Hi everyone!
I’m looking into getting a basic oscilloscope. I’ve been using the Siglent SDS2304X at work and its great but I’m heading back to school to finish of my studies and think it would be overkill for my private/school use.
I’ll be using the scope for debugging low speed analog signals and digital protocols/ communication.
I need a 4-channel scope mostly when debugging protocols and mainly never use more than 2-channels for just analog use.
If I ever need more digital channels (Witch is rare) then I’ll just my knockoff Salea logic analyzer.
As for the DS1054Z vs the SDS1104X-E, I have them both. They both work fine, especially at their price points, but neither is perfect.
The only quirk I worry about is that the Rigol has some issues about what it is actually displaying and how it is interpolating that I don't understand--this has been discussed elsewhere.
I don't own 1054Z, but I recall someone on the forum saying that he has been using 1054Z in his work, and he doesn't like it, because display is sluggish.
a) "Display is sluggish" is a lie, the display is just fine.
b) It's true that the vertical position control (and only the vertical position control) is a bit sluggish but in daily use it turns out to be a superficial, "First world" problem that doesn't affect work at all.
As for the DS1054Z vs the SDS1104X-E, I have them both. They both work fine, especially at their price points, but neither is perfect.
This.
Dismiss any idea that the Siglent is "perfect", it has issues too.The only quirk I worry about is that the Rigol has some issues about what it is actually displaying and how it is interpolating that I don't understand--this has been discussed elsewhere.
It's not difficult to understand it's just that the Rigol-hater-club that inhabits this forum tries to exaggerate it beyond all reason and the details get lost.
Some oscilloscopes have the option to turn off sin(x)/x signal reconstruction. Not all of them do (most expensive ones don't!) because it makes no sense to do so. It's a fundamental part of signal reconstruction and drawing the wiggly lines on screen.
The Rigol does have it but it only appears when you turn on more than two channels enabled and it's sampling at 250Mhz. It's greyed out at all other times because the sample rate isn't anywhere near the Nyquist limit so sin(x)/x is the correct thing to do.
What the Rigol-hater club discovered is that when you turn sin(x)/x "Off", it doesn't really turn off. Instead it changes to a "Rigol interpolation".
We don't know the exact math of this interpolation, hence the FUD. The only 'issue' is that it's not what the OCD types think "sin(x)/x turned off" ought to be.
(note: Nowhere is it written what "sin(x)/x turned off" should be, it's undefined, it's an error condition...)
OTOH we can see that Rigols' mystery interpolation reduces the Gibbs Phenomenon when you're on the limit, ie. it's better than sin(x)/x when you're on the Nyquist limit.
The whole point of wanting to eliminate interpolation is that sometimes you want to see the raw data that the scope is receiving so you have a better idea of what it actually knows and what it is 'reconstructing'.
This is very important because the reconstruction theory depends on certain conditions being met--bandwidth limitations and so on--and sometimes there isn't an actual guarantee that they ARE met.
The whole point of wanting to eliminate interpolation is that sometimes you want to see the raw data that the scope is receiving so you have a better idea of what it actually knows and what it is 'reconstructing'.
I'm not sure how looking at dots tells you anything though. It's like looking at the pixels in a zoomed image and telling me you know the detail in between them.
The correct thing to do would be turn off other channels and get 500MHz or 1GHz sample rate on the channel you're interested in. That way you move away from the Nyquist limit and see the true signal.This is very important because the reconstruction theory depends on certain conditions being met--bandwidth limitations and so on--and sometimes there isn't an actual guarantee that they ARE met.
It's perfectly possible that they aren't being met on a Rigol DS100Z. It has about 130MHz bandwidth and the sample rate drops to 250MHz when you turn all channels on.
The Siglent SDS1204 has the exact same problem, it has about 280Mhz measured bandwidth and sample rate can drop to 500Mhz with all channels on - not enough to garantee the conditions required by signal theory.
To beat this you have to go up in price, eg. The Rigol MSO5000 has 350MHz bandwidth and at least 2GHz sample rate per channel. It's never going to get anywhere close to Nyquist with that ratio.
If you have only 339€+VAT, go for the DS1054Z. If you have 429€+VAT, go for the SDS1104X-E.
It's that simple!
I'm not referring to the sampling/bandwidth issue directly, I'm referring to interpolation sometimes being implausible. How do I know what is between the dots? I don't--and this is my point. I want to see the samples displayed directly with no interpolation or interpretation so that I understand what information the scope is working with.
The OP implied his budget was up to around $500.
I'm not referring to the sampling/bandwidth issue directly, I'm referring to interpolation sometimes being implausible. How do I know what is between the dots? I don't--and this is my point. I want to see the samples displayed directly with no interpolation or interpretation so that I understand what information the scope is working with.
My points were:
a) Looking at the dots doesn't tell you anything. If you disagree then feel free to start a thread with screenshots and explanations. I'm sure a lot of signal theorists will be interested in techniques to reconstruct information above the sample rate.
And ... much more importantly:
b) The only correct thing to do is to turn off a channel or two to get a higher sample rate on the channel of interest.
nb. When you do this the Rigol DS1054Z will disable the option to turn off sin(x)/x, which indirectly proves the point being made.
I'm not referring to deselecting sin(x)/x at lower sampling rates. I'm talking about one channel, 1GSa/s and selecting 'DOTS' instead of 'VECTOR'. If it did what I expected, the dots would actually tell me a lot--not about additional magically interpolated information, but rather about how much information I actually had and how accurate it is.
Anyway, we've hijacked a thread over something that has been hashed to death elsewhere. The 1054Z would be fine choice for the OP--unless he has more 'additional information' for us.
I’m looking into getting a basic oscilloscope[...]
I’ve been using the Siglent SDS2304X[...]I’m heading back to school to finish of my studies and think it would be overkill for my private/school use.[...]
I’ll be using the scope for debugging low speed analog signals and digital protocols/ communication.[...]
I need a 4-channel scope[...]
[...]and it seems like the Rigol DS1054Z + unlock is the cheapest and best option.
Got any other recommendations or is this still the way to go for budget oscilloscopes.
No other recommendation from me, I would too get the DS1054Z with this recommendations.