Author Topic: Hantek - Tekway - DSO hack - get 200MHz bw for free  (Read 1646547 times)

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Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #500 on: April 23, 2011, 12:49:09 pm »
If Tekway disable the UART port,What can I do?My dso 's UART not transmit any message.Before this,I let after-sales department to handle this so-called update .I don't know is or isn't this(http://www.xici.net/#b1293165/door.asp)
How am I to open the UART port? what to writer the vivi.bin or the original bootloader ,I want knoe the specific address or offset ?

Currently the UART is still open, just connect to uart and boot the DSO. You should see some messages in the window.
You can interrupt the DSO application by CTRL+C and Enter. Sometimes you have to do it during the dso is booting linux or just
multiple times, but it still works.

I don't think they will disable UART port, but if then you have still other way to connect to shell:
- over LAN-Addon board (i posted full schematics and Eagle brd files, so you can produce your own LAN board)
- you can dump the firmware, patch it and restore on s3c2440 board (for test reason). I did it before for older Tekway DSOs,
all you need is to stop the rcS from executing dso.exe by simple hex editing the firmware dump. After that i was able to connect
over UART, do changes and restore back. So this way will alyway work for the current Tekway DSOs (it is Linux, so there is alway a hole).
- we can still create a fake firmware update files, downgrading the firmware to version where UART is working.

So just don't worry, there is nothing they can do against.

Vivi is always loaded from adress 0x0 of the NAND, the maximum length in Tekway DSOs is currently 128kb (the org. Tekway vivi is about 94kb only, but there is 128kb spae reserverd for vivi, i did used matching supervivi and own compiled vivi already) , so you can create your own vivi as long it is not larger than 128kb and "burn" to NAND 0x0 address.

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 carloscuev

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #501 on: April 23, 2011, 04:41:42 pm »
Hello tinhead, first of all I want to thank you for your time and dedication to this subject, this thread definitively made me decide which DSO to get, my DST1102B is on its way bought from Mr. Pioneer Huang at Aliexpress.

I'll sure take it apart after a quick DOA check, will post 8MPX pics of the boards. The scope will arrive in chinese and I will change it to engish, does this will require a complete firmware change or just some setup? AFAIK the latest FW is 2.6.3 right? But at the Tekway homepage theres only 2.5 version. Where can I find the latest english version? Sorry I have not finished reading all the thread since Im currently in a extensive work project that takes almost all of my time.

I cant wait to have my own scope, currently using a Fluke 199 Scopemeter from the company I work for which does not have all the complete DSO functionality (also, the horizontal black line disease, common for this series fluke scopmeters, is stating to appear)

Can it be possible that I get that new redesigned PCB with SD, Ethernet footprints? Or currently its only possible with Hantek DSOs like RobertB's?

Thanks !
 

Offline ccatt

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #502 on: April 23, 2011, 05:33:14 pm »
tinhead,thank you!
Yes,I do it in accordance with your same step before ask you,  press the CTRL+C and Enter many times (in SecureCRT and HyperTerminal ).But am I wrong,is it possible in DNW.exe.
but whatever l tried, wouldn't get  any message  in windows .  
My USB  FT232 converter  is normal when connection rx to tx itself.
What time to Post your matching supervivi and own compiled vivi ,and the interrelated files of other ways?
In addition, I do not have the qualifications to DIY LAN.
You know  (Attempt to disassemble the product can damage it and void your warranty),I don't want to miss the boat 3 years easily.Because  JTAG  20 pins not solder.Although I bought the H-JTAG .
If you are interested,I can post my backup files (  boot.bin  kernel.bin  root.bin  )
« Last Edit: April 23, 2011, 06:43:09 pm by ccatt »
 

Offline rf-loop

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #503 on: April 23, 2011, 07:03:37 pm »
ccatt

maybe you can test it with scope itself if there is signal. (but be careful... repeat... be careful do not damage UART.

Start scope.

Let it run.


Connect probe center pin carefully to UART 0 Tx so that it do not make any short circuit to neighbours.

(all time as scope is on it sends data out from uart! Also if you turn or push some knob UART send it out.
If you do nothing and scope is on with default setup... it sends some short string around 10seconds inteval.

This data stream you can detect with probe. If there is nothing maybe UART 0 Tx is damaged.

UART have not any buffer/protection so it is very extremely easy to defect and it may die very easy!

There need normally connect only UART0 Rx to module Tx and UART0 Tx to module Rx and GND to GND

(my experience is about Hantek and USB to TTL UART made with CP2102)
If practice and theory is not equal it tells that used application of theory  is wrong or the theory itself is wrong.
It is much easier to think an apple fall to the ground than to think that the earth and the apple will begin to move toward each other and collide.
 

Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #504 on: April 23, 2011, 07:06:48 pm »
Hello tinhead, first of all I want to thank you for your time and dedication to this subject, this thread definitively made me decide which DSO to get, my DST1102B is on its way bought from Mr. Pioneer Huang at Aliexpress.

I'll sure take it apart after a quick DOA check, will post 8MPX pics of the boards. The scope will arrive in chinese and I will change it to engish, does this will require a complete firmware change or just some setup? AFAIK the latest FW is 2.6.3 right? But at the Tekway homepage theres only 2.5 version. Where can I find the latest english version? Sorry I have not finished reading all the thread since Im currently in a extensive work project that takes almost all of my time.

I cant wait to have my own scope, currently using a Fluke 199 Scopemeter from the company I work for which does not have all the complete DSO functionality (also, the horizontal black line disease, common for this series fluke scopmeters, is stating to appear)

Can it be possible that I get that new redesigned PCB with SD, Ethernet footprints? Or currently its only possible with Hantek DSOs like RobertB's?

Thanks !

i did posted the latest Tekway firmware (2.6.3) on other forum, http://www.mikrocontroller.net/attachment/106249/dst1kb_2.06.3_01102b_fc_110225.0_.up
You can use it to update your language files.

