Author Topic: I Need Help With Choosing a Budget Oscilloscope!  (Read 5132 times)

0 Members and 1 Guest are viewing this topic.

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
I Need Help With Choosing a Budget Oscilloscope!
« on: October 17, 2020, 08:24:35 pm »
Hi everyone! :D

So I'm a 18 y/o EE who likes working with precision parts. I mostly design switchmode PSUs and precision low-noise voltage references for fun. Will be going to a university hopefully this year to study EE.

I already have a pretty nice kinda hard-to-find GW Instek GDM 450A DMM which is a 20,000 count meter with very good accuracy (I believe around 0.05%).
What my poor man's lab is missing is a low-end/mid-range oscilloscope. Now this being Iran with the awful inflations, it's super expensive for us to buy a $350 DS1054Z. Luckily, I was able to sell my graphics card to get around $270. But it's still not enough to buy and import a DS1054Z as it would cost north of $600 to do so. But I found a very reasonably priced Hantek DSO1062B for about $370 which is a 60MHz (lower than a hacked DS1054Z with 100MHz), 1GS/s sample rate (the same), and 2 channels (compared to Rigol's 4). It also has a built-in DMM with capacitance measurement which makes it pretty much a Chinese Fluke ScopeMeter. It's portable, affordable and an added bonus for a portable meter, FFT! I doubt it's powerful, but for my low frequency uses it should be just fine.

There's also this Iwatsu SS-7635 350MHz, 4Ch analog/digital scope for about $470. Great value, but too expensive for me. :(

I'm kinda stuck scratching my head honestly. Can anyone help me choose a decent scope for my purposes?

Thank you! :3
 

Online ataradov

  • Super Contributor
  • ***
  • Posts: 6958
  • Country: us
    • Personal site
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #1 on: October 17, 2020, 09:36:54 pm »
I would do whatever I can to avoid those all-in-one button-only control portable things. They all universally terrible and frustrating to use. Their specs and performance are also questionable in many cases.

I personally would take way lower speced ,but a real scope any time. Something like Hantek DSO5072P or DSO5102P.  Their only real limitation is the memory depth.
Alex
 
The following users thanked this post: ROFLCat

Online bob91343

  • Super Contributor
  • ***
  • Posts: 1139
  • Country: us
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #2 on: October 17, 2020, 09:51:03 pm »
Why not consider an older, used unit?  You can get a good Tektronix 465 for instance, for very little money.  I use one regularly and love it.  I have others but that's my main one.  Even my very old 453 is perfectly useful.

My digital unit does FFT but not in such a way as to be useful for most purposes.  I have spectrum analyers for that.
 
The following users thanked this post: ROFLCat

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #3 on: October 17, 2020, 10:06:38 pm »
I see a future member of the TEA group in the making :-DD

I also come from a country where buying test equipment is rather expensive, and there's not many options to acquire good gear without having to sell your organs to afford them.
My first scope was a Rigol DS1052E (which I still think is an amazing entry level scope -especially if you hack it to unlock 100 Mhz bandwidth-) that I bought 10 years ago, and I kinda burned all the money I had at the time on that purchase.

If you only want to see waveforms and do basic measurements, an analog scope is definitely an option (and I love them, they are beautiful things), but since you mentioned that you like working with precision and low-noise stuff, I guess it would be useful to you to be able to capture glitches, measure jitter, etc. With that in mind I think a digital scope would be a better option.

I normally would advice against handheld scopes for a "main" scope (they are fine as a secondary or "field" tool) because they usually have pretty awkward controls, lack features (limited triggering options, limited storage capabilities, poor measurement capabilities, barely meet specs, etc) BUT that Hantek scope you mentioned seems to be fairly decent on paper (I went through the manual and looks fine, BUT I'm yet to see a review showing if it meets its specs, and all the features actually work, though).

There's a recent review from Defpom on a budget scope that looked pretty promising:

That instrument seems to be exactly the same as the OWON SDS1102, which is available even here in my country at a reasonable price (still higher than its standard price, but definitely cheaper than the Rigol I purchased as my first scope) Maybe it's also something you can get where you live?

Aggressively stalking local auction sites is also recommended  :D. Hopefully the second hand market in your country is bigger than here, though. Apparently VERY few people in my country worked on electronics in the past couple of decades, so it takes a miracle to find good used instruments at decent prices.


« Last Edit: October 17, 2020, 10:08:23 pm by battlecoder »
 
The following users thanked this post: ROFLCat

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #4 on: October 17, 2020, 10:30:53 pm »
What my poor man's lab is missing is a low-end/mid-range oscilloscope. Now this being Iran with the awful inflations, it's super expensive for us to buy a $350 DS1054Z.

How much is a Rigol DS1052E there?
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #5 on: October 18, 2020, 02:58:16 am »
Why not consider an older, used unit?  You can get a good Tektronix 465 for instance, for very little money.  I use one regularly and love it.  I have others but that's my main one.  Even my very old 453 is perfectly useful.

My digital unit does FFT but not in such a way as to be useful for most purposes.  I have spectrum analyers for that.
Yeah there were a few second hand 465s for sale but they were ridiculously priced TBH and actually Tek scopes are kinda rare. Common analogs in here are mostly Japanese stuff and mostly 20MHz, which I think is a bit too low.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #6 on: October 18, 2020, 03:10:17 am »
I normally would advice against handheld scopes for a "main" scope (they are fine as a secondary or "field" tool) because they usually have pretty awkward controls, lack features (limited triggering options, limited storage capabilities, poor measurement capabilities, barely meet specs, etc) BUT that Hantek scope you mentioned seems to be fairly decent on paper (I went through the manual and looks fine, BUT I'm yet to see a review showing if it meets its specs, and all the features actually work, though).

There's a recent review from Defpom on a budget scope that looked pretty promising:

That instrument seems to be exactly the same as the OWON SDS1102, which is available even here in my country at a reasonable price (still higher than its standard price, but definitely cheaper than the Rigol I purchased as my first scope) Maybe it's also something you can get where you live?

Aggressively stalking local auction sites is also recommended  :D. Hopefully the second hand market in your country is bigger than here, though. Apparently VERY few people in my country worked on electronics in the past couple of decades, so it takes a miracle to find good used instruments at decent prices.

I honestly had not thought about the awkward controls of handheld scopes until you and ataradov mentioned it.

I had seen these Owons and they're pretty common but I had doubts since I had only seen Dave's review of one and IIRC, it wasn't good. xD
But to be honest, at such a low budget there's not much choice to get a decent entry scope. I'll check out these Owons to see if there are any suitable models for me.

Oh I'm always on a website similar to Ebay checking the test equipment section every single day. I'm OK with a second-hand scope even if it has cosmetic damage, just need it to perform well according to the specs.
 

Offline james_s

  • Super Contributor
  • ***
  • Posts: 12967
  • Country: us
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #7 on: October 18, 2020, 05:28:36 am »
Why not consider an older, used unit?  You can get a good Tektronix 465 for instance, for very little money.  I use one regularly and love it.  I have others but that's my main one.  Even my very old 453 is perfectly useful.

My digital unit does FFT but not in such a way as to be useful for most purposes.  I have spectrum analyers for that.

In Iran? I have no idea what the market is like there but I would not expect used instruments to be nearly as plentiful there, especially A-list American brands.
 
The following users thanked this post: gnavigator1007

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #8 on: October 18, 2020, 10:45:53 am »
Maybe the FNIRSI-1013D (tablet oscilloscope) is also an option. There is a long thread about it with comments from people who bought it:
https://www.eevblog.com/forum/testgear/fnirsi-1013d-100mhz-tablet-oscilloscope/msg3022032/#msg3022032

I think it is a better choice compared to a handheld 'automotive style' or analog oscilloscope because in the end it offers more features. Then again I wouldn't spend more than US $200 on it including shipping.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #9 on: October 18, 2020, 12:32:43 pm »
How much is a Rigol DS1052E there?

I second this recommendation. It's an "old scope" by now, but it's a pretty solid option; good performance, can be hacked to 100 Mhz, and it's simple to use but powerful, and with enough features for most use cases. As I mentioned, this was my first scope, and it took me nearly 10 years of tinkering with electronics to need something slightly more powerful and feature-rich.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #10 on: October 18, 2020, 02:48:16 pm »
Why not consider an older, used unit?  You can get a good Tektronix 465 for instance, for very little money.  I use one regularly and love it.  I have others but that's my main one.  Even my very old 453 is perfectly useful.

My digital unit does FFT but not in such a way as to be useful for most purposes.  I have spectrum analyers for that.

In Iran? I have no idea what the market is like there but I would not expect used instruments to be nearly as plentiful there, especially A-list American brands.
Actually, I think there are lots of them and brands like Tek and HP are well-know, but the problem is that the owners would never let such good instruments go. That's why they only pop-up occasionally and at high prices.
 
The following users thanked this post: gnavigator1007

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #11 on: October 18, 2020, 02:52:18 pm »
What my poor man's lab is missing is a low-end/mid-range oscilloscope. Now this being Iran with the awful inflations, it's super expensive for us to buy a $350 DS1054Z.

How much is a Rigol DS1052E there?
There is a website that has it in stock and for about $300.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #12 on: October 18, 2020, 03:14:35 pm »
From what I've seen, the other options compared to a DS1052E are, bad. xD
The desktop Hanteks and Owons probably have smoother UIs and more modern hardware, but their memory depths are really bad. Like a Hantek 100MHz or a 70Mhz model has 40kpts and an Owon 100MHz model has 10kpts, you kidding me?! Is it that hard to implement 1Mpts or something? Rigol did it over a decade ago LOL.

Anyway, I'll probably save up a bit for the DS1052E and 100% put on a hacked firmware. Too bad I can't afford a DS1054Z, the 2 extra channels could be pretty damn useful.

