Author Topic: EEVblog #487 - Tekway DST1102B Oscilloscope Review  (Read 42879 times)

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Offline Mike Warren

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EEVblog #487 - Tekway DST1102B Oscilloscope Review
« on: June 25, 2013, 01:08:40 pm »


With the latest firmware from Tekway I've had no more crashes, but as Dave says, you get what you pay for.

Hantek/Tekway thread:
http://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/
« Last Edit: June 25, 2013, 01:10:54 pm by Mike Warren »
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #1 on: June 25, 2013, 06:45:05 pm »
Ok, before i edit this response (and add a loooong list of things) let me tell you soemthing Dave, your model is a bit strange. The serial number on the enclosure didn't match the serial number of the mainboard, so someone have already played with that board/DSO.
Hard to say how deep playd and if/what changed (you can e.g. disable the bw filter), but that just a side note.


Let me answer few things here:

- Long memory (4k and 40k are working however fast and good, it make as well to enable "50" refresh rate in display menu to speedup a lot knobs response) is just crap slow. Sure, it can be used for one off things, but to work all the time enabled you would get crazy. The reason is actually simple, they reading the whole 1M from sample buffer (SRAM connected to FPGA and CPLD) into the ARM buffer and working with that data (measurments, what so ever) and displaying that whole waveform. Today this is very uncommon way, normally you would leave the whole data in buffer and read only what necessary to be displayed at once on screen (e.g. 800pts). Btw, the sample buffer is like on Rigol DS1000E in external SRAM, so they filling the stream from FPGA to SRAM already at slower speed (this is why all these DSOs can't do 1GS/s and 1M at time). When you enable the long memory on Rigol, the screen is much faster than on Tekway, already here the difference in data readback is visible (but it should not as both doing the same on hardware level, actually Rigol is even slower here due the non DPO-like buffer). I don't have access to fw sources, but to debug versions, and from what in the code i can see that they working like described, and well, reading the whole buffer only once per second (see init_store_depth functions). This can't be simply changed as the ARM SoC can't just read much more at once. When measuring/looking on the SRAM/CPLD on FPGA (the trigger registers) i can see the DSO running muuuch faster, sure, it is always 4k ring buffer running at full speed. They would have to change the firmware to read only that part what need to be displayed, not the whole buffer.


- Tekway confirmed that wfms/s is up to 2500, like mentioned on their website http://www.tekway.net/views2.asp?newsid=205&sess=2
Hantek told me 2000, but they haven't even edit properly the user manual so who knows :P Not that i really trust them both, but i trust my measurment and my eyes. From the code i can see that 40 captured frames will get read at once from sample buffer and that 50 times per second when the screen refresh is set to 50. So 2000 wfms/s max here. The firmware before "merger" with Hantek was much faster (responding), so i assume the 2500wfms/s was measured on that version. When i change the on current version the size of DPO-like buffer all i can get is ~2152 wfms/s is max. So that can be the limit, but of course it can be as well FPGA firmare limit. Anyway, due the fast that the "40 frames to one" buffer can be read back 50 times per second the wfms/s can't be constant, it will be more like burst mode. You can see it on that video i made some time ago (don't get confused, i'm stopping ACQ as soon captured and restarting, so count only the second from restart point to captured on screen^^)



and here compared to TDS700A (doing here 6k wfms/s)



Of course both didn't said anything to question "is the wfms/s conctant or burst mode?", not a real issue as persistency can help here out to let the glitch visible, but it would be better t have constant wfms/s rate.


- there are bugs, as mentioned below i'm helping them out with that. Lot of things fixed since Jan 2013, but not all. Let's hope the best^^. I will not give up that fast, i have a lot of time now.


- there is no intensity grading as know from other DSOs, Tekway/Hantek is using DPO-like grading, 4 steps (each in 4 intensity steps, so 16 steps total in intensity but still only 4 depth, anyway^^). In run mode, with persistency on auto which is the "off" position, the waveform looks like attached picture - same sine waveform captured twice as screen snapshoot (and zoomed on PC to show details). The DPO-like grading is clearly visible (no, this is not a TFT display persistency error, that are captures from memory), however, i would prefer to have here higher depth. Probably FPGA is too small for more. Easier could be to implement only the intensity grading, like Riolg did it on DS1000Z/DS2000, instead of trying to simulate Tektronix. Not that i don't like that idea, as TEK fan i do for sure, but it is not easy to achieve good results at no price. Even TEK didn't managed it in their low-end models.




- the frontend story :P For a long time i was fighting with ppl in German forum, i was wondering why they getting crap waveforms on their scopes where my was looking much better. Long story short said - for (unknown to me) reason Tekway/Hantek changed some resistors in their frontend. Btw, this is the same frontend what Rigol is using in DS1000E (that affected part exists even on DS2000). Of course Siglent/ATTEN are using exact the same frontend, hehe. Anyway, i and some other ppl made lot of measurments and simulations, finally we have working combination, it is even better that original DS1000E and even better than my old Tekway. There is no need to change anything on org. DSOs, but on hacked (or all what need to work over 100MHz, this is why this never was an issue on DS1000E). All the necessary information about is in the Tekway hack thread: http://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/msg212054/#msg212054


- jitter, yeah. I actually made measurments (with proper equeipment) and reported the skew between clocks, Tekway almost fixed it (not perfectly but definitely acceptable). Since Nov 2012 they have again new FPGA design (83EB) which seems to be worse than the working one (83E9). The DSO you tested have the 83EB. It seems that very few (i know only 2 by now) current models can't use 83E9, reason seems to be on power rail (smaller caps than before, heh). Some have different DAC installed (on botton side of PCB, so visible from outside), with that DAC 83EB need to be used. For all others is a good idea is to use FPGA design 83E9. Before someone ask "why is 83E9 not perfectly fixed?" Well, don't be naive, Siglent/ATTEN/Rigol C/D/E are clocked by FPGA, and if that not enought with not dedicated clock out pins, this is a worst case 300ns jitter. What all these manufacturer doing is to calculate avg values to middle the results. So far everything ok. However Tekway is having different architecture (DPO-like), so the resulting waveform jumps bit more (as it can be avg and DPO-like together). I worked here with external jitter cleaning chips (thanks again to Silabs for providing me dev boards, lot of samples and lot of help), that solution was working perfectly, but it was too expensive for undr 1k DSO. Honestly i wish Rigol will make lot of presure on other DSO manufactuers with their DS1000Z (they doing it already with DS2000). That will help a lot, the only way to fix such jitter/interleave distortion issues is to use less ADCs and proper clocking, and nobody will spend money without a need. For existing users, well, a very good clock source for FPGA (like CCHD-575) is reducing the jitter as well. More information in the Tekway hack thread.


- i have no idea who is that "smart person", but someone is always trying to cut some parts and save money. I told them this multiple times, it seems they ignoring it and trying it each every few months again. Your review would probably help to fix that. Examples are the forntend (as said above), or some caps near FPGA (they released different FPGA design to fix potential issues, lol), JFET in frontend was changed to crap solution for 3 months or so (they fixed it, but fuck why they did it in first place?), voltage ref is different (still acceptable but it was better one), XO is ±50ppm (but it was for some time ±25ppm, ok datashee talk about 50ppm for timebase so still within specs somehow). I know that the engineer behind the hardware/software is a smart person, all the hidden things in firmware and all the potential extension in hardware are really great, i doubt he is the person reducing costs. Sure, as entrepreneur i know how important is cost reduction, as EE i know there is invisible line which should be not crossed over. Some ppl in china seems to not know that to cut by 1% (with "component savings") works only once and that every month "only 1%" means 12.68% after a year, and thats crap and not quality.

##################################################


So let's summarize - as you said Dave, they almost there, but here and there small and less small things that need to be fixed. Firmware is the "easy" part (if i and they didn't give up), hardware can be only fixed with newer hw revisions (but as said above, others with similar hardware are not better here, that means all Siglent/ATTEN (except the 4channel models), Rigol DS1000E, most UNI-T models), and new models are on the way. No idea how many hw things has been fixed in these Hantek "P" models (with 24k memory only!) and how many will be in new "B" models, but we will soon see it.

I bet all chinese manufacturers (except Rigol, they seems to have good contract with RuiFeng? or AD?) will switch to ADC08D500 as soon they recognize how Instek overclocked these ADCs ^^. That will change the game again.

I'm sure Tekway will learn as well how to achieve higher wfms/s, not that they are bad with 2000 (2500) wfms/s, but Rigol DS1000Z with 30000 and UNI-T with 150000 is complettly different story. Sure, Tekway decided to do it DPO-like, but that was in 2009 and today they can give that up and simply do the "Rigol" (i would say Agilent way here, but i know that Rigol was using that way already in CA models, so before E models has been designed. They simply frozen that idea due costs, E models are working and cheaper).

Anyway, thanks for the review (yes, i know it was not a real review).
« Last Edit: June 26, 2013, 07:43:09 am by tinhead »
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Offline fenclu

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #2 on: June 25, 2013, 06:55:08 pm »
Ehh, too bad. Looks like every DSO under ~$400  is a piece of shit (except for the Rigol of course). Isn't there really anything useful on the market in that price range except for a 5 year old Rigol with a small screen (both size and resolution)?
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Offline kaushleshchandel

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #3 on: June 25, 2013, 07:10:12 pm »
I bought a Rigol two years back only after seeing Dave's video. I am pretty happy with it.

