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Products => Test Equipment => Topic started by: jsi on May 13, 2016, 08:57:06 pm

Title: Oscilloscope Buying questions
Post by: jsi on May 13, 2016, 08:57:06 pm
Guys I need a little help in purchasing a good oscilloscope and I am a little overwhelmed by all the choices, new, used, 50 MHz, 100 MHZ, etc, etc.  First this is what I need it for: My project “listens” to a telephone signal and depending on what it “hears” different actions are taken.  For example, if it hears DTMF tones different things happen than if it hears someone talking.  I’m getting strange results that I’m attributing to noise on the line, but I don’t really know for sure.  I’d like to plug in an oscilloscope and see what’s going on.  Beyond that I’d like to be able to use it at a logic probe to see what state different pins on the IC’s are in from moment to moment.

I think my needs are really simple, for now.  But, I can see more uses in the future so I want to buy a quality piece of kit that will last.  I’m a firm believer in crying once about the price of a tool than crying every time you use a cheap one.  That said my budget is $300 - $400 USD give or take.  Used is an option for sure.  Also my future uses could require the device to be portable so the new LCD screens are attractive.

There are a number of new oscilloscopes in my price range and more than quite a few on ebay.  Beyond a brand name what should I be looking for?  50, 100, 200 or more MHz? Other stuff?
Title: Re: Oscilloscope Buying questions
Post by: PartialDischarge on May 13, 2016, 09:04:41 pm
You did pretty much say it all, if you want a portable LCD osc in that budget get a DS1054Z, or fish for something used on ebay...

That said, try to foresee your future projects and if you may be better off saving a few hundred more for a DS2000 for example, but hey a DS1054 will give you a lot to play with....
I dont even mention USB scopes... a waste of money....
Title: Re: Oscilloscope Buying questions
Post by: jsi on May 13, 2016, 10:38:02 pm
One thing I don't understand is the different MHz.  The Rigol DS2072A is 70 MHz and about twice the price of the 100 MHZ Rigol DS1102E.  So clearly it's not all about the MHZ. 

As for the $400 budget lets uh, just say that's a guideline ;) rather than a rule.  I'm at a stage in life where I can indulge a hobby.  And who knows, maybe this hobby can make me a few dollars to pay for the tools.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 13, 2016, 11:23:12 pm
What is pushing prices apart is bandwidth, samplerate, memory depth and maturity/functionality of the features. I think it is safe to say $400 doesn't buy you a new oscilloscope with features which all work as advertised or are actually useful. You really have to make a list with the features you want, look of oscilloscopes which provide those features and use reviews/comments on this forum to guage whether it is a good buy or not. This should get you a short list but be sure that you can return an oscilloscope if it turns out to be a lemon after all. The biggest mistake to make is to wait for a firmware update to fix a problem. If a feature isn't there 'out of the box' (after installing the most recent firmware) then return it ASAP.
Title: Re: Oscilloscope Buying questions
Post by: DimitriP on May 13, 2016, 11:31:11 pm
Quote
My project “listens” to a telephone signal and depending on what it “hears” different actions are taken.

Potentially you can get away with any used , functional scope even if it has a single digit BW.
Even a cheapo Ebay $30 USB scope will allow you to look at "telephone line audio"
 
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 14, 2016, 12:08:39 am
It appears as though your experience with scopes might be a little thin.  If that's wrong, my apologies...

So, you can't make a list of features you need, you can't add in features you might want down the road, you're pretty much stuck at the starting point.

You mention a logic analyzer - that's not a scope!  An MSO scope can handle this kind of stuff but those tend to cost quite a bit more.

Most everybody is going to say "Get a DS1054Z 4 Channel scope, hack it to get to 100 MHz and it includes decoding for serial buses".  I haven't done that but I probably will and the procedure is well established.

Watch Dave's videos on the 1054 and see what he has to say.  For goodness sake STAY AWAY from the negative threads on this forum.  There are some truly vitriolic haters on those threads.  You will also see it in just about every thread that even mentions the word 'scope!

Rigol is pretty good bang for the buck at every level.  There are others such as Siglent and on up the food chain to Tektronix.  The cost just keeps climbing.

I bought a used Tektronix 465 scope about 12 years ago from eBay for a couple of hundred bucks.  They're still about that price...  It is rated for 350 MHz, only handles 2 channels and has no digital features at all.  It does, however, take care of any high frequency stuff I might want to do.  Realistically, the 1054 will handle most of my projects - actually all of them if I do the well-documented hack.

My advice (not that I expect anybody to pay attention to what I have to say), buy the DS1054Z, learn what digital scopes can or should do and, later on when needs change, buy something else and sell the 1054 if needed.  At least, the 1054 is a good place to start.  Right away it's got more channels than my 465 - that's why I bought it!

Title: Re: Oscilloscope Buying questions
Post by: jsi on May 14, 2016, 01:13:30 am
It appears as though your experience with scopes might be a little thin.  If that's wrong, my apologies...

You nailed it - no apologies needed

Quote
So, you can't make a list of features you need, you can't add in features you might want down the road, you're pretty much stuck at the starting point.

You mention a logic analyzer - that's not a scope!  An MSO scope can handle this kind of stuff but those tend to cost quite a bit more.

In the latest EEVblog #879 post Dave uses a scope to peer into the inner working of a chip (here's a link to where that starts in the video  https://youtu.be/3THvWEKGOwE?t=15m28s (https://youtu.be/3THvWEKGOwE?t=15m28s)) and this is the sort of thing I want to do.  Is that pin high or low and when did it happen?  I noticed he is using an MSO scope.  But, confusingly for me, in this video https://youtu.be/MC9_4mpqVgU (https://youtu.be/MC9_4mpqVgU) Dave says you can use the DS1054Z as a simple logic analyzer, and you can upgrade it to a true MSO scope if/when you need that functionality.

Quote
Most everybody is going to say "Get a DS1054Z 4 Channel scope, hack it to get to 100 MHz and it includes decoding for serial buses".  I haven't done that but I probably will and the procedure is well established.

Watch Dave's videos on the 1054 and see what he has to say.
I've watched that and it does look interesting

Quote
For goodness sake STAY AWAY from the negative threads on this forum.  There are some truly vitriolic haters on those threads.  You will also see it in just about every thread that even mentions the word 'scope!
Yeah isn't that true for every thing nowadays.  Fanboys are everywhere.

Title: Re: Oscilloscope Buying questions
Post by: billfernandez on May 14, 2016, 01:37:17 am
Given that presently you're only dealing with audio frequencies all you really need is 1MHz in scope bandwidth.

Scoping out logic will take more bandwidth depending on how fast it runs and what you want to see.

For this kind of basic tool I personally prefer to buy new, modern equipment rather than something used and/or something older and less current.

The Rigol DS1054Z is currently in the "best bang for the buck" sweet spot for a general-purpose, introductory-level scope.  I would think that this would last you many years, give you plenty of room and functionality to grow into, and depending on where you go with your hobby you might never have to upgrade.

And don't forget that if you make requests in the appropriate threads you can get discount codes for ordering through Tequipment.net and Saelig.
Title: Re: Oscilloscope Buying questions
Post by: bitseeker on May 14, 2016, 03:11:13 am
Since you're starting out with very modest requirements as far as the signals you're wanting to see (audio is pretty low bandwidth), almost any scope will work. Hence the comment that a 1 MHz scope will be plenty, including for looking at noise within the signal. The bandwidth rating indicates the highest frequency sine wave that can be measured before a given amount of attenuation occurs to the signal. More complex signals have higher frequency components that require more bandwidth to see correctly.

As has been mentioned already, for your budget you can get what you need and much more in the DS1054Z. Its 50 MHz bandwidth is many times more than what you currently need. If you outgrow it, you can sell it for something else (or keep it for projects where it fits), but that may be a while especially if you hack it to enable all the features, such as the protocol analysis, and 100 MHz bandwidth.

Later, if you want to analyze a lot of simultaneous digital signals, get a separate logic analyzer unless you really need to see the timing of analog signals concurrent with digital ones, which is where an MSO can be beneficial depending on how many you need to see at the same time. The four channels in the 1054Z can take you quite far.
Title: Re: Oscilloscope Buying questions
Post by: uncle_bob on May 14, 2016, 03:34:52 am
Hi

One of the modern facts of life is that all projects eventually go digital. That may not happen for a few years, but it does happen. When it does, a 1054 is a pretty good thing to have. Until then, it does what you need to do at lower frequencies just fine.

