Basic scope question  - Page 1
Forum section: electronics / beginners

author: reno
author_rank: Newbie
timestamp: November 06, 2011, 02:48:50 pm
content: Hello Dave and all the guys, I have some beginner's question here.I am completely newbie to electronics, implementing my first projects (audio synthesizers, specifically) and looking for a scope. Due to cost-benefit, I intend to get a Tektronix, like TDS1001 or TDS1012. The dumb question is: in a so basic scope (its the most basic line of Tek), the bandwitch still conclusive? That is, with so many other specs, make sense buy a 100MHz scope? For example, even the TDS1012 (100MHz) has constraints like bandwitch limit of 20Mhz at max vertical sensitivity, and possibly unflat frequency response.Thanks.

author: Unknown
author_rank: Unknown
timestamp: November 06, 2011, 04:55:23 pm
content: Quote from: reno on November 06, 2011, 02:48:50 pmAre they competitive with the low-end Chinese Rigol/Atten/Owon/Hantek models?Quote from: reno on November 06, 2011, 02:48:50 pmBandwidth depends on your application. The 100MHz number indicates the frequency where the response is -3dB (~30%) down, so the response is never flat across the spectrum. It does not indicate the repetition rate of your signal, a 100MHz scope is a poor tool for a signal with a 100MHz repetition rate since the signal will contain higher harmonics. Old rule of thumb was 3-5x more bandwidth than repetition rate of your signal, better way (for digital signals) might be to compare the rise time to the rise time of the scope, scope rise time should be significantly less than signal rise time if you want to measure it accurately.Almost all scopes have lower bandwidth at max. sensitivity. Other important figures are sample rate (I believe Tek got that one right), sample memory per channel (extremely low if I remember correctly, 2.5k?). For analog applications noise at high sensitivity might be important, not sure how the TDS1000 series performs in that regard.

author: reno
author_rank: Newbie
timestamp: November 06, 2011, 06:08:17 pm
content: Thank you alm.Curiously, the Tek TDS1012 (100MHz) is slightly cheaper than the Rigol DS1052E (50MHz) here! But the first really has just 2.5kp of sample memory, against 8k in Rigol model. About the noise, seems to be a hidden info, right?So, I think it make more sense to buy an 40MHz scope and save money, because a similar 100MHz scope will still have the same specs that in practice make that unusable in more critical work, like microcontrollers debuggin, for example. My reasoning is correct? Or the 100MHz is even so a better choice, thinking ahead?

