Input on 1st digital oscllioscope purchase

[videobruce]

Coming from the world of analog scopes which was a number of years ago, when digital scopes first came on the market in force, I remember warnings about some of the misleading specs. Not that any professional manufacture (importer) would try to mislead anyone in the T&M field mind you.  Sampling rate I believe was one that can be misleading depending on how it was spec'd.

I'm looking for a halfway decent scope, NOT entry level, but not 'lab grade' either. The question is, how much does one have to spend to get a 'decent' model for mostly 'hobby' use that has a at least an average level of accuracy, dependability and stability. I would prefer to stay under $1k US unless that isn't realistic. I see these ones for under $500, but I didn't want to go that low.

Battery operation not necessary,
Color LCD is,
Two channel should be fine (I don't see a need for more)
Typical, common control layout, no 'odd' designs
I don't need 'lab' precision, but again I don't want the low cost models.
Used or demo ok, but I do not want any boat anchors.

Anyone suggest good reading material (online pdf documents for example) to bring me up to speed as I like to digest all of this before the purchase?

[dr.diesel]

There are a ga-billion threads here on this very subject, read through, you'll find lots of good info.  One thing you don't mention, how much bandwidth do you need?  Do you need protocol decoding, etc?

What kind of signals/projects do you intend on probing?

[videobruce]

I have already started reading through them.
From an analog standpoint I would say at least 100MHz. Can't answer the other specific.

[Fungus]

There are a ga-billion threads here on this very subject

Orders of magnitude more than that (last time I counted....)

I have already started reading through them.
From an analog standpoint I would say at least 100MHz. Can't answer the other specific.

Without knowing that stuff, it's a bit like asking "how long is a piece of string?"

All advice is useless until you fill in the blanks, you might even end up with a boat anchor!

PS: https://www.eevblog.com/forum/testgear/newbies-please-read-before-posting/

[dr.diesel]

Without knowing more, if you wanna just start playing around, something like the Rigol DS1000s/1100s are hard to beat on price/performance.

Maybe something like, this.

[nixfu]

As a newbie I would suggest one thing for sure.  Get a Rigol. 

I don't know which model is right for you, but I do highly suggest it's a Rigol. 

Why?   Not because they are the absolute "best" or anything, but simply because they are the most widely used in the Amature community and so you will have LOTS of help, and people to answer questions, there are many many examples to learn from, there are tips and tutorials all over the place etc.    As a new guy that might be much more valuable than getting something that might have a few bells and whistles or a few % better specs etc.  The community for something like Owan, etc are much much smaller than that of Rigol users.   It's somehing importsnt to keep in mind. 


For 100mhz depending on your budget the older ds1000/1100 series rigols or what appears to be the new best values for your money are probably the brand new 1054z that you can upgrade the 2 channel model from 50mnz to 100mhz with a simple hack MAYBE, or the 4 channel 1074z model that you can upgrade from 70mhz to 100mhz with a hack for sure.   I have the 1074z and its a great value.   

BTW, Dave is supposed to be getting one of the brand new 1054z scopes soon so look for it on eevblog. 

And don't forget that eevblog members get a 6% discount from tequipment.net which makes the rigols even a better deal from them.   

[frenky]

fyi ds1054z has 4 channels...

[Lightages]

Based on what I have been reading on the forums, and from information from trusted members here, I would get the Rigol DS1054Z and hack it. You get 4 channels, 100MHz bandwidth in one channel mode, fast update speed, protocol decoding, long memory, nice big screen, all for $400 plus shipping. I make this recommendation based on the fact that you aren't sure what you need and this will do almost everything well. It is more than most people need unless you need higher bandwidth.

If you need higher bandwidth, then we need to hear about it.

[nctnico]

Nowadays there is no reason to limit yourself to 2 channels either. Just get a 4 channel oscilloscope.

[Mark_O]

Coming from the world of analog scopes which was a number of years ago, when digital scopes first came on the market in force, I remember warnings about some of the misleading specs. Not that any professional manufacture (importer) would try to mislead anyone in the T&M field mind you.  Sampling rate I believe was one that can be misleading depending on how it was spec'd.

It's really not, these days.

I'm looking for a halfway decent scope, NOT entry level, but not 'lab grade' either. The question is, how much does one have to spend to get a 'decent' model for mostly 'hobby' use that has a at least an average level of accuracy, dependability and stability. I would prefer to stay under $1k US unless that isn't realistic. I see these ones for under $500, but I didn't want to go that low.