Bob
Title: Re: Oscilloscope Buying questions
Post by: Tomorokoshi on May 14, 2016, 03:46:20 am
Do those models have a basic FFT or spectrum analyzer view? With DTMF that would be a useful diagnostic feature.
Title: Re: Oscilloscope Buying questions
Post by: uncle_bob on May 14, 2016, 03:53:52 am
Do those models have a basic FFT or spectrum analyzer view? With DTMF that would be a useful diagnostic feature.

Hi

Yes, the 1054 has a basic FFT spectrum capability. It's not super duper, but it works. A sound card might do a better job for audio.

Bob
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 14, 2016, 04:05:49 am
Dave says you can use the DS1054Z as a simple logic analyzer, and you can upgrade it to a true MSO scope if/when you need that functionality.

I'm not sure how that could be done.  MSOs will have a separate port with the parallel inputs.  The DS1054Z with 4 channels will make a pretty decent analyzer for 3 channels + a clock or just 4 channels.

If you're going to be working at less than 1 MHz, the Hobby Components 8 channel logic analyzer seems pretty good.  I was testing it yesterday and I would be quite happy using it at sub-megahertz frequencies as long as I could sample at 24 MHz (USB 3.0 is probably required).

http://hobbycomponents.com/test/243-hobby-components-usb-8ch-24mhz-8-channel-logic-analyser (http://hobbycomponents.com/test/243-hobby-components-usb-8ch-24mhz-8-channel-logic-analyser)

The software (open source) is pretty decent.  Just sample fast, don't take too many samples and keep the frequencies low.

There is no reason the scope has to perform as a logic analyzer and a LA certainly can't replace a scope.

I have a LA based on a project at www.sump.org (http://www.sump.org).

Title: Re: Oscilloscope Buying questions
Post by: ez24 on May 14, 2016, 04:32:21 am
You mention portable in the future.  They why think about a bench one ?  If you can spring for a little more take a look at this

http://www.amazon.com/Handheld-Portable-Oscilloscope-Multimeter-Hantek/dp/B00CTHC0O6/ref=sr_1_12?ie=UTF8&qid=1463200018&sr=8-12&keywords=hantek+oscilloscope (http://www.amazon.com/Handheld-Portable-Oscilloscope-Multimeter-Hantek/dp/B00CTHC0O6/ref=sr_1_12?ie=UTF8&qid=1463200018&sr=8-12&keywords=hantek+oscilloscope)

What ever you do buy one in the country you live in for the warranty.  For example if you live in the US and buy one from HK, you would have to mail it back to HK to fix.  Postage will cost a fortune.

Title: Re: Oscilloscope Buying questions
Post by: JPortici on May 14, 2016, 05:58:54 am
I dont even mention USB scopes... a waste of money....
In the low price range, of course. But hey, tell pico technology they just sell crap!

I agree with rstofer. Get the 1054z, go on with the hobby, learn it and learn to live with its many limitation and issues (still, the best you can get new in the low price area) and learn not to blindly trust your measurement tools :)
Then in the future when you'll get a scope that's not really better on paper but better in reality -less feature but that works as advertised, more responsive interface and so on.. i'll never buy a rigol scope again, the ds2k and ds4k have almost all the same hardware bugs.- you can still use it for less critical stuff for example, or sell it.

If you want to see the spectrum of signals in the audio frequency range any low tier usb audio interface will be eons better than any oscilloscope that hasn't got more than real 12 bits resolution, which rules out basically every scope in the "humane" price range, because a soundcard adc has got much more resolution and even if you throw away 4-5 bits for cheap adcs your true resolution will be higher so better noise floor.
If you need to accurately measure audio signals at dc to <10hz  you'll need a dc coupled audio interface, like MOTU's
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 14, 2016, 06:03:18 am
Dave says you can use the DS1054Z as a simple logic analyzer, and you can upgrade it to a true MSO scope if/when you need that functionality.
I'm not sure how that could be done.

It can't be done with a basic DS1054Z. You need to buy the model with the extra connector on the front (which is more expensive).

But yeah, the correct answer to "I have $400 and I want to buy an oscilloscope" is to get a DS1054Z. It's head and shoulders above anything else in that price range.

Four channels is enough for simple logic analysis work.

There are a number of new oscilloscopes in my price range

But only one worth having.

Beyond a brand name what should I be looking for?  50, 100, 200 or more MHz? Other stuff?
More MHz is always good. More channels is always good for logic work.

A new $400 'scope with more MHz and channels than a DS1054Z? Impossible.
Title: Re: Oscilloscope Buying questions
Post by: Wuerstchenhund on May 14, 2016, 07:29:41 am
Most everybody is going to say "Get a DS1054Z 4 Channel scope, hack it to get to 100 MHz and it includes decoding for serial buses".  I haven't done that but I probably will and the procedure is well established.

Watch Dave's videos on the 1054 and see what he has to say.  For goodness sake STAY AWAY from the negative threads on this forum.  There are some truly vitriolic haters on those threads.  You will also see it in just about every thread that even mentions the word 'scope!

Well, to be fair there's some basis to the critics of Rigol:
https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/ (https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/)

That doesn't render the scope useless, but it is a pretty stark display of incompetence in terms of designing hardware properly, and a prospective buyer should be at least aware of the problem and what's required to fix it.

Quote
Rigol is pretty good bang for the buck at every level.

No, certainly not at every level. Rigol offers without doubt the best value for money at the bottom end (DS1054z), and the DS2000A has been similar value for money back then when it was only competing with the Agilent DSOX (but these days there are more alternatives), but the DS4000 in general isn't (again, there are other alternatives these days), and the DS6000 is pretty much a bad joke with a ridiculous price tag.

Quote
There are others such as Siglent and on up the food chain to Tektronix.  The cost just keeps climbing.

Yes, but Siglent, while producing good hardware, has a long and very poor track record with their firmware quality. It doesn't mean the scope won't do what the OP wants it to do, but it's important to be aware of the limitations and issues, and as nctnico says, if it doesn't work today don't get fooled into waiting for a fix, return it.

It also shows that in general you get what you pay for, although Tek (the once great brand that gave us the best analog scopes but since the advent of DSOs has only come up with mostly mediocre at best products, and today it pretty much represents the bottom-end of the big brands) shows that this isn't always true.

Quote
My advice (not that I expect anybody to pay attention to what I have to say), buy the DS1054Z, learn what digital scopes can or should do and, later on when needs change, buy something else and sell the 1054 if needed.

I fully agree. At a budget of $400 the DS1054z offers the most bang for the buck. The 2nd hand market often has great deals but at $400 there's pretty much only "untested" (i.e. known defective) digital stuff, some old sampling scopes (useless for everything except some niche tasks) and some analog antiques (which realistically shouldn't cost more than $50 or so). So yes, the DS1054z is the best option here.

Title: Re: Oscilloscope Buying questions
Post by: EEVblog on May 14, 2016, 08:32:00 am
In the latest EEVblog #879 post Dave uses a scope to peer into the inner working of a chip (here's a link to where that starts in the video and this is the sort of thing I want to do.  Is that pin high or low and when did it happen?  I noticed he is using an MSO scope. 

I did not use the MSO function of that scope Keysight scope!
I used the analog channels, because I like to look at the actual waveforms.
Just get the Rigol DS1054Z, it will do everything you want
https://www.youtube.com/watch?v=ETCOhzU1O5A (https://www.youtube.com/watch?v=ETCOhzU1O5A)
Title: Re: Oscilloscope Buying questions
Post by: DimitriP on May 14, 2016, 09:03:14 am
...in the meantime , while you are deciding how to spend $400 to deal with DTM tones,

download this  http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=18988 (http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=18988)  ,  feed the sound to your soundcard and get some work done :)

Title: Re: Oscilloscope Buying questions
Post by: PartialDischarge on May 14, 2016, 10:33:26 am
I dont even mention USB scopes... a waste of money....
In the low price range, of course. But hey, tell pico technology they just sell crap
I said they are a waste of money, I dont care if its 10MHz or 2Ghz bandwidth. A scope is a scope and a laptop/PC running Windows plus an usb box is crap ( and a waste of money) no matter how good the specs.

Same applies for example to hikers/mountaineers saying "hey my phone has a gps, so Ill use that one during the hike" :-- A phone is a phone( low battery life, useful for emergency calls, no waterproof...) and a Hiking gps is a GPS.