The reason why Tekway is having only the 2.5.x firmware on the website is the hack itself. They sending via email without any issues firmwares,
but they asking always for what model. This is only because after the hack prevention (try) they need separate firmwares for each model, and
not like before one universal firmware. So it is my fault why there is only 2.5.x. Anyway, i heard from Tekway that this will change soon (meaning they will update the website).


Well, it can be that oyu got the latest hardware, but it can be also old stock. You don#t have even to open, just check the utility->system status.
It the [hardversion] starts with 0x then you have old stock hardware.

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: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #505 on: April 23, 2011, 07:10:31 pm »
tinhead,thank you!
Yes,I do it in accordance with your same step before ask you,  press the CTRL+C and Enter many times (in SecureCRT and HyperTerminal ).But am I wrong,is it possible in DNW.exe.
but whatever l tried, wouldn't get  any message  in windows .  
My USB  FT232 converter  is normal when connection rx to tx itself.
What time to Post your matching supervivi and own compiled vivi ,and the interrelated files of other ways?
In addition, I do not have the qualifications to DIY LAN.
You know  (Attempt to disassemble the product can damage it and void your warranty),I don't want to miss the boat 3 years easily.Because  JTAG  20 pins not solder.Although I bought the H-JTAG .
If you are interested,I can post my backup files (  boot.bin  kernel.bin  root.bin  )

maybe uart port is broken, the S3c2440 is easy to destory :) i did it already (and had to re-solder the chip).

The supervivi is on the very first page of this thread, 3rd posting ... :)

And sure, if you have h-jtag and created NAND backup (wth OOB blocks) or if you crated via the utility posted here (so then these 3 files)
you can upload them somewhere and give me the link.
I can then restore it on my dev board and do whatever you like, no problem.
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 ccatt

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #506 on: April 24, 2011, 06:23:33 am »
 thank you,tinhead!
My USB  FT232 converter  must be marked wrong .swap the pin  (tx rx) ,  UART is working.
 :D

link
https://rapidshare.com/files/458915396/dst1062b.rar
« Last Edit: April 24, 2011, 10:53:22 am by ccatt »
 

Offline clonecrp

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #507 on: April 25, 2011, 11:57:07 pm »
e-priest:

Received my Hantek 100MHz scope today. How have you progressed w/yours ? ::)

Thanks !

Doug
 

Offline colinbeeforth

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #508 on: April 26, 2011, 03:30:59 pm »
Hi tinhead,

Many thanks for your excellent work!

I have recently bought Hantek DSO5102B and have noticed some bizarre behaviour when using it on the 40k acquisition memory setting.

When testing at lower timebase settings, if you go one timebase setting faster, and the sample rate will increase and memory used usually stays around 32k or 25.6k - this is just because of timebase/div x 16divs x sample rate = acquisition memory used.  Normal situation with all DSOs.

At 20uS per division, sample rate is 100MS/s the memory taken is 32k, and the table of data looks like this:

Timebase          Samplerate        Memory
20uS/div           100MS/s            32k
8uS/div             200MS/s            25.6k
4uS/div             400MS/s            25.6k
2uS/div             400MS/s            12.8k
800nS/div          400MS/s            5.12k
400nS/div          400MS/s            2.56k
200nS/div          400MS/s            1.28k
80nS/div            500MS/s            640
40nS/div            1GS/s                640

As the time/div increases from slow, the sample rate is in a 1-2-5 pattern until it reaches 8uS/div, then it switches to 200MS/s, then 400MS/s and locks at 400MS/s for many settings.  This is pretty crazy behaviour.

A LeCroy 9310 using same time base settings and 50k acquisition memory is totally logical, running slower digitising speed for low timebase settings, and speeding up to maximum sample rate, then it decreases memory taken until you reach top time/div setting.  This makes sense.

It is tested by setting the scope to Dots interpolation, and 40k max acquisition memory.  Take a single shot of anything, then when sweep is stopped, increase the timebase control until you see the dots, then use time cursors to measure across ten dots and read time between points and sample rate from cursor display.

Have you experienced this weirdness in your scopes?

Cheers, Colin


 

Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #509 on: April 26, 2011, 06:15:53 pm »
Colin,

actually it is very hard to say what is the real sample rate on these scopes. From a ADC clock point of view everything below
8ns/div is sampled with 100MHz x amount of ADC = 800MSs. Starting from 8ns/div up to 2ns/div it is 125MHz x 8 = 1GSs.
That's the measured clock on ADC pins and actually the physical sample rate. So for single channel, 4k this could be
the "real" sample rate. It changes of course as soon two channels are enabled (div by 2).

Probably we should ask the original developer, which i think is someone worked for Instek before (or contractor? maybe).
I stopped to try to understand why something is build in the one or other way, as long it works i'm fine.
Some ideas are very nice, others are price driven.


About the DSO design and measurments:

The DSO is using Altera Cyclone II, if you check the specs you will see the amount of internal SRAM is "big" enough for
only one channel 4k sampling, so everything beyond that is saved into long memory (btw, same for Rigol DSOs - they have 16k per
channel which didn't match the FPGA size as well by factor 4!!). Data shifting costs time anyway, so that's one of
the reasons why Rigol's wfrm/s is much lower than Hantek (just because they shift 4times more data for short memory shot).

Anyway, due the data shifting/short shots into FPGA memory you can't just measure the sample rate by dots difference
(not only that, see below). Someone told me "FFT is displaying sample rate", well yes, it does but it didn't really match
just because in FFT mode the FPGA design is working in a different mode (you can actually see this on the DSO shell,
there is "debug log" running).

The data is finally calculated/mixed together within the FPGA and moved to SoC/UI. This is definitely different than on LeCroy 9310
where the sample rate is physically changing and the memory deep makes more sense (just because of the fact that the LeCroy
is sampling with different rates and the memory is writable on full speed).

Note, the external SRAM here is clocked with 200MHz only so there are some limits within the shifting from FPGA to external SRAM,
in both short and long memory mode (except short mem 1 channel).