At the rate we're going, if everyone thinking of buying their first DSO starts their own thread, we're going to have a lot of redundant topics.   

The answer to your question of how much one needs to spend, blah, blah, is $399.  I'm not sure why you have an aversion to spending less than $500.

Battery operation not necessary,
Color LCD is,
Two channel should be fine (I don't see a need for more)
Typical, common control layout, no 'odd' designs
I don't need 'lab' precision, but again I don't want the low cost models.
Used or demo ok, but I do not want any boat anchors.

Your specs are inadequate to make an informed recommendation.  However, if you're not averse to spending more than the minimum, and see no need for more than 2 channels, the DS2000 would be a good choice.  Especially since your moniker is 'videobruce', and the DS1000z series video triggers aren't spec'ed to handle more than 576p.  In addition to providing extra bandwidth (and lots of other useful capabilities), the DS2000 triggers on HD, to 1080p.

[nctnico]

I'm wondering where you'll find analog video signals nowadays.

[Mark_O]

I'm wondering where you'll find analog video signals nowadays.

VGA, etc. on computers.  HD component video outs on consumer gear.  It's not ALL gone (yet).  Though I'm sure the studios would like it to be.

[EEVblog]

You mention "accuracy, dependability and stability"
All modern digital scopes should have essentially zero stability and accuracy issues.
Out of the big names, the clear winner at the low end is Rigol, and their new DS1054Z is unbeatable value. DS1072 if you want more performance, bigger screen, and separate vertical controls that is closer to the $1K mark.
Coming form the analog world you want one with a "variable intensity" display that looks and feels like an analog. The Rigol's are excellent in this regard, see here:

[true]

...the clear winner at the low end is Rigol, and their new DS1054Z is unbeatable value. DS1072 if you want more performance, bigger screen, and separate vertical controls that is closer to the $1K mark.

I think you typo'd DS2072.

But to add content to this post, I agree with what Dave said DS1054Z hard to beat at $400USD, DS2072 with bigger screen, separated vertical and playback controls really comes in handy for some of the digital or mixed stuff I debug. One is $400 class, the other is $800 class - and if you don't like these, there are others around the $1k mark (usually a bit over) that are nice.

In addition to the DS2072 I also have DS1074Z-S and the screen is not a bad size compared to entry scopes of only ~3 years ago.

[videobruce]

Thanks for all the input. Sorry for starting another 'scope' thread, but from the few that I have read, I needed more info and didn't want to barge in.

I do highly suggest it's a Rigol. Why?
Not because they are the absolute "best" or anything, but simply because they are the most widely used in the Amature community and so you will have LOTS of help, and people to answer questions, there are many many examples to learn from,.

Rigol was on my short list already. I know there are popular here and I have had experience with Rigol in the past which supports that as a leading choice. Looking for a make/model of anything I factor in the popularity (or lack of) of the item as much as possible though sometimes you have to look elsewhere.

Quote from: nctnico on Today at 07:00:18 AM
I'm wondering where you'll find analog video signals nowadays.

VGA, etc. on computers.  HD component video outs on consumer gear.

You can add CCTV cameras, but that would not be a mainstream use.

There are a number of specs that are new to digital scopes I will have to read up on that I won't ask here unless I can't find sufficient data elsewhere.

[EEVblog]

There are a number of specs that are new to digital scopes I will have to read up on that I won't ask here unless I can't find sufficient data elsewhere.

There isn't much you can do wrong in terms of specs these days. Any scope with MB worth of sample memory is what you want, and 1GS/s sample rate, and pretty much every scope of the market meets that except for Tek's pathetic low end TBS digitals.
The other major thing is the variable intensity analog-like display as I mentioned, and not all the cheapies have that, or have it implemented as well as Rigol or Agilent do it.

[videobruce]

This "variable intensity", is this what you are talking about?

A disadvantage of digital oscilloscopes is the limited refresh rate of the screen. On an analog oscilloscope, the user can get an intuitive sense of the trigger rate simply by looking at the steadiness of the CRT trace. For a digital oscilloscope, the screen looks exactly the same for any signal rate which exceeds the screen's refresh rate. Additionally, it is sometimes difficult to spot "glitches" or other rare phenomena on the black-and-white screens of standard digital oscilloscopes; the slight persistence of CRT phosphors on analog oscilloscopes makes glitches visible even if many subsequent triggers overwrite them. Both of these difficulties have been overcome recently by "digital phosphor oscilloscopes", which store data at a very high refresh rate and display it with variable intensity, to simulate the trace persistence of a CRT oscilloscope.

