02:03 amThere usuallyisa high frequency (noise), it's just that the CRO is hiding it from you:DSOs have a 20Mhz (or thereabouts) filter that you can enable to get them back to CRO noise levels.

author: GregDunn
author_rank: Frequent Contributor
timestamp: September 20, 2018, 05:06:43 pm
content: Quote from: Fungus on September 20, 2018, 03:49:55 pmSpot on. In college, we had mostly Tek 503 scopes with a bandwidth of under 1 MHz; they worked OK on audio signals and looked pretty good. Later, when I was working in the electronics industry, we had a few Tek 545s and 555s (20 MHz or higher bw depending on plugin) and I noticed how noisy they looked in comparison. Moderns DSOs typically run from 50-200 MHz (comparable to something like a 465), so of course you're going to see more of the crud which the older tube-based vertical amps couldn't pass. As Fungus said, if you want a smoother trace, switch in the filter and it will look better - at the risk of not seeing parasitic oscillations, induced noise, etc.

author: bd139
author_rank: Super Contributor
timestamp: September 20, 2018, 06:16:10 pm
content: Also if you have a DSO most of them have a sample averaging function. That will give you the same lie that analogue scopes like to tell.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 20, 2018, 06:58:54 pm
content: I think some of the comments about CRO vs DSO are naive or unsubstantiated.My CRO was 50MHz, so a lot of high-frequency stuff is visible even if the very highest of it was being attenuated by the scope's roll-off. Others here had and have CROs with much higher bandwidth into 100s of MHz and more, so my comment from post-19 still stands and is a reflection of my own experience. If your CRO experience is only with 1Mhz scopes - which I've never seen - then you could justly feel that DSOs are light years ahead of CROs in all aspects of what a scope should do. At this point, I don't believe that.Have you ever seen superimposed waveforms? The 8-bit wave looks like a high-frequency riding a low-frequency, so suggests more than one frequency is present. The fact is, that the 8-bit scope fed with a single pure sine wave will produce that output NOT because there is a "noise" frequency present; rather, it produces that output because it is not capturing the entire wave. It is a limitation of quantisation. The only way to reduce this error is to have many more increments of measure available and that means having more bits. It would be awesome to have 24-bit resolution like an Audio Precision, but the cost of this into the MHz range is prohibitive.I guess we'll have to agree to disagree.CROs may be being obsoleted but they still have advantages for linear testing. DSOs and DPOs and all the clever processes involved and advances in technology can make the digital display "good enough" for most things, but that can be perceived as a tiny erosion of expectation - something that happens in every aspect of our modern life where technology is involved, or worse, is central to the situation. Politeness is eroded with texting. Emails are already a pretty cold medium and emoticons can help assuage that. Having to look at jagged waves when you expect smooth ones erodes your confidence in what you've built and/or in the tests you do.I love this forum and all you guys that are so knowledgeableYou made buying a DSO a lot easier.

author: Old Printer
author_rank: Frequent Contributor
timestamp: September 20, 2018, 08:51:32 pm
content: I just looked at the spec sheets for a couple of Keysight's, a 4000 & a 6000 series, that ran anywhere from 1 to 6 Ghz and $15,000 to 25,000 USD. They are all 8 bit and these are some pretty serious scopes. I am curious to see how much difference you will see with the extra 4 bits in a sub $500 scope. I don't have any experience in audio use of a scope, so hopefully I will learn something here.

author: bd139
author_rank: Super Contributor
timestamp: September 20, 2018, 09:06:45 pm
content: Personally I think 8 bits is fine for a scope. A scope is pretty much just a good time domain diagnostic tool but a crappy analytical tool. If you want an analytical tool, it's worth looking into something specifically designed for the use case. Spectrum analysers, distortion analysers etc. Or pay for a high end MDO with SA built in.

author: nctnico
author_rank: Super Contributor
timestamp: September 20, 2018, 09:55:00 pm
content: Quote from: bd139 on September 20, 2018, 09:06:45 pmI don't agree. I have a 10 bit scope on my bench and the FFT is much more useful compared to an 8 bit oscilloscope. Sure I could pull out a spectrum analyser but for a quick look the FFT function on an oscilloscope is just easier. Also you can see both time and frequency domain signals on an oscilloscope which has FFT.