If you analyze these dots:
Starting from 4µs/div to 2ns/div the amount of captured data (40k setting) is always 100µs long.
With 4µs/div the diff between dots is 2.5ns, so we have exactly 40000 dots.
With 80ns the diff is changing to 2ns, so we have 50000 dots, then with 40ns the diff is again switching to 1ns
so we have already 100k and finally with 20ns/div the diff is 500ps so we have 200k dots.

I said "finally" because in 8ns/4ns/2ns/div the diff is very small and hard to count exactly, but it seems to be
200ps, 100ps and 50ps.

And it is exact same behaviour with 2 channels enabled or 4k/512k or 1M memory (except of course the recorded data length
and count of dots, but same logic behind - look on 20ns/div and 1M memory - that's 4M dots!).


This is of course with real time mode sampling selected. With equ mode selected and 20ns/div the diff between dots
is 100ps instead of 500ps like in real time mode.

So is Hantek cheating a bit and running the DSO in kind of equ mode where real time is selected ? No, it is not.
This is just result of how they using sin/x interpolation and the way how the DSO is designed.

Therefore don't count the dots, they not one per sample and don't compare to other DSOs as they designed different
(except Rigol and Instek - as they designed similar, Rigol having 2 more ADCs so no 125/100Mhz switching and Instek having
much bigger FPGA so no data shifting in short memory mode, but the idea is the same).
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 colinbeeforth

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #510 on: April 27, 2011, 01:56:54 am »
Hi tinhead,

Thanks for the lengthy reply, I'll try to understand what you have said in small sections.

I often work with short single pulses, so I need to know what the scope is doing if I am to trust what I see on the screen.  If I want to look at a repeating waveforms I have several analogue scopes I can use that are much faster to drive.  The thing that DSOs do, that beats analogue scopes, is single shot storage of a waveform.  There's not a lot of point talking about DSOs for repeating waveforms, that has already been solved.  So for this discussion, I always refer to single shot operation.

On my LeCroy there is an info screen, one button, anytime and you see all the channel settings, timebase settings, sample rate and memory acquired at a single glance.  It is very clear to me what it is doing, and I know what pulses I can sensibly measure and what is likely to be aliased.  By comparison, the Hantek/Tekway design seems to be hiding that information, so I wonder why.  Also, they hide the change from Real Time operation to Equivalent Time operation, that is deeply annoying.  LeCroy automatically switch to Equivalent Time (they call it RIS, or Repetitive Interleaved Sampling) but it is clearly visible at all times.  The operator really <needs> to know when this is happening, otherwise the data on the screen might be totally undersampled and quite untrustworthy.


You said:
"actually it is very hard to say what is the real sample rate on these scopes." and "Probably we should ask the original developer"

I agree completely with these comments, but are we never likely to find who it was and ask them...


You said:
"The DSO is using Altera Cyclone II, if you check the specs you will see the amount of internal SRAM is "big" enough for
only one channel 4k sampling"

OK, thanks for that information, I'm not experienced with FPGA so their specs are confusing to me.  That would explain the default back to 4k with Autoset.  It does change the way the scope must work, there are many compromises compared to my old LeCroy.  Even though my 9310 is only 100MS/s, I can trust that what I have on the screen, since I know always what sample rate it being used.


You said:
"The data is finally calculated/mixed together within the FPGA and moved to SoC/UI. This is definitely different than on LeCroy 9310
where the sample rate is physically changing and the memory deep makes more sense (just because of the fact that the LeCroy
is sampling with different rates and the memory is writable on full speed)."

I don't know what SoC/UI means.  In the LeCroy, the sample rate changes are completely logical and in keeping with the published limitations and specs.  The Info screen always tells you precisely what is happening.  In my LeCroy, the scope acquisition memory defaults to 10k, but you can select 50k.  Using 50k increases the processing required to display the waveforms, so drops the update rate, but the choice is yours.  As you increase the timebase setting, the scope it will automatically change to RIS (Repetitive Interleaved Sampling) or Equivalent Time automatically, but it clearly tells you this is the case, so you can't be easily fooled alias.


You said:
"I said "finally" because in 8ns/4ns/2ns/div the diff is very small and hard to count exactly, but it seems to be
200ps, 100ps and 50ps."

Of course, this is what it would do for repeating waveforms.  I was testing it for single shot only.  Single shot waveform storage is the banner capability that separates DSOs from analogue scopes, so my focus is on single shot.


You said:
"This is of course with real time mode sampling selected. With equ mode selected and 20ns/div the diff between dots
is 100ps instead of 500ps like in real time mode."

Agreed, but I did all my tests on single shot acquisitions.  I have analogue scopes and didn't buy a a digital scope to show easy repetitive waveforms.


You said:
"So is Hantek cheating a bit and running the DSO in kind of equ mode where real time is selected ? No, it is not.
This is just result of how they using sin/x interpolation and the way how the DSO is designed."

Clearly the maker must work within the limits of physics and with difficult cost restraints.  So, I am not being critical of the makers.  But, there is no reason for not letting the user know what the scope is doing.  There is still something weird happening with the sample rate getting stuck at 400MS/s for so long.  I cannot understand why this should happen.  At higher time base settings, the scope appears to use 500MS/s and 1000MS/s sample rate, so it's not like the digitiser can't do it.  It's not because of a 4k fast RAM limitation, since at 200nS/div, it samples 1.28k at 400MS/s.  It just makes no sense to me.  I can't understand why they break the 1-2-5 sequence of sample rate at lower timbase settings and go to 1-2-4.  I'm looking to explain why it is like this.  I can accept quirks of design, but I like to know <why> it is like that.