Thanks everyone for your input! :D
 
The following users thanked this post: Fungus

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #13 on: October 18, 2020, 04:12:57 pm »
Is it that hard to implement 1Mpts or something? Rigol did it over a decade ago LOL.

Maybe it is. They could be using the RAM inside an FPGA which is usually very limited. Adding an external RAM chip could cost a lot more.
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 19593
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #14 on: October 18, 2020, 06:26:11 pm »
Anyway, I'll probably save up a bit for the DS1052E and 100% put on a hacked firmware. Too bad I can't afford a DS1054Z, the 2 extra channels could be pretty damn useful.
If you can get by with just 2 channels maybe a SDS1202X-E can better suit your needs but might be at the top end of your budget.
At least it has some reasonable memory depth (14 Mpts), 7" display, better sensitivity than most others in this class and a suite of decoders.
Avid Rabid Hobbyist
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #15 on: October 18, 2020, 06:38:09 pm »
Anyway, I'll probably save up a bit for the DS1052E and 100% put on a hacked firmware. Too bad I can't afford a DS1054Z, the 2 extra channels could be pretty damn useful.
If you can get by with just 2 channels maybe a SDS1202X-E can better suit your needs but might be at the top end of your budget.
At least it has some reasonable memory depth (14 Mpts), 7" display, better sensitivity than most others in this class and a suite of decoders.

Or there's the new 2-channel Rigol DS1052Z, which is even cheaper.

https://www.aliexpress.com/item/4001268857855.html

 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #16 on: October 18, 2020, 07:16:14 pm »
OP's biggest problem is his/her location. As stated there is a near 100% premium on top of importing something.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline tv84

  • Super Contributor
  • ***
  • Posts: 1839
  • Country: pt
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #17 on: October 18, 2020, 07:59:54 pm »
What about a GW Instek GDS-1000B Series? Since the OP has a GW Instek DMM maybe that brand is easier to find...
 
The following users thanked this post: gnavigator1007

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #18 on: October 18, 2020, 09:34:46 pm »
What about a GW Instek GDS-1000B Series? Since the OP has a GW Instek DMM maybe that brand is easier to find...

They're not easy to find even here in Europe.
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #19 on: October 18, 2020, 10:19:23 pm »
What about a GW Instek GDS-1000B Series? Since the OP has a GW Instek DMM maybe that brand is easier to find...

They're not easy to find even here in Europe.
Nonsense. There are several webshops where you can buy them. Even RS sells these: https://nl.rs-online.com/web/p/oscilloscopes/1233540/ (at an inflated price as you can expect from a distributor).
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #20 on: October 18, 2020, 11:02:04 pm »
Anyway, I'll probably save up a bit for the DS1052E and 100% put on a hacked firmware. Too bad I can't afford a DS1054Z, the 2 extra channels could be pretty damn useful.

That's what I thought when I upgraded my oscilloscope a few years ago. Turns out I've only used channel 3 once. Channel 4 remains untouched :-DD. Bear in mind that enabling extra channels reduce your sampling rate and memory, so having more than 2 channels is not *that* great. For a bunch of logic signals (which is what I look at the most) a logic analyzer is more practical anyway. Even a cheap Saleae clone (which is what I have) works wonders.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #21 on: October 18, 2020, 11:50:41 pm »
That's what I thought when I upgraded my oscilloscope a few years ago. Turns out I've only used channel 3 once. Channel 4 remains untouched :-DD.

I use mine for looking at Arduino pins. It's great to be able to put out pulses when you're debugging things.

Bear in mind that enabling extra channels reduce your sampling rate and memory, so having more than 2 channels is not *that* great. For a bunch of logic signals (which is what I look at the most) a logic analyzer is more practical anyway. Even a cheap Saleae clone (which is what I have) works wonders.

The problem is that those don't have a real time display of the signals. You have to press "record" and then go back and analyze.

(unless you have some software that I don't...)

I just got an Analog Discovery 2 and that does have real time display (16 digital channels, 2 analog). Maybe a 2-channel 'scope would be OK for me now.
« Last Edit: October 19, 2020, 12:17:48 am by Fungus »
 

Offline 0culus

  • Super Contributor
  • ***
  • Posts: 2643
  • Country: us
  • Electronics, RF, and TEA Hobbyist
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #22 on: October 19, 2020, 12:02:30 am »
Real time display of logic signals is often not wanted anyway...you want to record and go back to study what happened in detail. This is normal behavior for every logic analyzer I've used.
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #23 on: October 19, 2020, 12:02:54 am »
@Fungus: please fix the quotation. I didn't write the text you attribute to me.

@Oculus: A logic analyser is for different kinds of measurements. The ones where the signals in the analog domain are known to be good.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #24 on: October 19, 2020, 12:07:44 am »
@Fungus: please fix the quotation. I didn't write the text you attribute to me.

I guess we are now one and the same.  :-//
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #25 on: October 19, 2020, 12:21:01 am »
Real time display of logic signals is often not wanted anyway...you want to record and go back to study what happened in detail.

Imagine having to click record then stop then mouse around a bit every time you compile/run a program. It's a complete pain in the ass.

Sometimes you just need to see the signals.

 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #26 on: October 19, 2020, 12:21:37 am »
@Fungus: please fix the quotation. I didn't write the text you attribute to me.

I guess we are now one and the same.  :-//

Yeah, there's no going back after three people have quoted it.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #27 on: October 19, 2020, 12:26:58 am »
I use mine for looking at Arduino pins. It's great to be able to put out pulses when you're debugging things.

I do the same, but I've rarely needed to check more than 2 channels at once. For digital signals it's usually "something" vs the clock. And if there's any jitter/timing issue, it's "normally"** a problem only if it messes things up in the digital domain, in which case a logic analyzer should help you see quickly that something is off.

** For most cases.

The problem is that those don't have a real time display of the signals. You have to press "record" and then go back and analyze.

(unless you have some software that I don't...)

I just got an Analog Discovery 2 and that does have real time display (16 digital channels, 2 analog). Maybe a 2-channel 'scope would be OK for me now.

.
Fair, but recording is normally a good thing when you are working with signals that change million times a second. Can't see myself debugging fast changing signals in realtime. I'd miss like half a million transitions just by blinking.

Also, thanks for reminding me that I wanted an Analog Discovery board at one point. Now I'll probably spend the rest of the night watching video reviews and trying *not* to start saving for one. Maybe if I start a diet of cheap instant noodles AND I can get everyone a cheaper Christmas present this year there might be a chance I can get one for myself before the year ends?  :-DD
 

Offline 0culus

  • Super Contributor
  • ***
  • Posts: 2643
  • Country: us
  • Electronics, RF, and TEA Hobbyist
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #28 on: October 19, 2020, 12:30:36 am »
Real time display of logic signals is often not wanted anyway...you want to record and go back to study what happened in detail.

Imagine having to click record then stop then mouse around a bit every time you compile/run a program. It's a complete pain in the ass.

Sometimes you just need to see the signals.

Sure, that's what the o-scope is for. The logic analyzer is a different instrument, and it works differently than an oscilloscope. Mine has a lot more memory depth available than most oscilloscopes too, as well as a fully configurable state machine trigger.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #29 on: October 19, 2020, 12:44:10 am »

Imagine having to click record then stop then mouse around a bit every time you compile/run a program. It's a complete pain in the ass.

Sometimes you just need to see the signals.

Sure, that's what the o-scope is for. The logic analyzer is a different instrument, and it works differently than an oscilloscope. Mine has a lot more memory depth available than most oscilloscopes too, as well as a fully configurable state machine trigger.

Definitely a different instrument, but one "common" use of >2 channels is debugging communication/logic signal errors, in which case I was saying that a logic analyzer is better suited.
There are definitely legitimate uses of 4 analog channels in an oscilloscope, but I don't think OP will miss having 4 channels as much as he/she thinks.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #30 on: October 19, 2020, 01:24:41 am »
Also, thanks for reminding me that I wanted an Analog Discovery board at one point. Now I'll probably spend the rest of the night watching video reviews and trying *not* to start saving for one. Maybe if I start a diet of cheap instant noodles AND I can get everyone a cheaper Christmas present this year there might be a chance I can get one for myself before the year ends?  :-DD

There's a MASSIVE shortage of the chips at the moment so you'll be very lucky to get one this year. I only got mine by blagging my way through a special university education program.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #31 on: October 19, 2020, 01:26:20 am »
There are definitely legitimate uses of 4 analog channels in an oscilloscope, but I don't think OP will miss having 4 channels as much as he/she thinks.

Depends on what you use it for. I use more than 2 channels very often, eg. for timing how long a function takes to execute, that sort of thing.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #32 on: October 19, 2020, 02:07:51 pm »
If you can get by with just 2 channels maybe a SDS1202X-E can better suit your needs but might be at the top end of your budget.
At least it has some reasonable memory depth (14 Mpts), 7" display, better sensitivity than most others in this class and a suite of decoders.
[/quote]

Or there's the new 2-channel Rigol DS1052Z, which is even cheaper.

https://www.aliexpress.com/item/4001268857855.html
[/quote]

I had never heard of this model. Is it new or something?
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #33 on: October 19, 2020, 02:10:08 pm »
What about a GW Instek GDS-1000B Series? Since the OP has a GW Instek DMM maybe that brand is easier to find...

Actually, there is a GDS-1052U 50MHz, 2ch 'scope for about $340 second-hand, which I think is a bit too much.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #34 on: October 19, 2020, 02:13:48 pm »
Anyway, I'll probably save up a bit for the DS1052E and 100% put on a hacked firmware. Too bad I can't afford a DS1054Z, the 2 extra channels could be pretty damn useful.