author: bd139
author_rank: Super Contributor
timestamp: September 20, 2018, 10:11:03 pm
content: If course it is. However if I was going to do that, I'd probably buy an Analog Discovery 2. That has 14-bit 100MS/s which is better price/performance ratio than standalone digital scopes of any class:https://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/

author: Sylvi
author_rank: Regular Contributor
timestamp: September 21, 2018, 03:29:25 am
content: The AD2 was referred to previously: it is a toy with no proper connectivity. Electrically it has merit, but only 30MHz bandwidth and 14-bit. Were I going to get a USB scope and deal with its latency issues I would get the Picoscope 16-bit unit, which also has limited bandwidth and is a lot more expensive but is aimed more at audio work.Alternatively, there is Dr.Jordan-MLS and similar that use 24-bit sound cards, but then you have uncalibrated inputs and outputs to deal with and the silly 3mm jacks to adapt to.The stand-alone DSO as it is today seems to have a very quick probe-to-display time, which used to be much worse and was one of the things that kept me from going with a DSO when my first CRO died and I replaced it with an inferior CRO still in production last year. That one died at 18-months of age and will be fixed once the OWON arrives and I get it working for me.Whether you have or get a USB scope, a DSO, or a used scope of any kind, it will be a novelty and allow you to explore and do new things. So of course it is great! If you get serious about whatever you are doing, then you will move towards the "real deal" for whatever that niche demands. For example, the digital channels on all these USB scopes and DSOs seem to only be able to handle TTL voltages at best, and some are only 3V or so. That is actually fine if all you look at is recent production digital. I'm old school and use CMOS at 9-15V in hard-ware-only circuits when I need something "digital". Even though the chips are capable of high speed, my applications are distinctly ultra-low speed inasmuch as they are logic for channel selection, on/off muting and similar things in audio equipment. So, the digital inputs on modern scopes are useless for what I do.I'm not an RF guy, nor do I have a complete handle on all the DSO specs, but I believe that for those very high bandwidth apps, like GHz+ scopes, the low-bit converters are the only ones fast enough to do a capture AND the sample rate must be extremely high AND the memory depth must be higher than for a mere 1-200Mhz scope. All of that costs money. Lucky for me I don't need such a thing since I don't have that kind of budget.

author: Fungus
author_rank: Super Contributor
timestamp: September 21, 2018, 04:40:34 am
content: Quote from: Sylvi on September 20, 2018, 06:58:54 pmSure, but at "normal" brightness levels they don't show the high frequency noise in the same way that a DSO does. It's just a faint glow around the trace due to the high horizontal scan rate and your eye ignores it.To see the noise properly on a CRO you have to turn the brightness way up, but nobody does that because it looks wrong.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 21, 2018, 04:59:51 am
content: Um... you can't say no one turns the brightness up on a CRO to see the noise because that is what they do to see the noise.Maybe it's been a while since you've used an analogue scope? Analogue is my reference and I have not yet used a digital scope, so I have a lot to learn yet.I will be getting my CRO fixed after I have the DSO running as I can't imagine never needing the CRO for audio. DSOs are getting better at mimicking CRO appearance, with DPO techniques and increasing bit-resolution, but what does that tell you? It says that there is still something missing in the digital offerings that the analogue offerings can still deliver. Yes, absolutely there are things you can do with a DSO that are extremely difficult or even impossible with a CRO, so I see that there is room for both on my test bench.

author: David Hess
author_rank: Super Contributor
timestamp: September 21, 2018, 05:17:05 am
content: Quote from: Sylvi on September 21, 2018, 03:29:25 amThe newest oscilloscopes which I really like are the almost 40 year old 7000 mainframe and 22xx portable oscilloscopes from Tektronix simply because they have the absolutely fastest probe to display time under all conditions. Even the later Tektronix oscilloscopes are slower.Give me peak-to-peak automatic triggering, or give me death! - Patrick Henry

author: james_s
author_rank: Super Contributor
timestamp: September 21, 2018, 03:45:38 pm
content: I was an analog scope holdout for a long time, citing most of the reasons that have been discussed here. After a couple years with a good DSO though I'd have a hard time going back. Using one requires a slightly different technique, it's not the same instrument, but once you get used to it they're really powerful. You can do things easily with a DSO that would be very challenging to do with analog. I like the "real" feel of analog, but it sure is nice to be able to capture a single shot several screen widths long, then zoom in and take measurements of various parts of the waveform at my leisure, or take screen captures at any point to review later.