This one seems nice for the price band.
 

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #4 on: June 25, 2013, 08:43:24 pm »
Ehh, too bad. Looks like every DSO under ~$400  is a piece of shit (except for the Rigol of course). Isn't there really anything useful on the market in that price range except for a 5 year old Rigol with a small screen (both size and resolution)?
A pc oscilloscope maybe. I tried it. I's pretty annoying compared to a bench oscilloscope.... Anyway, if you want something good at least $500 you have to spend... If you are lucky you may found something refurbished and calibrated for interesting price.....
 

Offline amyk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #5 on: June 25, 2013, 09:11:19 pm »
Am I the only one who thought "why did they call the menu on/off F0", and the one at the very bottom F6, and then have the lone F7 up near the V0"? I also looked around for a V1 or V2... ??? somewhat weird UI there.
 

Offline valentinc

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #6 on: June 25, 2013, 09:29:35 pm »
Quote
Ehh, too bad. Looks like every DSO under ~$400  is a piece of shit (except for the Rigol of course). Isn't there really anything useful on the market in that price range except for a 5 year old Rigol with a small screen (both size and resolution)?


     There is, the Siglent SDS1xxxCML, for example, the differences between that and the Rigol DS1052E were discussed in another thread...

And I totally agree with Dave, this scope is damn slow in my opinion, why do they put 2 Mpts of memory if you can't use it because of the slow update rate ?  It's just useless... And even considering it's hackable, I much prefer a Tektronix 2235 analog scope than this one, any time... Or the Rigol DS1052, if the space on my bench is a problem... Or the Siglent... But this is a waste of money in my opinion...
Valentin
 

Offline JackOfVA

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #7 on: June 25, 2013, 09:45:13 pm »
As a guess with respect to the pulse fidelity ... since the Tekway is hackable for 200 MHz, this suggests a switchable input filter under firmware control. If the filter is not a Gaussian type, it can introduce pulse ringing when enabled.

One way to determine the input filter characteristics in the frequency domain would be to plot the frequency response and look for dips or peaks and also look at the roll off rate. Gaussian should not have peaks and dips and should give a smooth roll off.

Also with respect to the periodic small peaks in the pulse response seen on all the 200 MHz and above scopes at around 15 ns intervals, that looks a lot like cable reflection from mismatches - even though a 50 ohm through is used.
 

Offline iloveelectronics

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #8 on: June 25, 2013, 10:38:23 pm »
For what it's worth, the Uni-T UTD1102CM I spent a couple of hours with was MUCH MUCH more responsive!

I was actually surprised Dave sounded rather happy and diplomatic at the beginning of this video and and it took him almost 20 minutes to really started entering his usual ranting mode  :-DD
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Offline dr.diesel

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #9 on: June 25, 2013, 10:41:44 pm »
For what it's worth, the Uni-T UTD1102CM I spent a couple of hours with was MUCH MUCH more responsive!

I was actually surprised Dave sounded rather happy and diplomatic at the beginning of this video and and it took him almost 20 minutes to really started entering his usual ranting mode  :-DD

Yeah, assuming the front-end problem not a botched hardware design, both serious issues could be fixed via firmware, might change his rating.

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #10 on: June 25, 2013, 10:44:59 pm »
Ehh, too bad. Looks like every DSO under ~$400  is a piece of shit

a ty co qwra? co ci w moim arcydziele przeszkadza?  :box:

Ehh, too bad. Looks like every DSO under ~$400  is a piece of shit (except for the Rigol of course). Isn't there really anything useful on the market in that price range except for a 5 year old Rigol with a small screen (both size and resolution)?

as i compared directly Tekway vs Rigol, i decided to take Tekway. That was 2009. Today i would still do the same, but probably i would be bit more pissed off about thing which has been not yet fixed or has been disabled (sure, on my request, but better without them than with bad implementation which might cause misinterpretation of results). Honestly today the firmware is "almost there", like a dejavu as in 2009 it was same situation, but then instead of fixing few things they started to add more and more things (and there are a LOT of things not finished in the firmware, hidden from enduser) which increased amount of (potential) bugs, and they they lost the track complettly (hw1005 disaster).

On the other side, a 400$ street price means something like 200$ at 1k pcs manufacturer price, when you count BOM there is not much left, hard (actually i have no idea how they can pay anthing) to pay development, support, what so ever. This is one the biggest issues today, in 2009 it was easier for all manufacturers.

For Rigol it was bit easier anyway, their firmware is in principle taken from their former models, and they already 10 yrs old today. In the golden time period Rigol made lot of money, the DS1000E has been paid out by far before they started with the production (as lot of things in E models are coming directly from other models, so only bit of modifications they made). Today with all the good contracts they managed to earned lot of money, and a lot of knwledge from e.g. Agilent. This is a complettly different player today.

For Siglent/ATTEN almost same situation, they didn't spend lot of money on hw dev, they copied simply. Sure, they wrote won firmware for that, no doubt, that costs time/money as well. Today they have contract with LeCroy, not sure how this really works and who is the winner, but for sure this helpd them a bit as well.

Tekway started their dev and production in 2008, so really new company. Yes, sponsored by Synway (www.synway.net), but their budget was by far not that high. The first models was actually ok, i do have it here as well, the current (and second) model was ok as well in 2009, sure few things open but as i said "nothing what can't be fixed". The disaster started as Hantek started the production.

That was costs consolidation as the Hantek and Tekway shareholders are the same people. And that the problem, already in 2011 Hantek screwed up the whole hw1005, 90% of boards not working. They lost half a year to design new working boards, a realy crap situation.
Tekway told me once "when you would pay for x or y we would implement it". That was for me, together with the Hantek hw1005 disaster, the idiction that i have to spend more time on these DSO to help them fix issues, and of course for free. I proposed some help, unfortunately they recognized that the bad ass hacker is the same person who wish to help, so it tooks some time (for them) to recognize that free of charge help from a hacker is better than no help. Since Jan 2013 many things has ben fixed, few still open.
I had to made some break due my company bankruptcy, but i got now another test hardware (yeah, the court took everything) so i will continue my work. And no, i don't have (for reason) access to any code, i do only debug and testing, which is actually lot of work.

In principle, due all the unfortunately things and delays which happened, i could say the Tekway/Hantek firmware is today 2yrs old.
As Rigol started with E series, their firmare was already 4 yeras old, even ATTEN/Siglent had at that time 2yrs old firmware (and search inet, you will find how many ppl was pissed off about the bugs at that time). I'm sure, if we give them some time, they will manage to fix all issues. Or maybe not, f* who knows, maybe their management will screw it again up, with "savings" (see my first reply to Daves video to see what i mean).
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Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #11 on: June 25, 2013, 10:48:31 pm »
I was actually surprised Dave sounded rather happy and diplomatic at the beginning of this video and and it took him almost 20 minutes to really started entering his usual ranting mode  :-DD

Well I got a good vibe when I first looked at it and turned it on, I was quite hopeful...
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #12 on: June 25, 2013, 10:50:11 pm »
Yeah, assuming the front-end problem not a botched hardware design, both serious issues could be fixed via firmware, might change his rating.

Of course. My ratings are always subject to change. Fix the firmware issues and it's probably not a bad scope aside from the pulse response. That needs to be investigated more, and IMO is a killer if it's confirmed as being poor on all units.
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #13 on: June 25, 2013, 10:53:58 pm »
For Rigol it was bit easier anyway, their firmware is in principle taken from their former models, and they already 10 yrs old today. In the golden time period Rigol made lot of money, the DS1000E has been paid out by far before they started with the production (as lot of things in E models are coming directly from other models, so only bit of modifications they made). Today with all the good contracts they managed to earned lot of money, and a lot of knwledge from e.g. Agilent. This is a complettly different player today.

Yes, and that is not to be underestimated. The Rigol was an $800 scope 5 years ago. And it took advantage of few generations of previous model development.
New scopes coming in at the new Rigol price point have to cut corners. It's no surprise many just don't cut it.

 

Offline dr.diesel

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #14 on: June 25, 2013, 10:56:14 pm »
You hit the nail on the head when you said these cheap Chinese scope almost got it.

I know their resources are limited but I'd assume a few of the manufactures watch these videos, with minimal effort they could make a ~$500 scope with reasonable performance that didn't suck.

I bet they are soon coming.


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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #15 on: June 25, 2013, 11:54:40 pm »
I know their resources are limited but I'd assume a few of the manufactures watch these videos

They often can't. The Chinese government block Youtube.
One of the agents for a company had to physically burn a DVD with my video and hand it to them at a meeting when he went.