author: rf-loop
author_rank: Super Contributor
timestamp: November 06, 2011, 08:06:07 pm
content: Quote from: alm on November 06, 2011, 04:55:23 pmThese are very clearly in different categories.There is Rigol/Atten/Siglent etc cheap category (example R 1000E series)Owon and Hantek are really and clearly in different littlebit upper class.And far away over example these Tektronix cheapest really "out of date" models.2.5k memory meand really slow samplerate, really slow exept fastest time/div settings.Hantek have 4 and 40k fast memory. And "up to" 1M (800kpoints) half speed memory.Hantek is tiny DPO principle scope. (with low capture memory it give good waveforms per second display rate. Not high but good in this class.Owon SDS7102 have 1k - 10M memory with maximum full 1GSa/s samplerate.And 1+1k - 10+10M with two channel mode also with full samplerate, but two channel samplerate is maximum 500MSa/s per channel (simultaneous) and also - NOT interleaved sampling. It have true direct full speed sampling with one fast ADC chip. It means clearly better sampling guality what any other in this class of scopes.Owon is full real time DSO principle scope. (there is not at all this "equal time - joke"fast speeds short memory waveforms per second rate is slow if compare to Hantek but with higher memory in use, owon is faster.And both of these dislpay is really amazing good, just as from different planet, if compare to this Tektronix or these Atten/Siglent/Rigol/Uni-toy group.Owon and Hantek display quality is same. TFT is good quality Innolux standard panel and with LED backlight.(Owon is littlebit dimmer becouse they drive backlight LED's well under manufacturer specified value for normal brightness.)Compare this 320x240 pixel 5" monitor to 800x480 or 800x600 resolution 7" and 8" display. (And H&O drive display with native resolution.)Also both of these have separate adjustments for channels.I admire Tektronix and they are really good if go real professional models or example old analog scopes. There can tell that in world have tree oscilloscope brand. They are Tektronix, Tektronix and Tektronix. But, it is also only history. (and honestly some other manufacturers have also made some good or even exellent oscilloscopes but... still my 7000 series Tek Rolls_Royce work as dream and also these later models.But today, in some cheap models... tektronix and agilent or some other name what I do not remember are just 5cent nameplate on the plastic cheap snacking box. Well, still we can believe this name is something.These cheap chinese are clear winner if look scope in this specs and price class. Also some chinese companies have slowly started customer care lessons. So we can wait also it go better and better.Just one chinese company (some electronic test equipment manufacturer ) tell to me in warranty fail situation that please package it and give it free to shipping courier (they pick-up) - and wait new or repaired. (free) And it works like dream in movie.(this pick-up and delivery is maybe many times more than this equipment price for factory). But if they do it just for 0.1% equipments and customers are happy... it is win-win. In this kind of things they just have started as basic school. But after soon they learn and after they start copy this from each others... well. We can soon forget many things what we have thinked about chinese business.But no need afraid chinese companies - these companies who have started this better care of things. They are seroius, they really want develop and give better customer care. But they have just started these lessons.

author: Unknown
author_rank: Unknown
timestamp: November 06, 2011, 08:33:44 pm
content: Quote from: reno on November 06, 2011, 06:08:17 pmI believe the Rigol has 1M memory in 'long memory mode' (halves the max. sample rate).Noise is not usually specified. I know the old TDS-200 series was quite bad in this respect, and the Rigol DS1052E doesn't appear that great either. I remember Dave comparing it to the Tek TDS-200 series scope and saying that the Rigol didn't look too bad, even though the TDS-200 is almost the worst in the business as far as noise is concerned. There also appear to be some issues with noise with the latest models/firmware (see the thread about the Rigol hack or the one by A Hellene). Not sure about the newer TDS-1000 series.Quote from: reno on November 06, 2011, 06:08:17 pmDepends on your requirements. The 100MHz TDS-1012 doesn't fix any of the limitations like the memory depth. With the 2.5k sample memory it is basically an analog scope with storage, which is how these scopes were targeted. You can't zoom in on a stored waveform on an analog scope either. For some applications where you just need to look at a fairly simple signal requiring more bandwidth the 100MHz/2.5k scope might be useful. For general purpose I would consider a 50MHz long memory scope more useful than a 100MHz short memory one. As for the TDS-1002 vs. TDS-1012, I wouldn't pay too much of a premium for the extra bandwidth. You can do a lot with 40MHz of bandwidth.