That's what I thought when I upgraded my oscilloscope a few years ago. Turns out I've only used channel 3 once. Channel 4 remains untouched :-DD. Bear in mind that enabling extra channels reduce your sampling rate and memory, so having more than 2 channels is not *that* great. For a bunch of logic signals (which is what I look at the most) a logic analyzer is more practical anyway. Even a cheap Saleae clone (which is what I have) works wonders.
[/quote]

Yes I'm aware of the reduction in sample rate on these mid-range 'scopes. Well you'll never know when you'll need them so... .
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #35 on: October 19, 2020, 02:21:13 pm »
There is this company that takes orders from China, especially TaoBao (Tmall.com). I'm a long-time customer of theirs and I have ordered some LR8 regulators through them; it was all fine, especially the price. The only problem was that they had told me it would take 3-4 months but my order took around 7 months to arrive. I think the major delay was because of the human malware that caused every shop and stuff to close down at the beginning of 2020, so I don't blame them.

I'll ask them and get a quote on the price and time on a DS1054Z, provided that Tmall has some for a good price.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #36 on: October 19, 2020, 05:12:27 pm »
So I'm a 18 y/o EE who likes working with precision parts. I mostly design switchmode PSUs and precision low-noise voltage references for fun. Will be going to a university hopefully this year to study EE.

Neither require anything special in an oscilloscope.  Low noise would be nice for references however no modern oscilloscope is that low and a low noise amplifier allows the use of any oscilloscope.  An oscilloscope which can perform low frequency network analysis would be nice but this is not available in anything except high end instruments.

Storage is useful in general but not overwhelmingly so that I would exclude an old but working analog oscilloscope if it is inexpensive.

100 MHz of bandwidth or even 50 MHz is sufficient except for the highest performance switching regulators.

Do not underestimate the importance of probes.  A lower bandwidth oscilloscope with better probes, differential, current, whatever, will be more useful than a higher bandwidth oscilloscope without them.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #37 on: October 19, 2020, 07:26:03 pm »
So I'm a 18 y/o EE who likes working with precision parts. I mostly design switchmode PSUs and precision low-noise voltage references for fun. Will be going to a university hopefully this year to study EE.

Neither require anything special in an oscilloscope.  Low noise would be nice for references however no modern oscilloscope is that low and a low noise amplifier allows the use of any oscilloscope.  An oscilloscope which can perform low frequency network analysis would be nice but this is not available in anything except high end instruments.

Storage is useful in general but not overwhelmingly so that I would exclude an old but working analog oscilloscope if it is inexpensive.

100 MHz of bandwidth or even 50 MHz is sufficient except for the highest performance switching regulators.

Do not underestimate the importance of probes.  A lower bandwidth oscilloscope with better probes, differential, current, whatever, will be more useful than a higher bandwidth oscilloscope without them.

Quite true. I've actually never used a proper oscilloscope so I don't know how much of a difference there is between 10kpts and 1Mpts of memory but I guess 10kpts would make waveforms look very inaccurate when measuring 0.1 to 10Hz noise.

I'll still be waiting for that company's response. If the total cost comes out less than about $370, I'll order a DS1054Z.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #38 on: October 19, 2020, 10:33:06 pm »
Quite true. I've actually never used a proper oscilloscope so I don't know how much of a difference there is between 10kpts and 1Mpts of memory but I guess 10kpts would make waveforms look very inaccurate when measuring 0.1 to 10Hz noise.

The problem is that the impedance buffer stage at the input of the oscilloscope has quite poor low frequency noise with a high flicker noise corner frequency.  It is just a compromise to be made for high bandwidth and fast recovery from overload.  Oscilloscope front ends designed for low noise have a much more limited bandwidth.

But noise is not a problem when you can easily build an external low noise amplifier.

Limited record length creates more aliasing of high frequency noise to low.  So for instance 10 kpoints from 0.1 to 10Hz has a sample rate of 1kHz so input bandwidth needs to be limited to below 500Hz.  A 1 Mpoint record length considerably relaxes this requirement.

I do not have any DSOs suitable for FFT noise measurement so I still rely on spot noise measurements using the oscilloscope to measure RMS noise.  In practice spot noise is usually more relevant anyway, like measuring total noise from 0.1 to 10 Hz.  You can bet that if I ever design a DSO, it will include this capability and network analysis as well.
 

Offline james_s

  • Super Contributor
  • ***
  • Posts: 12967
  • Country: us
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #39 on: October 20, 2020, 12:58:13 am »
It really depends on what you're trying to do. The scope I use the most is a TDS3000 with 10k points and in most cases I have not found that to be a major limitation. I have a TDS700 with the 8M points option and I very rarely make use of that extra memory depth because it just results in capturing a ton of excess waveform to scroll through and it slows down the interface when you have a really big capture. IMHO it's better to focus on setting up the triggering to capture what you want instead of using massive amounts of memory to capture everything.
 
The following users thanked this post: ROFLCat

Online tautech

  • Super Contributor
  • ***
  • Posts: 19593
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #40 on: October 20, 2020, 01:25:56 am »
It really depends on what you're trying to do. The scope I use the most is a TDS3000 with 10k points and in most cases I have not found that to be a major limitation. I have a TDS700 with the 8M points option and I very rarely make use of that extra memory depth because it just results in capturing a ton of excess waveform to scroll through and it slows down the interface when you have a really big capture. IMHO it's better to focus on setting up the triggering to capture what you want instead of using massive amounts of memory to capture everything.
Quite so however it much depends on your use case as one channel might be triggered on to capture an event while other channels might be monitoring so to find what might have caused such an event.
Of course success depends on how time correlated the channels and events actually are, timebase settings and the mem depth available.
When working like this there is never too much mem depth.
Avid Rabid Hobbyist
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #41 on: October 20, 2020, 06:20:36 am »
It really depends on what you're trying to do. The scope I use the most is a TDS3000 with 10k points and in most cases I have not found that to be a major limitation. I have a TDS700 with the 8M points option and I very rarely make use of that extra memory depth because it just results in capturing a ton of excess waveform to scroll through and it slows down the interface when you have a really big capture. IMHO it's better to focus on setting up the triggering to capture what you want instead of using massive amounts of memory to capture everything.
No. Use an oscilloscope with a faster hardware platform. Those TDS700 are rather slow to drive (been there, done that). Modern oscilloscopes have no problem dealing with tens of megapoints worth of data.
« Last Edit: October 20, 2020, 06:22:31 am by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #42 on: October 20, 2020, 03:13:56 pm »
The problem is that the impedance buffer stage at the input of the oscilloscope has quite poor low frequency noise with a high flicker noise corner frequency.  It is just a compromise to be made for high bandwidth and fast recovery from overload.  Oscilloscope front ends designed for low noise have a much more limited bandwidth.

Interesting. Didn't know about that. But then again, I want some rough measurements on the noise of precision parts and being able to debug my power supplies and take output ripple measurements is really good. One other reason I want a decent digital oscilloscope is the ability to decode I²C and SPI signals as I'm also into data acquisition.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #43 on: October 20, 2020, 03:21:34 pm »
Thankfully, there's a deflation happening and the Rials per US Dollars ratio dropped by about 10% today which is great. The chances of getting a DS1054Z increases. :D

Also, if I there's a bit of money left in my pocket after an oscilloscope, I'll get this very unique and extremely rare frequency counter from a reputable and old manufacturer of test equipments. Stay tuned? ;D
Let's just say that it has a unique display with an affordable price.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #44 on: October 20, 2020, 07:25:23 pm »
The problem is that the impedance buffer stage at the input of the oscilloscope has quite poor low frequency noise with a high flicker noise corner frequency.  It is just a compromise to be made for high bandwidth and fast recovery from overload.  Oscilloscope front ends designed for low noise have a much more limited bandwidth.

Interesting. Didn't know about that. But then again, I want some rough measurements on the noise of precision parts and being able to debug my power supplies and take output ripple measurements is really good. One other reason I want a decent digital oscilloscope is the ability to decode I²C and SPI signals as I'm also into data acquisition.

It is not a big deal; it just means do not look to oscilloscopes for low noise measurements unless you want to deal with something like a Tektronix 7A22.  Designing and building a low noise preamplifier to test reference and regulator noise is not difficult and then any oscilloscope can be used.
'
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 19593
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #45 on: October 20, 2020, 08:53:08 pm »
But then again, I want some rough measurements on the noise of precision parts and being able to debug my power supplies and take output ripple measurements is really good. One other reason I want a decent digital oscilloscope is the ability to decode I²C and SPI signals as I'm also into data acquisition.
How good will you require ?
As we mainly use a scope with 10x probes a scopes max sensitivity can limit how far down we can go without switching to a 1x probe.
Study of scope datasheets and marketing blurb might reveal some brands are better suited down in the mV/div region due to high sensitivity and lower noise inputs.
Avid Rabid Hobbyist
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #46 on: October 21, 2020, 05:01:07 am »
The problem is that the impedance buffer stage at the input of the oscilloscope has quite poor low frequency noise with a high flicker noise corner frequency.  It is just a compromise to be made for high bandwidth and fast recovery from overload.  Oscilloscope front ends designed for low noise have a much more limited bandwidth.

Interesting. Didn't know about that. But then again, I want some rough measurements on the noise of precision parts and being able to debug my power supplies and take output ripple measurements is really good. One other reason I want a decent digital oscilloscope is the ability to decode I²C and SPI signals as I'm also into data acquisition.