 

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #16 on: June 26, 2013, 01:07:36 am »
Hmmmmm, been looking at the cheap scopes, I have made my decision , despite the Rigol  DS1052E may be old , that is the one I'm going for, I think as a hobbyist, who does a few repairs, I think will be a really good Oscilloscope, and I would say it will  really useful in my Amateur radio station too.
Paul M0BSW
 

Offline dr.diesel

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #17 on: June 26, 2013, 01:18:14 am »
Hmmmmm, been looking at the cheap scopes, I have made my decision , despite the Rigol  DS1052E may be old , that is the one I'm going for, I think as a hobbyist, who does a few repairs, I think will be a really good Oscilloscope, and I would say it will  really useful in my Amateur radio station too.
Paul M0BSW

You've read about the new models just about to hit right?

http://www.eevblog.com/forum/testgear/new-rigol-ds1000z-and-mso4000/

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #18 on: June 26, 2013, 05:24:20 am »

So, lets summ it up:

First Issue :"Alternate trigger mode not available"=> not actually an issue if you read the Dsiplay/Manual

Second Issue: "XY Mode doesn't work? with normal mode at the same time"=>Dave only connected one Channel, thats why it seems that XY Mode isnt working O RLY? (just tested my DSO-1062D, everything works fine, not very smooth, but works).

Third Issue: "Overshoot":Tested my DSO-1062D with HP 33120A @1MHZ Square wave. Any overshoot/undeshoot.



Sorry, but it looks like Rigol paid you to give negative feedback to their compatitors on low end market, like :"all those new scopes sucks, keep buying our outdated Rigol 1052e or pay more for our newer models...;)"
« Last Edit: June 26, 2013, 05:43:49 am by Citizen »
 

Offline staze

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #19 on: June 26, 2013, 05:38:53 am »
ugh... it's ugly. jebus. I mean, the DS1000 series aren't the most attractive things in the world, but damn... the fonts just look terrible and nobs, etc. ugh.

Maybe I'm just not old-school enough to appreciate the looks. =P
« Last Edit: June 26, 2013, 05:42:32 am by staze »
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Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #20 on: June 26, 2013, 06:18:57 am »
Third Issue: "Overshoot":Tested my DSO-1062D with HP 33120A @1MHZ Square wave. Any overshoot/undeshoot.

Sorry, but it looks like Rigol paid you to give negative feedback

nah .. don't say that. Show me pictures of your frontend, maybe Voltcraft/Hantek finally decided to implement my changes to make the response better, here is what i mean :

http://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/msg212054/#msg212054

As a guess with respect to the pulse fidelity ... since the Tekway is hackable for 200 MHz, this suggests a switchable input filter under firmware control. If the filter is not a Gaussian type, it can introduce pulse ringing when enabled.

One way to determine the input filter characteristics in the frequency domain would be to plot the frequency response and look for dips or peaks and also look at the roll off rate. Gaussian should not have peaks and dips and should give a smooth roll off.

right, this is the case here, these DSOs have definitely flat and not gaussian response, so some ringing have to be there.

http://www.eevblog.com/forum/testgear/frequency-response-of-your-dso/new/?topicseen#new
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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #21 on: June 26, 2013, 06:42:55 am »
nah, i dont want to take my  Voltcraft apart, it still has warranty i think.
 

Offline bilko

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #22 on: June 26, 2013, 07:09:20 am »
Sorry, but it looks like Rigol paid you to give negative feedback to their compatitors on low end market, like :"all those new scopes sucks, keep buying our outdated Rigol 1052e or pay more for our newer models...;)"
I thought Dave's review was excellent. An unbiased independent review from somebody well qualified and respected for his opinion.

Just for the record I own both Rigol 1052 and Tekway 1102. Both have pro's and con's, although I must say that the Tekway/Hantek is far more quirky than the Rigol. I have much less confidence in the Tekway and usually have to double check my measurements. When you add up all the extra time involved, maybe the Tekway is not so cheap in the end.  I don't get paid by Rigol either.
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #23 on: June 26, 2013, 07:15:11 am »
here we go, i edited my first post in this thread, and i hope answered all the questions/findings.
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Offline LoyalServant

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #24 on: June 26, 2013, 08:27:53 am »
I have a rigol and I have been very happy with it.
Of all the Chinese scopes IMHO they have come the farthest in actually making some decent test gear.

I was with Dave in the beginning... it really was looking good but the slow display and then the lockups were a major, major putoff.

Why is it that they can't seem to get the UI and the functionality all the way at times?
They get like 90% of the way there then fall on their face.

 

Offline bilko

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #25 on: June 26, 2013, 08:39:07 am »

Why is it that they can't seem to get the UI and the functionality all the way at times?
They get like 90% of the way there then fall on their face.

Because in any project it costs 10% to get 90% of the way there and another 90% to get the last 10%.
Most Chinese manufacturer's avoid the last 10%
 

Offline dexters_lab

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #26 on: June 26, 2013, 08:40:47 am »
 :( my rigol is "ancient"
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Offline cloudscapes

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #27 on: June 26, 2013, 09:23:55 am »
I'm not getting much overshoot on high frequency square waves. Then again I'm using the Hantek (not Tekway) and it's the MSO version with logic. Maybe there are differences to the front-end between Hantek and Tekway, or maybe because the MSO line is newer? (I actually don't know)
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #28 on: June 26, 2013, 01:59:47 pm »
ugh... it's ugly. jebus. I mean, the DS1000 series aren't the most attractive things in the world, but damn... the fonts just look terrible and nobs, etc. ugh.

i don't mind its looks actually. The OWON I found ugly but I don't mind the Tekway.
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #29 on: June 26, 2013, 02:06:19 pm »
Ok, so it seems I'm getting my arse chewed out for some operational errors/oversights I made in this video, and rightly so of course.
These things can happen because of the first impressions nature, but that's no real excuse.
I want to add some annotations, so if anyone can point out a time in the video and error I made, I'll correct it.

However, my first impressions conclusions stand.
The scope had poor pulse response, poor trigger jitter/stability, it's slow, and the firmware locked up.
If it turns out that my unit was faulty for some reason, then so be be it. But I can only review and comment on the facts I saw and presented in the video for the unit I had.
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #30 on: June 26, 2013, 05:27:36 pm »
However, my first impressions conclusions stand.

and that's ok, it is your first impression and it should not be changed by any comments etc.


The scope had poor pulse response,

yes, the scope you tested have have pure response, it might be faulty unit, manipulated unit
or one of the units with bad response (see my first comment in this thread)


poor trigger jitter/stability,

yes, the scope you tested is having 83EB FPGA design which sucks. The explanation and possible
solution is in my fist comment in this thread, but this does nt change anything on first impression.


it's slow

yes, it is slow as hell, as i mentioned in my first reply in theis thread only 4k and 40k are useful for
daily work, the 512k/1M/2M are for one off measurments. Actually if someone worked with older TEK
DSO with lot of memory then there would be no change^^


it's slow

and something like XY-mode with 512k memory and dual window is actually an bug, there is no other name
for waiting 5 seconds to get an key response. I have no idea WHY this is sill enabled.


and the firmware locked up.

yes it does, this could be fw revision related


If it turns out that my unit was faulty for some reason, then so be be it. But I can only review and comment on the facts I saw and presented in the video for the unit I had.

you know what, i could be the person protecting something here, but i don't see a reason to protect anything.
The first impression is first impression, when someone got faulty or "monday unit" it still does not matter, the first
impression stays the same. There should be no "monday units" nor faulty if QC would be properly working.

Same for firmware bugs, sure when some not fixed yet then they not fixed, but in principle manufacturer (or at least dealer)
should have installed latest firmware to avoid some revision issues, but that was not the case for your unit.
Does it have any influence on your impression? not at all, you got what you got any saw what you saw, and that's ok.

In my opinion you don't have to add any annotations (of course some fixing RTFM are always good). This is test gear and it have to work directy, there should be no locks or bugs, no user/community or what so ever "aftersale solutions". People producing test gears have to understand that they have to be reliable, shit, imagine a car which stops reacting on anything when you try to accelerate too fast when it's cold (i remember i got such E-class MB few years ago, THAT was a dangerous crap) or imagine someone on the gas station (which can be compared to forum) tells you "hey, you could use ferrari engine, then your car would drive properly and not jump around" Your answer would be probably "F* what?" So no, even if there are user made solutions to fix x or y and a and b is RTFM and .... it still does not change anything on first impression!
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
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Offline lemon

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #31 on: June 26, 2013, 10:10:10 pm »
Probably this scope is faulty!

But I have a concern about how the scopes demonstrate the square pulse. And the test done with the same signal generatoror and the same 50 Ohm resistor.
OK, this Tekway unit has a lot of ringing and over or undershooting.
Rigol's scope has a identical pattern without any over or under-shooting.
Agilent and Owon has a almost identical patterns that differs than Rigols.

Wich pattern is true, Agillent/Owon or Rigol. For me the pattern of Rigols it seems to have a lot of smoothness.
What is your opinion for this differences?
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #32 on: June 26, 2013, 10:28:46 pm »
Dave, why did the distributor send you a faulty scope? That's strange.
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Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #33 on: June 26, 2013, 10:35:06 pm »
Dave, why did the distributor send you a faulty scope? That's strange.

I have received no notification that this was a faulty or suspect unit at all. So I can only presume it is a good and typical performance unit unless I hear otherwise.

Tinhead is saying there are several hardware versions that have different performance?
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #34 on: June 26, 2013, 10:38:52 pm »
Probably this scope is faulty!
But I have a concern about how the scopes demonstrate the square pulse. And the test done with the same signal generatoror and the same 50 Ohm resistor.
OK, this Tekway unit has a lot of ringing and over or undershooting.
Rigol's scope has a identical pattern without any over or under-shooting.
Agilent and Owon has a almost identical patterns that differs than Rigols.
Wich pattern is true, Agillent/Owon or Rigol. For me the pattern of Rigols it seems to have a lot of smoothness.
What is your opinion for this differences?