You said:
"This is just result of how they using sin/x interpolation and the way how the DSO is designed. "

What?  Surely this must be a mistake.  I saw nothing in the manual about the scope using sinx/x interpolation between actual data points.  I detest sinx/x interpolation.  I used to sell LeCroy DSOs many years ago, and I have seen many many comparisons of different digital scopes.  I finished that work 8 years ago, so I have not seen the latest HP DSOs.  Apparently, they have improved dramatically, but in my past experience, by far the worst alias problems my customers encountered were cases where sinx/x was operating.  Linear interpolation is the safest method.  As soon as you see the very characteristic alpine looking sharp peaks, you know you have undersampling and need to take care to ensure you aren't looking at alias.  Since Hantek/Tekway under the Display menu allows selection of Dots or Vectors, I assumed Vectors meant linear interpolation.  We must find some way to be sure about this, it really matters to me.


You said:
"Therefore don't count the dots, they not one per sample and don't compare to other DSOs"

If the dots are not actual sample points, what else could they be?  Don't forget, I have always used single shot mode and ensured Real Time mode was operating.

Please don't think I am full of criticism, I'm just trying to understand how this thing works, and whether I can trust its single shot screens.  I deal with photomultiplier and gas radiation detectors and fast one-ff pulses matter to me.

As general DSO philosophy, the vital thing is to understand the limitations of the technology so you are not fooled by alias.  Aliasing happens all the time, we just don't often realise it.  Trusting a DSO screen without questioning is a good way to fool yourself.

Another interesting factor is screen alias.  The screen only has a limited number of dots across it, if you squeeze memory down to show the pixels, then data is not being shown and alias can occur.  To my best knowledge, Hantek/Tekway at least make an effort to capture spikes that are present in memory and display something on the screen that grabs your attention and makes you zoom for more info.  LeCroy have always done this.  I believe GW Instek take the trouble also.  Many little modern scopes simply ignore the spike in memory and if luck has it fall into the data that is decimated for screen display, then bad luck, you never see it.  If you ask a Tek salesman about this, they get excited and say the data isn't lost, it's still in memory.  But so what, why would you scroll through anything up to 1 meg of waveform data <every single time> to find something that you don't know is there!!

I have no trouble with instrument and technology limitations.  I have no trouble with compromise made for better cost.  But if you can't find out what those imitations are, how can you ever know when to be alert for alias?  Even a car manual tells you what speeds to use for each gear...

Please keep up the good work, I have very much appreciated your work in informing us all about these scopes.  I'm enjoying tinkering with the HAntek/Tekway scope, the screen readability for my older eyes is very nice, I just don't trust it yet and may never fully, unless I get some answers.  I have emailed this issue to Hantek, who have sent a polite "gone to engineering evaluation" reply, so I wait with interest.  In the mean time, I thought it would be interesting to ask your thoughts on the matter. *smile*

Cheers, Colin
 

Offline carloscuev

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #511 on: April 27, 2011, 09:57:09 am »
My DST1102B arrived today :D
Just after a DOA check I opened it up !!
Here the pictures:



I tried to find the resistors which determine the lowpass filter value, but I did not find them, I guess they are on the other side and I was lazy to do that.

Something that I noticed is that it gets really hot inside. After 30 minutes of playing with it, when I opened it, all the metal plates were REALLY hot (I dont want to know the ICs). In fact before opening it I noticed a very intense heatwave coming from the top. I installed a 5cmx5cm fan in the place designed for that, and soldered a header in the power supply where it says "fan". Now it runs cool after hours of use. Sure its noisy but if it's a guarantee of a better lifespan i think it's not a big sacrifice, anyway I always have earphones listening some good music ;)


UPDATE: NOW HACKED !!!
At first I was afraid but the procedure seemed to be very easy, so i did it. Now I'm happy and grateful for tinhead :)

During the process:


Voila!


I also wanted to do something about the PSU's 3.3v but didnt have much caps or regs lying around so I installed 2 extra 220uF Tantalum caps in the 3.3v output:


Tinhead, do you think the tantalums are helping? Im looking towards fully hack the device including Ethernet, PSU mods, etc.

Something curious is that my DSO had a permanent +20mV offset on CH1, I did not took pictures of the shorted probe showing the offset. After the hack and tantalum caps the problem has dissappeared, I dont know why.
« Last Edit: April 27, 2011, 02:15:45 pm by carloscuev »
 

Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #512 on: April 27, 2011, 03:37:53 pm »
Colin,

I often work with short single pulses, so I need to know what the scope is doing if I am to trust what I see on the screen.  If I want to look at a repeating waveforms I have several analogue scopes I can use that are much faster to drive.  The thing that DSOs do, that beats analogue scopes, is single shot storage of a waveform.  There's not a lot of point talking about DSOs for repeating waveforms, that has already been solved.  So for this discussion, I always refer to single shot operation.

All my comments above are valid for single shot, the buffer need to be filled no matter
if this is repeating or single event.
The “logic” behind the dots on screen is also valid for average and peak sampling modes,
the resulting count of dots might be different but that’s different story.

On my LeCroy there is an info screen, one button, anytime and you see all the channel settings, timebase settings, sample rate and memory acquired at a single glance.  It is very clear to me what it is doing, and I know what pulses I can sensibly measure and what is likely to be aliased.  By comparison, the Hantek/Tekway design seems to be hiding that information, so I wonder why.  Also, they hide the change from Real Time operation to Equivalent Time operation, that is deeply annoying.  LeCroy automatically switch to Equivalent Time (they call it RIS, or Repetitive Interleaved Sampling) but it is clearly visible at all times.  The operator really <needs> to know when this is happening, otherwise the data on the screen might be totally undersampled and quite untrustworthy.

Right, but that’s the major diff between brand names and china manufacturers. Actually not everything will be displayed and if there is information you can’t really trust.
Why ? Well very simple, all china DSOs (except Rigol 6000) are sampling always with fixed and highest sample rate of the ADCs, the resulting information is just “converted” to kind of sample rate information on the display (if available).  So actually you can’t undersample, the firmware is correcting automatically based on the horizontal settings. Of course they could do it different (meaning the sample rate setting will reflect changes to ADC clock), but then they would need better clock sources, an FPGA PLL is not good enough, some external clock logic would be necessary, probably with good clock jitter attenuators which cost money – so that’s why.


