Author Topic: New Rigol DS1054Z oscilloscope  (Read 1457937 times)

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Offline sweesiong78

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Re: New Rigol DS1054Z oscilloscope
« Reply #75 on: September 26, 2014, 11:26:38 pm »
A sample 1054Z is on it's way to me end of next week.
And I should have my own unit some time after that.

So you 'll be doing a review?? :D
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #76 on: September 27, 2014, 12:31:23 am »
Your problems with them from the past are meaningless to this discussion, IMO - virtually every single company has made mistakes with some product at some point or another. The point is rather that you started this theory of yours in response to a MISTAKE that was posted in this thread by an owner (Fungus) about the way the DSO dealt with with sin(x)/x.

They are meaningful in questioning the credibility of Rigol and especially so since they have continuously made the same mistake for years and have not corrected it yet.  Perhaps I am too strident at times.

I admit that I mistakenly thought Rigol was disabling sin(x)/x at low sample rates to conceal digitizer non-linearity and sampling jitter.  Now I am suspicious that they are doing the same at higher sample rate to conceal the same problems when interleaving is used.

What other oscilloscopes disable sin(x)/x reconstruction at high sample rates where it is still useful?  Oscilloscopes operating with equivalent time sampling do so because they can fill the entire waveform record with real sample points.  These 1 Gsample/second real-time only DSOs certainly cannot do that.

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It does NOT make sense for it to be disabled (or enabled) to avoid aliasing because sin(x)/x reconstruction neither causes nor increase aliasing.  It merely makes it more apparent.

As has been mentioned before: for sin(x)/x interpolation to be accurate, you have to have an analog input signal that has no frequency content above the Nyquist frequency - which, when 3 or 4 channels are on, is 125MHz. The normal frequency response of the DS1000Z does not roll-off fast enough to minimize aliasing for sin(x)/x interpolation ...

I agree.

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... - i.e. LINEAR interpolation should be used  - or-  to put it another way, there exists a good reason for being able to manually keep sin(x)/x turned OFF when 3 or 4 channels are on, if you need to. ...

The aliasing produced in the digitizer between an input signal which is completely below the Nyquist frequency and the sample clock occurs whether sin(x)/x reconstruction is used or not.  If you were to collect the sample points over multiple acquisitions, they would show thickening of the waveform which is *not* caused by noise.

I have often wondered if DSOs which support some form of persistence and appear to show excessive noise actually suffer from this but that is a different discussion.

I also wonder if this is why they do not support equivalent time sampling with their digital triggers but that is also a different discussion.

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... On the other hand, if you enable the 20MHz bandwidth limiter for each channel that's turned on, you can use sin(x)/x interpolation without problems on the higher sample rates

I agree but for a specific reason; with the bandwidth limit engaged or with a lower frequency signal, the mixing products between the signal and the sample clock produced by the non-linearity and sample jitter in the digitizer are *also* below the Nyquist frequency so no aliasing is produced.

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I would love to link to a set of screen shots or videos showing if the aliasing problem exists or not in a Rigol DSO but I do not have one to test.  I can show it on other (old) DSOs and in Agilent's application notes but that is not very helpful except to show that the problem exists in a general sense.  Agilent pointed the problem out to distinguish themselves from Tektronix.

Again, where are these application notes? I want to see a document describing turning off sin(x)/x interpolation because of interleaving problems at the fastest real-time sampling rates. I can link to reams of literature about the problem of aliases in sin(x)/x interpolation, if you like.