Unless the input signal is perfectly terminated etc the bandwidth of the scope bandwith will determine what high frequency content (overshoot/undershoot is an example) is shown.
That is why the 500MHz Agilent differs and shows that higher frequency content.
Of course, that assumes that all scopes have the same rolloff response, which they should ordinarily do to a reasonable order.
In theory the 100MHz Rigol 1052E and Tekway should have had the same "rounded" response that lacked that high frequency content. The Rigol 1052E is the response you would expect, with the DS2000 showing a bit more content, and the Agilent and OWON the most.
From this it is clear that the Tekway has a major problem. What that problem is unclear.
« Last Edit: June 26, 2013, 10:53:01 pm by EEVblog »
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #35 on: June 26, 2013, 10:39:15 pm »
The distributor is weird.  :--
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Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #36 on: June 26, 2013, 10:54:51 pm »
The distributor is weird.  :--

Why?
They had every reason to believe that this was a good production unit, it's not their fault.
 
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Offline Rasz

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #37 on: June 26, 2013, 11:25:05 pm »
The distributor is weird.  :--

That distributor is honest. You can tell he doesnt cheat the "Dave test". After all he will get a lot of customers when he finally scores the big one and gets Daves thumbs up on some product :) Rigol got huge bump in sales thanks to Dave, and that was before eevBlog channel got popular.
 I worked for PC parts distributor over 10 years ago (third in sales in my country, sole distributor of some big brands at the time etc) and it was common for sales/PR people to come down to the service area basement and tell us to find a "perfect unit" because some IT Paper had a hardware shootout. All of a sudden shitty brand CRT monitor/CDrom was scoring perfect marks.
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Offline lemon

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #38 on: June 26, 2013, 11:27:44 pm »
At the "Hantek-Tekway-DSO cack - get 200M..." there is a reference (#1807) of member "rf-loop" about faulty Chinese products.
http://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/1800/

He said:
...
(I have always made "pre-ageing" and tests for every single scope I have sell.
What ever model or brand it is. Also other new equipments. All go to burn in tests before accepted for sell. failed units stop to my barrier and did not go to end users. This is one reason why I do not so much admire these re-shipper sellers who only receive parcels, get orders and send parcels to end users. But cheapest price win - of course, or is it so...

In this time average was around 50% failed after arrive from factory.

Here one fun sample image.
Signal is around 16MHz quite clean sinewave from medium grade generator HP8657B.

Probably this happens to all Chinesse scopes (Rigol, Owon, Siglent, e.t.c).

David, have you all this scope, or you have returned the Owon and Tekway?
OK, I undertand that the scopes with high BW has a lot of frequency content. The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol with 200MHz why seems like other Rigol and not to 300MHz Owon.
Please, if you don't have the Owon and Tekway can you examine the Agilent and Rigol the same frequency with a limited BW?
« Last Edit: June 26, 2013, 11:30:31 pm by lemon »
 

Offline John Coloccia

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #39 on: June 26, 2013, 11:37:08 pm »
Look at time 36:30.  Is that some big DC offset that crept in after the cal?  As an engineer, I really scratch my head and wonder how some of this stuff gets out the door.
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #40 on: June 26, 2013, 11:53:08 pm »
David, have you all this scope, or you have returned the Owon and Tekway?

The OWON and Tekway have gone back, I only had them for a day or two.

Quote
OK, I undertand that the scopes with high BW has a lot of frequency content. The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol with 200MHz why seems like other Rigol and not to 300MHz Owon.

Because it's 200MHz and not 300MHz. Cutting out a harmonic or two can make all the difference.
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #41 on: June 27, 2013, 01:54:40 am »
nah, i dont want to take my  Voltcraft apart, it still has warranty i think.
Does it have a date of manufacture on it somewhere?
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #42 on: June 27, 2013, 02:02:54 am »
At the "Hantek-Tekway-DSO cack - get 200M..." there is a reference (#1807) of member "rf-loop" about faulty Chinese products.
http://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/1800/

He said:
...
(I have always made "pre-ageing" and tests for every single scope I have sell.
What ever model or brand it is. Also other new equipments. All go to burn in tests before accepted for sell. failed units stop to my barrier and did not go to end users. This is one reason why I do not so much admire these re-shipper sellers who only receive parcels, get orders and send parcels to end users. But cheapest price win - of course, or is it so...

In this time average was around 50% failed after arrive from factory.

Here one fun sample image.
Signal is around 16MHz quite clean sinewave from medium grade generator HP8657B.

Probably this happens to all Chinesse scopes (Rigol, Owon, Siglent, e.t.c).

David, have you all this scope, or you have returned the Owon and Tekway?
OK, I undertand that the scopes with high BW has a lot of frequency content. The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol with 200MHz why seems like other Rigol and not to 300MHz Owon.
Please, if you don't have the Owon and Tekway can you examine the Agilent and Rigol the same frequency with a limited BW?

How did you miss this part of that post in big bold red letters?:

And note: This is from APRIL 2011

This is history. This must not connect with today Hantek equipments.

This is probably a demonstration of the problem with the catastrophic hardware revision that Hantek did in 2011 as described elsewhere by tinhead.

 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #43 on: June 27, 2013, 02:06:20 am »
At the "Hantek-Tekway-DSO cack - get 200M..." there is a reference (#1807) of member "rf-loop" about faulty Chinese products.
NO, this was in 2011, affecetd was hw1005, we now at hw1007


The Agilent is 500MHz, the Owon is 300MHz the Rigol 1052 is hacked 100MHz (50MHz) but the other Rigol
with 200MHz why seems like other Rigol and not to 300MHz Owon.

it is not only the 200MHz bw on Rigol DS2202 (Actually 250), it is how the frontend has been developed.
There is a JFET/NPN combination, very similar to what in DS1000E, with good flat response. However Rigol
decided to have more gaussian response here, the resulting waveform shows a littebit less overshoot.

OK, I undertand that the scopes with high BW has a lot of frequency content.

i show differences between bandwidth on exact the same DSO (only the software based filter set to one of the bw below)
a 60MHz Tekway


a 100MHz Tekway


a 200MHz Tekway


and 350MHz Tekway


One can ask "where i got the 350MHz", well, the filter can be set to everything between 60 and 900MHz,
of course with 1GS/s it does not make sense to do anything above 400MHz.

The 350MHz results from pulse measurments, following square signal


has been applied and measured. I use 500MHz probes, so the real frontend rise time is
sqr((1.250ns)²-(0.7ns)²), so 1.036ns. I know that this frontend have flat response so i should
use 0.4 factor to calculate bw (so 386MHz), but i prefer to use mid value (0.4 + 0.34 /2), that ~ 350MHz.


« Last Edit: June 27, 2013, 02:09:41 am by tinhead »
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Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #44 on: June 27, 2013, 02:08:05 am »
Probably this scope is faulty!
But I have a concern about how the scopes demonstrate the square pulse. And the test done with the same signal generatoror and the same 50 Ohm resistor.
OK, this Tekway unit has a lot of ringing and over or undershooting.
Rigol's scope has a identical pattern without any over or under-shooting.
Agilent and Owon has a almost identical patterns that differs than Rigols.
Wich pattern is true, Agillent/Owon or Rigol. For me the pattern of Rigols it seems to have a lot of smoothness.
What is your opinion for this differences?

Unless the input signal is perfectly terminated etc the bandwidth of the scope bandwith will determine what high frequency content (overshoot/undershoot is an example) is shown.
That is why the 500MHz Agilent differs and shows that higher frequency content.
Of course, that assumes that all scopes have the same rolloff response, which they should ordinarily do to a reasonable order.
In theory the 100MHz Rigol 1052E and Tekway should have had the same "rounded" response that lacked that high frequency content. The Rigol 1052E is the response you would expect, with the DS2000 showing a bit more content, and the Agilent and OWON the most.
From this it is clear that the Tekway has a major problem. What that problem is unclear.

Possibly due to this as pointed out by tinhead in an earlier post in this thread?:

- the frontend story  For a long time i was fighting with ppl in German forum, i was wondering why they getting crap waveforms on their scopes where my was looking much better. Long story short said - for (unknown to me) reason Tekway/Hantek changed some resistors in their frontend. Btw, this is the same frontend what Rigol is using in DS1000E (that affected part exists even on DS2000). Of course Siglent/ATTEN are using exact the same frontend, hehe. Anyway, i and some other ppl made lot of measurments and simulations, finally we have working combination, it is even better that original DS1000E and even better than my old Tekway. There is no need to change anything on org. DSOs, but on hacked (or all what need to work over 100MHz, this is why this never was an issue on DS1000E). All the necessary information about is in the Tekway hack thread: http://www.eevblog.com/forum/testgear/hantek-tekway-dso-hack-get-200mhz-bw-for-free/msg212054/#msg212054
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #45 on: June 27, 2013, 02:13:30 am »
exact!