"actually it is very hard to say what is the real sample rate on these scopes." and "Probably we should ask the original developer"
I agree completely with these comments, but are we never likely to find who it was and ask them...

Actually in begin of 2007 a developer named “rgj” started development of a DSO 1.0 platform.
Later, in April 2008 Tekway company was founded and started production of the first DSO models DST3000/DST4000/DST1000 – based on DSO 1.0 platform. End of 2008 this developer worked again on DSO development – named DSO2.0 platform – mid of 2009 Tekway started development and end of 2009 sales of this new (DSO 2.0 platform based) series - DST1000B/DST3000B/DST4000B, which was bought by Hantek shareholders June 2010. Since them developer teams from both companies merged together and started with firmware optimization – of course for both Tekway and Hantek models. (Btw, since them firmware issues started, probably the joined HanTekway team should ask “rgj” how to optimize the firmware …)

No idea if “rgj” was/is working for Tekway or only external resource (which I think),
the fact is this developer is not located in China.
Maybe he/she is reading this thread and will answer us some questions.

At same time Instek and Rigol started of development and later production of very similar DSO.
Coincident?  no, I don’t think so.

You said:
"The DSO is using Altera Cyclone II, if you check the specs you will see the amount of internal SRAM is "big" enough for
only one channel 4k sampling"
OK, thanks for that information, I'm not experienced with FPGA so their specs are confusing to me.  That would explain the default back to 4k with Autoset.  It does change the way the scope must work, there are many compromises compared to my old LeCroy.  Even though my 9310 is only 100MS/s, I can trust that what I have on the screen, since I know always what sample rate it being used.

The Cyclone III, EP3C5 have 414kbits memory, Tekway/Hantek is using 8 ADCs x 8 bit x 4000 point,
so 250kbits, no way to have both channels sampled at same time into internal memory. Rigol is using exact the same FPGA, and sampling 2 x 16k (or it was 2 x 8k? no matter), this can’t match even for single shot, so they already shifting the information to external SRAM during short-memory shot /which is slowing down the design). Instek is using EP3C16, having 515kbits, this is big enough for single 8k or 2 channels 4k. I didn’t found any information about the memory size in short mem setting, but it would be probably 4 or 8k.
I don't know what SoC/UI means.

The SoC is actually ARM9 Samsung application processor responsible for GUI. This baby is reading the sampled data and displaying on screen. It is doing additionally some math/FFT things and the communication to outside world.

In the LeCroy, the sample rate changes are completely logical and in keeping with the published limitations and specs.  The Info screen always tells you precisely what is happening.  In my LeCroy, the scope acquisition memory defaults to 10k, but you can select 50k.  Using 50k increases the processing required to display the waveforms, so drops the update rate, but the choice is yours.  As you increase the timebase setting, the scope it will automatically change to RIS (Repetitive Interleaved Sampling) or Equivalent Time automatically, but it clearly tells you this is the case, so you can't be easily fooled alias.

All china DSOs are doing is exact in same way, except the fact that ADCs are hard-clocked so everything in done in firmware itself.

You said:
"I said "finally" because in 8ns/4ns/2ns/div the diff is very small and hard to count exactly, but it seems to be
200ps, 100ps and 50ps."
Of course, this is what it would do for repeating waveforms.  I was testing it for single shot only.  Single shot waveform storage is the banner capability that separates DSOs from analogue scopes, so my focus is on single shot.
You said:
"This is of course with real time mode sampling selected. With equ mode selected and 20ns/div the diff between dots
is 100ps instead of 500ps like in real time mode."
Agreed, but I did all my tests on single shot acquisitions.  I have analogue scopes and didn't buy a a digital scope to show easy repetitive waveforms.
Me too, there is no difference between single and repetitive run in the logic, except the fact that the memory will be purged and filled again and again and again.

This is just result of how they using sin/x interpolation and the way how the DSO is designed."
Clearly the maker must work within the limits of physics and with difficult cost restraints.  So, I am not being critical of the makers.  But, there is no reason for not letting the user know what the scope is doing.  There is still something weird happening with the sample rate getting stuck at 400MS/s for so long.  I cannot understand why this should happen.  At higher time base settings, the scope appears to use 500MS/s and 1000MS/s sample rate, so it's not like the digitiser can't do it.  It's not because of a 4k fast RAM limitation, since at 200nS/div, it samples 1.28k at 400MS/s.  It just makes no sense to me.  I can't understand why they break the 1-2-5 sequence of sample rate at lower timbase settings and go to 1-2-4.  I'm looking to explain why it is like this.  I can accept quirks of design, but I like to know <why> it is like that.

The 1-2-4 sequence is probably because of clock rates for FPGA/SRAM/ADC and amount of ADCs. (100MHz clocked, 200Mhz clocked, 8ADCs)
They could probably do 1-2-5 but it will cost some FPGA time slowing down waveforms refresh.
I don’t like it, but can live with that, one of the reason why I bought it was the 2500wfrm/s, the other choise would be at that time Rigol with 1-2-5 seq. but 800wfrm/s.

You said:
"This is just result of how they using sin/x interpolation and the way how the DSO is designed. "

What?  Surely this must be a mistake.  I saw nothing in the manual about the scope using sinx/x interpolation between actual data points.  I detest sinx/x interpolation.  I used to sell LeCroy DSOs many years ago, and I have seen many many comparisons of different digital scopes.  I finished that work 8 years ago, so I have not seen the latest HP DSOs.  Apparently, they have improved dramatically, but in my past experience, by far the worst alias problems my customers encountered were cases where sinx/x was operating.  Linear interpolation is the safest method.  As soon as you see the very characteristic alpine looking sharp peaks, you know you have undersampling and need to take care to ensure you aren't looking at alias.  Since Hantek/Tekway under the Display menu allows selection of Dots or Vectors, I assumed Vectors meant linear interpolation.  We must find some way to be sure about this, it really matters to me.