It is not a big deal; it just means do not look to oscilloscopes for low noise measurements unless you want to deal with something like a Tektronix 7A22.  Designing and building a low noise preamplifier to test reference and regulator noise is not difficult and then any oscilloscope can be used.
'

Oh yeah I'm trying to build a cascaded Sallen-Key low-pass filter based on two LTC2055s (the lowest noise op amps that I can find and purchase). I might buy more in the future and connect them in parallel to achieve even lower noise?
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #47 on: October 21, 2020, 05:09:57 am »
But then again, I want some rough measurements on the noise of precision parts and being able to debug my power supplies and take output ripple measurements is really good. One other reason I want a decent digital oscilloscope is the ability to decode I²C and SPI signals as I'm also into data acquisition.
How good will you require ?
As we mainly use a scope with 10x probes a scopes max sensitivity can limit how far down we can go without switching to a 1x probe.
Study of scope datasheets and marketing blurb might reveal some brands are better suited down in the mV/div region due to high sensitivity and lower noise inputs.

Well, power supply noise and ripples are usually taken with a 20MHz bandwidth limit so that's completely fine on the 1x setting. Decoding I²C and SPI buses is fine with a 10x too since they're logic level and 3.3Vpp or 5Vpp.
And about the low-noise references, I'll be using a low-noise amplifier to boost up the signal by a factor of 10 or 100 as reading microvolts isn't too easily with any oscilloscope. ;D
Bandwidth on these measurements is irrelevant to be honest as it will mostly likely be low-frequency stuff (0.1 to 10Hz).
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #48 on: October 21, 2020, 05:43:18 am »
And about the low-noise references, I'll be using a low-noise amplifier to boost up the signal by a factor of 10 or 100 as reading microvolts isn't too easily with any oscilloscope. ;D

Yep.

There's people here who'll go on and on about how their brand of oscilloscope can do 0.5mV instead of 1mV but is that really a make/break difference when a cheapo amplifier can let you see 1uV noise on any oscilloscope?
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #49 on: October 21, 2020, 09:10:04 am »
Oh yeah I'm trying to build a cascaded Sallen-Key low-pass filter based on two LTC2055s (the lowest noise op amps that I can find and purchase). I might buy more in the future and connect them in parallel to achieve even lower noise?

Usually the problem is removing the DC component while passing frequencies down to 0.1 Hz.  Low noise and low drift with a 0.1 Hz low frequency cutoff is somewhat contradictory because of the impedances required to get such a long time constant with a reasonable value of capacitance.  Check out Linear Technology application notes 83 and 124 for example circuits.

Another method is to use an "offset probe" or differential comparator which subtracts the DC voltage.  This is essentially a differential probe with one input connected to the source to measure and the other connected to a low noise reference of the same voltage.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #50 on: October 21, 2020, 08:07:23 pm »
Check out Linear Technology application notes 83 and 124 for example circuits.

^This. Application notes are gold mines of good advise and practical uses of different components and technologies. On the topic of low-noise amplifiers for instance there's this guy who built a reasonable amplifier circuit based on a couple of application notes:


AND he builds the device to characterize low-noise regulators and power supplies, so it might be well in line with OP's request.

Even more, the guy is actually using a 70Mhz Hantek DSO5072P scope (which is a model someone here already suggested) and seems to work just fine for the job.

I think brands like Hantek/Mustool/Owon/whoever-the-original-oem-of-those-devices-is are doing a pretty good job at making decent entry-level oscilloscopes that are WAY beyond the specs of what hobbyist had access to even 10 years ago. They are definitely not state of the art, but I would have killed for one of those scopes when I started. Some of them are terrible, sure, but we are starting to see some models that definitely meet the specs, have a reasonable range of features, and don't have that many UX glitches as previous "budget" scopes.

Now, sure, if you can afford a Rigol or a Siglent ( or if you happen to find a good deal for a second hand <reputable brand>) by all means go for it. Just don't overlook the few little gems that are coming from "generic" manufacturers. I've seen a lot of people doing amazing stuff with them already.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #51 on: October 22, 2020, 11:52:14 am »
You can buy a pre-built signal amplifier on Aliexpress for $5 and add a battery and biscuit tin.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #52 on: October 25, 2020, 08:11:11 am »
Oh yeah I'm trying to build a cascaded Sallen-Key low-pass filter based on two LTC2055s (the lowest noise op amps that I can find and purchase). I might buy more in the future and connect them in parallel to achieve even lower noise?

Usually the problem is removing the DC component while passing frequencies down to 0.1 Hz.  Low noise and low drift with a 0.1 Hz low frequency cutoff is somewhat contradictory because of the impedances required to get such a long time constant with a reasonable value of capacitance.  Check out Linear Technology application notes 83 and 124 for example circuits.

Another method is to use an "offset probe" or differential comparator which subtracts the DC voltage.  This is essentially a differential probe with one input connected to the source to measure and the other connected to a low noise reference of the same voltage.

Thanks for the tip! I'll definitely check them out.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #53 on: October 25, 2020, 08:17:05 am »
Check out Linear Technology application notes 83 and 124 for example circuits.

^This. Application notes are gold mines of good advise and practical uses of different components and technologies. On the topic of low-noise amplifiers for instance there's this guy who built a reasonable amplifier circuit based on a couple of application notes:


AND he builds the device to characterize low-noise regulators and power supplies, so it might be well in line with OP's request.

Even more, the guy is actually using a 70Mhz Hantek DSO5072P scope (which is a model someone here already suggested) and seems to work just fine for the job.

I think brands like Hantek/Mustool/Owon/whoever-the-original-oem-of-those-devices-is are doing a pretty good job at making decent entry-level oscilloscopes that are WAY beyond the specs of what hobbyist had access to even 10 years ago. They are definitely not state of the art, but I would have killed for one of those scopes when I started. Some of them are terrible, sure, but we are starting to see some models that definitely meet the specs, have a reasonable range of features, and don't have that many UX glitches as previous "budget" scopes.

Now, sure, if you can afford a Rigol or a Siglent ( or if you happen to find a good deal for a second hand <reputable brand>) by all means go for it. Just don't overlook the few little gems that are coming from "generic" manufacturers. I've seen a lot of people doing amazing stuff with them already.

I'll check it out. Thanks :D

Yeah some of these are making a comeback.
I'm still waiting for the prices to drop down and seeing if there are going to be any good second-hand models for sale.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #54 on: October 25, 2020, 08:18:04 am »
You can buy a pre-built signal amplifier on Aliexpress for $5 and add a battery and biscuit tin.

Oh I don't know about that. I wouldn't wanna count on a low-noise reference with fake chips.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #55 on: October 25, 2020, 11:27:43 am »
You can buy a pre-built signal amplifier on Aliexpress for $5 and add a battery and biscuit tin.

Oh I don't know about that. I wouldn't wanna count on a low-noise reference with fake chips.

Not everything is "fake" on there.  :-//

The point is that no oscilloscope magically solves the problem of measuring noise.
 

Online mawyatt

  • Frequent Contributor
  • **
  • Posts: 363
  • Country: us
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #56 on: October 25, 2020, 01:30:29 pm »
You can buy a pre-built signal amplifier on Aliexpress for $5 and add a battery and biscuit tin.

Oh I don't know about that. I wouldn't wanna count on a low-noise reference with fake chips.

Not everything is "fake" on there.  :-//

The point is that no oscilloscope magically solves the problem of measuring noise.

Nope, Tektronix did this 50 years ago with the 7A22 Differential plug-in. Quite good actually at measuring low frequency noise, even had selectable built-in separate LP and HP filters for setting the BW as well as variable offset introduced near the front end to help with post-amplifier saturation. We had a number of these for use with our sub-nanovolt/root Hz amplifiers/systems and other ultra-low noise endeavors.

The amplifier you mentioned is worthless for the low noise low frequency reference measurements, the LT app notes mentioned by D Hess is what's required, especially in front of a really noisy low-resolution scope ;)

If you want to learn about low noise scope measurements, study the 7A22 design/notes, the mentioned LT App notes, and the video.

BTW the old Tektronix Main Frame scopes allowed various "plug-ins" for both vertical and horizontal, these were the workhorse analog scopes which could be tailored by plug-ins for covering a large range of measurements, including the mentioned low noise references.

Best,
« Last Edit: October 25, 2020, 01:32:07 pm by mawyatt »
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike
 
The following users thanked this post: 2N3055

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #57 on: October 31, 2020, 10:18:38 am »
Hello again!

So today a new ad popped up, it's a Philips PM3315 125MHz, 2 channel 'scope with 3 waveform memories and good amounts of trigger options for less than $90. The tube seems bright and consistent, the chassis looks extra clean but the seller says that some volts/divs need calibration and they're a bit off and he says the main power button sometimes doesn't turn it on and it can probably be fixed with some cleaning. It doesn't have any probes though. I don't know, do you guys think I should just go for it and buy separate probes? (Most probes available are Chinese with crappy plastic :( ) I can see a 60MHz Taiwanese probe for about $20 and from the same company but 250MHz is $50, more than half the price of the scope LOL.
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #58 on: October 31, 2020, 05:04:54 pm »
Hello again!

So today a new ad popped up, it's a Philips PM3315 125MHz, 2 channel 'scope with 3 waveform memories and good amounts of trigger options for less than $90. The tube seems bright and consistent, the chassis looks extra clean but the seller says that some volts/divs need calibration and they're a bit off and he says the main power button sometimes doesn't turn it on and it can probably be fixed with some cleaning. It doesn't have any probes though. I don't know, do you guys think I should just go for it and buy separate probes? (Most probes available are Chinese with crappy plastic :( ) I can see a 60MHz Taiwanese probe for about $20 and from the same company but 250MHz is $50, more than half the price of the scope LOL.
First, that's a REALLY good price in my opinion.  HOWEVER...
From my experience I can tell you that calibrating a scope normally requires pretty precise function generator and other gear. This is especially an issue when it comes to >20 Mhz scopes, because you start getting into the terrain of reasonably high-frequency signals where no cheap instrument will dare tread.
In fact, this is something I struggled A LOT with, when I had to calibrate a 100Mhz analog scope. The HF circuitry was reasonable complex and required gear I didn't have. I ended up cobbling together a high-frequency square-wave generator myself, and verifying the readings against a 100Mhz digital scope, which is definitely NOT the way the service manual recommended. At most I can say it ended up "more or less as poorly or well calibrated as the other guy"  :-//

So buying that scope might end up buying yourself a week (or more) of quality time with the scope partially disassembled over your dining table while you desperately try to come up with the signals and measurements you need to verify that it's performing as expected trhough its full bandwidth.