So yes, Dave tested DSO where S/N on outside case was from hw1005, but on mainbaord from hw1007, from let me guess Nov 2012^^ I didn't saw 2ns/DIV timebase, so for sure 200MHz bw was not enabled, but it is actually enough to manipulate the bw filter (like in my posting just above, ups, on bottom of page 3 here). When Daves DSO have mainboard from Nov 2012, then it was for sure affected with bad resistors (well, they not bad, they only bad if bw is higher than 100MHz, hehe). The amount of ringing/overshoot is actually typical for "hacked" DSO with not proper components in frontend, but as i said, bandwidth does not need to be set by model number, it can be as well set with a special file to what so ever (don't forget Nyquist).

This is response from original 200MHz Tekway with not affected mainboard (RG174 and 50R terminated)


and here the same signal measured on TDS754A


here the same signal however measured with HF512 500MHz passive probes and original not affected 200MHz Tekway


and here with TDS754A and 1GHz active probes



So once again, originaly a 200MHz DSO was having already good response, this has been changed for some unknown reason (i assume f* cost savings) end of 2011 and was like that until i don't know, maybe even today. My last mainboard was from Jan 2013 and it was still wrong, however, other people with newer DSOs reported no issues, so probably Tekway/Hantek changed it back.

The pictures above are taken on unmodified Tekway, the picture here is from affected unit (and hacked to 200MHz, again, not hacked no problem at all, but hacked is simply crap response), so you can see the ringing and overshoot:


isn't that like on Dave's video? i would say yes, it is.


such unit (and even the original working DSOs!) can be however improved to have much besser response,
here RG174 and 50R terminated


and with HF512 500MHz passive probe:


« Last Edit: June 27, 2013, 02:49:40 am by tinhead »
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
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Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #46 on: June 27, 2013, 02:25:04 am »
I also find it interesting that the reviewed Tekway DST1102B had no fan while the mainboard identical Hantek DSO5102B apparently does:

http://www.circuitsathome.com/measurements/hantek-dso5000-series-oscilloscope-modifications-part-2-reducing-fan-noise

Could this mean that Tekway has found that the fan is not really needed in the first place or have they used larger heatsinks for passive cooling?  Is so, that would be great as we'd all prefer silent test equipment.
« Last Edit: June 27, 2013, 02:29:51 am by Winston »
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #47 on: June 27, 2013, 03:05:46 am »
Could this mean that Tekway has found that the fan is not really needed in the first place or have they used larger heatsinks for passive cooling?  Is so, that would be great as we'd all prefer silent test equipment.

Tekway told me once that these DSOs can run without fan, in most countries ^^

Later as Hantek started the hw1005 production they recognized that the heat inside the DSO is too high (actually not, but when you overclock ADCs and run FPGA at high speed then you might see more distortion without heatsinks and fan). So they started to populate fan and as well heatins for FPGA and ADCs (originaly there was nothing and it was running well - but hot^^).

The most heat is being produced by the KA378R33 lin reg on PSU PCB. Some people mounted here bigger heatsink, others used dc/dc converter from TI (PTG08080WAZ), the last idea was to use Mircrel HELDO (which is low noise dc/dc and lin reg in one package).

Some simply mounted the fan directly over the KA378R33, replaced the org. 7812 (for fan) by 7805 or 7808 to slow down it a bit.

I'm using right now Mircrel HELDO with 12V Noise Blocker fan, running at 5V, so very slow and very silent. I could use no fan now, but i prefer to not stress components to much. 

For MSO owners: it is important to know that MSO models are consuming more current (0.5W more dissipation on the KA378R33)
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Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #48 on: June 27, 2013, 11:08:32 am »
Oh, Dave's Tekway is really crappy... I want to believe that other Tekway scopes are better.
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Offline John Coloccia

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #49 on: June 27, 2013, 11:34:31 am »
I guess the real question is why would I buy this over a new Rigol, or a used something else.  Seems like a hard sell.  Glad Dave is around to flesh some of this stuff out for people like me that don't get to take these things for a test drive.
 

Offline Hypernova

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #50 on: June 27, 2013, 11:54:10 am »
David, have you all this scope, or you have returned the Owon and Tekway?

The OWON and Tekway have gone back, I only had them for a day or two.

Note to self: If you want Dave to post his review ASAP set a return date on your stuff.  :D
 

Offline Stonent

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #51 on: June 27, 2013, 12:14:55 pm »
David, have you all this scope, or you have returned the Owon and Tekway?

The OWON and Tekway have gone back, I only had them for a day or two.

Note to self: If you want Dave to post his review ASAP set a return date on your stuff.  :D

Yeah but Dave does not return stuff mailed to him. He's said that at least once or twice. I think the scope he got was borrowed from a local supplier.  I don't think it was new because it had a sticker of the company on the side that looked like it had been partially caught in the groove on the inside or closed on it. It might have been a shelf display.
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Offline TRIO_Smartcal

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #52 on: June 28, 2013, 06:21:09 pm »
The distributor is weird.  :--

That distributor is honest. You can tell he doesn't cheat the "Dave test". After all he will get a lot of customers when he finally scores the big one and gets Daves thumbs up on some product :) Rigol got huge bump in sales thanks to Dave, and that was before eevBlog channel got popular.
 I worked for PC parts distributor over 10 years ago (third in sales in my country, sole distributor of some big brands at the time etc) and it was common for sales/PR people to come down to the service area basement and tell us to find a "perfect unit" because some IT Paper had a hardware shootout. All of a sudden shitty brand CRT monitor/CDrom was scoring perfect marks.

Thanks for the vote of confidence in our honesty. It is appreciated.  To set the record straight here's the history of this instrument.
It was not a new unit.
It had been sold previously and had developed a problem while the customer had it.
The company that bought it needed it for their business and they were unable to work without it.
We did not wait for a spare mainboard to repair it.
We gave the customer a new scope from our stock to get him back to work immediately.
When we got the replacement board from Tekway we fitted it in this unit.
That is the reason the serial numbers on the screen and on the back are different.
(If Tekway is reading this, my suggestion to them is that they should also send distributors a new serial number label when they send a replacement main board.)  So that's the history of that one.

Anyway, because the scope had been used already it obviously could not be sold as new, so we just use it as a spare scope in the office or for demo. Dave wanted some low-end scopes to play with so we gave it to him with the Owon.

First impressions are lasting impressions and Dave's first impression of the TEKWAY started off well but then deteriorated and not all of that was attributable to the scope.  What I thought was missing or was not considered is product positioning in the marketplace. (this applies to the OWON as well)

Personally, I think because Dave was in a rush as we needed  it back here, there was not as much thought put into what he was doing. A good example is the  X-Y situation. "Seek to understand not to criticise" is generally what engineers do and not a lot of that was present in either of the "reviews." 

We've sold a lot of these Tekway scopes and we've had 2 failures (this was one of them) and we've had no negative customer feedback.

What was surprising in the review was the pulse response of the OWON. For a sub-$1500 scopes with 300 MHz it was excellent. It represents value for money in it's price bracket.  It's got all the basics a scope needs for waveform capture and viewing in terms of Bandwidth, Sample Rate and Memory Depth. Who else offers a 300 MHz with similar specs for under $1,500?

As for the TekWay no-one I know of no company that offers a 100 MHz scope for under $500 with a hi-res display as good as the Tekway including good basic scope specs and some neat measurement functions.

As said above, I think we saw Dave's impressions from a hurried perspective. I don't disagree with the pulse response issue, it certainly could be better, but on-balance (and that's what was missing) one area of weakness is certainly overcome by the positives when this sub-$500 scope is positioned properly in the marketplace.  And if you want the best of everything especially signal fidelity then move up the price bracket and buy Agilent.  Dave know's and loves the X-series and spent a lot more time reviewing it!

 
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Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #53 on: June 28, 2013, 06:52:16 pm »
As said above, I think we saw Dave's impressions from a hurried perspective. I don't disagree with the pulse response issue, it certainly could be better, but on-balance (and that's what was missing) one area of weakness is certainly overcome by the positives when this sub-$500 scope is positioned properly in the marketplace.

I'll have to disagree with Charles here.
It wasn't just the crappy pulse response. It was also the very substantial trigger jitter issue, plus the firmware lockups.
I can look past the firmware lockup issue, that can be fixed in software, but I simply cannot recommend a scope that does not give measurement confidence in the signal you are viewing. The trigger issues and pulse response on their own are enough not to get this scope a recommendation. But it has a double whammy there + firmware issue.

And I was considering the market space and competition. In Oz the Rigol 1052E is $100 cheaper for the same bandwidth, and has none of these issues, it is a rock solid and well proven device.
Sure, the Rigol has a smaller screen and few less features, but is that worth trading measurement confidence for? In my book, no way, but each to their own.

Quote
And if you want the best of everything especially signal fidelity then move up the price bracket and buy Agilent.  Dave know's and loves the X-series and spent a lot more time reviewing it!

The sub $400 Rigol has excellent signal and trigger integrity.
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #54 on: July 01, 2013, 12:58:52 am »
sorry Dave, but that bullshit what you said. Maybe you don't know, or just don't care, but when you would spend a minute to compare schematics of Rigol and Tekway you would recognize that there can't be difference in signal/trigger. Jitter, well, when you ever did FPGA design you would know what jitter is possible on FPGA when using non-dedicated clock out pin, and btw, Rigol is using even 5 clocks, where Tekway only 4 clocks, so the chance to get more distortion due jitter from ADC clock is even higher on Rigol.