author: rf-loop
author_rank: Super Contributor
timestamp: November 07, 2011, 10:57:10 am
content: Quote from: alm on November 06, 2011, 08:33:44 pmBut also it can look opposite.Analog scope is full BW also with lower time/div. And long time it was analog scopes super advantage far over digitals. (more in history)If digital scope have small memory, it affect just so that BW (related to realtime samplerate) is extremely limited if small memory.Example as Owon, it makes just thisadvantagethat it is nearly as analog scope becouse deep fast memory.I do not know how Tek 2.5k is arranged related to display time/div.IF display is example 10div horizontally and if whole capture memory is displayed on the screen it means 250sample / div.(it is not if I quess right becouse Tek have long practice to put around half outside of display.. (1/4, display 1/2, 1/4 or something like this if trigpoint is selected middle) in some older digitals. But lets assume it is all in display.Ok what happend if set example 500us/div. What is then samplerate.10div is (in this imagined example) 5000us. Memory is 2500points.5000/2500 =2. It can take every 2us one sample to memory. It is then 500kSa/sWell with this speed it is 250kHz scope if look theory as Nyquist. (This is only if we KNOW that maximun frequency component is 250kHz then we can say it can display 250kHz (sinewave).In practice we can better talk that it is 50 - 100kHz scope with this speed. (if it is arranged so that example there is 20div capture but display window to captured signal is 10div wide it do not change in practice in this meaning)Yes, Tek have 1GSa/s maximum but, with 2.5k memory, what time/div it can use it?It means ADC data byte every 1ns. So there is 2500ns time to fill memory.If think it is 10div. It meand it is 250ns/div. (But in Tek solution it is maybe 100ns/div or nearly where it do 1GSa/div but it is only quess becouse do not know how they arrange horizontal divisions releted to memory... maybe it is 100us/div where is reach 1GSa/s but it can not happend lower than 250ns/div if there is 10 horz divs on the screen.Look example Owon.Also with this 500us/div it is still sampling 1GSa/s and so it is fully and clearly 100MHz scope.Even if go 1ms/div (500MSa/s) it is still 100MHz scope.This imagined example (nearly as this Tek) 100kHz -- compared to Owon example what is more than 100MHz.1:1000 difference.small difference?Ok lets think you look only 100kHz. Why need more BW... well where you need oscolloscope if you really know your signal what you are looking. Example if you look pulses or some oscillator or what ever and if there are example parasitic oscillating... what you see with this 100kHz scope... nothing but screen full og aliases. Analog oskilloscope never do it... and fast sampling realtime oscilloscope much more less that this kind of Tektronix slow sampling piece of history.More slow time/div speed but more sampling speed give more this effect what analog scope can do and what still digital scopes try emulate. (yes best realtime scopes are today better than even best analog scopes in mosta cases.This more sampling speed with lower horizontal timies can do only adding more fast speed sampling memory.(I talk also now only about realt time sampling... this "equal time" sampling or "repetitive" is piece of bullshit in cheap oscilloscopes.)And in this meaning 1000E Rigols are far below Owon.Also in this special meaning Hantek is some amount below Owon.Rigol is ok and it is cheaper than Owon, it is cheaper than hantek but difference is not much.Of course sometimes this money difference is much and in this meaning I think Rigol is still very good value for money.If can use littlebit more money you get much more with Hantek or Owon.No need take more than display. tiny 320x240 5" compared to really good 7" 800x480 or 8" 800x600 TFT is really BIG difference and these scopes also use TFT in native full resolution.And no need hack and crack... these are allready 140-150MHz oscilloscopes. (both 100MHz models)Hantek 60MHz is nearly as Rigol 100MHz. And more if do FW modification what is also more easy and safe to do than Rigol.(becouse Hantek have doors open Linux)So, what is Rigol...It is good scope if can not use anymore than its price.It is lot of better oscilloscope than this Tektronix.If need something more with littlebit more money.Hantek and Owon is good. (they are not real competitors becouse they have so different strong and weak points)

author: EEVblog
author_rank: Unknown
timestamp: November 07, 2011, 11:07:43 am
content: Quote from: reno on November 06, 2011, 06:08:17 pmNo, the Rigol has 1M of sample memory.Don't buy the Tek scope, I've mentioned before that it's very poor value for money and not competitive in today's market.At the very least buy the Rigol instead.QuoteThe 50MHz Rigol can be software hacked to 100MHz, as can at least one other low end scope.100MHz over 50MHz is nice, but not worth paying a lot extra for.Dave.