Regarding Chinese probes, some are pretty decent, to be fair. I have bought a couple sets for different scopes, and I'm yet to find a reason to complain about them. In fact, I'd say the last set I bought seems to work better than the probes that came with my Rigol scope (that doesn't make them good probes, but at least makes them better than what Rigol considers a good probe set for their entry-level scopes). Just make sure they are reasonably above the scope's bandwidth to avoid problems with the conversion ratio between "real Mhz" and "$20 with free shipping Mhz".  :-DD
« Last Edit: October 31, 2020, 06:13:52 pm by battlecoder »
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #59 on: October 31, 2020, 05:59:13 pm »
You're right, the calibration does need good equipment that I don't have either. The price/performance is amazing but the calibration thing... Oof.

I found a set of two 100MHz probes for $12 LOL.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #60 on: October 31, 2020, 06:16:51 pm »
You're right, the calibration does need good equipment that I don't have either.

It doesn't have to be very precise for you to be able to use the 'scope. Most usage of an oscilloscope is looking at the shape of waves together with an approximate voltage measurement, eg. many DSOs are only specified to about 5% accuracy on the voltage readings.

So... if you can generate an accurate 5V square wave then
a) You can calibrate the most common scales directly from that.
b) For the mV voltage scales you can feed your 5V though a 10 turn potentiometer, adjust it to output the voltage you need by measuring with a multimeter, now feed your square wave through that to calibrate the 'scope.

I found a set of two 100MHz probes for $12 LOL.

Finding probes for a 125MHz 'scope shouldn't be a problem.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #61 on: October 31, 2020, 06:24:28 pm »
You're right, the calibration does need good equipment that I don't have either.

It doesn't have to be very precise for you to be able to use the 'scope. Most usage of an oscilloscope is looking at the shape of waves together with an approximate voltage measurement, eg. many DSOs are only specified to about 5% accuracy on the voltage readings.

So... if you can generate an accurate 5V square wave then
a) You can calibrate the most common scales directly from that.
b) For the mV voltage scales you can feed your 5V though a 10 turn potentiometer, adjust it to output the voltage you need by measuring with a multimeter, now feed your square wave through that to calibrate the 'scope.

I found a set of two 100MHz probes for $12 LOL.

Finding probes for a 125MHz 'scope shouldn't be a problem.

Ah true. An "issue" that has come up is that the seller has made the 'scope private for an individual who may be buying. If they don't, then I can maybe buy it.

Probes are easy to find, just a bit expensive.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #63 on: October 31, 2020, 08:00:58 pm »
It doesn't have to be very precise for you to be able to use the 'scope. Most usage of an oscilloscope is looking at the shape of waves together with an approximate voltage measurement, eg. many DSOs are only specified to about 5% accuracy on the voltage readings.

Well yes and no.
Yes; It doesn't need to be precise to be useful for watching shapes (unless you want to look into high-frequency ringing and artifacts). But from what I remember OP was interested in measuring ripple, noise, and whathaveyou. For that I think he'd need the device to be as precise as possible, so a quick basic calibration with a breadboard square gen might not be enough.

Of course buying it now, and solving the calibration aspect later is an option. I'm sure there's a lot of people here who can MacGyver a calibration procedure for a 125Mhz scope with readily-available parts and gear, and would be happy to chime in.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #64 on: October 31, 2020, 08:49:32 pm »
from what I remember OP was interested in measuring ripple, noise, and whathaveyou. For that I think he'd need the device to be as precise as possible.

yes and no.

You want to be able to see it. You want to know how it changes when you do things to the circuit. Absolute accuracy? Maybe not as important as you might think. A bigger problem would be if there was a huge jump between ranges.

I'm sure something reasonably accurate can be done without spending a lot of money. The "square wave and pot" was just a starting point.

It might just be a dirty switch and the problem will go away with a can of contact cleaner.  :-//

The best thing is to find a place where people know that model and ask their opinion.
« Last Edit: October 31, 2020, 08:54:30 pm by Fungus »
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #65 on: October 31, 2020, 08:55:56 pm »
It might just be a dirty switch and the problem will go away with a can of contact cleaner.  :-//
Please no contact cleaner! Makes things work for a week or two and then everything is fubar due to corrosion. A better approach would be to get a service manual first to see what can be adjusted and perhaps clean switches and potmeters gently with alcohol. Not sure whether that will improve things because once a switch or potmeter is worn it simply needs to be replaced in order to get a piece of equipment back to work properly.

Given the problems the OP describes I'm not sure whether the scope was a really good purchase but then again it was cheap. I would have gone for any reasonable modern DSO.
« Last Edit: October 31, 2020, 08:58:58 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline rf-loop

  • Super Contributor
  • ***
  • Posts: 3343
  • Country: cn
  • Born with DLL21 in hand
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #66 on: November 01, 2020, 05:15:38 am »
...and perhaps clean switches and potmeters gently with alcohol.

There are many many alcohols.

I do not recommend ethyl alcohol for this kind of work. Ethanol need keep away until very special known reason for use it in some specially named place.

Mostly, right alcohol is isopropyl alcohol (isopropanol) Aka IPA.


If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
-
Harmony OS
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #67 on: November 01, 2020, 09:51:03 am »
So... Anymore ideas and reasons to buy it?
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #68 on: November 01, 2020, 10:01:29 am »
The seller just messaged me that the other person didn't buy it and they've re-posted the ad. He says he wants to sell it outside of the website and "you'd better get it soon", probably trying to trigger me LOL.

I still haven't decided because even though I probably could fix it, I don't like the chance of blowing off the money I can't restore on something that's half working.

Update: I told the guy that I'm not interested and that he shouldn't wait for me.
« Last Edit: November 01, 2020, 10:19:21 am by ROFLCat »
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #69 on: November 01, 2020, 10:39:36 am »
The seller just messaged me that the other person didn't buy it and they've re-posted the ad. He says he wants to sell it outside of the website and "you'd better get it soon", probably trying to trigger me LOL.

I still haven't decided because even though I probably could fix it, I don't like the chance of blowing off the money I can't restore on something that's half working.

Update: I told the guy that I'm not interested and that he shouldn't wait for me.
Good choice. BTW don't worry about probes. Used probes that come with oscilloscopes are usually crap and need replacing anyway.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #70 on: November 01, 2020, 11:13:29 am »
Update: I told the guy that I'm not interested and that he shouldn't wait for me.

What's the plan now? Rigol DS1052E?
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #71 on: November 01, 2020, 04:13:20 pm »
The seller just messaged me that the other person didn't buy it and they've re-posted the ad. He says he wants to sell it outside of the website and "you'd better get it soon", probably trying to trigger me LOL.

I still haven't decided because even though I probably could fix it, I don't like the chance of blowing off the money I can't restore on something that's half working.

Update: I told the guy that I'm not interested and that he shouldn't wait for me.
Good choice. BTW don't worry about probes. Used probes that come with oscilloscopes are usually crap and need replacing anyway.

Yeah that's not an issue. I can get two 100MHz probes for $12 which I think is a pretty good deal.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #72 on: November 01, 2020, 04:16:30 pm »
Update: I told the guy that I'm not interested and that he shouldn't wait for me.

What's the plan now? Rigol DS1052E?

Yes and no. I'm still waiting for that company to give me a quote on the price to order a DS1054Z from China. I'm also waiting for other ads for 'scopes to pop up.
They do from time to time but most of them are crappy 20MHz broken ones which are also way overpriced.
« Last Edit: November 01, 2020, 04:22:48 pm by ROFLCat »
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #73 on: November 05, 2020, 10:16:17 pm »
*Sigh*
The company I was hoping to be able to import from TaoBao for cheap just told me it would be about $900 to import a DS1054Z which is just stupid frankly.

I guess I'll just wait for the economy to get better or until I find a good second-hand one.

Meanwhile, I got into a great university with amazing labs and stuff (haven't seen the EE lab but the labs for other fields are just chocked full of equipment worth tens of thousands of Dollars). The problem is that the human malware won't let me go into the building and use the equipment. Great.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #74 on: November 07, 2020, 12:44:55 pm »
Wow! An ad for a Tektronix TDS 220 popped up. 100MHz, 1GS/s, and 2 channels. It's a bit of an old model but I think it's pretty sweet, listed for about $330 and I can buy it in less than a day. The seller says it's fully functional and clean. I don't know if he would include the probes or not so I just asked and I'm waiting for an answer.

Should I go for it? An alternative to this would be a DS1052E which is more expensive or a GW Instek 'scope with very low specs (like 40MHz or something).

Update: They replied and told me it has 1 probe.
« Last Edit: November 07, 2020, 01:19:34 pm by ROFLCat »
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #75 on: November 07, 2020, 01:27:23 pm »
I don't think it's a good 'scope after seeing the reviews and stuff. Commonly BNCs break, slow UI, slow updating, no advanced math features, dim and slow LCD, they all make me go "meh".
 

Offline smaultre

  • Contributor
  • Posts: 28
  • Country: ru
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #76 on: November 07, 2020, 03:21:49 pm »
I think Tek TDS3000(b) series is the most preferred for 1-st osc.
0) Small.
1) Can be upgraded (FOR~FREE) to 500(600)MHz@5Gs its a very good for its price.
2) Can be upgraded (FOR~FREE) with universal module to support advanced triggering modes.
3) Have professional 50Ohm inputs, that supported the ultra wide range of active probes (High frequency, differential, mA current, high voltage dif, e.t.c).
4) Active probes REALLY CHEAP (compared with other brands) and its so much on stock.
5) (B) series can be easy connected to PC by LAN.
6) Noisy fan can be replaced with quiet "hydra-bearing" from  the PC store.
7) Really cheap for its pros.