But anyway, it was your first impression^^ so actually didn't mater if that Tekway was broken or not or if ti was one of these unit what didnt have nice response after hack or not factory calibrated or what so ever (because a working DSO is response like on my pictures).

I remember i got brand new MB E350 few years ago, and few days after i got it it stopped while i was about to overtake another car, no steering, no anything, i just made to brake/slow down to hide my ass between another car and some trees. Sure MB updated firmware, the car was again ok for some time, then that shit happened again. It was a good car, but i repalced it after that by another brand, and honestly i tooks 2-3 years for me to trust MB again. So yes, my first impression was "no thanks" even if i was only in the 2% of broken firmware group, but that wasn'T important for me but only my personal first impression.
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Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #55 on: July 01, 2013, 05:48:56 am »
Firmware in a car.  :wtf: I would rather use this Lada instead.
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Online SeanB

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #56 on: July 02, 2013, 01:49:00 am »
My car has 5 sets of firmware in it. So far ( touch wood) no issues with that part, just the usual mechanical parts wearing out.
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #57 on: July 02, 2013, 10:06:36 am »
To set the record straight here's the history of this instrument.
It was not a new unit.
It had been sold previously and had developed a problem while the customer had it.
The company that bought it needed it for their business and they were unable to work without it.
We did not wait for a spare mainboard to repair it.
We gave the customer a new scope from our stock to get him back to work immediately.
When we got the replacement board from Tekway we fitted it in this unit.
That is the reason the serial numbers on the screen and on the back are different.
Never give Dave a potentially faulty scope. Always give him a new unit, if you want a positive review.


« Last Edit: July 02, 2013, 11:29:31 pm by Hydrawerk »
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Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #58 on: July 02, 2013, 12:25:28 pm »
sorry Dave, but that bullshit what you said.

I can only base my opinion on the scope I tested, anything else would be 2nd hand opinion.
That's what this forum is for, if you have experience with the scope add your own opinions.
Then based on that info, people can make up their own minds.
I have facts and video evidence of why I said what I said about the Tekway, it was not bullshit.
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #59 on: July 02, 2013, 12:28:17 pm »
Never give Dave a potentially faulty scope. Always give him a new unit, if you want a pisitive review.

To be fair, Charles had no way of knowing that it would have response issues, trigger issues, or firmware lockups unless he tested it in the exact same way I did.
By all accounts other people have had the same issues, and it seems to be a bit of "pot luck" about which hardware/firmware combo you get.
 

Offline Stonent

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #60 on: July 02, 2013, 02:20:13 pm »
Well I see a few ways where this could go.

Option A: Nothing is done and the review stands.

Option B: If Trio is close enough to where Dave is, maybe he could drop by with his camera and repeat the same test on another unit (if available)

Option C: Trio or Tekway mails a unit to Dave for a follow-up test.

Option D: Someone else repeats the full test on video and Dave provides a link to it in his video.
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Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #61 on: July 02, 2013, 10:20:50 pm »
sorry Dave, but that bullshit what you said.

I can only base my opinion on the scope I tested, anything else would be 2nd hand opinion.
That's what this forum is for, if you have experience with the scope add your own opinions.
Then based on that info, people can make up their own minds.
I have facts and video evidence of why I said what I said about the Tekway, it was not bullshit.

i didn't spoke about what you saw on the DSO which you tested, that was for sure crap.

The statement "you said bullshit" is related to "Rigol is having better"
- excellent signal
- trigger signal
- jitter
- pulse response


This is because as already said in Tekway thread, both Rigol and Tekway have:
- same frontend
- same trigger circuit
- same mux/opamps/ref
- same FPGA
- same ADCs

so from a signal flow point of view there is no winner, both are exact good/bad, the signal from BNC to FPGA is looking on both devices same. But hey, maybe Rigol is soldered by chinese virgins giving the DSO some magic ? I don't know, but as EE i doubt that.
« Last Edit: July 02, 2013, 10:35:33 pm by tinhead »
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Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #62 on: July 02, 2013, 11:45:11 pm »
maybe Rigol is soldered by chinese virgins giving the DSO some magic ?
That's it. Her name is Anna Ohura.
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Offline rf-loop

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #63 on: July 03, 2013, 12:28:16 am »
maybe Rigol is soldered by chinese virgins giving the DSO some magic ?
That's it. Her name is Anna Ohura.

Perhaps she can not get even visa for mainland China.

If japanese or half japanese people go to working in some chinese factory there come perhaps some problems.... depends...

When someone talk about chinese working in chinese factory and you show japanese public w....e  picture...  really difficult to understand.
« Last Edit: July 03, 2013, 12:30:31 am by rf-loop »
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Offline John Coloccia

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #64 on: July 03, 2013, 01:08:59 am »
So I'm a little confused.  The scope had problems and was returned.  Tekway sent out a board intended to fix the scope.  Scope was sent to Dave for review and it he finds problem after problem.  Someone else claims that the reviewed scope is just faulty and that the scopes have no issues....even though this particular scope originally had issues, and the new board that was sent out to fix them also has issues.

What have I missed?  It's not Dave's fault he has a crap scope.  Maybe someone out there will take a brand new, off the shelf, factory sealed scope and send it to him for test.  What else should he do?  Tell everyone to disregard what he's found because someone claims the Tekway and Rigol should theoretically have the same performance?  Who are we going to believe...the specs or our lying eyes?  Whatever front-ends, ass ends, book ends and whatever other ends the scopes share, this isn't a verification by inspection.  It's a hands on review of what was believed to be a representative sample.

The day Dave starts tip-toeing around bad performance is the day his blog becomes useless.  Someone send him a new scope.  I'm sure he's anxious to see one that's not full of excuses.
 

Offline rsjsouza

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #65 on: July 03, 2013, 02:15:06 am »
 :-+
The Rigol and the Tekway may even have similar front ends, but zillions of other factors may be factored and possibly cause the problems seen in the review. 

The one that strikes me the most is temperature. How several other manufactures see the need (and added costs) to slap a damn fan to push cold air into the case (or pull it out, it doesn't matter) while Tekway gets by without it? One of the easy way out is to clock down the main processors and digital circuitry to reduce heat from them and from the power regulators (could explain the slow GUI, maybe?). This is a potential candidate to cause runtime bugs if the firmware is not properly validated to run in this new frequency (which could include faulty reads from the interface with the analog front ends, but I am not an expert in this). 

Of course I don't have the information tinhead has, but in the light of the review that seemed very plausible.
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Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #66 on: July 03, 2013, 03:54:11 am »
Of course I don't have the information tinhead has, but in the light of the review that seemed very plausible.

i actually said everything what new to be said, it is not that hard to get one or two pages back and read my technical explanation of that what Dave saw on the test unit.

So I'm a little confused.

yes you are, completly.


ok, i will shot a short video, it seems that some ppl need visual things and not just few lines of "technical crap" text.
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Offline Bored@Work

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #67 on: July 03, 2013, 03:58:23 am »
Someone else claims that the reviewed scope is just faulty and that the scopes have no issues....even though this particular scope originally had issues, and the new board that was sent out to fix them also has issues.

What have I missed?

That "someone" is tinhead, no need to use the common backstabbing tactics of referring to "someone" and THEM.

And what you missed is that tinhead  doesn't say these oscilloscopes have no issues. For a year or two he is raising hell with Hantek/Tekway to get stuff fixed. What he is saying is that, based on his experience with multiple hardware and multiple firmware versions, that particular oscilloscope did not behave like what is considered "normal" for these oscilloscopes.
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Offline John Coloccia

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #68 on: July 03, 2013, 05:07:35 am »
Someone else claims that the reviewed scope is just faulty and that the scopes have no issues....even though this particular scope originally had issues, and the new board that was sent out to fix them also has issues.

What have I missed?

That "someone" is tinhead, no need to use the common backstabbing tactics of referring to "someone" and THEM.

And what you missed is that tinhead  doesn't say these oscilloscopes have no issues. For a year or two he is raising hell with Hantek/Tekway to get stuff fixed. What he is saying is that, based on his experience with multiple hardware and multiple firmware versions, that particular oscilloscope did not behave like what is considered "normal" for these oscilloscopes.

Backstabbing?  I just didn't see any reason to really call him out because it's not anything personal about him.  I read where he's fighting Tekway to get the issues fixed, but I also read where he calls "bullshit" and basically says Dave should base his opinion on some schematic, not the actual scope.   :-//  Geez...just get him non-broken scope to test.
 

Offline Stonent

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #69 on: July 03, 2013, 05:41:27 am »
- same FPGA

That one's a bit of a stretch, the only thing you can get on that is theoretical maximum gate speed, but they have to be programmed.
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Offline rsjsouza

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #70 on: July 03, 2013, 06:37:39 am »
i actually said everything what new to be said, it is not that hard to get one or two pages back and read my technical explanation of that what Dave saw on the test unit.

ok, i will shot a short video, it seems that some ppl need visual things and not just few lines of "technical crap" text.