Well, that’s what you can find in the user manual – waveform interpolation : (sin x)/x
therefore you will see aliasing on all china DSOs.
Generally spoken all china DSO have a different understanding of sin x as for example Tektronix has,
however it is hard to guess what they exactly doing without source code.

You said:
"Therefore don't count the dots, they not one per sample and don't compare to other DSOs"
If the dots are not actual sample points, what else could they be?  Don't forget, I have always used single shot mode and ensured Real Time mode was operating.
Physically these dots have to be interpolated dots and not actual sampled points.

Please don't think I am full of criticism, I'm just trying to understand how this thing works, and whether I can trust its single shot screens.  I deal with photomultiplier and gas radiation detectors and fast one-ff pulses matter to me.

I can’t answer this question, these DSOs are comparable to Tektronix TDS2012, is such Tek is good for you then you fine, if not you will have to change it to better model, maybe Agilent DSOX will fit your need.
As general DSO philosophy, the vital thing is to understand the limitations of the technology so you are not fooled by alias.  Aliasing happens all the time, we just don't often realise it.  Trusting a DSO screen without questioning is a good way to fool yourself.
Another interesting factor is screen alias.  The screen only has a limited number of dots across it, if you squeeze memory down to show the pixels, then data is not being shown and alias can occur.  To my best knowledge, Hantek/Tekway at least make an effort to capture spikes that are present in memory and display something on the screen that grabs your attention and makes you zoom for more info.  LeCroy have always done this.  I believe GW Instek take the trouble also.  Many little modern scopes simply ignore the spike in memory and if luck has it fall into the data that is decimated for screen display, then bad luck, you never see it.  If you ask a Tek salesman about this, they get excited and say the data isn't lost, it's still in memory.  But so what, why would you scroll through anything up to 1 meg of waveform data <every single time> to find something that you don't know is there!!

Actually Hantek/Tekway are very similar to Instek, and to be very honest good for spikes detection.
The only thing I’m missing is search function, sure with the double window (F7) you can switch both normal and zoomed view and actually you will see these spikes in normal view, you can set some markes but there is room for improvement.

I have no trouble with instrument and technology limitations.  I have no trouble with compromise made for better cost.  But if you can't find out what those imitations are, how can you ever know when to be alert for alias?  Even a car manual tells you what speeds to use for each gear...

Well, no idea why these guys (now talking about all chinese DSO manufacturers) can’t just write everything down into the manual. Sure, even brand manufacturers are doing this, hiding some information’s, but you can always find such hidden information if you look on the competitor website …
What the do is to write down highlights, sure everything what good need to be known, everything else hidden.
I guess they doing this just because they worry nobody would buy their products. But actually we all know that you will have to pay a lot of money to get really good product, everything else is always compromise.


Please keep up the good work, I have very much appreciated your work in informing us all about these scopes.  I'm enjoying tinkering with the HAntek/Tekway scope, the screen readability for my older eyes is very nice, I just don't trust it yet and may never fully, unless I get some answers.  I have emailed this issue to Hantek, who have sent a polite "gone to engineering evaluation" reply, so I wait with interest.  In the mean time, I thought it would be interesting to ask your thoughts on the matter. *smile*

Sure you welcome and i hope my answer will help a bit to understand some things about chinese DSOs.
I remember how hard was to get any answer from Tekway at the beginning of my Tekway-adventure, especially because I did found some
“strange things” and asked directly. Today the communication is better, especially after Hantek shareholder bought Tekway,
Hantek’s international experience is good for us.


« Last Edit: April 27, 2011, 03:52:08 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.
 

Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #513 on: April 27, 2011, 04:02:56 pm »

I tried to find the resistors which determine the lowpass filter value, but I did not find them, I guess they are on the other side and I was lazy to do that.
they located in the (shielding) input channel part of the PCB, which you already opened - i can see tme on your pics :)

Something that I noticed is that it gets really hot inside. After 30 minutes of playing with it, when I opened it, all the metal plates were REALLY hot (I dont want to know the ICs). In fact before opening it I noticed a very intense heatwave coming from the top. I installed a 5cmx5cm fan in the place designed for that, and soldered a header in the power supply where it says "fan". Now it runs cool after hours of use. Sure its noisy but if it's a guarantee of a better lifespan i think it's not a big sacrifice, anyway I always have earphones listening some good music ;)
right, the most heating comes from PSU, then the input circuit then FPGA and ADC.

My PSU, with the PTH04070 instead of KA378R33 is producing no heat at all, input channel can't be fixed (these chips will get hot)
and FPGA/ADCs have already heatsinks installed. A 12V fan powered with 5V (just replace the 7812 on the PSU by 7805 and connect the fan)
will do the rest.

UPDATE: NOW HACKED !!!
At first I was afraid but the procedure seemed to be very easy, so i did it. Now I'm happy and grateful for tinhead :)

you welcome

I also wanted to do something about the PSU's 3.3v but didnt have much caps or regs lying around so I installed 2 extra 220uF Tantalum
caps in the 3.3v output:

Tinhead, do you think the tantalums are helping? Im looking towards fully hack the device including Ethernet, PSU mods, etc.
you can measure the ripple by yourself :)
The Ethernet mod, yeah, maybe i should produce some PCBs. Few ppl asked already, it seems that the 6mil is to small for home made PCBs.

Something curious is that my DSO had a permanent +20mV offset on CH1, I did not took pictures of the shorted probe showing the offset. After the hack and tantalum caps the problem has dissappeared, I dont know why.

well, the time you spend on hacking the DSO, the device got over the warm-up time so the drift was gone, the explanation for this drift is here

https://www.eevblog.com/forum/index.php?topic=2961.0

there is nothing wrong about.
« Last Edit: April 27, 2011, 04:07:36 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.
 