The next-one goes TDS5000B series its cheap
and provides a big screen and huge of functionality.
« Last Edit: November 10, 2020, 04:13:27 pm by smaultre »
 
The following users thanked this post: uski

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #77 on: November 07, 2020, 03:28:23 pm »
I don't think it's a good 'scope after seeing the reviews and stuff. Commonly BNCs break, slow UI, slow updating, no advanced math features, dim and slow LCD, they all make me go "meh".
And terribly noise too. Tek made a lot of nice DSOs but the TDS200 series isn't one of them.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
The following users thanked this post: ROFLCat

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #78 on: November 07, 2020, 05:33:57 pm »
I still think a Rigol DS1052 makes a really good first scope, even if it's "old". I used one for 10 years and I kinda regret selling it when I "upgraded". Sometimes I still wish I had it here.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #79 on: November 07, 2020, 06:06:01 pm »
I think Tek TDS3000(b) series is the most preferred for 1-st osc.
0) Small.
1) Can be upgraded to 500(600)MHz@5Gs its a very good for its price.
2) Can be upgraded with universal module to support advanced triggering modes.
3) Have professional 50Ohm inputs, that supported the ultra wide range of active probes (High frequency, differential, mA current, high voltage dif, e.t.c).
4) Active probes REALLY CHEAP (compared with other brands) and its so much on stock.
5) (B) series can be easy connected to PC by LAN.
6) Noisy fan can be replaced with quiet "hydra-bearing" from  the PC store.
7) Really cheap for its pros.

The next-one goes TDS5000B series its cheap
and provides a big screen and huge of functionality.

Thanks for your reply.

Well, there are lots of good oscilloscopes for decent prices, but my country makes everything absurdly expensive for no reason and I have a very limited budget of about $350.
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #80 on: November 07, 2020, 06:09:16 pm »
I still think a Rigol DS1052 makes a really good first scope, even if it's "old". I used one for 10 years and I kinda regret selling it when I "upgraded". Sometimes I still wish I had it here.

Yeah, I still have that on my list. A bit expensive for me but I'll get one if I can't find anything within a month or something.

Thankfully, there has been a huge drop on the exchange rate of US Dollars to Rials so, I might be able to get something good if it keeps dropping?
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #81 on: November 07, 2020, 07:36:44 pm »
I still think a Rigol DS1052 makes a really good first scope, even if it's "old". I used one for 10 years and I kinda regret selling it when I "upgraded". Sometimes I still wish I had it here.

Yep. I played with one of those older Rigols the other day when I was visiting a factory and I was, like, "Hey, this is really fun/cute to use".

Simplicity can be good. I'd be perfectly happy to own one of those.

The only thing that would be missing (for me) would be serial decoders but you can get really cheap devices for that.

Edit: And I'm not sure if it does FFT.
« Last Edit: November 07, 2020, 11:26:50 pm by Fungus »
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #82 on: November 07, 2020, 09:33:01 pm »
I still think a Rigol DS1052 makes a really good first scope, even if it's "old". I used one for 10 years and I kinda regret selling it when I "upgraded". Sometimes I still wish I had it here.

Yep. I played with one of those older Rigols the other day when I was visiting a factory and I was, like, "Hey, this is really fun/cute to use".

Simplicity can be good. I'd be perfectly happy to own one of those.

The only thing that would be missing (for me) would be serial decoders but you can get really cheap devices for that.
Indeed. Modern scopes with more features can be overwhelming or cumbersome to use, especially for quick measurements. Having a bunch of features and settings is great, but if you don't have the right combination of options selected you can easily sabotage your measurements. Funny that you mention serial decoding; one of the reasons I upgraded to a more modern scope was actually serial decoding. Turns out I've rarely used that feature. I have a dirt cheap logic analyzer that works great for that, and it's way easier to explore and dump serial data with it, than it is to do it with the scope.
 

Offline uski

  • Regular Contributor
  • *
  • Posts: 226
  • Country: us
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #83 on: November 09, 2020, 03:51:50 am »
Wow! An ad for a Tektronix TDS 220 popped up. 100MHz, 1GS/s, and 2 channels. It's a bit of an old model but I think it's pretty sweet, listed for about $330 and I can buy it in less than a day. The seller says it's fully functional and clean. I don't know if he would include the probes or not so I just asked and I'm waiting for an answer.

Should I go for it? An alternative to this would be a DS1052E which is more expensive or a GW Instek 'scope with very low specs (like 40MHz or something).

Update: They replied and told me it has 1 probe.

Be aware it has very limited memory, absolutely no decode feature, and unless it has the TDS2MM or TDS2CM module, no communication capabilities at all, which is annoying since you can't do screenshots or anything. It seems like a very steep price given the age of the instrument. But it's good quality, I liked it. I owned it for years, more than a decade, but I sold it.

A DS1054Z from Rigol would be a thousand times better in my opinion.
 

Offline Electro Fan

  • Super Contributor
  • ***
  • Posts: 2527
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #84 on: November 09, 2020, 04:17:01 am »
Find a way to go for this:

http://www.saelig.com/product/sds1202x-e.htm

It will be 200 MHz and have two probes, and will be new and will have a 7” 800x480 color screen instead of a 5.7” 320x240 monochrome screen plus a bunch of additional useful and enjoyable features including color intensity grading :)

It is a no brainer.
« Last Edit: November 09, 2020, 04:26:42 am by Electro Fan »
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #85 on: November 09, 2020, 04:26:04 am »
Find a way to go for this:

It is a no brainer.

It might be if OP didn't live where he lives.

 

Offline Electro Fan

  • Super Contributor
  • ***
  • Posts: 2527
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #86 on: November 09, 2020, 04:29:15 am »
Find a way to go for this:

It is a no brainer.

It might be if OP didn't live where he lives.

OP is resourceful and if he can maybe find a Rigol he can maybe find a Siglent.  First step is to know what he is looking for.
 
The following users thanked this post: uski

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #87 on: November 09, 2020, 12:35:29 pm »
I still think a Rigol DS1052 makes a really good first scope, even if it's "old". I used one for 10 years and I kinda regret selling it when I "upgraded". Sometimes I still wish I had it here.

My first encounter with Rigol was the DS1052D/E and it made a very bad impression on me.  It lacks peak detection which I consider essential on any DSO but you would not immediately know it because the documentation lies by referring to envelope detection as peak detection.  I only knew because I had tested one.  Rigol's customer service was less than helpful and tried to convince me that they were the same thing.

I bought and refurbished Tektronix 2230 instead.  I would never recommend the Rigol DS1000D/E series.
« Last Edit: November 09, 2020, 12:37:18 pm by David Hess »
 

Offline ROFLCat

  • Contributor
  • Posts: 31
  • Country: ir
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #88 on: November 09, 2020, 10:03:41 pm »
Find a way to go for this:

http://www.saelig.com/product/sds1202x-e.htm

It will be 200 MHz and have two probes, and will be new and will have a 7” 800x480 color screen instead of a 5.7” 320x240 monochrome screen plus a bunch of additional useful and enjoyable features including color intensity grading :)

It is a no brainer.

Oh I doubt I could get one. The companies that import stuff only purchase from websites like Amazon and TaoBao, I don't think they would purchase from that website.

The specs are impressive and well, it's from Siglent.
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 19593
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #89 on: November 10, 2020, 06:08:46 am »
Dubai is your closest Siglent dealer:
https://www.anaum.ae/
Avid Rabid Hobbyist
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #90 on: November 10, 2020, 01:48:19 pm »
My first encounter with Rigol was the DS1052D/E and it made a very bad impression on me.  It lacks peak detection which I consider essential on any DS

You're special.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #91 on: November 10, 2020, 05:09:18 pm »
My first encounter with Rigol was the DS1052D/E and it made a very bad impression on me.  It lacks peak detection which I consider essential on any DS

You're special.

Is that your only reply?  Don't you have some better personal insults to make?  Don't hold back; tell us what you really think.

What part of what I said about the DS1052D/E series was wrong?
« Last Edit: November 10, 2020, 05:13:38 pm by David Hess »
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #92 on: November 10, 2020, 06:35:13 pm »
Actually I don't think the DS1052 lacks peak detect. One of my customers has one (without digital channels) and I recall it being able to do peak detect. The problem is that Asian oscilloscope brands (most notably the Japanese) mis-label peak detect as envelope mode.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #93 on: November 10, 2020, 07:41:01 pm »
What part of what I said about the DS1052D/E series was wrong?

The part that was incorrect was telling somebody with limited budget in a country where test gear cost a fortune that they can't possibly buy a DS1052E because it doesn't have a feature they might never need.


Edit: I don't have a DS1052E in front of me but the manual says it has it, in section 2-56:

https://cdn-shop.adafruit.com/datasheets/Users+Guide+DS1000E.pdf

Quote
Peak  Detect Acquisition: Peak  Detect  mode  captures  the  maximum  and minimum  values  of  a  signal.  Finds  highest  and  lowest  record  points  over  many acquisitions.
« Last Edit: November 10, 2020, 07:48:20 pm by Fungus »
 

Offline battlecoder

  • Regular Contributor
  • *
  • Posts: 87
  • Country: cl
    • A BIT of Mystery
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #94 on: November 10, 2020, 08:44:34 pm »
I really don't quite remember if the DS1052 had Peak Detect or not. I vaguely remember using it, but wouldn't trust my memory on that one.
Having said that, I managed to find a video review (in Spanish, though. Was hard to find a video where they would actually get into the Acquisition Mode menu. Most reviewers just ignore it) that shows that the feature is indeed there, and it's properly called "Peak Detect". It's not under a different name (as already shown in the manual shared by @Fungus)) or anything.

https://youtu.be/htBXEjGV5CY?t=461

Maybe you are thinking of a different scope, @David Hess?
 