Don't be a jerk; I am not your short attention span person that can't read more than five lines of text and can't understand what was just read - I meant all the information and experience you gathered by plowing through the circuits and comparing board revisions and model numbers. I am not against you or the Tekway brand, I am talking about the reviewed scope and a possible explanation for what may be happening with it (it is clear from my post).

I stand for what I have said before, where your explanation about the front end and hardware revisions only covers part of the problem. All the other problems related to the GUI and the lockups can be (up to a certain extent) be explained by what I said - even some signal problems, but as I mentioned before I am not an expert in this particular area.

Therefore, please take off the Tekway shirt and keep a cool attitude. I am discussing the issues seen on the review, not fighting for who or what is better or not. If Tekway is reading these lines, they will surely get something out of this discussion, either figuring out a better system in dealing with repairs done by their official distributors (as suggested by Trio) or recalling older and less performing units with hw1005 hardware.
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Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #71 on: July 03, 2013, 08:20:03 am »
- same FPGA

That one's a bit of a stretch, the only thing you can get on that is theoretical maximum gate speed, but they have to be programmed.

it didn't matter what "program" inside the FPGA, the i/o jitter on non-dedicated "clock out" pins will be always the same. Sure,  i/o standard could have influence as well, but both DSO are using the same ADC / parallel clock termination so we can ignore it. It depends as well on input clock jitter, and for sure was Rigol smart and used dedicated quarz+inverter combination to archieve low jitter, but then they ruined by using another one inverter gate to drive the FPGA. Tekway is using directly crap quarz oscillator.

Whatever both used, it is not good enought^^. No matter what design inside FPGA, the output clock for ADCs will have max 650ps period jitter. So even when we ignore the i/o skew on FPGA, we will have up to 1.3ns period jitter worst case between 2 output clocks. Rigol is using 10ADCs, so 5 clocks (+5 inverted). Tekway is using 8 ADCs, so 4 clocks (+4 inverted). For Rigol it means when sampling with 1GS/s each of the 100MHz clocks is delayed by 1ns, and for Tekway as well 1ns (but clocks at 125MHz). Sure, this are max values, typical you can get less jitter, but it does not matter for product comparision as both products affected in same way. Sure, Rigol can have total higher jitter, but Tekway can have higher gain drift due ADC overclocking.

So you can see pure from hardware point of view you can have only crap results on both^^ The trick both manufacturer using is to check when after rising edge of ADC 1 ->8 (10) the data is showing zero crossing. These values are then taken to build a skew table to allign the sampled data. But of course the interleave distortion is already in the signal (you can observ on both models that when using single shot a  RF wave is more distroted in single shot than when in run mode, for single shot you can't filter out any variation to skew table, for run mode there are some tricks to made signal looking better that it is). The way to work with interleaved ADCs is to measure during calibration the skew (which is different between devices due parts/pcb variance) and to allign all clocks to get same zero cross from all ADCs, but never ever to sample with bad clock and to allign the data afterall. But that's different story. I don't know by 100% who was the first with that idea, from the information about release dates and teardown i would say Instek did it first (and btw, they did it better), then Rigol adapted it into their E models. Short after that others (Tekway/Siglent/ATTEN) adapted it as well. You might find small differences here, like different opamp in S&H on Siglent to reduce the drift on cold DSO, but all these modifications are more or less too small to talk about real differences in signal/trigger integrity.

And yes, firmware A can maybe allign the crap data better than firmware B, as well device A could be better calibrated as deivce B because the technician plugged the cable properly into BNC, and manufacturer A can implement better algos to filter variations as manufacturer B did. But that's are things applied afterall. Knowing hardware on both models, and knowing how they work i know that one can't say "Rigol has excellent signal and trigger integrity" and "Tekway have trigger / jitter issue" at same time. And of course other models using similar/same hardare are affected as well (Siglent/ATTEN).

And once again, there was nothing wrong with Dave's review, he didn't cheated (on purpose'), so yes his statement based on his result is ok. But on the other side i (and other as well) do have working models and i/we know what one can achieve on these DSOs. So there is difference between "Dave's DSO" and "all these DSOs" and all i'm trying to do is to stop people from seeing only "back and white" when there is a rainbow on the sky^^.

I said as well that Tekway/Hantek produced lot of crap in last 3 years (e.g hw1005 disaster or some FPGA design versions), i did said as well that they do firmware issues (sometimes they simply sleeping, like on the long memory in XY trigered mode ... that should be not possible together, but it is and it does produce overflow and dso.exe is crashing^^), but i said as well that they working on it. It is not that the firmware is not sufficient to do most of the work, sure, it is, but there are things like digital filter or equ mode sampling missing/disabled, as well few limitations like zoom in dots mode is not "exact" in last 3 zoom stages. And finally i did said that for a year of so Tekway/Hantek populated very "unfortunate" combination of resistors in frontstage, but this is still within specs on non-hacked DSO but 3-5dB deviations on hacked DSOs - and i did said how this can be fixed (for 8USD).
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Offline marmad

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #72 on: July 03, 2013, 08:37:54 pm »
And once again, there was nothing wrong with Dave's review, he didn't cheated (on purpose'), so yes his statement based on his result is ok. But on the other side i (and other as well) do have working models and i/we know what one can achieve on these DSOs. So there is difference between "Dave's DSO" and "all these DSOs" and all i'm trying to do is to stop people from seeing only "back and white" when there is a rainbow on the sky^^.

I understand all that you're writing - but the question remains - when you buy a $400 - 500 product (or get one for review), should you have to search and install the perfect combination of FW for your hardware in order to prevent hangs and crashes - and make it 'achieve' the performance you expect it should have out of the box?
« Last Edit: July 03, 2013, 10:26:51 pm by marmad »
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #73 on: July 03, 2013, 11:41:00 pm »
I understand all that you're writing - but the question remains - when you buy a $400 - 500 product (or get one for review), should you have to search and install the perfect combination of FW for your hardware in order to prevent hangs and crashes - and make it 'achieve' the performance you expect it should have out of the box?

- because not everybody can spend 1000$ (EU price) for better, but still not bug free DS2072
- because all the others in < 1k USD have issues/not that good things as well, like smaller display, 3-4 times higher ground
  noise (after DIY fix!), less functions, smaller display resolution and finally less support from manuafcturer or community.

these Tekway/Hantek "P" models, with 24k memory, they costs 260USD delivered to EU, that's 240EUR in Germany (with tax).
When one buy such DSO and spend 8EUR for other resistors, then it didn't matter how bad the forntend was populated originaly,
such DSO would have perfect response up to 220MHz, no issues with "long memory is slow", no "XY mode and long memory slow",
no "firmware hangs while long memory and alterate trigger enabled".  So what left from Dave's review? Nothing.

But even a Voltcraft/Hantek/Tekway for regular price can be, even if you got crap version, fixed for few bucks. Yes, why i have to fix
DSO when there are others ... wait, what others? Owon? Sure, 50USD for replacement PCB and 50USD for shipping, lol, and then the gnd noise is still 3-4 times higher than on Tekway. Sure, such B/BMV/MSO models will still be ass slow responding when long memory enabled,
but that's different story (nobody is forcing ppl to enable all the memory all the time, but if then buy Owon, simple).

The whole game will change a bit when Rigol DS1000Z will be available, but still, you will not get any other DSO with big screen, fast update and 200MHz for 250EUR. Sure, one need maybe to solder few resistors, but i think a DSO will be anyway used by ppl who know what to do with soldering iron? I hope so.
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Offline rsjsouza

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #74 on: July 04, 2013, 12:02:36 am »
The whole game will change a bit when Rigol DS1000Z will be available, but still, you will not get any other DSO with big screen, fast update and 200MHz for 250EUR.
Maybe we won't have to wait for too long: Franky is just showing off his new toy here :)
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #75 on: July 04, 2013, 04:27:35 am »
The whole game will change a bit when Rigol DS1000Z will be available, but still, you will not get any other DSO with big screen, fast update and 200MHz for 250EUR.
Maybe we won't have to wait for too long: Franky is just showing off his new toy here :)

ahh cool! when you do teardown? :)
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #76 on: July 04, 2013, 06:43:41 am »
Tinhead - I'm definitely reading your posts and greatly appreciate them.

A few questions:

"Long memory (4k and 40k are working however fast and good, it make as well to enable "50" refresh rate in display menu to speedup a lot knobs response) is just crap slow. Sure, it can be used for one off things, but to work all the time enabled you would get crazy. The reason is actually simple, they reading the whole 1M from sample buffer (SRAM connected to FPGA and CPLD) into the ARM buffer and working with that data (measurments, what so ever) and displaying that whole waveform"

Could this eventually be corrected in firmware?

"jitter, yeah. I actually made measurments (with proper equeipment) and reported the skew between clocks, Tekway almost fixed it (not perfectly but definitely acceptable).. Since Nov 2012 they have again new FPGA design (83EB) which seems to be worse than the working one (83E9)"

Is jitter the main problem with this FPGA design version?  Could this eventually be corrected or compensated for in firmware?  I understand that the FPGA version in a particular 'scope can be determined by looking at the "hardware version" in the "system information" screen?

