Author Topic: EEVblog #487 - Tekway DST1102B Oscilloscope Review  (Read 44455 times)

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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 »
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.
 

Online 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 »
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 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.
Amazing machines. https://www.youtube.com/user/denha (It is not me...)
 

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 ^^

https://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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