author: Axel1973
author_rank: Regular Contributor
timestamp: November 07, 2011, 04:44:08 pm
content: Quote@Dave:you probably talked about that before somewhere. and ive seen some of your scope reviews on the eevblog n all. But now that im looking for some "modern" digital storage scope i find myself pretty much lost between old well known names like tektronix, hameg and whatnot and those all new rigol, owon and whatever. who to trust, and who to spend money on?Spend money on more Gig-Samples and Memory and have just a 2ch. scope, or get a low cost 4channel scope with less gig samples and mem?What to look after if you need a good all day general purpose scope beside some ancient old philips 30 (or 50 mhz?) analog scope?The higher Owon SDS82xx looks nice on specs. but who the phuck is owon ?! will there ever be a firmware update? is this a name you can trust ?Maybe i should turn the whole thing upside down. Lets say, WHAT NEW SCOPE TO BUY for round about 800 EUR (<1000EUR) ?How much should an Amateur AT LEAST spend on a scope and where it starts to be just a waste of money?Any tip is welcome. (anyone)best regardsAxel

author: rf-loop
author_rank: Super Contributor
timestamp: November 07, 2011, 05:38:34 pm
content: Quote from: Axel1973 on November 07, 2011, 04:44:08 pmI have seen and tested Owon SDS7102, 8102, 8202.Rigol 1102E, Rigol 1052EHantek 5062B, 5102BOwon is "nobody" Owon is product brand.Company is part of Lilliput group who make small entertainment displays for cars in low end and Marine Radars in higher end.Years ago Owon start with oscilloscopes. Some product was also disappoint and not very good. Displays was cheap dstn, all was littlebit training. But they have do homeworks and develop themselves. One point is that they do not simple copy products.Also this "Owon" have some connection to Canada.They are not best and most big. But very honestly they try learn and also they care customers.FW, they have updated now 3 times inside this time what I have followed.2.1.1 original. 2.1.1 with repair patch. Now 2.2.1HW I have seen some small update one time. (Power unit is updated)Owon FW policy is littlebit strange but maybe they have they own reasons. Not public downloadables. You get update from factory or from Owon accepted co-working reseller who also may have Owon service.If think prices and scope models. This is my individual citizen opinion.SDS7102 is best model in this Owon SmartDS serie if think what get with money.SDS8xxx have not more than also 1GSa/s if use more than 10k capture memory.But with 2 channel use it can serve also 1GSa/s per channel (memory limited also). It give also advantage becouse there it is 1GSa/s per channel.But not so often needed.You can find this table about samplerate from some other thread in this forum.QuoteQuoteQuotehttp://www.owonchina.com/eng/about.aspThis part of Corporate Group have also phone numbers and they also answer. There you can ask "who the phuck is owon ?!"Small nice and honest company. They really try do something littlebit different as normal grey copycat companies in every corner in China.But as all Chinese companies with test equipments, also Owon, - all they need carefully learn more and this is long hard road. There is hope in Owon becouse there is company who do not close eyes if there is problems.. they try develop products and themselves. This keep hopa that it is possible one company who do not forget after some years.Here is tableIf you look SDS7102 change only and all green 2Gs to 1Gs and all green 1Gs to 500Ms(this is only difference afaik.)

author: Unknown
author_rank: Unknown
timestamp: November 07, 2011, 09:32:40 pm
content: Quote from: rf-loop on November 07, 2011, 10:57:10 amFast edges will be very faint at slow sweep speeds to to the low intensity, so full BW is a bit misleading. X resolution is also finite due to spot size.Quote from: rf-loop on November 07, 2011, 10:57:10 amPeak detect is a workable workaround, it will always sample at its highest sample rate, at the cost of higher noise. Yes, a cheap DSO is not a complete replacement for an analog scope, they don't have any intensity grading, but they are a good replacement in many cases or the basic analog service scope, which was the target market.Quote from: rf-loop on November 07, 2011, 10:57:10 amI'm not claiming that the low end Teks are competitive with the latest Asian designs, but that doesn't make them useless. I'm not the one making the choice, I'm just trying to present facts and opinion to help Reno make up his mind.