"the frontend story :P For a long time i was fighting with ppl in German forum, i was wondering why they getting crap waveforms on their scopes where my was looking much better. Long story short said - for (unknown to me) reason Tekway/Hantek changed some resistors in their frontend. Btw, this is the same frontend what Rigol is using in DS1000E (that affected part exists even on DS2000)"

Is there a manufacturing date range or something on the 'scope's "system information" screen which could be used to determine if a given 'scope has the front end resistor values that cause this problem?
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #77 on: July 04, 2013, 08:33:09 am »
A few questions:

sure

"Long memory is just crap slow"

Could this eventually be corrected in firmware?

sure, others (Rigol) is doing this properly with 2 times slower DSP (from a pure bus speed), the FPGA/SRAM/CPLD are not an issue here.


Is jitter the main problem with this FPGA design version?  Could this eventually be corrected or compensated for in firmware?  I understand that the FPGA version in a particular 'scope can be determined by looking at the "hardware version" in the "system information" screen?

jitter is the main problem with ADC designs, ADC driven by FPGA is fr sure acceptable, but only up to x bit and y input signal frequency.

Check that app note for details: http://www.analog.com/static/imported-files/tech_docs/clock_optimization.pdf
EDIT: there is whole section about FPGA and ADC.


Could this eventually be corrected or compensated for in firmware?  I understand that the FPGA version in a particular
scope can be determined by looking at the "hardware version" in the "system information" screen?

compensation is as good as the jitter itself, it is more or less "random". Talking about Tekway, the 800MS/s was never an issue. I did measured the ske between clocks and that was under 50ps difference, that was good. In 1GS/s mode however the skew was crap, that was FPGA design 83E8. The 83E9 is better here, there is improvement to 1GS/s mode. I haven't measured 83EB design, but pure visually it is worse than 83E9. Even after factory calibration and customized bw filter (to 60MHz bw to filter any crap out) the 1GS/s mode on 83EB design is not looking good. So the compensation fails already here. The only "working" design is for me 83E9, and only the DSO or Handheld version (handheld have the best FPGA design). MSO does have as well version 83E9, but something is wrong there, probably due the fact that MSO is using multiple FPGA synced to each other.

The last part of the hardware version is the FPGA design version, actually 555583Ex is it.

"the frontend story :P"

Is there a manufacturing date range or something on the 'scope's "system information" screen which could be used to determine if a given 'scope has the front end resistor values that cause this problem?

no, there is no way to see it from outside.
« Last Edit: July 04, 2013, 08:37:33 am by tinhead »
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Offline rsjsouza

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #78 on: July 04, 2013, 10:52:35 am »
ahh cool! when you do teardown? :)
Ahhh, I can only wish to have one of these beauties with me for a teardown... With twin babies such oscilloscope is worth a good load of diapers, formula, wipes...   :-/O
« Last Edit: July 04, 2013, 10:54:17 am by rsjsouza »
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline Ericho

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #79 on: July 05, 2013, 05:43:40 am »
I'm in the market for a new DSO.
After this and some of the other video's, like the Owon one, I'm staying away from the current +-400$ scopes.

70-100mhz is more then I need but I do want something that can be switched on and be trusted to be correct.

The ds1000z may be worth waiting for ? I hope dave gets a hold of one and does his thing on it  :-+

Eric
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #80 on: July 05, 2013, 06:48:25 am »
I do want something that can be switched on and be trusted to be correct.

sure, equipment have to work within its own specs without any hacks/tricks/quirks.

On the other side the quality of measurment (the result) depends on the person infront of the test equipment,
when there is something wrong (with DUT, configuration or test equipment itself) the operator have to identify it.
Most people fail already here, having then an equipment what is not within specs (which was for sure with all these ringing on Dave's Tekway video) makes the situation crazy complex.

I can only recommend to have always spare probes, cables, terminators, etc. (and of course test them from time to time).
For beginners i recommend to have as well signal generator (an integrated generator with help function like on Agilent, Tonghui, Instek and soon Rigol is really usefull here) to test/double test equipment when measurment results looks wired.
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline Winston

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #81 on: July 05, 2013, 11:12:02 pm »

"Long memory is just crap slow"

Could this eventually be corrected in firmware?

sure, others (Rigol) is doing this properly with 2 times slower DSP (from a pure bus speed), the FPGA/SRAM/CPLD are not an issue here.
 
How long has this been a problem and why hasn't it been corrected?  This is a major flaw.  There is no use in having great memory depth if you can't use it.
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #82 on: July 05, 2013, 11:28:50 pm »
Option A: Nothing is done and the review stands.

The review will stand. I tested a unit that had crap pulse response, crap trigger jitter, and locked up.
I can fix any errors I made with annotation, but they don't affect my overall opinion of the scope which was based mostly on those 3 major things.

Quote
Option B: If Trio is close enough to where Dave is, maybe he could drop by with his camera and repeat the same test on another unit (if available)

Charles is just down the road, he can drop by any time with a replacement.
Although frankly I don't think that many people care for another follow up video?
But if Charles thinks I've done him wrong with my review, I'll happily do it for him.
But the answer is obvious anyway. Fix those 3 issues, well, two actually, the firmware lockup is not major, and it's not a bad little scope for the price bracket.
Would get a resounding thumbs up? No, because there is still too much uncertainly in what scope people are going to get. It is not a proven scope. But it would not get a thumbs down if those things are fixed.

Quote
Option D: Someone else repeats the full test on video and Dave provides a link to it in his video.

Everyone is always welcome to post a video repose, the button is right there on Youtube. All approve all on-topic responses even if they are critical of me.
 

Offline EEVblog

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #83 on: July 05, 2013, 11:44:29 pm »
Backstabbing?  I just didn't see any reason to really call him out because it's not anything personal about him.  I read where he's fighting Tekway to get the issues fixed, but I also read where he calls "bullshit" and basically says Dave should base his opinion on some schematic, not the actual scope.   :-//  Geez...just get him non-broken scope to test.

Also, as I mentioned in the video, Tinhead knew I had the scope and sent me a whole host of info before I finished shooting about how he's been helping/fighting Tekway to fix issues for years etc, and gave a big list (no less than 11 items) of "bad things" about the scope and stuff that didn't work etc.  If anything he helped reinforce my opinion that this scope (or precisely, the scope I had) was crap.
At the time that info did not include the pulse response or trigger jitter, I found those major issues myself, which for me were the deal breaker.
Now he calls my opinion of thing Bullshit? I don't get it  :-//
 

Offline Hydrawerk

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #84 on: July 06, 2013, 12:38:36 am »
Well, one thing is clear. This Tekway is not a new scope. It was developed in 2009. It should be bug-free after four years.
On the other hand, I can tolerate bugs of Rigol DS2000 or DS1000Z. Both scopes are younger than one year.
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Offline ddavidebor

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EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #85 on: July 06, 2013, 01:16:34 am »
Well, major bug MUST be stopped before a product is released
Davide Bortolami,
Fermium LABS srl
 

Offline itdontgo

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #86 on: July 23, 2013, 10:11:17 pm »
Option D: Someone else repeats the full test on video and Dave provides a link to it in his video.

I might take you up on that  ;)  I have one the 70MHz Hantek jobs.  I can only compare it to my analogue scope but it's been really good so far.  It looks different from yours (different mold, redesigned graphics).  It's never locked up and has been really straight forward to use so far.  I just need to get myself a Jim Williams pulser to check that front end!  Admittedly I've only used it at a few MHz so far.  The trigger is a bit mad but it's useable.

« Last Edit: July 23, 2013, 10:12:56 pm by itdontgo »
 

Offline itdontgo

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #87 on: July 23, 2013, 10:21:07 pm »
Jesus I thought my office was a shit hole


Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #88 on: July 23, 2013, 10:32:12 pm »
Option D: Someone else repeats the full test on video and Dave provides a link to it in his video.

I might take you up on that  ;)  I have one the 70MHz Hantek jobs.  I can only compare it to my analogue scope but it's been really good so far.

i've actually even posted compare pictures and as well links where other ppl compared with other DSOs, but that seems to be not good enought ^^

http://www.eevblog.com/forum/blog/eevblog-487-tekway-dst1102b-oscilloscope-review/msg252723/#msg252723
http://www.biasedlogic.com/index.php/hantek-dso1062b-dso1102b-dso1202b-vs-5gss-lecroy-waverunner/


on the other side, who cares? Hantek/Tekway new hardware seems to have different forntend anyway (not a Rigol copycat anymore)
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 

Offline tinhead

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Re: EEVblog #487 - Tekway DST1102B Oscilloscope Review
« Reply #89 on: July 23, 2013, 10:40:31 pm »
Also, as I mentioned in the video, Tinhead knew I had the scope and sent me a whole host of info before I finished shooting about how he's been helping/fighting Tekway to fix issues for years etc, and gave a big list (no less than 11 items) of "bad things" about the scope and stuff that didn't work etc.

that's truth

Now he calls my opinion of thing Bullshit? I don't get it  :-//

but i will not explain it again. If you wish just go back, read my postings and you will get it. It not, well, then not.
« Last Edit: July 23, 2013, 10:52:26 pm by tinhead »
I don't want to be human! I want to see gamma rays, I want to hear X-rays, and I want to smell dark matter ...
I want to reach out with something other than these prehensile paws and feel the solar wind of a supernova flowing over me.
 


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