Offline dave j

  • Regular Contributor
  • *
  • Posts: 65
  • Country: gb
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #95 on: November 10, 2020, 08:51:35 pm »
My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

Attached are two images of my DS1102E's probe compensation waveform captured in single shot mode and zoomed in. Displayed as dots and vectors.

Admittedly the way it's presented might not match other scopes. Having the two lines, one that links the max values and the other that links the min values, might be better than having one line that alternates between max/min values but that's a presentation issue.


[1]Tektronix's definition
Quote
Envelope mode: Builds a waveform “envelope” from the highest maximum values and lowest minimum values among the corresponding samples from two or more trigger events (acquisitions).
I'm not David L Jones. Apparently I actually do have to point this out.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #96 on: November 11, 2020, 04:10:40 am »
Having said that, I managed to find a video review (in Spanish, though. Was hard to find a video where they would actually get into the Acquisition Mode menu. Most reviewers just ignore it) that shows that the feature is indeed there, and it's properly called "Peak Detect". It's not under a different name (as already shown in the manual shared by @Fungus)) or anything.

The point is that the DS1052D/E series has a feature called peak detection, which on other DSOs going back decades is called envelope detection.  Envelope detection is as easy as averaging to implement during processing but peak detection requires hardware and happens during decimation.

And then when you get to the DS1000Z series, peak detection as described in the manual is different since they actually implemented it.

My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

And that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.

Quote
Attached are two images of my DS1102E's probe compensation waveform captured in single shot mode and zoomed in. Displayed as dots and vectors.

Admittedly the way it's presented might not match other scopes. Having the two lines, one that links the max values and the other that links the min values, might be better than having one line that alternates between max/min values but that's a presentation issue.

That does not show anything.  A common test is to use a slow time/div and short record length to deliberately cause aliasing, and then switch to peak detection.  On the DS1052D/E series this would have to be done with a single shot acquisition to prevent envelope detection since there is no way to limit the number of envelopes to 1 as on the Tektronix 2440 series.  Other Tektronix DSOs had separate peak detection and envelope detection modes but for some reason they were combined on the 2440 series.  The lack of a way to set that is another clue that the DS1052D/E series does not implement peak detection.

If you have a pulse generator which can produce narrow variable width pulses, then you can quantitatively test how peak detection is occurring although DSOs now tend to have high enough sample rates that this is not practical beyond existence.  When I ran this test on the Tektronis 2230 which only has peak detection to 100 nanoseconds, it really did detect every pulse of 100 nanoseconds or longer, and miss shorter pulses, which was doubly interesting because the 2230 uses an analog channel switch.

Actually I don't think the DS1052 lacks peak detect. One of my customers has one (without digital channels) and I recall it being able to do peak detect. The problem is that Asian oscilloscope brands (most notably the Japanese) mis-label peak detect as envelope mode.

The DS1052D/E series mislabels envelope mode as peak detection.

If peak detection is supported, then envelope mode should use it, but not the reverse.

The part that was incorrect was telling somebody with limited budget in a country where test gear cost a fortune that they can't possibly buy a DS1052E because it doesn't have a feature they might never need.

Then that is all you had to say rather than starting in with the personal insults.

Quote
Edit: I don't have a DS1052E in front of me but the manual says it has it, in section 2-56:

https://cdn-shop.adafruit.com/datasheets/Users+Guide+DS1000E.pdf

I am aware of the manual.  It lies.  Rigol lied, and did so repeatedly when I contacted them.  Is that so surprising?

Quote
Peak  Detect Acquisition: Peak  Detect  mode  captures  the  maximum  and minimum  values  of  a  signal.  Finds  highest  and  lowest  record  points  over  many acquisitions.

"over many acquisitions" should tell you something.
« Last Edit: November 11, 2020, 04:20:09 am by David Hess »
 

Offline Shiv

  • Contributor
  • Posts: 36
  • Country: es
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #97 on: November 11, 2020, 09:10:55 am »
I went through analogs.
Thats fun, because you can repair it almost eternally...

468 was my first one... get it for free and sell it for 400 euros 3 months ago... but is toooo big for home.

I would recomend something about 50-100 MHz, analog/digital... (Philips PM3375, Tek TDS310, Iwatsu oldies,...)
468 in digital is only 10 MHz, but that works well for audio signals.

There are too many of them and are usually cheap and repairable (try to find one with 1 functional channel and repair the others) ,but the problem is your country, don´t take it badly, simply I doubt there are too many tek or Philips equipment (fck politics...)


For cheap new equipment, I saw UNI-T UTD2102e but I don´t know nothing about the brand (only that I like his mini function generator), but it´s only 179 bucks for 100 MHz
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #98 on: November 11, 2020, 07:13:17 pm »
My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

And that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.
Today I had a chance to test with a DS1102E myself and peak-detect is definitely doing peak detect and not envelope mode. However I'm not ruling out that firmware for this oscilloscope has changed over the years.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline TurboTom

  • Frequent Contributor
  • **
  • Posts: 907
  • Country: de
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #99 on: November 11, 2020, 09:18:37 pm »

Oh I doubt I could get one. The companies that import stuff only purchase from websites like Amazon and TaoBao, I don't think they would purchase from that website.

The specs are impressive and well, it's from Siglent.

How much hassle would it be for you to import the scope yourself? I don't know how burocracy works in your country and if you need to pay a lot of import tax / customs duty, but just for fun I checked shipping from my country to Iran of a 5kg package -- it would be round about 45 Euros. And I don't think there would be any legal difficulty to send a "second hand entry level" DSO your way, maybe even declared as a "present". I'm pretty sure many members of this forum (myself included) wouldn't have much problem parting with one of their "toys" for a compensation that would fit within your financial frame, including postage. And you can be pretty sure that noone around here would cheat you.

So if a second hand instrument would be okay for you, why don't you try it that way. I guess a Rigol DS1000Z should be within reach. Of course, it will only work that way if the import procedure until you finally can take it home, isn't too troublesome and expensive.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #100 on: November 13, 2020, 01:51:48 am »
My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

And that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.

Today I had a chance to test with a DS1102E myself and peak-detect is definitely doing peak detect and not envelope mode. However I'm not ruling out that firmware for this oscilloscope has changed over the years.

If it does do peak detection when set to envelope mode, that would sure be annoying for routine use when you really wanted peak detection on individual acquisitions.

I distinctly remember trying to do that when I tested it and having no luck.  It operated like it had envelope mode, which is what the manual shows and describes, and single shot acquisitions in envelope mode were identical to single shot acquisitions in normal mode which was the only way to test it.

 

Offline rf-loop

  • Super Contributor
  • ***
  • Posts: 3343
  • Country: cn
  • Born with DLL21 in hand
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #101 on: November 13, 2020, 03:51:22 am »
My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

And that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.

Today I had a chance to test with a DS1102E myself and peak-detect is definitely doing peak detect and not envelope mode. However I'm not ruling out that firmware for this oscilloscope has changed over the years.

If it does do peak detection when set to envelope mode, that would sure be annoying for routine use when you really wanted peak detection on individual acquisitions.

I distinctly remember trying to do that when I tested it and having no luck.  It operated like it had envelope mode, which is what the manual shows and describes, and single shot acquisitions in envelope mode were identical to single shot acquisitions in normal mode which was the only way to test it.

As you can see, and many others who know, there is always peoples and even manufactures who do not even know or care what is digital oscilloscope peak detect mode and how it work and how it need work. Sad.

If practice and theory is not equal it tells that used application of theory is wrong or the theory itself is wrong.
-
Harmony OS
 

Offline Fungus

  • Super Contributor
  • ***
  • Posts: 11388
  • Country: 00
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #102 on: November 13, 2020, 05:14:31 am »
Today I had a chance to test with a DS1102E myself and peak-detect is definitely doing peak detect and not envelope mode.

So it seems a safe bet that it has it.

However I'm not ruling out that firmware for this oscilloscope has changed over the years.

Occam's razor would suggest it hasn't.
 

Offline Shiv

  • Contributor
  • Posts: 36
  • Country: es
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #103 on: November 13, 2020, 08:27:42 am »
Hello again!

So today a new ad popped up, it's a Philips PM3315 125MHz, 2 channel 'scope with 3 waveform memories and good amounts of trigger options for less than $90. The tube seems bright and consistent, the chassis looks extra clean but the seller says that some volts/divs need calibration and they're a bit off and he says the main power button sometimes doesn't turn it on and it can probably be fixed with some cleaning. It doesn't have any probes though. I don't know, do you guys think I should just go for it and buy separate probes? (Most probes available are Chinese with crappy plastic :( ) I can see a 60MHz Taiwanese probe for about $20 and from the same company but 250MHz is $50, more than half the price of the scope LOL.


WARNING

PM3315 is a good thing amd good price BUT I doubt it reaches 125MHz, I don´t find it, but if I´m correct, it will be 125MHz SAMPLING RATE, thats 60MHz on sines and crappy squares.

The calibration of v/div can be done at home with a well known DMM, a DC generator and pacience, but the frequency response is quite dificult without equipment, same as timebase (you need a good reference)


EDIT: Yeah, I was late, I didn´t see it has been discarded.

Same with TDS200, I have a 220 at work and is a BAD scope.
Everything of it breaks appart.

I mean: screen backlight, CH1 connector dead and irreparable, plastics broken,...
I think is the worse tek scope by far.

« Last Edit: November 13, 2020, 08:44:48 am by Shiv »
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 19593
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #104 on: November 13, 2020, 08:51:10 am »
Hello again!