author: EEVblog
author_rank: Unknown
timestamp: November 07, 2011, 10:05:46 pm
content: Quote from: Axel1973 on November 07, 2011, 04:44:08 pmDown at this low price point, it doesn't really matter.The Rigol is a proven performer, and almost certainly the most popular out there.Owon, Hantek, and the other cheapie brands has less of a reputation, but can offer slightly better bang-per-buck.Instek are a decent brand.As I said, forget the Tek, unless you are absolutely obsessed with getting a Tek. Their technology is old and they don't offer competitive models in today's market.Buying a digital scope with 2.5K of memory is about the worst move you can make, and you WILL regret it.QuoteMost people rarely have a need for 4 channels in general use. But if you need it, you need it.Quote#1 = memory depth.Sample rate doesn't matter once it's 4-5 times more than the bandwidth, and these days almost every scope on the market meets this. These are called "real-time" digital scopes.Bandwith is the same question as it always has been.QuoteBasically, no. It does not have a good industry reputation.QuoteI would get the Agilent 2000X series. It starts at $945EURhttp://www.datatec.de/Agilent-DSOX2002A-Oszilloskop.htmUnless you absolutely need more channels or other features at the same price point.QuoteUS$400 for the Rigol DS1052E is the minimum I would recommend.Dave.

author: Unknown
author_rank: Unknown
timestamp: November 07, 2011, 10:29:57 pm
content: Quote from: EEVblog on November 07, 2011, 10:05:46 pmIt does filter out some the cheap crap which is limited to 100MS/s, though.

author: rf-loop
author_rank: Super Contributor
timestamp: November 08, 2011, 09:06:29 am
content: http://forums.tm.agilent.com/community/viewtopic.php?f=19&t=27796&sid=f40753bbbc485e657db2aec5b4d6404c------------------------------AGILENT TECHNOLOGIESDSOX2012Ajust basig unit without any options.1 412,04 € including VAT without shipping.100kmaxcapture memory.-------------------------------------------------Yes if look all things and price, of course it is not comparable to 450 - 550Euro Chinese 100MHz oscilloscopes. But with this nearly 1000 euro I can buy example old high end spectrum analyzer. Sorry but cheap agilent is just as far away golden Hewlett Packard what ever can be.What piece of signal I can not see with Rigol, Hantek or Owon what this Agilent can.Maybe I need buy one and then make real labs with all these. Then I know if this extra 1000 euro give me some important value. Or maybe I can save and buy Tek2465 for use together with Hantek or Owon. This combination beats this one Agilent in all meanings what I need in my works. This combination working power is lot of over this Agilent box. Still I save money. I can buy good probe or one second hand Kethley and push my old Fluke to trash can.-------------------------------------------------Popularity (Rigol): Where, in EEVblog what is whole world? Popularity: Yes of course I remember time where Philips was far over Quad popularity and some know Racal and Hammarlund and still Heathkit was popular. But this I do not understand that Nike is popular in China - just can not understand - I can not find any real reason, nothing. same is Coca-Cola - it must be good becouse it is popular.It is cheap trick to rise popularity if make 50MHz scope hackable to 100MHz.If they sell this 50MHz model directly FW modded to 100MHz and not anymore posibility to mod, where is popularity... laughing.Then, what is Rigol users profile if copmare to Hantek, Owon and others brand. What kind of peoples select what?(here locally I know some data (it is from one source and just what have happend there in real life): (I can not exactly proof it becouse I do not have bacround knowledge about this):Rigol 9:1 young entry level hobbyists:professional, Hantek 6:4, Owon 3:7. Can you understand why?This is only hard data, not opinion, this have happend)Do you think most of these real professionals hang around here forum. What is popularity meaning.Do you know if Rohde&Schwarz is popular?So: Please do not use popularity as argument!It can mostly shoot down most easy than any other argument and specially if argument have any real data.-------------------------------------------------Where is nearest Rigol warranty time repair service and what it cost?I really do not know.For Owon and Hantek example here in my country is local warranty time repair service.Owon and Hantek in China answers normally inside 24-48 hour if take contact by email. Phone answer is immediate if office time.Owon and Hantek service works here. Just my friend get his Owon warranty changed inside 24 hour + 2 days for two way shipping. He was happy.More than year ago I try ask Rigol service. No way. Rigol China, never any answer.