author: precaud
author_rank: Frequent Contributor
timestamp: September 22, 2018, 01:54:41 pm
content: Quote from: nctnico on September 20, 2018, 09:55:00 pmI totally agree, 10 bits is much more useful for FFT than 8, especially for sinewave test signals. In a modern 10-bit DSO, an FFT'd data record of multiple sine cycles gives the similar SNR improvement as time domain averaging of multiple records combined with numeric accuracy improvement of freq domain averaging. With solid triggering and an ADC with low DNL, averaging as few as four of these records will easily give 80dB of useful, repeatable dynamic range.Early DSOs and FFT analyzers didn't give this benefit due to data processing limitations (slow cpus, no math co-processors, small memory maps).1. They used pre-weighted integer math in their averaging routines. Ex: for 8 averages, each integer ADC sample was right-shifted 3 bits and then added to an integer accumulator. This is fast but results in averaged data that is no better than the ADC's inherent bit depth.2. Their FFT routines also used integer data throughout, using lookup tables for things like trig functions, log conversions, etc.One of the 10-bit DSO's I still use (a Lecroy 9430) has some of these limitations in its FFT. No matter how many time domain averages you do before FFTing the data, you'll never get even 2-bits of dynamic range improvement from it. But if I pull its individual time records into the computer, average and FFT them using real numbers, I get 80 dB easily. This shows that its ADC is very good but it is crippled by the scope's data processing.Despite these limitations, they sold the FFT package as a $1500 option! My, how times have changed...

author: David Hess
author_rank: Super Contributor
timestamp: September 23, 2018, 12:24:15 am
content: Quote from: james_s on September 21, 2018, 03:45:38 pmThat is why I like the Tektronix 2232. Only that series of DSOs had automatic peak-to-peak triggering (that I know of) so I get the best of both worlds although you would not use it for single shot captures or at slow time/div but that applies to any automatic triggering.Tektronix lost that feature in the following generation of both digital storage and analog oscilloscopes which sort of makes sense. (1) Later when digital triggering was implemented on DSOs, it could have been reintroduced but that was 20 later and it had been forgotten by designers and new users.(1) The last Tektronix analog oscilloscopes had a different technique which involved using the trigger itself to make amplitude measurements and this allowed inferior automatic level triggering for essentially free. Modern DSOs duplicate this in one way or another; there might be some exceptions but I have not found them.

author: Old Printer
author_rank: Frequent Contributor
timestamp: September 23, 2018, 02:53:45 am
content: Quote from: Sylvi on September 21, 2018, 03:29:25 amDismissing the AD 1 or 2 as a toy is nonsense, it has earned it's reputation as an excellent educational tool that fulfills several T&M jobs. The "proper connectivity" is a $25 option, hardly a barrier. It's input voltage range is +_ 25V @ 1M ohm with a 1X probe, neither TTL or CMOS limited.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 23, 2018, 04:40:56 am
content: Yes, the AD1 can have some dangling BNCs tied to it while itself dangles from a computer. That is not exactly a proper format for serious test equipment. For a uni student on a budget in a dorm it will suffice.I'm used to "real" test equipment that is unitised in a box with all the right connectors securely in place.Obviously, those are two aesthetics that you either like one or the other, can tolerate, or just are used to. I'm used to the the Test-equipment aesthetic particularly for my bench. I have no desire to have a computer there as well. For many people, especially more computer-savvy people than me and/or younger than me, their aesthetic incorporates a computer for everything they do, so add-ons are not a nuisance; rather, the add-ons are just more stuff tied to the centre of their world. I guess in my aesthetic there is more compartmentalisation and separation.I don't have anything wireless (I've opted out of that experiment), so all the links between potential devices or add-ons is by wire, which makes the AD2 and its accessories more messy to me.Respectability of or for a given device is not the issue here and I don't generally choose things on that basis. Although, I do admit to having more respect for Keysight because of its HP heritage. I find their "get rid of the toys" slogan a bit offensive in their literature, where all the techniques they use are given a Keysight buzz-name that is meaningless rather than saying how they make 8-bits looks like a scope of yore. The images of displayed data don't actually look all that hot. In any case, Keysight is respected and so is the AD2 for what they do for the people who choose to use them, just in the same way that a Ferrari is respected for what it can do even though that is different than what the grocery-getter reliable Chevy can do, which is respected for its virtues.

author: Old Printer
author_rank: Frequent Contributor
timestamp: September 23, 2018, 01:41:34 pm
content: Quote from: Sylvi on September 23, 2018, 04:40:56 amDigilent uses a pin and socket joint to connect the BNC board to the main board. If you pop the hood on much of the older "real" test equipment you are "used to" you will find that companies like Tektronix used the same type of joint for many years to connect a myriad of vaccume tubes and then transistors to the main boards. That's not even mentioning the inter-board connections of more modern equipment. Is it unsuitable now because it can be seen?

author: Fungus
author_rank: Super Contributor
timestamp: September 23, 2018, 01:44:55 pm
content: Quote from: Sylvi on September 23, 2018, 04:40:56 amIt wouldn't be difficult to make a box.Much more difficult would to meet the performance specs of the AD2 with a piece of "real" equipment.