Title: Re: Oscilloscope Buying questions
Post by: JPortici on May 14, 2016, 10:55:21 am
I disagree. It's not that there are plenty of scopes that are
-battery powered
-with isolated channels
-with good analog front ends
That also are not crippled or limited in the software side.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 14, 2016, 11:27:20 am
Well, to be fair there's some basis to the critics of Rigol:
https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/ (https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/)

That doesn't render the scope useless, but it is a pretty stark display of incompetence in terms of designing hardware properly, and a prospective buyer should be at least aware of the problem and what's required to fix it.

Has anybody demonstrated that any of those design defects has an effect on the 'scopes output?

Because if they don't, then...who cares?  :-//
Title: Re: Oscilloscope Buying questions
Post by: alsetalokin4017 on May 14, 2016, 01:58:06 pm
In the latest EEVblog #879 post Dave uses a scope to peer into the inner working of a chip (here's a link to where that starts in the video and this is the sort of thing I want to do.  Is that pin high or low and when did it happen?  I noticed he is using an MSO scope. 

I did not use the MSO function of that scope Keysight scope!
I used the analog channels, because I like to look at the actual waveforms.
Just get the Rigol DS1054Z, it will do everything you want
https://www.youtube.com/watch?v=ETCOhzU1O5A (https://www.youtube.com/watch?v=ETCOhzU1O5A)

Right!

After all, what other scope can display 5 bugs at once?

(Don't get me wrong, I ordered the scope based on Dave's reviews, and overall am very happy with it, and with RigolUSA's customer service. But.... there are some bugs that some people might find critical...)
Title: Re: Oscilloscope Buying questions
Post by: MT on May 14, 2016, 02:43:57 pm
List the 5 bugs! Hmm.. are there a 6'th bug?!
Title: Re: Oscilloscope Buying questions
Post by: jsi on May 14, 2016, 03:47:16 pm
...in the meantime , while you are deciding how to spend $400 to deal with DTM tones,


 :) not quite up to $400 for the DTMF tones.  I salvaged a MT8870 DTMF processor out of an old call processing box. And thank you for the link, you never know when stuff like that will prove useful.  Eventually this project is going to go into a project box and be used daily, but I'm a long ways from that right now. 

And a big thanks to everyone that chimed in, my next post will on the TEquipment thread to request a discount for the Rigol DS1054Z. It's in my price range, small and portable for my other uses, it's new with a warranty so I don't have to worry about getting a bad used one, sexy looking, and after everyone's input I'm sure it will do what I need. 


(to my dear sweet wife I'm going to say "your brother just spent $500 on a single golf club and he's still a lousy golfer, so really my hobby isn't that expensive"  ;D)
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 14, 2016, 04:20:30 pm
Look at the GW Instek GDS-1054B if you don't care about hacking and decoding. It is cheaper than the Rigol 1054Z at Tequipment. It will also be the better buy.
Title: Re: Oscilloscope Buying questions
Post by: jsi on May 15, 2016, 12:22:47 am
Look at the GW Instek GDS-1054B if you don't care about hacking and decoding. It is cheaper than the Rigol 1054Z at Tequipment. It will also be the better buy.

I looked at the GDS-1054B and I like that it has separate controls for each channel.  That said I'll probably end up hacking the Rigol which makes it quite a deal.
Title: Re: Oscilloscope Buying questions
Post by: bitseeker on May 15, 2016, 02:54:13 am
I agree. The separate controls for each channel are ideal. If only it had the protocol decoding, I'd be OK with the bandwidth.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 10:03:50 am
Look at the GW Instek GDS-1054B if you don't care about hacking and decoding. It is cheaper than the Rigol 1054Z at Tequipment. It will also be the better buy.

Hmmm... seems like other people are finally dropping prices to Rigol levels to try and keep from going out of business. They're even copying the Rigol numbering system (1054Z or 1054B - you decide).

Maybe we can petition Dave to do a shootout video.  :box:

At the end of the day, the Rigol's hackability still gives it the edge though. Your only argument against it seems to be a very short list bugs that may be fixed at any moment. Weigh that list against having double the bandwidth, serial decoders, etc., and ... the Rigol is a clear winner.  :-//

Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 10:28:20 am
Rigol (or Siglent) releasing a decent firmware version will require a cold day in hell to happen first so I rather buy something which works today. And even then the platforms Rigol and Siglent use in their current scopes are way slower than the dual core 1GHz ARM Cortex in the GW Instek. So GW Instek dead in the water? What have you been smoking? The GW Instek GDS2204E I have even managed to move itself in the place of an Agilent DSO7104A (that is a $25k scope) on my bench. The GW Instek is that good and easy to use!
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 10:47:47 am
Rigol (or Siglent) releasing a decent firmware version will require a cold day in hell to happen first

I must have been imagining all those previous updates (and Dave's blog videos on them).

....in the place of an Agilent DSO7104A (that is a $25k scope) on my bench.

Was a $25k scope. I've thrown $250,000 SGI computers in the skip because a $250 PC graphics card was better.  :-//

Your 'scope cost three times as much as a DS1054Z. I'd expect some improvement, yes.

Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 11:10:41 am
....in the place of an Agilent DSO7104A (that is a $25k scope) on my bench.
Was a $25k scope.
You can still buy the DSO7104B from Keysight (the only change between the A version is a different front panel) so it is not like comparing 30 year old technology with today's technology like you are doing. And sure the GDS2204E is 3 times more expensive but it is at least 10 times better. Once you have learned the value of good tools you know that spending more will make your life a whole lot easier.
Title: Re: Oscilloscope Buying questions
Post by: Wuerstchenhund on May 15, 2016, 01:52:07 pm
....in the place of an Agilent DSO7104A (that is a $25k scope) on my bench.

Agilent is expensive but the DSO7104A didn't cost anywhere near $25k but more like $15k ($19k for the MSO variant) (http://www.agilent.com/about/newsroom/presrel/2009/03mar-em09043.html).

Keysight has artificially inflated the RRP of the DSO7104B to $24k to push customers to the larger DSO-X models. I doubt any DSO7104B has sold for more than $18k.

I've thrown $250,000 SGI computers in the skip because a $250 PC graphics card was better.  :-//

Me, too.  :-+

Ah, SGI, good old times of way overpriced hardware with various design flaws put in a beautiful housing ;)
Title: Re: Oscilloscope Buying questions
Post by: jsi on May 15, 2016, 03:56:42 pm
Maybe we can petition Dave to do a shootout video.  :box:

+1 to that idea.  Multimeter shootouts are a dime a dozen (and very helpful mind you)  But if there are any scope shootouts I haven't found them.  Not that it will do me any good at this point, I will have bought the Rigol 1054Z by then.  I hope it doesn't turn out like my multimeter, I found about about the EEVBlog meter after I'd already bought one.   >:(  (oh well, I'm still going to buy one for the cool factor)
Title: Re: Oscilloscope Buying questions
Post by: Howardlong on May 15, 2016, 04:30:23 pm
....in the place of an Agilent DSO7104A (that is a $25k scope) on my bench.
Was a $25k scope.
You can still buy the DSO7104B from Keysight (the only change between the A version is a different front panel) so it is not like comparing 30 year old technology with today's technology like you are doing. And sure the GDS2204E is 3 times more expensive but it is at least 10 times better. Once you have learned the value of good tools you know that spending more will make your life a whole lot easier.

Having said that, the 7000B compared to 7000A is a bit like once you've used it you don't want to go back: things like every knob having an additional push function I have found I use extensively, but in the past I always saw this as a barely relevant feature. On the MDO3000 I have I find it positively irritating that I can't easily zero or default many functions.
Title: Re: Oscilloscope Buying questions
Post by: Howardlong on May 15, 2016, 04:34:47 pm

Maybe we can petition Dave to do a shootout video.  :box:


I strongly suspect that would be an extremely popular video, or even a series of two or three videos. I'd also imagine it'd take a while to make too.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 04:35:29 pm
Maybe we can petition Dave to do a shootout video.  :box:
+1 to that idea.
Only if there is an objective system for keeping scores like -10 points for each bug, +50 points for hackability, log10 points for (FFT length/1000), etc.
Title: Re: Oscilloscope Buying questions
Post by: jsi on May 15, 2016, 04:47:52 pm
....in the place of an Agilent DSO7104A (that is a $25k scope) on my bench.