When I first ran across this problem with my Tektronix 2440 which needed CCD calibration, Agilent had an application note describing the issue perfectly but I did not keep a copy and have not been able to find it again online.  I did find a couple of others:

This LeCroy application note mentions the sin(x)/x reconstruction problem in connection with interleaving on page 15 with a Tektronix DSO.  Agilent likes to pick on Tektronix about this as well:

http://cdn.teledynelecroy.com/files/whitepapers/wp_interpolation_102203.pdf

This Agilent application note discusses the interleaving problem and distortion from the digitizer itself as the source of aliasing when the input signal is completely within the Nyquist bandwidth.  I think I linked this one earlier:

http://literature.cdn.keysight.com/litweb/pdf/5989-5732EN.pdf

I even found a discussion thread on EEVblog with accompanying video which shows exactly the problem I described with a Rigol DS1102E.  I do not agree with the analysis that I have read so far there but am still working through the discussion:

https://www.eevblog.com/forum/chat/rigol-ds1000e-series-possible-errorfail-in-sin%28x%29x-interpolation/

At about 46 seconds into the video, it shows the results of sin(x)/x reconstruction on a sine wave that started out below the Nyquist frequency were higher frequency components created by mixing between the sample clock and the signal in the digitizer cause aliasing.

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No company in their right mind is going to include as a reason for turning off sin(x)/x interpolation that it is to conceal aliasing made worse by interleaving done to increase the real-time sample rate.

Do you mean that no company will have published literature about this made-up theory of yours?  ;)

Well, they are certainly not going to advertise it in their oscilloscope specifications or documentation unless for the purpose of distinguishing themselves from their competitors and maybe not even then. :)
« Last Edit: September 27, 2014, 12:33:35 am by David Hess »
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #77 on: September 27, 2014, 01:04:59 am »
They are meaningful in questioning the credibility of Rigol and especially so since they have continuously made the same mistake for years and have not corrected it yet.  Perhaps I am too strident at times.

You clearly have some bad feeling about Rigol based on some problem you have/had with their older technology. Peak Detect (not Envelope mode) works perfectly fine on my Rigol DS2000 - as opposed to, say, the new Siglent SDS2000.

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The aliasing produced in the digitizer between an input signal which is completely below the Nyquist frequency and the sample clock occurs whether sin(x)/x reconstruction is used or not.

I can't even believe this is something we need to debate - if the waveform is not-band limited properly, then it's generally agreed upon that linear interpolation usually provides a more faithful representation. That's why Rigol provides manual control of the interpolation when the sample rate is reduced to 250MSa/s when 3 or 4 channels are turned on - it's that simple.

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This LeCroy application note mentions the sin(x)/x reconstruction problem in connection with interleaving on page 15 with a Tektronix DSO.  Agilent likes to pick on Tektronix about this as well:

I certainly don't see anything of the sort written on page 15. I see LeCroy stating that, "The Tektronix scope shows some amplitude modulation in the result, but this thought not to be a result of interpolation, but instead interleaving performance."

What has this to do with your stated theory that a company will disable sin(x)/x at fast sample rates to hide interleaving problems?

Anyway, I'm finished debating this. You clearly have some pet theory about this DSO (and it's technology) that is unsupported by any evidence whatsoever because you feel burned by Rigol about something else. If you find ANY actual proof that Rigol is disabling sin(x)/x at higher sample rates to conceal interleaving problems, I'd be happy to hear about it.
« Last Edit: September 27, 2014, 01:48:18 pm by marmad »
 

Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #78 on: September 27, 2014, 04:37:40 pm »
Another day, and other 5 minutes of test:

The first image is of a 130MHZ signal (50% AM modulated by 1khz sine)  just to push the scope to its limits.
The second is about the trigger out jitter time (3nS) measured from the rear output.

Moreover following results are measured by a calibrated 5334B and 1MHZ square wave:
  • in dot mode the best wfps i saw was 52.8k @50nS/div 600 pts memory.
  • in vector mode it was 28.8k @50nS/div 600 pts memory.
The acquistion modes doesn't affect the wps rate.

These results simply make me sad because now I have to get one!  ;D




Semel in anno licet insanire.
 

Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #79 on: September 27, 2014, 04:50:40 pm »
The second is about the trigger out jitter time (3nS) measured from the rear output.

What would a trigger output with that much jitter be used for?  Qualifying a logic analyser or word recognizer?

I have used gate outputs from analog oscilloscopes and trigger outputs from DSOs which have analog triggering but I always relied on very low jitter unless I was measuring update frequency.
 

Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #80 on: September 27, 2014, 05:13:01 pm »
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What would a trigger output with that much jitter be used for?  Qualifying a logic analyser or word recognizer?
IMHO 3nS jitter on a 100MHZ cheap scope is a decent time and it is difficult to have better results with digital triggers feeded by 1G samples per second. It's just three sample uncertainty.
 
Personally I don't use measuring tape when I look for millimeters.

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Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #81 on: September 27, 2014, 05:35:12 pm »
The second is about the trigger out jitter time (3nS) measured from the rear output.
Are you sure your tests are completely accurate? In your image, I don't see a separate input channel being used to generate the Trigger Outs (unless the output is from a different DS1000Z).

The Trigger Out jitter of the DS1074Z - as measured by two different owners here and here - was reported as 8ns. I doubt it's been changed by Rigol on the DS1054Z model - although it would be nice if they had  :)
« Last Edit: September 27, 2014, 05:42:19 pm by marmad »
 

Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #82 on: September 27, 2014, 05:48:03 pm »
In fact I didn't use two channels.
I just let the scope autooscillate on a single channel after an external stimulus and set the scope to trigger both negative and poitive edges.
When you turn on two channels you have 8nS jitter.
With three and four channels active 9nS jitter.
Now I'm having my dinner but I'll post some other pictures later.
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Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #83 on: September 27, 2014, 06:43:44 pm »
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What would a trigger output with that much jitter be used for?  Qualifying a logic analyser or word recognizer?

IMHO 3nS jitter on a 100MHZ cheap scope is a decent time and it is difficult to have better results with digital triggers feeded by 1G samples per second. It's just three sample uncertainty.

I am actually surprised they include a trigger output at all but I guess it is easy enough to do.  It is certainly handy for measuring the acquisition rate.

I understand where the jitter and delay come from in the implementation.  Do all DSOs with digital triggering have the same limitation?

I wonder what would be the best way to eliminate it in this type of design short of implementing an external analog trigger which would be unlikely to provide any additionally useful function.  I guess a programmable delay should be all that is needed although that would do nothing to lower the delay.

On two channel DSOs, is there similar jitter between the external trigger and the internal trigger?  If there is the easy way to solve that is to digitize the external trigger and use transition midpoint timing but I have no idea if they go that far.

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Personally I don't use measuring tape when I look for millimeters.

I don't either.

Just the other day I was using the gate out on my 7904 like this to measure jitter at specific trigger levels because analog delayed sweep was not up to the task.  My much slower 7603 at 100 MHz would have worked just as well but the sweep gate output is on the back and difficult to reach.
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #84 on: September 27, 2014, 06:49:59 pm »
In fact I didn't use two channels.

But neither did the other two people that measured the jitter (if you follow the links I posted above) - they used a second DSO (DS2000) to measure the jitter.

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I just let the scope autooscillate on a single channel after an external stimulus and set the scope to trigger both negative and poitive edges.

I don't think that's going to give you a real world representation of the output jitter.
« Last Edit: September 27, 2014, 06:53:34 pm by marmad »
 

Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #85 on: September 27, 2014, 07:01:06 pm »
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Just the other day I was using the gate out on my 7904 like this to measure jitter at specific trigger levels because analog delayed sweep was not up to the task.  My much slower 7603 at 100 MHz would have worked just as well but the sweep gate output is on the back and difficult to reach.
I still am a proud tek 7854 owner and I know what are you saying.  ^-^

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I wonder what would be the best way to eliminate it in this type of design short of implementing an external analog trigger which would be unlikely to provide any additionally useful function.  I guess a programmable delay should be all that is needed although that would do nothing to lower the delay.
There are several ways but are all expensive if compared to the street price of this scope.


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But neither did the other two people that measured the jitter (if you follow the links I posted above) - they used a second DSO (DS2000) to measure the jitter.
I'm at home now. On monday I'll go to the lab and give that a shot.

Anyway, attached you'll find the 6.4nS jitter when both channel 1 and 2 are on with the same measuring method I used before.


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Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #86 on: September 27, 2014, 07:35:02 pm »
A small update:

with the same method and AC coupling for the triggering I can't see the jitter at all.  ;D
And is not affected by the number of turned ON channels.
« Last Edit: September 27, 2014, 07:48:39 pm by 0xfede »
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Offline David Hess

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Re: New Rigol DS1054Z oscilloscope
« Reply #87 on: September 27, 2014, 08:42:18 pm »
A small update:

with the same method and AC coupling for the triggering I can't see the jitter at all.  ;D
And is not affected by the number of turned ON channels.

So what exactly is being measured here?

The interesting thing would be internal trigger or external trigger in to external trigger out delay and jitter.
 

Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #88 on: September 27, 2014, 09:03:42 pm »
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So what exactly is being measured here?

The interesting thing would be internal trigger or external trigger in to external trigger out delay and jitter.
Since the DS1000z series haven't an external trigger input I have simply connected the trigger out to channel 1 input with a BNC cable.

To let someone else replicate:
  • Channel 1 settings: 500mV, DC
  • Trigger settings: Edge, Ch1, either rising and falling edge, Coupling AC, Noise Reject ON
  • Trigger level: -120mV

If it doesn't start immediately move the trigger level back and forth.
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Offline Fungus

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Re: New Rigol DS1054Z oscilloscope
« Reply #89 on: September 28, 2014, 03:09:12 pm »
So....after a bit of back-and-forth it seems clear that the DS1054Z indeed has something like 100MHz bandwidth after inputting the codes.

What we really need is somebody who can do a test before/after, preferably with two scopes side by side. Maybe Dave will do it.

PS: Is there any way to "remove" a key? Some sort of factory reset?

PPS: Is Dave brazen enough to post a video telling people to hack the DS1054Z? I know it's not exactly a secret and Rigol is fully aware of the practice (they're probably reading this thread right now), but...

Then again, what's the worst than can happen? That Rigol sell a load more oscilloscopes? If anybody gets angry at the video it should be Agilent, Tektronix, et. al., not Rigol.
 

Offline nixfu

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Re: New Rigol DS1054Z oscilloscope
« Reply #90 on: September 28, 2014, 03:20:07 pm »
So just to confirm the 1054z can be changed to 100mhz just like the 1074z?

 

Offline Fungus

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Re: New Rigol DS1054Z oscilloscope
« Reply #91 on: September 28, 2014, 03:31:02 pm »
PS: How does hacking affect the warranty? Has anybody ever sent a 'scope in for repair with the wrong name in the system info (eg. it says DS1054Z on the hardware and "DS1104Z" on the system info screen).

It's not like anybody opened it up or modified the hardware in any way...all they did was press the buttons on it in a certain sequence.

« Last Edit: September 28, 2014, 03:37:14 pm by Fungus »
 

Offline DanielS

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Re: New Rigol DS1054Z oscilloscope
« Reply #92 on: September 28, 2014, 03:41:47 pm »
PPS: Is Dave brazen enough to post a video telling people to hack the DS1054Z? I know it's not exactly a secret and Rigol is fully aware of the practice (they're probably reading this thread right now), but...
There is not much of a video to make about this: you take your serial number, put it in the code generator, take the code the generator spits out and enter it on the scope.
 

Offline Fungus

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Re: New Rigol DS1054Z oscilloscope
« Reply #93 on: September 28, 2014, 04:22:08 pm »
PPS: Is Dave brazen enough to post a video telling people to hack the DS1054Z? I know it's not exactly a secret and Rigol is fully aware of the practice (they're probably reading this thread right now), but...
There is not much of a video to make about this: you take your serial number, put it in the code generator, take the code the generator spits out and enter it on the scope.

(Maybe you need to look up "brazen" in the dictionary)

Obviously I don't mean the physical process of doing it, more the morality of posting videos about it (and saying "beauty!" at the end).

Would you do it if it was your blog?

 

Offline 0xfede

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Re: New Rigol DS1054Z oscilloscope
« Reply #94 on: September 28, 2014, 04:44:09 pm »
Quote
PS: Is there any way to "remove" a key? Some sort of factory reset?
Just go to the UltraSigma Utility, send SCPI command
:SYSTem:OPTion:UNINSTall
and reboot the scope.

Tomorrow I'll make the test you are asking for and after I have to return the scope to the owner.
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Offline Orange

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Re: New Rigol DS1054Z oscilloscope
« Reply #95 on: September 28, 2014, 04:44:37 pm »
PPS: Is Dave brazen enough to post a video telling people to hack the DS1054Z? I know it's not exactly a secret and Rigol is fully aware of the practice (they're probably reading this thread right now), but...
There is not much of a video to make about this: you take your serial number, put it in the code generator, take the code the generator spits out and enter it on the scope.

(Maybe you need to look up "brazen" in the dictionary)

Obviously I don't mean the physical process of doing it, more the morality of posting videos about it (and saying "beauty!" at the end).

Would you do it if it was your blog?
If Dave starts making videos /promote hacks, its over with the free stuff he gets from Agilent,Fluke and Rigol.
 

Offline Fungus

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Re: New Rigol DS1054Z oscilloscope
« Reply #96 on: September 28, 2014, 05:08:11 pm »
If Dave starts making videos /promote hacks, its over with the free stuff he gets from Agilent,Fluke and Rigol.

EEVblog #70  ?

 

Offline i4004

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Re: New Rigol DS1054Z oscilloscope
« Reply #97 on: September 28, 2014, 05:45:29 pm »
rigol has a way to prevent this, just make DIFFERENT scopes ie front-ends...

 i would say hacking actualy works for them, ie they'll sell more, like i wrote on some yt comment
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as somebody just mentioned 100mhz hack for DS1054Z.... if true, it suggests they think hackability works for them, and if you think about it for a moment, it's quite possible that they sell more scopes in this way... (consumer just thinks he got something for nothing, and consumer likes that! heh...but he did pay for the scope...)

(i mean the hacking just got even easier with z series...that doesn't suggest rigol hates it, does it?)

dave already did it once, so why stop now?
i think that video actually helped sell a awhole lot of 1052 sopes.

also, if your motto is "no script no fear all opinion" do you  have a choice?  ;D

video should be made, because people started to search the yt instead of google.  :-//
(video of 30sec length, just the hack... )

this does void the warranty but what if you have a dealer that will backup your machine prior to shipping it and then put it back in case it needs to go back to rigol on repair?  ;)
 

Offline marmad

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Re: New Rigol DS1054Z oscilloscope
« Reply #98 on: September 28, 2014, 06:03:44 pm »
PPS: Is Dave brazen enough to post a video telling people to hack the DS1054Z? I know it's not exactly a secret and Rigol is fully aware of the practice (they're probably reading this thread right now), but...

video should be made, because people started to search the yt instead of google.
(video of 30sec length, just the hack... )

It seems you guys are rather late to the party. We've been discussing, posting, rehashing, etc. about the UltraVision (and other new Rigol products) hacks on this blog for about a year and a half. Why would Dave feel compelled to do a video blog about it now?
« Last Edit: September 28, 2014, 06:05:40 pm by marmad »
 

Offline Fungus

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Re: New Rigol DS1054Z oscilloscope
« Reply #99 on: September 28, 2014, 06:55:42 pm »
(i mean the hacking just got even easier with z series...that doesn't suggest rigol hates it, does it?)

I agree. I'm 100% sure they could have made this scope so the 100MHz thing didn't work, it's up to their firmware to accept the code or not. Fact is: They just launched a new 'scope with a firmware that appily switches to 100MHz using an existing, widely known key generator.

They knew exactly what would happen and have already crunched the sales numbers.

Thir sales numbers will say: Fungus just bought one, his friend is buying one this week...anybody who sees one will say "Take my money!". They're going to sell a shedload of 'scopes and take the entire home-user market for themselves.

A lot of (most?) serious professionals and education will still pay for the one that says "DS1104Z" on the front. They'll suspect that something has to be different.


Why would Dave feel compelled to do a video blog about it now?

Not a video just about hacking, a video on the DS1054Z itself. We know he's getting one, we kinda know he's going to do a video on it (it's the biggest news in the oscilloscope world for a long time!) Will he mention the hacks?

 


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