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2018, 02:07:50 pm
content: https://store.digilentinc.com/bnc-adapter-for-analog-discovery/?And anyone who complains about this not being “real test gear” and “real BNCs” hasn’t seen a default state fucked up 54600 or TDS scope. Alas any further discussion on that may make me dig out the photos of cracked boards, broken off connectors and my favourite, the ext trigger that Tek forgot to solder on...The metric of success isn’t the lore around the equipment, nor the spec sheet but the ability to solve a problem and deliver a product or repair. AD2 is a compromise but a quite decent one. Plus the pricing is disposable territory.

author: james_s
author_rank: Super Contributor
timestamp: September 23, 2018, 03:28:46 pm
content: I personally don't like PC based test gear. It originally promised lower cost, but today the display and interface subsystems have become so cheap that there is little savings. I have had issues getting it to work properly with some computers, the software is often lousy and gets abandoned at some point, and I don't like having to drag around a laptop and the test gear. I still have an older Bitscope and a couple different PC based logic analyzers and they're not nearly as nice to use as a standalone instrument.

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2018, 03:35:07 pm
content: All my big test gear gets plugged into the PC anyway. That's where the useful analysis is done, usually with numpy/scipy/sympy/matplotlib.

author: nctnico
author_rank: Super Contributor
timestamp: September 23, 2018, 04:15:48 pm
content: Quote from: Fungus on September 23, 2018, 01:44:55 pmI think that is the whole point. The digilent AD2 would be much more interesting if it didn't had such a high DIY factor. There certainly is a market for high resolution oscilloscopes so it would make sense to have something like the AD2 with BNC inputs and some protection circuitry.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 23, 2018, 04:27:24 pm
content: Quote from: nctnico on September 23, 2018, 04:15:48 pmBut it could not be knobbed box, that would be just silly. Usage scenario / target group is too different. Sometimes I wonder why Pico does not have "do it all" box to compete (with some digital outputs and 2x signal gen). There should be similar but dirt cheap ADALM2000, which I orderedlast summer. Still have not received it, you see its not shipping yet...

author: james_s
author_rank: Super Contributor
timestamp: September 23, 2018, 05:40:21 pm
content: Quote from: bd139 on September 23, 2018, 03:35:07 pmI guess if that's your use case then PC based makes sense. Personally for what I do with a scope I can count on one hand the times I've wanted to do any sort of analysis on a PC beyond storing a screen capture. Normally I'm testing something in real time and just want to see the waveform and measure things like frequency and voltage levels.

author: Old Printer
author_rank: Frequent Contributor
timestamp: September 23, 2018, 07:09:46 pm
content: I did add a couple switches to my BNC adapter to control the AC-DC Coupling. Those fiddly little blue jumper blocks were a PITA.

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2018, 07:42:32 pm
content: Quote from: james_s on September 23, 2018, 05:40:21 pmDisplay is much bigger on a PC though...

author: Fungus
author_rank: Super Contributor
timestamp: September 23, 2018, 07:49:43 pm
content: Quote from: bd139 on September 23, 2018, 07:42:32 pmAnd an extra digit!

author: bd139
author_rank: Super Contributor
timestamp: September 23, 2018, 08:01:18 pm
content: Yes that was interesting to find. Also there is an entirely undocumented SCPI interface hiding in it.

author: james_s
author_rank: Super Contributor
timestamp: September 23, 2018, 09:25:52 pm
content: Again if one's use case requires a bigger display then that's another reason a PC interface could be useful. I have no trouble reading the display on my multimeter though and I don't have to find a spot on my workbench to put my laptop.

author: mtdoc
author_rank: Super Contributor
timestamp: September 23, 2018, 09:31:20 pm
content: Quote from: Old Printer on September 23, 2018, 07:09:46 pmNice mod. I like it! How did you make those panels? Do you have a laser cutter?

author: Old Printer
author_rank: Frequent Contributor
timestamp: September 24, 2018, 02:22:27 am
content: Quote from: mtdoc on September 23, 2018, 09:31:20 pmYes, I have a laser, actually 2, an Epilog 50 & 75 watt. I am the production manager for a sign shop, lots of neat toys.

author: Sylvi
author_rank: Regular Contributor
timestamp: September 24, 2018, 04:14:05 pm
content: Old Printer wrote in post-60:"Digilent uses a pin and socket joint to connect the BNC board to the main board. If you pop the hood on much of the older "real" test equipment you are "used to" you will find that companies like Tektronix used the same type of joint for many years to connect a myriad of vaccume tubes and then transistors to the main boards. "In those units, all the wiring between the fiddly multipin connectors and the front-panel user interfaces is fixed in place and has negligible if not zero stress on the wiring or the connections. With the AD2 and similar, all of the connections are flexed and pulled and can break much more easily. Not a good road to reliability.The AD2 isn't even shielded