Not to go OT, but this is exactly where/what I'm having trouble dealing with looking for a spectrum analyzer that I had a hard time explaining in another thread.

Since you mention this, "memory depth". How much is enough for between "hobby" use and low end lab grade and what does more get you?

[Fungus]

This "variable intensity", is this what you are talking about?

A disadvantage of digital oscilloscopes is the limited refresh rate of the screen. On an analog oscilloscope, the user can get an intuitive sense of the trigger rate simply by looking at the steadiness of the CRT trace. For a digital oscilloscope, the screen looks exactly the same for any signal rate which exceeds the screen's refresh rate. Additionally, it is sometimes difficult to spot "glitches" or other rare phenomena on the black-and-white screens of standard digital oscilloscopes; the slight persistence of CRT phosphors on analog oscilloscopes makes glitches visible even if many subsequent triggers overwrite them. Both of these difficulties have been overcome recently by "digital phosphor oscilloscopes", which store data at a very high refresh rate and display it with variable intensity, to simulate the trace persistence of a CRT oscilloscope.

Not to go OT, but this is exactly where/what I'm having trouble dealing with looking for a spectrum analyzer that I had a hard time explaining in another thread.

Even the bottom-of-the range DS1054Z can sit there waiting for "runt" pulses and do pass/fail testing (if a waveform goes outside a specified boundary it flags it for you), eg. In this image the single wave that didn't stay inside the black boundary area has caused a trigger:

[nctnico]

A disadvantage of digital oscilloscopes is the limited refresh rate of the screen. Both of these difficulties have been overcome recently by "digital phosphor oscilloscopes", which store data at a very high refresh rate and display it with variable intensity, to simulate the trace persistence of a CRT oscilloscope.

I'm not sure analog oscilloscope simulation is such a good thing. People tend to forget that seeing narrow pulses on an analog oscilloscope was very hard to do. Crank the brightness up beyond sane levels and then hope the spike becomes visible a low sweep rates. A good digital oscilloscope has peak detect which is a much better way to spot narrow pulses than ever possible on an analog oscilloscope. Same goes for finite/infinite persistance modes.

[videobruce]

Is this "analog" mode (for lack of a better term) an option on some of these scopes?

[Fungus]

Is this "analog" mode (for lack of a better term) an option on some of these scopes?

No, it's a standard feature even on the $400 model.

[EEVblog]

Since you mention this, "memory depth". How much is enough for between "hobby" use and low end lab grade and what does more get you?

Even the cheap hobby ones have just as much if not more than the "lab grade" scopes.

[EEVblog]

Is this "analog" mode (for lack of a better term) an option on some of these scopes?

It comes standard with the $399 Rigol DS1054Z and all the above models. The higher models like the DS2000 series have more intensity grading shades though.

[EEVblog]

This "variable intensity", is this what you are talking about?

Yes, every manufacturer calls it something different. DPO for Tek for example. Rigol just call it "multiple intensity levels waveform display"
Some have a colour intensity, others have mono like an analog CRO.

[tggzzz]

There are a number of specs that are new to digital scopes I will have to read up on that I won't ask here unless I can't find sufficient data elsewhere.

There isn't much you can do wrong in terms of specs these days. Any scope with MB worth of sample memory is what you want, and 1GS/s sample rate...

Be aware that a modern 1GS/s scope almost certainly won't let you see a 500MHz signal. (Older digital scopes did; I once used a 1GHz scope to see sub-ns risetimes, but it only did 40MS/s)

For digital signals, decide on the risetime of the signals that you wish to see. That will determine the bandwidth of the analogue front end using the standard equation BW = 0.35/tr. For digital circuits 100MHz is probably the lowest you should use, since many circuits have 1ns risetimes and you may well want to see time differences of the order of a few ns.

Consider that for digital circuits you might only need a scope to ensure signal integrity. Once integrity is ensured, capture and debug in the digital domain, not the analogue domain.

Don't forget to add in the cost of the probes. Be aware that typical *10 probes with a 6" ground lead and a 15pF tip capacitance will self resonate at ~100MHz (and lower if circuit capacitance is added to the calculation).