So today a new ad popped up, it's a Philips PM3315 125MHz, 2 channel 'scope with 3 waveform memories and good amounts of trigger options for less than $90. The tube seems bright and consistent, the chassis looks extra clean but the seller says that some volts/divs need calibration and they're a bit off and he says the main power button sometimes doesn't turn it on and it can probably be fixed with some cleaning. It doesn't have any probes though. I don't know, do you guys think I should just go for it and buy separate probes? (Most probes available are Chinese with crappy plastic :( ) I can see a 60MHz Taiwanese probe for about $20 and from the same company but 250MHz is $50, more than half the price of the scope LOL.


WARNING

PM3315 is a good thing amd good price BUT I doubt it reaches 125MHz, I don´t find it, but if I´m correct, it will be 125MHz SAMPLING RATE, thats 60MHz on sines and crappy squares.

The calibration of v/div can be done at home with a well known DMM, a DC generator and pacience, but the frequency response is quite dificult without equipment, same as timebase (you need a good reference)


EDIT: Yeah, I was late, I didn´t see it has been discarded.

Same with TDS200, I have a 220 at work and is a BAD scope.
Everything of it breaks appart.

I mean: screen backlight, CH1 connector dead and irreparable, plastics broken,...
I think is the worse tek scope by far.
Easy fixes both of them and there's plenty of info on the forum of how to.
Avid Rabid Hobbyist
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20104
  • Country: nl
    • NCT Developments
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #105 on: November 13, 2020, 09:34:25 am »
My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

And that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.

Today I had a chance to test with a DS1102E myself and peak-detect is definitely doing peak detect and not envelope mode. However I'm not ruling out that firmware for this oscilloscope has changed over the years.

If it does do peak detection when set to envelope mode, that would sure be annoying for routine use when you really wanted peak detection on individual acquisitions.
On the DS1102E I used it is called 'peak detect'; not envelope mode.


Same with TDS200, I have a 220 at work and is a BAD scope.
Everything of it breaks appart.

I mean: screen backlight, CH1 connector dead and irreparable, plastics broken,...
I think is the worse tek scope by far.
Easy fixes both of them and there's plenty of info on the forum of how to.
But you still end up with a poor oscilloscope. Fine if you pay $40 (or less) for it but not more.
« Last Edit: November 13, 2020, 09:36:34 am by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online tautech

  • Super Contributor
  • ***
  • Posts: 19593
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #106 on: November 13, 2020, 09:41:15 am »
Same with TDS200, I have a 220 at work and is a BAD scope.
Everything of it breaks appart.

I mean: screen backlight, CH1 connector dead and irreparable, plastics broken,...
I think is the worse tek scope by far.
Easy fixes both of them and there's plenty of info on the forum of how to.
But you still end up with a poor oscilloscope. Fine if you pay $40 (or less) for it but not more.
Of course, by today's standards they're a POS but still better than no scope.
Broken BNC's were common in these as Tek only used a 2 prong fitting and zero chassis fixing.
They were built to break !  ::)
Avid Rabid Hobbyist
 

Offline Shiv

  • Contributor
  • Posts: 36
  • Country: es
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #107 on: November 13, 2020, 10:11:43 am »
Hello again!

So today a new ad popped up, it's a Philips PM3315 125MHz, 2 channel 'scope with 3 waveform memories and good amounts of trigger options for less than $90. The tube seems bright and consistent, the chassis looks extra clean but the seller says that some volts/divs need calibration and they're a bit off and he says the main power button sometimes doesn't turn it on and it can probably be fixed with some cleaning. It doesn't have any probes though. I don't know, do you guys think I should just go for it and buy separate probes? (Most probes available are Chinese with crappy plastic :( ) I can see a 60MHz Taiwanese probe for about $20 and from the same company but 250MHz is $50, more than half the price of the scope LOL.


WARNING

PM3315 is a good thing amd good price BUT I doubt it reaches 125MHz, I don´t find it, but if I´m correct, it will be 125MHz SAMPLING RATE, thats 60MHz on sines and crappy squares.

The calibration of v/div can be done at home with a well known DMM, a DC generator and pacience, but the frequency response is quite dificult without equipment, same as timebase (you need a good reference)


EDIT: Yeah, I was late, I didn´t see it has been discarded.

Same with TDS200, I have a 220 at work and is a BAD scope.
Everything of it breaks appart.

I mean: screen backlight, CH1 connector dead and irreparable, plastics broken,...
I think is the worse tek scope by far.
Easy fixes both of them and there's plenty of info on the forum of how to.



Why?

Oscilloscopes here (only my lab):
DPO4104
TDS3064
TDS3054
TDS784D
TDS520D
2465B (x2)
2445B
PM3375 (x2)
CSA804 (40GHz)
TDS8200 (50GHz)

Oh, I forget the "trash":
465
468
TDS320
TDS310

And failing/mules :
2465´s
PM33´s
TDS7000
TDS3xxx
TDS5xx

And that crappy 220 used as signal/config checker before plug the test leads on measurement system.

Basically is used as a fuse :-DD

Is the only Tek Scope that I don´t like.

Is better than nothing? yes

But the question is... is better than something? :-//

For me, I prefeer that shitty boards of aliexpress and play for 10 bucks audio frecuencies while wait to get 100-200 bucks more and get something useful and durable.
« Last Edit: November 13, 2020, 10:26:05 am by Shiv »
 

Offline dave j

  • Regular Contributor
  • *
  • Posts: 65
  • Country: gb
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #108 on: November 13, 2020, 02:46:19 pm »
My DS1102E seems to have peak mode. If envelope mode requires multiple trigger events[1] then it won't work in single shot mode.

And that is exactly why it is mislabeled peak detection, which works with single shot acquisitions.

Quote
Attached are two images of my DS1102E's probe compensation waveform captured in single shot mode and zoomed in. Displayed as dots and vectors.

That does not show anything.
Can you explain why the screenshots in my previous post have differing high/low values? My understanding of envelope mode with a single shot capture is that it will only have one sample to update each high/low pair with so they should be the same. The screenshots clearly show differing values.
I distinctly remember trying to do that when I tested it and having no luck.  It operated like it had envelope mode, which is what the manual shows and describes, and single shot acquisitions in envelope mode were identical to single shot acquisitions in normal mode which was the only way to test it.
Attached are two screenshots showing single shot captures in normal acquisition mode and what the scope calls peak detect acquisition mode. As you can see, they are different which implies the latter is not envelope mode.

My scope is on the latest firmware and I believe it's the latest hardware (version 58). I don't know which hardware/firmware combination you used but there does seem to be some difference in the behaviour between the two scopes.
I'm not David L Jones. Apparently I actually do have to point this out.
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 12045
  • Country: us
  • DavidH
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #109 on: November 14, 2020, 08:54:41 pm »
If it does do peak detection when set to envelope mode, that would sure be annoying for routine use when you really wanted peak detection on individual acquisitions.

On the DS1102E I used it is called 'peak detect'; not envelope mode.

That is right, the DS1102E calls it peak detect mode.  But what the manual describes and how it operated when I tested it was what other manufacturers and DSOs, including later Rigol DSOs, called envelope mode.

Attached are two screenshots showing single shot captures in normal acquisition mode and what the scope calls peak detect acquisition mode. As you can see, they are different which implies the latter is not envelope mode.

That might be what it should look like, but how exactly did you force a single shot acquisition for the second screenshot?

The screenshows do not show but what is the record length in the two modes?  Peak detection almost always halves the record length but envelope detection may not depending on the implementation.

Quote
My scope is on the latest firmware and I believe it's the latest hardware (version 58). I don't know which hardware/firmware combination you used but there does seem to be some difference in the behaviour between the two scopes.

When I tested the DS1000D/E series it was a couple years before the DS1000Z series was released.  It seems odd that they would update the hardware or firmware without fixing the user interface leaving peak detection crippled and also not update the manual.
 

Offline dave j

  • Regular Contributor
  • *
  • Posts: 65
  • Country: gb
Re: I Need Help With Choosing a Budget Oscilloscope!
« Reply #110 on: November 14, 2020, 09:49:08 pm »
That might be what it should look like, but how exactly did you force a single shot acquisition for the second screenshot?
Trigger menu->Sweep->Single for both.

Quote
The screenshows do not show but what is the record length in the two modes?  Peak detection almost always halves the record length but envelope detection may not depending on the implementation.
Record length Normal for both (you only get a choice of Normal or Long Mem on this scope). Zooming in, the samples are displayed at 200ns intervals for both traces. The 'peak detect' one has the same high/low zigzag pattern shown in my earlier screenshots so a high/low pair is over 400ns. That doubling of the sample time fits with the record length being halved as you suggest since it has to store high/low pairs instead of single samples. If the zigzag display is just a presentation thing because the hardware can't display two separate lines for high and low values it seems a reasonable compromise to make - you have to zoom in over 10x in order to see individual dots so it won't normally be an issue.

Quote
When I tested the DS1000D/E series it was a couple years before the DS1000Z series was released.  It seems odd that they would update the hardware or firmware without fixing the user interface leaving peak detection crippled and also not update the manual.
When I first looked at 'peak detect' I noticed the discrepancy between what the scope appears to do and the manual. I'd just assumed they hadn't updated the manual.

I freely admit I'm largely a novice at electronics, I'm really a software guy who's recently started looking at electronics as a hobby. I'd like to understand what the scope is actually doing but discrepancies between what the scope does and the manual says together with more experienced people saying it does peak detect/it's really envelope mode leave me a bit puzzled. What I can see the scope doing seems to fit with peak detect rather than envelope mode so I'm going with that for now but I'm open to hearing an explanation for what I'm seeing that fits envelope mode.
I'm not David L Jones. Apparently I actually do have to point this out.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf