Advice on buying first bench scope? Need to know whats best for me!

[Wuerstchenhund]

Uhm, nope, if you want to accurately reproduce digital waveforms (i.e. pulses, square waves) you need much higher bandwidth than the fundamental frequency. At least ten times the fundamental. To properly judge the edges you need even more bandwidth, since you likely want a faster rise time of your test setup than the rise time of the edge... else you can't judge it, really. So for most digital work a 100 MHz scope is more on the lower end of what is useful. For higher speed digital circuits it's no good anyway.

I have to agree with dom0, for a 20MHz bus a 100MHz scope isn't really going to cut it if you really want to see the true signal and not some waveform which doesn't have much to do with what's actually going on.

To make matters worse, I don't think a tiny budget of $350 will get you anything sensible. It's just too small for a decent scope. You might be able to stretch to a Rigol DS1054z but even after hacking you're still left with too little bandwidth, and in the used space anything that has the required bandwidth (200Mhz min), a decent sample rate (1GSa/s min) and at least somewhat decent sample memory (250k if you're really conservative, reasonably it should be at least 1MB; all per channel) and is in fully working condition will set you back more than $350. And what's left (slow antique DSOs with tiny memory, analog scopes) isn't really suited for the task, and especially with these old DSOs comes with a high chance of turning into a money pit.

[WattsUp]

  If you do manage to pick up a higher bandwidth scope, don't underestimate the cost of probes. Even passive probes up to 500MHz can cost well over £100 quid.

[rwgast_lowlevellogicdesin]

Hmm from what ive read a 100mhz scope can measure a 10Mhz square wave with no loss and up to a 3.5ns rise time. Is this correct?

My USB scope with 25Ms usb scope seems to do an alright job of measuring 1mhz squaves so I would hope a 1GA/s scopw would do much more.

[rob77]

actually if you have some imagination and you know what is a square wave technically (crapload of sine harmonics put together), then you can "see" even a 30-40MHz square wave on a 100MHz scope - obviously it will be not square but rather "wavy"
of course if you need accurately measure the rising and falling edges, then you need a huge bandwidth.

[Fungus]

actually if you have some imagination and you know what is a square wave technically (crapload of sine harmonics put together), then you can "see" even a 30-40MHz square wave on a 100MHz scope - obviously it will be not square but rather "wavy"
of course if you need accurately measure the rising and falling edges, then you need a huge bandwidth.

Yep. Ignore the pedants on here and go for the 1054Z. It's plenty good enough to look at a 10-20Mhz square wave and be able to say "that's a 10MHz square wave!" (or whatever).

[Wuerstchenhund]

Yep. Ignore the pedants on here

Sure, and a whole lot of physical laws along with it. But who needs that stuff anyways.

It's plenty good enough to look at a 10-20Mhz square wave and be able to say "that's a 10MHz square wave!" (or whatever).

Of course, what's so interesting on what's really happening in a circuit anyways. If it doesn't work as expected just build something else instead.

[EEVblog]

Uhm, nope, if you want to accurately reproduce digital waveforms (i.e. pulses, square waves) you need much higher bandwidth than the fundamental frequency. At least ten times the fundamental. To properly judge the edges you need even more bandwidth, since you likely want a faster rise time of your test setup than the rise time of the edge... else you can't judge it, really. So for most digital work a 100 MHz scope is more on the lower end of what is useful. For higher speed digital circuits it's no good anyway.

I argue that anyone who has to ask advice on buying their first scope is not going to understand, have the need for, nor care about accurately reproducing digital signal and their edges (i.e exact signal fidelity).
It's a complete non-issue.
The 50/100MHz Rigol DS1054Z is more than good enough for any job the OP or any other beginner will have.

[EEVblog]

What's your opinion on the ? Do you think there might be some tweaked hardware changes in the near future?

It seems to be fixed good enough. No one knows if hardware will change, but even if it does you won't notice.
No one should hold off buying the DS1054Z because a hardware change might come eventually.

[nctnico]

Uhm, nope, if you want to accurately reproduce digital waveforms (i.e. pulses, square waves) you need much higher bandwidth than the fundamental frequency. At least ten times the fundamental. To properly judge the edges you need even more bandwidth, since you likely want a faster rise time of your test setup than the rise time of the edge... else you can't judge it, really. So for most digital work a 100 MHz scope is more on the lower end of what is useful. For higher speed digital circuits it's no good anyway.

I argue that anyone who has to ask advice on buying their first scope is not going to understand, have the need for, nor care about accurately reproducing digital signal and their edges (i.e exact signal fidelity).
It's a complete non-issue.
The 50/100MHz Rigol DS1054Z is more than good enough for any job the OP or any other beginner will have.

I agree. You have to start somewhere and 100MHz is enough to begin with. My first oscilloscope was an 20MHz analog one and it served it's purpose well. Back then I couldn't not have dreamed about getting something like a Rigol 1000Z series as a first oscilloscope.

[rob77]

actually the 1000Z is so good i had to buy it bought it, asked rigol for a new firmware (had the jitter issue, but wasn't that bad as others had here) updated it and i'm more than happy now.
my other scope (hantek DSO1102B) is somehow less utilized now i love the speed of the 1054Z, it's awesome    the hantek is a good scope as well (and it's battery powered and portable - no mains earth on bncs), but the user interface is "dead-slow" while acquiring with long memory.
the 1054Z is pretty fast with even more memory, actually it's the fastest scope in it's price category.

so definitely the Rigol 1054Z is the best choice as a first scope.

[Fungus]

Yep. Ignore the pedants on here

Sure, and a whole lot of physical laws along with it. But who needs that stuff anyways.

If we're being pedantic then NO oscilloscope can reproduce a square wave.

If we're being sensible, I go along with Dave: Anybody who's asking this question doesn't need more then a DS1054Z.

[dom0]

If we're being pedantic then NO oscilloscope can reproduce a square wave.

Again, nope, guys, get your stuff right. Every signal above the noise in the universe is band-limited, and especially every signal on your workbench.

You're right, though, that you probably don't need XXX MHz bw in your first scope. But if you read the thread again you'll see that it wasn't the question at that point. Someone said "How much bw for square wave of 20 MHz? 200 MHz, right?", someone else said "Nooo, you need 200 MS/s, not 200 MHz bw". This led to my post above.

[Fungus]

Someone said "How much bw for square wave of 20 MHz? 200 MHz, right?", someone else said "Nooo, you need 200 MS/s, not 200 MHz bw". This led to my post above.

OK, that was a bit of a brain fart. 200MS/s is on the low side for a square wave. You'd see the signal but not much detail.

What I meant to say was that the "10 to 1" rule he mentioned applies to sample rate, not bandwidth. ie. The 1GHz sample rate of the 1104Z is what lets you see a 100MHz signal with useful fidelity. You're right about not being able to see a 100MHz square wave though.

[rwgast_lowlevellogicdesin]

how about this only 16 hours left?!!! I knoW ITS 80S BUT 500MHZ 1g/S? iS THIS JUNK COMPARED TO A HANTEK OR RIGOL?

[rob77]

how about this only 16 hours left?!!! I knoW ITS 80S BUT 500MHZ 1g/S? iS THIS JUNK COMPARED TO A HANTEK OR RIGOL?

as a first scope... yes it is the rigol has far more useful features than any 80's scope (intensity grading, advanced triggering, protocol decode...etc).  and don't forget that 80's digital scope will have few kilo points memory only - modern scopes got several megs of memory.  and as a special bonus the rigol 1000Z has a built in HELP with explanations of various stuff - extremely useful for young players

in short: as of today, the 1054Z is the beginner's "oscilloscope jackpot"

p.s. i'm not related to Rigol in any way... they just nailed it to the cross with the 1000Z series.

[rwgast_lowlevellogicdesin]

Well in case anyone is intrested I bit the bullet and bought the rigol 1054z from Tequipment I noticed it was on sale with thee eevblog discount you cant beet 375 for a 500 dollar scope! And I am truly excited about the help functions!

[rob77]

Well in case anyone is intrested I bit the bullet and bought the rigol 1054z from Tequipment I noticed it was on sale with thee eevblog discount you cant beet 375 for a 500 dollar scope! And I am truly excited about the help functions!

congrats !    now upgrade the firmware (you need to fill in a form on Rigol's website in order to get the firmware upgrade - they'll mail you a link to it) if your firmware is not SP4 already.

and then if you wish (only after your firmware is the latest one)... google for "riglol" to get some free lunch (no, it's not a typo)

[N8AUM]

I agree. You have to start somewhere and 100MHz is enough to begin with. My first oscilloscope was an 20MHz analog one and it served it's purpose well. Back then I couldn't not have dreamed about getting something like a Rigol 1000Z series as a first oscilloscope.
[/quote]

My 1st scope was a late 50`s Heathkit, couldnt measure DC but did the job for troubleshooting radios & TV`s.
I sure miss staying up at night waiting for the test pattern LOL !
What channel is that on now days ?
 

[Fungus]

I agree. You have to start somewhere and 100MHz is enough to begin with.

100MHz? Kids today...

My 1st scope was a late 50`s Heathkit, couldnt measure DC but did the job for troubleshooting radios & TV`s.

I've still got my first 'scope: Single channel, 10MHz bandwidth, tiny green screen.

I found it in a store room clearout when I was at university. They told a couple of us to just throw out everything in the room. Most of it was old ring binders piled up on ancient desks but there, hidden underneath it all, was a Hameg HM307 still in its box.

http://www.hameg.com/downloads/man/HM307_english.pdf      (with schematic!)

(Yes, it still works perfectly)

PS: My focus knob has gone missing. It's not broken, there's still a little plastic post sticking that the knob fits onto. I can turn that OK but it's fiddly and it would be nice to have a proper knob. Does anybody know where I can get one?