Offline carloscuev

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #514 on: April 27, 2011, 04:21:51 pm »
you can measure the ripple by yourself :)
The Ethernet mod, yeah, maybe i should produce some PCBs. Few ppl asked already, it seems that the 6mil is to small for home made PCBs.

Can the scope measure its own ripple by placing the probe in the +3.3v net?

wow 6mil sounds difficult but could be possible, I've done 8mil with a lot of problems, but got good results at last.
 

Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #515 on: April 27, 2011, 05:42:52 pm »
Can the scope measure its own ripple by placing the probe in the +3.3v net?

sure, the best is with short gnd connection directly near ADCs.

wow 6mil sounds difficult but could be possible, I've done 8mil with a lot of problems, but got good results at last.

well, the Eagle files i posted can be of course changed.
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 ccatt

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #516 on: April 28, 2011, 12:55:27 pm »
Tinhead,You saw that my upload files?Because i didn't have enough power to do that now. Only if i need to  enough to know to  do it .Can you tell me what the difference is between the received files and your previously  files,and reciprocal measures ?(if you can post the better nandflash backup file of dst1602, so much the better.)I only know a little Linux.used all your upgrade applications, always  reported error code . I don't know what Tekway did?
« Last Edit: April 28, 2011, 04:11:07 pm by ccatt »
 

Offline tinhead

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #517 on: April 28, 2011, 08:34:42 pm »
Tinhead,You saw that my upload files?Because i didn't have enough power to do that now. Only if i need to  enough to know to  do it .Can you tell me what the difference is between the received files and your previously  files,and reciprocal measures ?(if you can post the better nandflash backup file of dst1602, so much the better.)I only know a little Linux.used all your upgrade applications, always  reported error code . I don't know what Tekway did?

yes i saw and got it, i will check on weekend (quite busy right now)
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 clonecrp

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #518 on: May 03, 2011, 03:58:18 am »
Tinhead ...

Removed my new Hantek DSO5102B from shipping container here .... applied power .... the display is quite nice at quick look.
... looking around etc ... I notice Acquire Menu - 1M LongMem is not supported by the model. Is this a SW, HW issue or both ?

Very Interesying Features  ;D ... I think I am going to like this

Probably will do Power Supply mods this week ... got the TI PTH04070WAH Chip as sample.

Comments Please ...

Thanks!
Doug
 

Offline clonecrp

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #519 on: May 03, 2011, 05:51:17 am »
BTW ... Loaded TTScope Software from Scope CD ... plugged in USB ... and a bad bong ! Usb Driver failed to load ..... won't attach ... eMail off to Hantek Support just to see what happens ...  :(  ??? ..  :'(

Anyone w/similar USB problem ?

Thanks!
Doug 
 

Offline ECL

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #520 on: May 03, 2011, 07:27:03 pm »
BTW ... Loaded TTScope Software from Scope CD ... plugged in USB ... and a bad bong ! Usb Driver failed to load ..... won't attach ... eMail off to Hantek Support just to see what happens ...  :(  ??? ..  :'(

Anyone w/similar USB problem ?

Thanks!
Doug 

The version of TTScope on my CD was nonfunctional.  Use the version on Hantek's website.
Also, see this link, for where to find the driver, after installing TTScope (it says for Win7, but
I had to do the same for WinXP SP3):

http://www.hantek.com.cn//FAQ/Win7DriverInstall.pdf

BTW Greetings everyone.  Been following the EEVB for a while now.  Thanks to everyone's
hard work, on this thread, I decided to buy a Hantek DSO as well.  Honestly, I was leaning toward
another manufacturer, but changed my mind, once I read about the hack, and the data that had
been collected on the scope.  I would not have bought the Hantek, if it hadn't been for this thread.
Hopefully this factors into Hantek's (and all manufacturer's thinking) going forward.  Special thanks
to Tinhead, for all of his hard work, and support! 

ECL -K
 

Offline RFman

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #521 on: May 03, 2011, 10:32:52 pm »
Hi Tinhead.

I've been waiting for the Windows 7 64 bit driver for TTScope. Do you know if this has been released.

Thanks for all the work that you do for us. I also wouldn't have a Tekway 200MHz oscilloscope if it wasn't for you.

RFman.
 

Offline clonecrp

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #522 on: May 03, 2011, 11:09:49 pm »
Hey Guys !

Once my PS Mod is complete ...  I just might have a spare (one or two)  TI PTH04070WAH Chips if anyone needs one ... Just let me know  ;) .

Doug
 

Offline colinbeeforth

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #523 on: May 04, 2011, 10:14:34 am »
Hi tinhead,

Thanks for the very long and thorough reply.   I really appreciate the effort it means.  You have cleared up a major misunderstanding of mine.  Before buying I searched the Hantek manual for sinx/x.  There was no result, so I thought it did not use this limited method.  In the manual, just where you said, there was "sin(x)/x"  The horrible manual writer used brackets., so I did not think it was there.  I am not very happy about this now.  Even if a scope has sinx/x interpolation, most provide it as an option and it can be switched out.  I prefer to use DSOs without it.  sinx/x works ok in limited situations, but you have to be much more careful and watchful for alias problems.  Since Hantek/Tekway don't have an information screen, or even put the sample rate somewhere on the screen like most reputable makers, it is hard to know what the sample rate it uses, and therefore, how can I know whether alias is possible or not?  You can never be sure.  With linear interpolation, it is impossible to under-sample without very obvious spiky looking waveforms.  Linear interpolation is self policing, if there is risk of alias, you see sharp spikes, and it is a big warning to the user to check the signal and acquisition settings since it is under-sampled.

Let's look at a practical example:  If you feed a squarish waveform into the DSO, at say 250MHz.  At the fastest timebase settings the DSO will take 4 samples per repeating cycle.  If the input is a square wave, it will have quite high frequency components, and if you have a 200MHz front end bandwidth, I expect it will round off the sharp edges a bit.  The samples will go into memory, and be displayed with sinx/x interpolation.  This will force sine curves to join the dots.  The screen will display total lies compared to what is being fed into the ADC.  It will look nice rounded sine waves, you will have no reason to be suspicious or mistrust what you see.  If the scope used linear interpolation, you would see sharp spikes, and would immediately realise that you were seeing an alias.  It isn't happy when this happens, since you have limited ways of seeing what is actually there, but at least you know.  An analogue scope of 200MHz bandwidth will show far closer to the truth, although will slew rate limitations softening the sharper edges.  It is still useful to see.  This is why I think sinx/x is dangerous for DSOs, especially for inexperienced users.  Thing is, alias can happen at very slow timebase settings as well, so it isn't just something to worry about at the highest frequencies.

When I looked at the Hantek/Tekway Display mode menu and saw the "Vectors/Dots" switch.  I assumed this was the selection of display interpolation, as being no interpolation (Dots) or when switched on as simple straight line interpolation (Vectors).  I forgive myself for making this mistake - the DSO is very unclear about what this setting actually does.  But I am totally at a loss to describe what the points shown on the screen <actually are> if they are not acquired data points!!  If the dots are totally synthetic, what on earth are the designers thinking!  I can't even imagine what they must be showing me, if those dot displays are not actual sampled points.

You said: "all china DSOs (except Rigol 6000) are sampling always with fixed and highest sample rate of the ADCs, the resulting information is just “converted” to kind of sample rate information on the display (if available).  So actually you can’t undersample,"

I'll deal with this in two parts, the "So you actually can't under-sample" part first:

1:  I think this is not a good way of understanding what is happening.  Any DSO can under-sample.  I don't care who argues, any DSO can alias and show nonsense - I've done it myself and seen it on 1GS/s scopes with 500MHz bandwidth and huge memory that cost $70,000!!  I don't wish to sound horrible, but there can no argument about this.  It is a fact of the universe, like the speed of light.  If you sample in anyway, you can get alias.  We can get into a detailed argument about Nyquist criteria, but I think this may bore the forum senseless.  It is pretty easy to describe in simple language.  Digitising isn't actually complex in practical use, if you think a bit first.  If you sample less than 10 points of any cycle of a repeating waveform, or of a rising or falling edge, you will have a poor understanding of what is actually there.  If you know there is a simple square wave, then maybe 8 points is enough, let's not argue about exact numbers, but how many data points on a graph paper allows you to draw what looks like the signal at the input socket.  You can argue 8 or 10 samples, whatever, you need enough samples for your application, otherwise you don't really know what is there.  Nyquist criteria is two sample points per since wave cycle using sinx/x interpolation and brick wall low pass filtering - this is entirely academic, as sharp low pass filters are quite difficult at RF frequencies, and a DSO input bandwidth is a slow roll off, not a brick wall.  Despite my scope being 3dB down at 100MHz, if there is a large signal at 1000MHz at my input terminal, some of it will get to the ADC.  Therefore alias is quite possible and I maintain, fairly common, just most people aren't aware of it!  Depending on the circumstances of each acquisition, the alias may not be very serious, or it can make the screen display a total lie, it all depends on the exact circumstances, the input waveform and the scope settings.  That is why I want to know what the actual sample rate is, so I can know if I can trust the that the screen is showing me a <real> result.  If you work with fast non-repetitive pulses from scientific radiation detectors, like I do, this isn't just a pointless argument, it really matters to people - not just me.

2:"all china DSOs (except Rigol 6000) are sampling always with fixed and highest sample rate of the ADCs, the resulting information is just “converted” to kind of sample rate information on the display"  OK, thanks for the information, but this doesn't really mean anything important about aliasing or undersampling.  I don't care how fast the ADC runs, if you decimate the data coming from the ADC, and store the points in memory, what matters for alias is the time interval between data points.  If you are acquiring waveforms at a slow timebase setting, and the memory is set to 4k, then the time between samples is (timebase x 16divisions) / 4000 = time between samples.  Then 1 / (timebetweensamples) = samplerate.  This doesn't care if the original ADC ran at 1nS per sample, what is in the memory and what is displayed to the screen is what determines aliasing.  I hope this makes is clearer.  It is perfectly possible to undersample on any DSO, no matter what the ADC hardware speed.  At slower time base settings, the sample rate is basically determined by the amount of memory available for filling.  Logically, longer memory is better.  There are some compromises with the Hantek/Tekway for long memory, but they don't make it clear when and how those compromises happen, an information screen is absolutely necessary!

OK, this is enough for one post, as I have run over some big concepts that take time to think over.

Basically, I believe that a DSO should work for the user, not against the user.   Most Chinese models I have seen don't seem to do this.  It is a shame, I have no trouble with cost based limitations to a design.  Honest disclosure shows respect for the customer.  Would you get into an aeroplane that had "aerobatic" written on it without knowing the exact limits for vertical and inverted acceleration??? *laughs*

Cheers, Colin
 

Offline carloscuev

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Re: Hantek - Tekway - DSO hack - get 200MHz bw for free
« Reply #524 on: May 06, 2011, 01:13:50 am »
Hello, I've been using my DST1102B (my first scope :D) to design a microcontrolled buck converter and everything has been pure sweetness. The only things ths bugs me is when you save to USB, why does it save a .bmp and .gif of the picture? I can do just fine with .gif, Is there any way to make it only save .gif file? Or better ! is there any way to get fast oscillograph screenshots in the PC without using the slow TTScope?

I've found a way to use Tekway's TTScope in windows 7, Just copy and rename:
<Hantek's TTScope Installation Dir>\config\DSO5202B_eng.ini
to
<Tekway's TTScope Installation Dir>\config\DST1202B_eng.ini

This way I can use Tekway's TTScope, but it's still slow :( I suspect the scope sends *.bmp screenshots instead of some type of compressed image. Is there any third party software ?
« Last Edit: May 06, 2011, 01:52:13 am by carloscuev »
 


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