Rigol DS1202Z-E entry level scope (200MHz, 2 channel)

[Fred Basset]

IDEngineer, Maybe it takes a certain kind of imagination?  I quickly tried to make my mouth round to try and produce as clean a sine wave as I could, then found that I still could not tell unless I made my voice less loud and lower. Suddenly I had a very rough, but recognisable sine wave triggering on the scope.  I would only be able to hold it for a couple of seconds at a time, but it was magic to see it lock onto my voice.  It was just one of those things that I just knew I had to get someday...Along with a metal detector (got when I was 11) and a lathe (about 30 years old, but it was only a wood lathe and I want to be able to do metal as well.)

I am a nerd...can't hide it!  I am actually proud to say that I have been a member of FOUR of the organizations who's magazines/newsletters have been the "guest publication" on QI episodes...

[Fred Basset]

RHB, I have never scraped a lathe before.  Done a fair old bit of engineering though.  Bit limited in what I can do now thanks to ill health, so I might have to get a Sherline.  The 17" length is good, but a bit of a worry about only 3 1/2" width.  I will have to think about that.  Still it is not likely to be this year if I go for the Sherline.  With enough to get me started, maybe $2,500 including delivery and taxes?  Gives me something to aim for next year though.

Yes, I did spend most of last night, including a good chunk of sleeping time, watching how to upgrade and do things on youtube.  I even got a question answered I had always wondered.  Using a flute with three cutting edges, you can drill a square hole (no, not a joke if you have never heard of this before), but thanks to YT, I now know that it IS possible to drill any n-sided hole by using a floating flute with n-1 edges to it.  I have just realised that following that equation, a round hole must actually be considered to be a one-sided hole then.

OK, so maybe your timing is impeccable.  Took me a week to decide between this scope and the 54, can you imagine if you had thrown the Chinese lathe at me as well?  That smell of cooking would be my brain frying itself in indecision...  Just think, you could stick a bit of kitchen foil to the chuck and shine a light at it.  A simple detector circuit and I could use my new scope to calibrate the rpm.  well, under no load condition anyway.  I imagine the speed does vary if you try to remove too much material at once.

Come to think of it... If you used say strips of 1/2" adhesive tape and spaced them exactly 1/2" apart (might need to wrap the chuck in a layer or two of paper to make it an exact multiple of 1/2" strips), but you should get a pretty good 50% duty cycle square wave with either a focused laser, or IR, but with a slit over the detector.  Doing that might help find the roughness in the way the chuck runs?

[rhb]

The DS1202Z-E arrived today.

Rise time 1.386 ns avg. Overshoot 1.284% avg.  But that only applies in single channel mode.  With both channels operating it degrades quite a lot.

FFT is completely unusable.  I pretty much knew that going in, but I didn't expect it to be *worse* than my DS1102E.

"QuickPrint" of a screen .png file takes 30 seconds!  Oh, and if you power up the scope with a USB drive installed it doesn't find it.  So you have to unplug it and plug it back in.  That is almost grounds for returning it.  I can photograph my Tek 485 more quickly and easily.

I now have an Owon XDS-2102A, Rigol DS1102E and DS1202Z-E and Instek MSO-2204EA.  Everyone of them does some things well and other things abysmally badly.

I'm considering taking a sledge hammer to the lot of them.  So stay tuned.  It will be a different thread from this one.  Not sure if I'll cough for a Siglent or not to add to the comparison. A lot depends upon what that would cost.  I do not need another mediocre DSO.  But if I decide to spend the time on it, it will be a very thorough critique of what's wrong with each DSO.

Rather hilariously, the top corner of the rise of the <40 ps step is seven 1 ns long steps in a staircase approximating an exponential.  And it's every bit as crisp a staircase as the demonstration I did with the Tek 11801 & SD-24.  Except in this case the pulse generator is directly feeding the DSO input through a 50 ohm thru terminator.

The DS1102E does not show this behavior.  It is clearly linearly interpolating between samples when in dot mode at 2 ns/div whereas the DS1202Z-E is dithering the clock which makes the steps apparent.

Reg

[ExtraClassRed]

 Just so you all know. This article is the reason I ordered a ds1202z-e at TEquipment for the current special. $299 with free shipping and no tax! WOW! One of the last few posts talked about an awesome (supposedly for price) signal gen (feeltech fy6600) so I went to eBay and Amazon to get one. I read some awful reviews and it led me to a $150 one called the Koolertron 60 MHz DDS generator. Must have been meant to be because a amateur radio guy with failing health was selling one for $70 shipped on auction. 14 MINUTES LEFT! I got it! This forum is awesome! I’ve been watching some reviews from eevblog on YouTube for years. Now I find this forum!

 I’m a licensed amateur and have been building small kits and radio kits and messing with audio for years. I’ve never went beyond a weller soldering iron and multi meter but my radio modifications have lead me down the road I need more advanced equipment to get done what I want. Glad I found a decent blog and very helpful information here.

73 for now
N0TMY
I’ll be clear

[rhb]

I just realized the implications of this plot:



It rather blows my mind.  The DS1202Z-E  FW is *very* annoying, but.  The steps imply a >1 GHz BW for the analog part of the AFE.  And, unfortunately, a useless or non functional anti-alias filter.  The display does *not* change if I turn the anti-alias filter on or off in the UI which goes a long way towards explaining why the FFT is completely unusable.

What you are looking at is the charging of the DSO input transmission line which is ~ 10 cm long.  This is being fed by one of Leo Bodnar's excellent <40 ps rise time BNC pulsers through a 50 ohm thru termination.

You can see an example using a Tek 11801 & 20 GHz  SD-24 sampling head here:

https://www.eevblog.com/forum/chat/does-a-capacitor-charges-smooth-or-in-stairs/msg3092981/#msg3092981

That's a <20 ps rise time square wave feeding a <17 ps rise time sampling head.  Rise time for the combination is <26 ps.

Have Fun!
Reg

[tautech]

..................
I'm considering taking a sledge hammer to the lot of them.  So stay tuned.  It will be a different thread from this one.  Not sure if I'll cough for a Siglent or not to add to the comparison. A lot depends upon what that would cost.  I do not need another mediocre DSO.  But if I decide to spend the time on it, it will be a very thorough critique of what's wrong with each DSO.
................

What model are you considering Reg ?

[rhb]

SDS-1202X-E as it is the direct competitor to the DS1202Z-E and almost certainly the reason for the latter's  introduction.

Reg

[tautech]

SDS-1202X-E as it is the direct competitor to the DS1202Z-E and almost certainly the reason for the latter's  introduction.

Reg

You might also consider investigating SDS2202X-E the 2GSa/s variant that while seemingly very similar has Bode plot and webserver.

BTW, the 2kX-E model has a 350 MHz front end for the SDS2352X-E. 

[Fungus]

"QuickPrint" of a screen .png file takes 30 seconds!  Oh, and if you power up the scope with a USB drive installed it doesn't find it.  So you have to unplug it and plug it back in.  That is almost grounds for returning it.  I can photograph my Tek 485 more quickly and easily.

This seems to depend a lot on the USB stick, although I haven't seen a definitive analysis of what makes a good/bad stick.

They *can* do it in about 4 seconds when they feel like it.

Or ... if you do it a lot then it's easy to grab a screen over Ethernet. No need to go via USB stick.

[Fred Basset]

Reg, Could the time writing to the USB stick be caused by it having a lot of capacity and how it is formatted?  Originally I know they could only read FAT32, but now has a limit of 2GB I think?  So they have a different disk format enabled as well now.

Devastating to read the FFT is so bad when I have not even got mine yet.  It is a very significant investment for me, so I am hoping they will sort it out via an update eventually?

Thanks for the heads up though.

[Fungus]

FFT is completely unusable.  I pretty much knew that going in, but I didn't expect it to be *worse* than my DS1102E.

Just a thought: You are using "memory" FFT, right? There's two settings on these things. The original FFT used on-screen data so it only has 1200 points, they added an option to do FFT from memory with 64k points that's a better FFT but slower.

Devastating to read the FFT is so bad when I have not even got mine yet.  It is a very significant investment for me, so I am hoping they will sort it out via an update eventually?

Unlikely at this point in the lifecycle.

What are you using the FFT for? If it's anything audio then use a PC sound card instead. It's not just better than a cheap Rigol, it's better than just about any oscilloscope at any price.

[Fungus]

Not sure if I'll cough for a Siglent or not to add to the comparison. A lot depends upon what that would cost.  I do not need another mediocre DSO.  But if I decide to spend the time on it, it will be a very thorough critique of what's wrong with each DSO.

A Siglent will cost at least $100 more than this Rigol. I'd be interested to see an unbiased opinion how much difference there really is. Not many people own both and getting an unbiased opinion around here is like getting blood from a stone.

My gut feeling is that the Siglent will only a small step up (about $100 worth...!), not the utopia that the resident Siglent dealers would have us believe.

[tv84]

Not many people own both and getting an unbiased opinion around here is like getting blood from a stone.

 

See it this way: the bias is good if it measures the level of knowledge they have about their equipment. Then it's up to the reader to filter or incorporate the bias.

[Fungus]

I just realized the implications of this plot:

(Attachment Link)

What you are looking at is the charging of the DSO input transmission line which is ~ 10 cm long.  This is being fed by one of Leo Bodnar's excellent <40 ps rise time BNC pulsers through a 50 ohm thru termination.

I'm quite bothered by the fact that the signal and trigger point are way off screen. These things are driven by opamps that are prone tro overload/recovery so that can distort the signal a LOT.

[rhb]

The 11801 is a sampling scope.  It uses a fixed internal trigger, but most of the waveform was *way* off screen in those examples. It's clearly going to take some careful thought to sort out what is actually going on.  I can reduce the amplitude of the pulser step. 

I set up the pulser with a tee and open cable which duplicates the internal geometry of the SD-24 fairly closely.  It appears that this is related in some fashion to the way that the vertical scale is set.   The steps may be quantization in the ADC related.  I'll need the 7104 and 11801 to settle the matter.  I can connect the SD-24 directly to the Rigol input.  That will provide an unbiased TDR of the front end of the Rigol and determine whether my initial interpretation is correct.

My biggest problem is my current lab space is going to have trouble accommodating all the scopes.

So far as I know at present the only good FFT is the SA app of the Instek MDO-2000E which can be hacked to work on any of the GDS-2000E line. The Instek FFT is pretty good, but it doesn't provide the proper processing to produce a good result for spectrum analysis.

For audio, a sound card is the best route as you can correct for all the DAC and ADC errors using Octave.

For RF an RTL-SDR dongle will provide reasonable SA, though an SDRplay RSP1A or RSPdx  is much better.

Have Fun!
Reg

[Fungus]

For audio, a sound card is the best route as you can correct for all the DAC and ADC errors using Octave.

Yep.

The other day I found out you can use the Analog Discovery's software with a sound card for free. Just download the software on their website and select "Sound Card" after it starts up and says "Device not detected". I don't know about $100,000 Lecroys but the FFT is orders of magnitude better than on any 'scope I've seen.

https://www.analogdiscovery.com/download/

After playing with that for a while I've been trying to get an Analog discovery for myself but there's a massive worldwide shortage of them right now. There's none at all until the end of July and then the educational customers get priority. No chance at all for a small fish to get one.

https://store.digilentinc.com/analog-discovery-shortage/

[rhb]

There's a lot more value to using WAV files and Octave.  Write a program to generate a stereo WAV file which sweeps all frequencies and all amplitudes.

Play the WAV file with the R & L channels feeding straight through and crossed over and record the results.  A bit of algebra and you can turn the sound card into a very high accuracy distortion analyzer and audio signal source by then generating precorrected WAV files.

This will let you correct all the analog errors in the inputs and outputs.

Have Fun!
Reg

[CharlotteSwiss]

has anyone wondered if it is better to spend money on rigol 1202z-e, or better on siglent1202x-e? I am undecided between these two oscilloscopes 
thanks
Charlotte

[tv84]

has anyone wondered if it is better to spend money on rigol 1202z-e, or better on siglent1202x-e? I am undecided between these two oscilloscopes 

You'll have to wait for Reg's war. Until now nobody has done a true comparison between those 2 scopes. Although my advice would be to put more 100€ and buy Siglent SDS1104X-E. If you want to remain in the 400€ and 200MHz, you'll need to wait.

[Fungus]

has anyone wondered if it is better to spend money on rigol 1202z-e, or better on siglent1202x-e? I am undecided between these two oscilloscopes 
thanks
Charlotte

One is more expensive so the decision is between you and you wallet.

Features don't enter into the equation, they're similar value for money.

[tv84]

One is more expensive so the decision is between you and you wallet.

You know that is my answer but Batronix has both for the same price.

[CharlotteSwiss]

You'll have to wait for Reg's war. Until now nobody has done a true comparison between those 2 scopes. Although my advice would be to put more 100€ and buy Siglent SDS1104X-E. If you want to remain in the 400€ and 200MHz, you'll need to wait.

then to have 4 channels I could take rigol 1054, same price. It seems that rigol1202 is based on older hardware than the siglent 1202 ... I'm waiting for the war 

One is more expensive so the decision is between you and you wallet.
Features don't enter into the equation, they're similar value for money.

the price is similar, indeed siglent is also less
 

[rhb]

has anyone wondered if it is better to spend money on rigol 1202z-e, or better on siglent1202x-e? I am undecided between these two oscilloscopes 

You'll have to wait for Reg's war. Until now nobody has done a true comparison between those 2 scopes. Although my advice would be to put more 100€ and buy Siglent SDS1104X-E. If you want to remain in the 400€ and 200MHz, you'll need to wait.

I thought you had hacked the SDS1104X-E to 200 MHz.  Is that not correct? 

[CharlotteSwiss]

I thought you had hacked the SDS1104X-E to 200 MHz.  Is that not correct?

sds1104 costs too much, it is also wasted on me!
I can settle for 2 channels less... and no hack 

[rhb]

FYI I just posted a poll "Scope Wars Poll" to decide which scope to test.

Have Fun!
Reg