Agilent is expensive but the DSO7104A didn't cost anywhere near $25k but more like $15k ($19k for the MSO variant) (http://www.agilent.com/about/newsroom/presrel/2009/03mar-em09043.html).

Keysight has artificially inflated the RRP of the DSO7104B to $24k to push customers to the larger DSO-X models. I doubt any DSO7104B has sold for more than $18k.

I've thrown $250,000 SGI computers in the skip because a $250 PC graphics card was better.  :-//
Guys $18 - $25K scopes are way out of my price range  :-DD 

And, 30 years ago my company had their CAD system on an IBM mainframe.  It was state of the art at the time and about the size of 3 full sized American refrigerators.  It had a whopping 600 meg hard drive and 4 meg of RAM shared between 8 designers.  Lord only knows how much it cost.  My job was to replace it with high end workstations which seemed expensive to me at the time.  But, the bean counters were skipping down the hall with happiness when I pulled the plug on it. 

Now this thread is officially completely off topic
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 05:30:26 pm
Guys $18 - $25K scopes are way out of my price range  :-DD 
Just saying that spending a little bit more could be well worth it. Many years ago I bought a cheap Black&decker cordless screw driver/drill. When that started to get flaky I bought a Makita costing twice as much but it is such a joy to use that I regretted not buying a Makita when I bought the Black&decker. It is easy to become blinded by a low price and don't get me wrong here: the Makita cordless drill I have is still far from a professional's tool but it is already a major step up from the bottom-of-the-barrel products.
Title: Re: Oscilloscope Buying questions
Post by: ez24 on May 15, 2016, 05:37:42 pm
Guys $18 - $25K scopes are way out of my price range  :-DD 

Now this thread is officially completely off topic

OPs price range =   $300 - $400 USD give or take.

FYI  this is the way all these oscope questions go:

Q: "I want a $400 scope"       A: "Look at this one, it is only $20,000"







Title: Re: Oscilloscope Buying questions
Post by: jsi on May 15, 2016, 05:53:16 pm
Guys $18 - $25K scopes are way out of my price range  :-DD 
Just saying that spending a little bit more could be well worth it. Many years ago I bought a cheap Black&decker cordless screw driver/drill. When that started to get flaky I bought a Makita costing twice as much but it is such a joy to use that I regretted not buying a Makita when I bought the Black&decker. Don't get me wrong here: the Makita cordless drill is still far from a professional's tool but it is already a major step up from the bottom-of-the-barrel products.

I have the same story.  I bought a $30 POS 1/2" Harbor Freight drill because I only need to drill 6 big holes for one project and why spend all that money on a nice drill.  Fast forward and I'm using the drill all the time and the trigger sticks on and the damn thing near twists my hand off.  I threw the thing in the trash and bought a $150 DeWalt.  The DeWalt is an absolute joy to use compared to the Harbor Freight drill.  But, and this is a big but, who knew at the time I'd be using the 1/2" drill all the time?  So, do I spend 2, 4, 5 times as much on everything that I might only use once?  It's a judgement call and frankly in my judgement a USB scope would probably do my job just fine.  Stepping up to a dedicated, well reviewed scope, feels like spending that little bit extra to get a product that will last.  Is this a professional's scope, no, and I'm not a professional so the fit feels good to me.

Now, the next question is do I add this to my shopping cart: Cal Test CT4042 Oscilloscope Accessory Kit http://www.tequipment.net/Cal-Test/CT4042/ (http://www.tequipment.net/Cal-Test/CT4042/)  It's $65 before the discount and I don't have clue if I need such a thing.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 06:02:27 pm
Now, the next question is do I add this to my shopping cart: Cal Test CT4042 Oscilloscope Accessory Kit http://www.tequipment.net/Cal-Test/CT4042/ (http://www.tequipment.net/Cal-Test/CT4042/)  It's $65 before the discount and I don't have clue if I need such a thing.
That kit can be bought for around $10 (or less) from China through Ebay.
Title: Re: Oscilloscope Buying questions
Post by: ez24 on May 15, 2016, 06:08:32 pm
Now, the next question is do I add this to my shopping cart: Cal Test CT4042 Oscilloscope Accessory Kit http://www.tequipment.net/Cal-Test/CT4042/ (http://www.tequipment.net/Cal-Test/CT4042/)  It's $65 before the discount and I don't have clue if I need such a thing.
That kit can be bought for around $10 (or less) from China through Ebay.

Any links?  I could not find one.  tks
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 06:17:06 pm
Now, the next question is do I add this to my shopping cart: Cal Test CT4042 Oscilloscope Accessory Kit http://www.tequipment.net/Cal-Test/CT4042/ (http://www.tequipment.net/Cal-Test/CT4042/)  It's $65 before the discount and I don't have clue if I need such a thing.
That kit can be bought for around $10 (or less) from China through Ebay.
Any links?  I could not find one.  tks
Just look for the seperate parts (shipping from China is free):
www.ebay.com/itm/271657862398 (http://www.ebay.com/itm/271657862398)
www.ebay.com/itm/BNC-Female-Jack-to-Two-Dual-Banana-Male-plug-RF-Adapter-Connector-/271686023997 (http://www.ebay.com/itm/BNC-Female-Jack-to-Two-Dual-Banana-Male-plug-RF-Adapter-Connector-/271686023997)
http://www.ebay.com/itm/1PCS-BNC-Q9-Male-Plug-to-Test-Hook-Clip-Probe-Cable-Leads-DAU-/221964823338 (http://www.ebay.com/itm/1PCS-BNC-Q9-Male-Plug-to-Test-Hook-Clip-Probe-Cable-Leads-DAU-/221964823338)

The good thing is you can buy multiple items you find useful and skip the items you don't need.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 06:49:09 pm
Guys $18 - $25K scopes are way out of my price range  :-DD 
Just saying that spending a little bit more could be well worth it. Many years ago I bought a cheap Black&decker cordless screw driver/drill. When that started to get flaky I bought a Makita costing twice as much but it is such a joy to use that I regretted not buying a Makita when I bought the Black&decker. It is easy to become blinded by a low price and don't get me wrong here: the Makita cordless drill I have is still far from a professional's tool but it is already a major step up from the bottom-of-the-barrel products.

...and spending a bit more than your GW-Instek might be worth it, too.  Where do you stop? :popcorn:

PS: http://www.team.net/mjb/hawg.html (http://www.team.net/mjb/hawg.html)
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 06:52:06 pm
Maybe we can petition Dave to do a shootout video.  :box:
+1 to that idea.
Only if there is an objective system for keeping scores like -10 points for each bug, +50 points for hackability, log10 points for (FFT length/1000), etc.

Are you worried that the vibe and response-speed of your GW-Instek won't be enough...?

PS: Hackable to serial decoders, 100MHz, double memory, etc. is worth way more than 50 points on that scale.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 06:55:16 pm
Serial decoders which only decode what is on screen are utterly useless so they don't even count.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 07:11:46 pm
Serial decoders which only decode what is on screen are utterly useless so they don't even count.

Is it weird that I've done useful things with mine...?  :-//
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 07:16:24 pm
I did useful things with my Black&decker cordless drill too but life got so much better with the Makita cordless drill!  :box:
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 07:19:16 pm
I did useful things with my Black&decker cordless drill too but life got so much better with the Makita cordless drill!  :box:

Maybe so, but you were comparing owning the Black&decker with owning no drill at all (or at best, only owning a hand drill).

Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 07:23:24 pm
I did useful things with my Black&decker cordless drill too but life got so much better with the Makita cordless drill!  :box:
Maybe so, but you were comparing owning the Black&decker with owning no drill at all (or at best, only owning a hand drill).
:palm: It says Makita and Black&decker. Where does it say no drill??
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 07:57:43 pm
I did useful things with my Black&decker cordless drill too but life got so much better with the Makita cordless drill!  :box:
Maybe so, but you were comparing owning the Black&decker with owning no drill at all (or at best, only owning a hand drill).
:palm: It says Makita and Black&decker. Where does it say no drill??
Does your $400 GW-Instek have serial decoders?
Title: Re: Oscilloscope Buying questions
Post by: rf-loop on May 15, 2016, 08:13:57 pm
Serial decoders which only decode what is on screen are utterly useless so they don't even count.

What equipment can decode data what is not captured.

Example in Siglent. ALL captured data lenght is visible on the screen and it  decode whole lenght of captured data.

What data this your dream machine decode if not captured data. Example, Siglent can not decode at all anything what is out from screen. Because there is nothing. What scope can, I have not seen any.

I think you have used too long time oscilloscopes what have only very narrow window in the screen to captured data and lot of captured data is unvisble out from screen. Why need keep captured data unvisible out from screen and then tell that it can decode also this part of data and then tell machine is good because it can decode also out from screen. Perhaps this is some special kind of humor but I do not know where need laugh.

May I ask what clever is there if keep big part of captured data outside from screen and then tell that scope can decode also out from screen. Oh well it is nice machine - is it.

Can you understand: Independent of captured lenght,  screen width = capture lenght.  Zoom is for details. So simply.
Title: Re: Oscilloscope Buying questions
Post by: Howardlong on May 15, 2016, 08:16:56 pm
Serial decoders which only decode what is on screen are utterly useless so they don't even count.

While it is indeed a significant restriction, it's definitely better than no decode at all. Software based decoders are generally slow, so I can see why they did it that way. On the MDO3000 you can be waiting a _long_ time for a decode. The problem is if you've been used to hardware decode on Keysights, everything else seems a let down. The trick on the Rigols is to set up a serial trigger which unlike some decodes (on I2C) appears 100% reliable. To be fair, on any scope, including the Keysights, setting up a serial trigger is probably the way to go anyway for a reasonably long serial stream.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 08:29:08 pm
Serial decoders which only decode what is on screen are utterly useless so they don't even count.

While it is indeed a significant restriction, it's definitely better than no decode at all. Software based decoders are generally slow, so I can see why they did it that way. On the MDO3000 you can be waiting a _long_ time for a decode. The problem is if you've been used to hardware decode on Keysights, everything else seems a let down.
I'm starting to sound like a broken record but the decoding on the GD2204E is quick due to the hefty amount of CPU horsepower under the hood. Only at 10Mpts it needs a moment to catch up.

@Rf-loop: ofcourse you use zoom to look at more details (capture a whole bunch of messages in single shot mode and then zoom in) but if the decode gets confused because it only decodes part of the memory which is on the screen it is of no use because you can't zoom in to look at problems at the bit-level and for long messages you'll lose track of where you are in a message IF the oscilloscope can even determine the start of a frame (a given number of bits; usually a byte) within a message which is unlikely when looking at SPI or I2C busses. So yes it is important an oscilloscope with decoding can decode the entire memory and show partial messages/bits if necessary but also keep track of where you are in a message.
Title: Re: Oscilloscope Buying questions
Post by: rf-loop on May 15, 2016, 08:43:19 pm


@Rf-loop: ofcourse you use zoom to look at more details (capture a whole bunch of messages in single shot mode and then zoom in) but if the decode gets confused because it only decodes part of the memory which is on the screen

Also single shot, Siglent decode whole capture lenght.
On the screen is whole capture lenght and whole capture lencht is decoded. Zoom window can use where ever in this whole lenght for details.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 15, 2016, 08:45:36 pm
I'm starting to sound like a broken record but the decoding on the GD2204E is quick due to the hefty amount of CPU horsepower under the hood.
Well of course it is on your super-duper, three-times-the-price GD2204E

But... you were talking about the GDS-1054B before you started weaseling.

The GDS-1054B loses to the DS1054Z in a shootout because it has no serial decode at all.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 15, 2016, 08:49:27 pm
I'm starting to sound like a broken record but the decoding on the GD2204E is quick due to the hefty amount of CPU horsepower under the hood.
Well of course it is on your super-duper, three-times-the-price GD2204E

But... you were talking about the GDS-1054B before you started weaseling.

The GDS-1054B loses to the DS1054Z in a shootout because it has no serial decode at all.
Without hacking and the serial decode options the DS1054Z has no decoding either. You where the one who wrote you'd buy the DS1054Z even if it where not hackable! GW Instek just follows a different licensing scheme. They basically have 2 model lines where one has decoding and the other one doesn't. It's simple as that.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 16, 2016, 03:41:24 am
Without hacking and the serial decode options the DS1054Z has no decoding either. You where the one who wrote you'd buy the DS1054Z even if it where not hackable!

Yes I did, and yes I would. I think it's worth $400 of anybody's money.

On the other hand the Rigol is hackable and everybody knows it.

What would I choose in a shootout? A $400 scope with no frills or a $400 scope with twice the bandwidth plus serial decoders, extra memory, etc.? It seems a no-brainer. The GW-Instek loses even if the Rigol does have a couple of hard-to-find bugs.
Title: Re: Oscilloscope Buying questions
Post by: Howardlong on May 16, 2016, 07:13:30 pm
Serial decoders which only decode what is on screen are utterly useless so they don't even count.

While it is indeed a significant restriction, it's definitely better than no decode at all. Software based decoders are generally slow, so I can see why they did it that way. On the MDO3000 you can be waiting a _long_ time for a decode. The problem is if you've been used to hardware decode on Keysights, everything else seems a let down.
I'm starting to sound like a broken record but the decoding on the GD2204E is quick due to the hefty amount of CPU horsepower under the hood. Only at 10Mpts it needs a moment to catch up.


A video or it didn't happen ;-)
Title: Re: Oscilloscope Buying questions
Post by: alsetalokin4017 on May 17, 2016, 08:20:22 am
Without hacking and the serial decode options the DS1054Z has no decoding either. You where the one who wrote you'd buy the DS1054Z even if it where not hackable!

Yes I did, and yes I would. I think it's worth $400 of anybody's money.

On the other hand the Rigol is hackable and everybody knows it.

What would I choose in a shootout? A $400 scope with no frills or a $400 scope with twice the bandwidth plus serial decoders, extra memory, etc.? It seems a no-brainer. The GW-Instek loses even if the Rigol does have a couple of hard-to-find bugs.

Buy a Rigol DS1054z yourself and use it for something other than displaying pretty colored lines from a function generator. Then you can see for yourself how "hard to find" the "couple" of bugs are.
FYI: in English the word "couple" generally means "around 2". For you constantly to represent that the DS1054z has a "couple" of bugs that interfere with practical use of the scope is misleading, false and untrue. It's easy to find 5 that can even be displayed at the same time with a perfectly ordinary setup. A set of Measurements that fail without the user noticing it, requiring reboot to restart any measurements at all is a pretty darn severe bug in my opinion -- of course you may disagree but I think the first time that such a fault bites you, even you might change your mind. Trying to find the maximum slew rate of a signal and discovering that the "diff" math function is useless and returns garbage on-screen may leave you feeling like you've been... er.... shortchanged a little bit, to say the least.

Sure, the scope is a good value for the money, but it has some (many more than a "couple")  _severe_ problems that Rigol really should fix, and to brush these problems under the carpet and ignore them is doing future purchasers and current users a disservice.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 17, 2016, 09:32:56 am
Sure, the scope is a good value for the money, but it has some (many more than a "couple")  _severe_ problems that Rigol really should fix, and to brush these problems under the carpet and ignore them is doing future purchasers and current users a disservice.

Not as much of a disservice as telling them it's a useless piece of junk that no sane person should consider buying.

...how "hard to find" the "couple" of bugs are. ... Trying to find the maximum slew rate of a signal and discovering that the "diff" math function is useless and returns garbage on-screen

Because ... we all spend our lives trying to find the maximum slew rate of signals using the diff function, right?  :-//

it has some problems that Rigol really should fix
I agree that they should be releasing more fixes. The next update is well into the 'overdue' category now.

They have a good product, it must surely be earning enough to pay for its own support team. All the animosity in these forums could be silenced by being a bit more active with the fixes.
Title: Re: Oscilloscope Buying questions
Post by: JPortici on May 17, 2016, 09:37:09 am
features i don't use in my 1054z
- math: useless. seems like you're using 4 bit arithmetics, not even 8 bit. differentiation only gives back garbage
- x/y: scope becomes extremely slow. much much much much slower than enabling the fft and i can't conceive a reason for it. much slower than an older 1052 or a tek tps (and that one is REALLY slow)
- serial triggering. just doesn't work. actually none of the other trigger modes than edge that i've tested seem to work
at least i didn't have to waste money for those
and in general it's hard for me to get a stable trigger for something that isn't the built in calibrator where other scopes i use/have works just fine

they'd have a good product if things worked. it can be a good product, it's OK for now
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 17, 2016, 09:59:39 am
Example of Rigol design and build "quality". RP-3300A probe at the BNC connector side.  Central conductor living by it's own in the hole and shorting to the metal. Already repaired both of those I received with DS-2072 by bending the wire. But they failed again, guess will need to fill the hole with silicone to prevent them shorting again. Also you can see quality construction with 2 resistors soldered on top of each other, one of them upside down. Hook attachments never worked properly too. When you press it, it's very scratchy, often gets stuck and the gook on the end is no good too, very hard to attach to the measuring point. Piece of crap in one word.
(https://www.eevblog.com/forum/testgear/oscilloscope-buying-questions/?action=dlattach;attach=225650;image)
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 17, 2016, 11:04:35 am
none of the other trigger modes than edge that i've tested seem to work at least i didn't have to waste money for those and in general it's hard for me to get a stable trigger for something that isn't the built in calibrator where other scopes i use/have works just fine

I never had a problem with triggering, and if it was as bad as you say then the anti-DS1054Z crowd would be all over it

(obscure bugs in the slew rate calculation are nothing compared to triggers that don't work!)

The triggering is actually done in hardware by special circuitry. Maybe your 'scope has a hardware fault.

Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 17, 2016, 01:41:02 pm
He says none of the other trigger modes than edge works. So make a video of how your DS1054Z triggers on a specified character send by a UART.
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 04:41:58 pm
Boy, you guys had me going!

So, I set up an Arduino to send the character string "ABCD" followed by a 2 mS delay (just because).  I set up RS232 decode and, voila', I can trigger on any of the 4 characters.  It took me a moment to realize that the character was to the left of the trigger mark.  But of course!  You can't trigger on something until you have seen it all.

I also tried 115200 baud and no delay - it works even better.  And I put a very long string after the "ABCD" thing and it still works!

Code: [Select]
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
}

void loop() {
  // put your main code here, to run repeatedly:
  Serial.print("ABCD now is the time for all good men to come to the aid of their country");
  ;delay(2);
}


No, I'm not going to try to photograph the screen much less try to download an image.  Try the experiment yourself.  It works!

I have not tried I2C or SPI but, if I get bored later today, I might.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 17, 2016, 04:44:23 pm
Now make it trigger on A or C  >:D
Title: Re: Oscilloscope Buying questions
Post by: Howardlong on May 17, 2016, 04:49:09 pm
- serial triggering. just doesn't work. actually none of the other trigger modes than edge that i've tested seem to work
....
and in general it's hard for me to get a stable trigger for something that isn't the built in calibrator where other scopes i use/have works just fine

I can't say I've ever encountered either of these problems. Can you demonstrate how to reproduce them?
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 04:52:46 pm
Now make it trigger on A or C  >:D

As I said, I can make it trigger on ANY of the 4 chars.  All I have to do is turn the little knob to set the trigger value.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 17, 2016, 05:03:43 pm
Now make it trigger on A or C  >:D

As I said, I can make it trigger on ANY of the 4 chars.  All I have to do is turn the little knob to set the trigger value.

I think the weird little face means he wants a boolean "OR" function, ie. 'A' OR 'C'
Title: Re: Oscilloscope Buying questions
Post by: JPortici on May 17, 2016, 05:11:40 pm
Not really, the scope just doesn't trigger in any mode that isn't edge.
(Also i was playing around with a wall wart transformer that outputted a 18Vpk not so clean ac waveform on an old analog scope i just got. i measured it with the 1054 and at 50V/division it wasn't able to trigger on zero.. found out that by chance and it's ofncourse a very singular case that should not be taken into account in this scope's bashing. Anyway, depending on the timebase i adjusted the finetune scale until it triggered and it also changed between 40 and 35 v/div. It's a borderlone case because there is a different input circuit at that scale... and being sincronous with AC might also explain why the trigger was so difficul but that made me wonder if i actually have a faulty scope.. because a 30 years old analog scope will trigger with no problems at all)
I wonder if i indeed have a faulty scope. I'll make further tests and eventually contact rigol
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 05:17:51 pm
Now make it trigger on A or C  >:D

As I said, I can make it trigger on ANY of the 4 chars.  All I have to do is turn the little knob to set the trigger value.

I think the weird little face means he wants a boolean "OR" function, ie. 'A' OR 'C'

Ah...  Skipped right over my head.  The 'Evil' emoticon means BOOLEAN - good to know.  Upping my skills, one day at a time!

I'm not sure how to trigger on something with "don't care" bits.  I'm not even sure I could do it with my logic analyzer.  Of course, I couldn't trigger on the square root of 2 to 17 digits either.  Yup!  The scope must be defective.

The challenge was to trigger on an RS232 char and that absolutely works.  Nobody said anything about a square root of 2 challenge.  The original statement was that NONE of the triggers, other than edge, worked.  I don't think that is true, I have proven to my satisfaction that it isn't true yet it will forever be written as true.

Unfortunate...

This stuff just confuses the new guys!  Buy the scope?  Don't buy the scope?  Does it work?  Does it not work?  Who says so?


Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 17, 2016, 05:22:27 pm
There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 05:25:31 pm
Not really, the scope just doesn't trigger in any mode that isn't edge.
(Also i was playing around with a wall wart transformer that outputted a 18Vpk not so clean ac waveform on an old analog scope i just got. i measured it with the 1054 and at 50V/division it wasn't able to trigger on zero.. found out that by chance and it's ofncourse a very singular case that should not be taken into account in this scope's bashing. Anyway, depending on the timebase i adjusted the finetune scale until it triggered and it also changed between 40 and 35 v/div. It's a borderlone case because there is a different input circuit at that scale... and being sincronous with AC might also explain why the trigger was so difficul but that made me wonder if i actually have a faulty scope)
I wonder if i indeed have a faulty scope. I'll make further tests and eventually contact rigol

You should limit the scope of the statement highlighted above.  Your scope may not trigger, you may not be able to get it to trigger, but that doesn't mean the entire set of 1054 scopes don't trigger.  From my admittedly limited testing, my scope seems to work just fine.
Title: Re: Oscilloscope Buying questions
Post by: JPortici on May 17, 2016, 05:27:52 pm
And my doesn't, which is why i'm considering that mine have problems.
Actually i think i always say 'my' or 'mine' and never talked about all the 1054 in existence
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 05:28:17 pm
There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?

MSO or DSO?  Which model?

That is a very cool feature.  I don't know that I need it but it is very interesting.  I know my little FPGA Logic Analyzer won't do anything like that.  I can have don't cares in a parallel word but not in a serial stream.  Nice!
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 17, 2016, 05:29:03 pm
I wonder if i indeed have a faulty scope. I'll make further tests and eventually contact rigol

The thing to realize is that triggering isn't a software function. It's perfectly possible that an oscilloscope has a defective trigger.
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 17, 2016, 05:40:48 pm
There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?

MSO or DSO?  Which model?

That is a very cool feature.  I don't know that I need it but it is very interesting.  I know my little FPGA Logic Analyzer won't do anything like that.  I can have don't cares in a parallel word but not in a serial stream.  Nice!
There is no MSO model yet, bet seems will be in the future because there is a place for logic analyzer add-on board inside the scope.
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 05:47:09 pm
There is always a day some functionality comes in handy. Did I mention the GW Instek serial protocol decoding can trigger on don't care bits using up to 10 bytes so you can filter on very specific messages?

MSO or DSO?  Which model?

That is a very cool feature.  I don't know that I need it but it is very interesting.  I know my little FPGA Logic Analyzer won't do anything like that.  I can have don't cares in a parallel word but not in a serial stream.  Nice!
There is no MSO model yet, bet seems will be in the future because there is a place for logic analyzer add-on board inside the scope.

Which model should I research?  Is the cost in the same order of magnitude as the DS1054Z?
Title: Re: Oscilloscope Buying questions
Post by: JPortici on May 17, 2016, 05:52:34 pm
I wonder if i indeed have a faulty scope. I'll make further tests and eventually contact rigol

The thing to realize is that triggering isn't a software function. It's perfectly possible that an oscilloscope has a defective trigger.
I have no idea about rigol but i think that (almost) any other mode than edge triggering might need a software side to analyze the data
but iight be wrong of course :)
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 17, 2016, 05:59:23 pm
Which model should I research?  Is the cost in the same order of magnitude as the DS1054Z?
Direct competitor with not hacked DS1054Z is GDS-1054B. It is overall much better scope but there are no decoding options to unlock, not hacked DS1054Z has no decoding either. http://www.tequipment.net/rigol/gw-instek-gds-1054b-vs-rigol-ds1054z/ (http://www.tequipment.net/rigol/gw-instek-gds-1054b-vs-rigol-ds1054z/)
Or you can go to more expensive GDS-2000E series, decoding already included out of the box, no need to hack.  http://www.tequipment.net/instek/oscilloscopes/series_gds-2000e-series/ (http://www.tequipment.net/instek/oscilloscopes/series_gds-2000e-series/)
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 06:12:36 pm
No, I was asking about the specific model that allowed long strings of "don't cares" in a serial decode.  I wasn't looking for a substitute to the DS1054Z.  It would be nice if the decode was free but I'm more interested in how much it costs to get the feature.  I doubt that I'll even NEED the feature but it would be worth knowing about.  Once I get the model number, I'll hunt down the User Manual.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 17, 2016, 06:20:52 pm
No, I was asking about the specific model that allowed long strings of "don't cares" in a serial decode.  I wasn't looking for a substitute to the DS1054Z.  It would be nice if the decode was free but I'm more interested in how much it costs to get the feature.  I doubt that I'll even NEED the feature but it would be worth knowing about.  Once I get the model number, I'll hunt down the User Manual.
That is the GDS2000E series:
http://www.gwinstek.com/en-global/products/Oscilloscopes/Digital_Storage_Oscilloscopes/GDS-2000E (http://www.gwinstek.com/en-global/products/Oscilloscopes/Digital_Storage_Oscilloscopes/GDS-2000E)
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 06:43:54 pm
So, something like the GDS-2104E to get 100 MHz and 4 channels - $1200.
That's a little over the top for me and my little hobby.  Actually, the DS1054Z was a stretch since I already had a Tektronix 485.

Still, if that decoding feature is truly necessary in the commercial arena, $1200 isn't a lot of money.  Pretty nice!

Page 163 of the User Manual describes the 10 byte trigger setup.  It's also a neat feature to be able to trigger on the end of a message (CR, LF, etc), the start bit or even parity error although, in my limited experience, parity errors don't happen.  But I don't use long lines either.

For my purposes, I don't see any need to debug UART communications.  I can just jam the stream into a terminal.  But SPI and especially I2C decoding is much more problematic.  Any scope that will decode these streams will be a blessing.

For I2C, it is possible to use a couple of logic gates to find the START condition and use the output to trigger the scope.  Like this:
http://www.i2cchip.com/monitoring_i2c_bus.html (http://www.i2cchip.com/monitoring_i2c_bus.html)  This isn't a complete solution but it's a start.

SPI is triggered off of SEL' so no problems there.

Title: Re: Oscilloscope Buying questions
Post by: wraper on May 17, 2016, 07:08:07 pm
So, something like the GDS-2104E to get 100 MHz and 4 channels - $1200.
That's a little over the top for me and my little hobby.  Actually, the DS1054Z was a stretch since I already had a Tektronix 485.

Still, if that decoding feature is truly necessary in the commercial arena, $1200 isn't a lot of money.  Pretty nice!
Check 200 MHz GDS-2204E, it's actually cheaper than 100 MHz model because have bigger discount for some weird reason. Actually 100 MHz is more expensive than $1200, so likely you seen the price for 200 MHz model but read the model wrong.
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 17, 2016, 07:54:19 pm
I could have gotten distracted on the price.  The first price I saw was $1700 (more or less) and when I saw $1200, I changed my reply.  You're right, it is odd that the 200 MHz version would cost less.  In fact, there would be no reason for a distributor to stock the 100 MHz version.  Unless the 200 MHz version lost a feature...
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 17, 2016, 08:47:38 pm
For my purposes, I don't see any need to debug UART communications.  I can just jam the stream into a terminal.  But SPI and especially I2C decoding is much more problematic.  Any scope that will decode these streams will be a blessing.

If you're serious about serial decoding then a dedicated logic analyzer will always be better/cheaper than a general purpose oscilloscope.

Even if the 'scope has good decoding software the RAM will be limited, the screen will be cramped, and oscilloscope knobs and buttons are really the wrong user interface. A PC based logic analyser can record data for minutes at a time and a mouse/keyboard interface works much better.

Saleae devices are popular: https://www.saleae.com/ (https://www.saleae.com/)

Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 17, 2016, 09:14:05 pm
I disagree. The reason you want to look at serial data is usually because you (have to) expect a problem with the signal at the electrical level as well. Just hooking up a logic analyser will get you banging your head against the wall sooner or later because it doesn't show the problems in the analogue domain. Besides that a good scope allows to save the decoded data to a CSV file so you can go through it with Excel (or similar) on a PC.
Title: Re: Oscilloscope Buying questions
Post by: Howardlong on May 18, 2016, 04:47:52 pm
Have to say I'm with nctnico on this one, I hardly ever use a PC based logic analyser nowadays, although I did use them extensively back when I didn't have a scope with decoding capability.

Indeed, saving to CSV is one of the few reasons to ise a PC based LA, but that's not something I often find I need to do. My work tends to be in interactive debugging sessions rather than having any need to save a serial stream for later perusal.

PC based LAs don't often have the more complex triggering capabilities of a scope, and those such as the Saleae depend more on post processing. Also the sample rates of lower end LAs aren't enough for today's high speed serial busses.

Different strokes I guess, I know many prefer PC based LAs to scopes for this stuff.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 18, 2016, 05:06:16 pm
Have to say I'm with nctnico on this one, I hardly ever use a PC based logic analyser nowadays, although I did use them extensively back when I didn't have a scope with decoding capability.

Fair enough.

Just one more reason to prefer a DS1054Z over a GW-Instek if you're on a tight budget.

(free decoders!)
Title: Re: Oscilloscope Buying questions
Post by: rstofer on May 18, 2016, 05:21:16 pm
I have never needed to debug a serial stream.  I may display a trace on an analog scope just to check the logic levels and maybe look at the SPI chip select, clock idle condition and maybe one data byte but that's about it.  ETA: It just works out that way.  Others will have varying experiences.

For microcontrollers, the best debug tool is 'printf()' (or equal).  Seriously!  The first thing I do with bare iron uC projects is get the UART running.  Then I add in some conversion functions from K&R (The C Programming Language) and I'm ready to go.  This is a great time to implement the first interrupt routine - just to see...

OTOH, for FPGA projects, I want to trace states.  Since I use one-hot encoding, this often involves ginning up new debug signals and routing them out to the board along with the clock.  This is fine on the older boards with 40 or 50 pin headers, not so good for PMO connectors. Several years ago it was suggested that I build a logic analyzer internal to my project and this is probably a great idea.  It is so good that I am using the Xilinx ILA IP.  I don't have much experience yet but it appears to be a very slick solution and, apparently, I can have multiple instances.  This allows me to watch the interaction from the CPU and over at the peripheral.  I predict this gadget will get more use than the rest of my equipment combined!

Sure, I want my scope to decode buses.  But for a very long time, like up until a couple of weeks ago, I didn't have that capability and my projects still got built.
Title: Re: Oscilloscope Buying questions
Post by: PartialDischarge on May 20, 2016, 01:34:50 pm
Example of Rigol design and build "quality". RP-3300A probe at the BNC connector side.  Central conductor living by it's own in the hole and shorting to the metal. Already repaired both of those I received with DS-2072 by bending the wire. But they failed again, guess will need to fill the hole with silicone to prevent them shorting again. Also you can see quality construction with 2 resistors soldered on top of each other, one of them upside down. Hook attachments never worked properly too. When you press it, it's very scratchy, often gets stuck and the gook on the end is no good too, very hard to attach to the measuring point. Piece of crap in one word.
(https://www.eevblog.com/forum/testgear/oscilloscope-buying-questions/?action=dlattach;attach=225650;image)


Just got my DS2072a today, and had a look at the probe, its been fixed. It also has a "TUVRheinland" sticker attached (which  I believe is some kind of german quality board?? ) although don't know why...


Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 20, 2016, 01:43:42 pm
Just got my DS2072a today, and had a look at the probe, its been fixed. It also has a "TUVRheinland" sticker attached (which  I believe is some kind of german quality board?? ) although don't know why...

Don't let the Pesky Facts get in the way of a good rant.
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 25, 2016, 06:40:34 am
Just got my DS2072a today, and had a look at the probe, its been fixed. It also has a "TUVRheinland" sticker attached (which  I believe is some kind of german quality board?? ) although don't know why...

Don't let the Pesky Facts get in the way of a good rant.
Good for them that they fixed this. Though this still does not change the fact that Rigol made that kind of ridiculous crap on some point of time. Also it's only one of the "features" of these probes that pisses me off. Others are: attachable hooks are half-working crap because get stuck in pressed position (had read a lot of complaints about that). Hard to attach and does not hold well on the lead attached because of the shape of the hook itself. Rubber channel identification rings detach from the place multiple times a day. Probes are unnecessarily bulky at the BNC connector side, therefore hard to attach to the scope and obstruct attaching a second probe or accessing the scale knobs on the cramped DS2000 front panel (No such problem with GW Instek probes attached to the Rigol scope, LOL). And that's just because of rectangular plastic enclosure, probe is much smaller inside and has round shield. Why not put round enclosure  :palm: ? Probes are rubbery-bendy, therefore hard to precisely poke onto some tiny pads where it is easy to short something.
(https://www.eevblog.com/forum/testgear/oscilloscope-buying-questions/?action=dlattach;attach=227479;image)
Title: Re: Oscilloscope Buying questions
Post by: PartialDischarge on May 25, 2016, 08:38:07 am
Recenty I got a Keysight probe (350Mhz). Has the same "box" as the rigol or even bigger. The tip came bent, no worries its a keysight so it must be fine that way. Besides its the cheapest looking thing I've ever seen, the rigols has a soft plastic and looks great .

I guess the discussion will continue for ever, but if so many "electronics-hobbyist-who-write-on-forums" had Keysights and Teks instead of Rigols you'd see LOTS of complaints about their quality and software bugs online.

Title: Re: Oscilloscope Buying questions
Post by: wraper on May 25, 2016, 10:33:12 am
Recenty I got a Keysight probe (350Mhz). Has the same "box" as the rigol or even bigger.
Do you have rigol probe to compare side by side? Because Rigol apparently is much bigger than Keysight probe. Especially that huge BNC connector with plastic molded on top of metal. EDIT, after examining photos of keysight probe, that box actually seems maybe a little bit bigger than my instek probe on the photo. Nothing like that Rigol box.
Quote
the rigols has a soft plastic and looks great .
That "soft" (i think probably rubber) is a piece of shit. It's not good at all when the probe bends in your hand. And it's too small too. Very uncomfortable to hold.
(https://www.eevblog.com/forum/testgear/oscilloscope-buying-questions/?action=dlattach;attach=227501;image)

(https://www.eevblog.com/forum/testgear/oscilloscope-buying-questions/?action=dlattach;attach=227510;image)
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 25, 2016, 11:45:03 am
Don't let the Pesky Facts get in the way of a good rant.
Good for them that they fixed this. Though this still does not change the fact that Rigol made that kind of ridiculous crap on some point of time.

You're missing the point, which is: Rigol aren't the only company making sub-standard stuff. Two weeks ago everybody here was worshipping "Keysight" and saying their stuff was incredible quality and sales support was anazing.

Now the forum is full of threads proving that wrong - Keysight 'scopes dying all over the place and Keysight support asking people for 90% of the price of a new 'scope to fix theirs.

Nobody's saying Rigol's perfect, but neither is anybody else.

(And at least Rigol stuff is cheap - you're not paying $2000 for the problems).
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 25, 2016, 11:59:46 am
Don't let the Pesky Facts get in the way of a good rant.
Good for them that they fixed this. Though this still does not change the fact that Rigol made that kind of ridiculous crap on some point of time.

You're missing the point, which is: Rigol aren't the only company making sub-standard stuff. Two weeks ago everybody here was worshipping "Keysight" and saying their stuff was incredible quality and sales support was anazing.

Now the forum is full of threads proving that wrong - Keysight 'scopes dying all over the place and Keysight support asking people for 90% of the price of a new 'scope to fix theirs.

Nobody's saying Rigol's perfect, but neither is anybody else.

(And at least Rigol stuff is cheap - you're not paying $2000 for the problems).
Good luck getting that keysight scope for less than $5000 if you are located in Brazil. As of Rigol, even during the first weeks of warranty period I had very piss poor service from them. And this is in EU. In Brazil you already should be thankful that support exists as such.
Quote
Keysight support asking people for 90% of the price of a new 'scope to fix theirs.
In Brazil pricing, most likely it was below 40% of the new scope price.
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 25, 2016, 12:08:21 pm
Good luck getting that keysight scope for less than $5000 if you are located in Brazil. As of Rigol, even during the first weeks of warranty period I had very piss poor service from them. And this is in EU. In Brazil you already should be thankful that support exists as such.

You think Spain is any better?  :popcorn:

(well, ok, at least we're European so I can order my stuff from Germany)

Title: Re: Oscilloscope Buying questions
Post by: wraper on May 25, 2016, 12:19:02 pm
Good luck getting that keysight scope for less than $5000 if you are located in Brazil. As of Rigol, even during the first weeks of warranty period I had very piss poor service from them. And this is in EU. In Brazil you already should be thankful that support exists as such.

You think Spain is any better?  :popcorn:

(well, ok, at least we're European so I can order my stuff from Germany)
In Spain you don't have 60% import tax by itself (This is even not including their VAT equivalent).
Title: Re: Oscilloscope Buying questions
Post by: Fungus on May 25, 2016, 12:36:06 pm
Good luck getting that keysight scope for less than $5000 if you are located in Brazil. As of Rigol, even during the first weeks of warranty period I had very piss poor service from them. And this is in EU. In Brazil you already should be thankful that support exists as such.

You think Spain is any better?  :popcorn:

(well, ok, at least we're European so I can order my stuff from Germany)
In Spain you don't have 60% import tax by itself (This is even not including their VAT equivalent).

True, but we do have all the piss-poor service and the ridiculous markup by the authorised "dealers" who are only interested in lucrative corporate accounts.
Title: Re: Oscilloscope Buying questions
Post by: tautech on May 25, 2016, 06:00:54 pm
Especially that huge BNC connector with plastic molded on top of metal. EDIT, after examining photos of keysight probe, that box actually seems maybe a little bit bigger than my instek probe on the photo. Nothing like that Rigol box.

(https://www.eevblog.com/forum/testgear/oscilloscope-buying-questions/?action=dlattach;attach=227510;image)

That seems to be the way many probes are going these days and IMO it's to provide the user with additional insulation for safety reasons.
But as has been pointed out unless some thought has been given to front panel layout they can be a PITA to use.

Those users that for whatever reasons that use isolation transformers or float their scopes can some additional safety with these heavily insulated BNC connectors.

AFAIK all the Asian OEM manufacturers supply them with their new DSO's.
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 25, 2016, 06:37:24 pm
That seems to be the way many probes are going these days and IMO it's to provide the user with additional insulation for safety reasons.
But as has been pointed out unless some thought has been given to front panel layout they can be a PITA to use.
If you need them insulated, you already violate safety measures. After all, there is trigger input BNC sticking out nearby which is completely uninsulated even if the both probes are attached. Float the DUT if you really need that, not the scope. The fun fact is, those Rigol probes are easy to attach to GDS-2000E scope and don't obstruct any controls, but are pain to attach to Rigol DS2000, and obstruct accessing the scale knobs.
Title: Re: Oscilloscope Buying questions
Post by: tautech on May 25, 2016, 06:45:25 pm
That seems to be the way many probes are going these days and IMO it's to provide the user with additional insulation for safety reasons.
But as has been pointed out unless some thought has been given to front panel layout they can be a PITA to use.
If you need them insulated, you already violate safety measures. After all, there is trigger input BNC sticking out nearby which is completely uninsulated even if the both probes are attached. Float the DUT if you really need that, not the scope. The fun fact is, those Rigol probes are easy to attach to GDS-2000E scope and don't obstruct any controls, but are pain to attach to Rigol DS2000, and obstruct accessing the scale knobs.
I hear you loud and clear on all points.  ;)
Title: Re: Oscilloscope Buying questions
Post by: wraper on May 25, 2016, 06:48:57 pm
BTW, I just compared the probes, and cannot say that Instek probes are significantly less insulated than Rigols. Insulation is done much smarter, therefore does not take so much space.
Title: Re: Oscilloscope Buying questions
Post by: nctnico on May 25, 2016, 07:28:16 pm
Still you need to ask yourself whether you really want to use the probes supplied with a scope in the first place. I already have a whole bunch of identical oscilloscope probes so the probes which came with the last two scopes I bought are still in their original packaging.