Products > Test Equipment
Help me choosing new Oscilloscope
tautech:
smallfreak, you presume SDS1074X HD will come to the west when I'm reasonably sure it won't.
Here where I think out loud:
https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/msg4789955/#msg4789955
I've compared pricing against the US website SDS2352X-E which in Euro is 729 way less than your 900 Euro.
Certainly your pairing with a SDG1032X is the way to go and it's good to see a prospective buyer knowing the significant benefits of a 2ch standalone AWG vs an inbuilt or USB power module. :clap:
However something many overlook is SAG1021I is an isolated output AWG and while having basic specs isolation OTOH can be very useful in many applications.
Soon is soon in my book and I can't reveal the intended 1kX HD release date although it's around mid year. :-X
smallfreak:
--- Quote from: tautech on April 08, 2023, 10:45:10 am ---smallfreak, you presume SDS1074X HD will come to the west when I'm reasonably sure it won't.
...
I've compared pricing against the US website SDS2352X-E which in Euro is 729 way less than your 900 Euro.
--- End quote ---
If it's going to get cheaper, I see no problem :-)
If the lowest Euro model turns out to be the "SDS1104X HD between $849 and 999", then it's essentially the same calculation. I just would start at a higher base bandwidth. Reading the discussions, the hardware is assumed to be identical and "software upgradable options" are still the same. So in the end I glimpse at the minimum specs for financing and the maximum specs for usability.
Mid year could pose a problem with the insurance, as they might want close the case when I miss to claim my bill in time. I will talk with the agent after Easter Holidays. Eventually this helps decide between "higher maximum bandwidth" and "higher maximum resolution".
--- Quote from: tautech on April 08, 2023, 10:45:10 am ---However something many overlook is SAG1021I is an isolated output AWG and while having basic specs isolation OTOH can be very useful in many applications.
--- End quote ---
Good point. I did miss this. I learned about the advantages of isolated equipment some 40 years ago, when I stuck my soldering iron into the wrong place in a running TV, I was going to repair. It did survive and in the end I could fix the problem (thanks to my very first and very basic scope), but I had to take a break to get my hands calm again and the board had a bad scar. :palm:
Teenagers tend to do silly things at times.
Performa01:
--- Quote from: smallfreak on April 08, 2023, 10:21:28 am ---The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
--- End quote ---
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only. The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.
An ideal acquisition system with ideal AA (anti-aliasing) filter at the input and sin(x)/x (reconstruction) filter at the output would require barely more than twice the input bandwidth as the sample rate. Anything less would not work anymore, but also anything more would be just redundant data, using up additional sample memory without any benefit.
Of course, the (digital) reconstruction filter can only be near ideal because of the limited time interval it is processing. But in practice, we get quite decent reconstruction results with sample rates about 2.5 times the highest frequency component of the input signal.
Up to now, 1 GSa/s would be the correct sample rate for a 350 MHz bandwidth DSO. Anything above that is just a waste of memory.
Unfortunately, we cannot have a strict bandwidth limit in our scope frontends; effective AA-filters aren't going to happen for a number of reasons. Everything we can get in the real world, which does not distort the input signal in an unacceptable way, is fairly ineffective – especially close to the corner frequency.
That means, that a high amount of oversampling gives us the opportunity to apply a benign (e.g. Bessel) AA-filter, which is totally ineffective in the proximity of its corner frequency, but will be sufficiently effective at an adequate distance, hence at the Nyquist frequency of a heavily oversampled signal. On top of that, we can use digital filtering to support the suppression of aliased signals appearing in the region between analog input bandwidth and Nyquist. All in all, we simply trade aliasing protection for memory.
--- Quote from: smallfreak on April 08, 2023, 10:21:28 am ---So far the upcoming SDS1000 HD paired with an SDG1032X instead of the "standard" SAG1021I option seems to be a great package for everything up to 200MHz, if the hidden features can get unlocked cheaply. ::)
--- End quote ---
Absolutely.
If you ever want a MSO and think about getting this by adding the SLA1016, then you should be aware that this isn't a great solution. It still remains some separate piece of hardware, attached to the scope via a data link with limited speed. The integrated digital channels of the SDS2000X Plus and any higher series are considerably better.
tggzzz:
--- Quote from: Performa01 on April 09, 2023, 10:39:52 am ---
--- Quote from: smallfreak on April 08, 2023, 10:21:28 am ---The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
--- End quote ---
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.
--- End quote ---
Yes.
--- Quote ---The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.
--- End quote ---
No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].
I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.
Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.
Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).
[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?
2N3055:
--- Quote from: tggzzz on April 09, 2023, 01:17:36 pm ---
--- Quote from: Performa01 on April 09, 2023, 10:39:52 am ---
--- Quote from: smallfreak on April 08, 2023, 10:21:28 am ---The MSO5074 is at the same price level, excelling only in the proposed 8G sampling that might have a marginal advantage at the max 350MHz on a single channel.
--- End quote ---
This is not correct. Signal detail at higher frequencies depends on the input bandwidth, nothing else. So it is a frontend feature only.
--- End quote ---
Yes.
--- Quote ---The sample rate on the other hand has to be twice the max. input frequency in order to satisfy Nyquist.
--- End quote ---
No. Or rather the sample rate has to be at least twice the bandwidth of the signal to satisfy Nyquist[1].
I have a 1972 portable scope (which can be stored underwater!) which takes one sample every 75µs (i.e. 13kS/s), and has a bandwidth of >5GHz; it measures risetimes of <0.14ns.
Back in the 80s I used a top-of-the-range HP 1GHz scope, which sampled at 25MS/s.
Nowadays you can see that principle in action in various scopes with modes called various things like Equivalent Time Sampling, and in the mixer of every SDR dongle (multiGHz inputs sampled at ~10MS/s).
[1] Standard interview question... You have an audio signal transmitted on a 10MHz carrier. What is the minimum sampling rate you can use?
--- End quote ---
Again with that.
Nobody cares for repetitive sampling scopes. We are talking about real time samplings scopes.
And you are wrong: repetitive sampling scopes EFFECTIVE sample rate is defined by 1/t of sampling aperture time and fine resolution timing of taking sample in regards to trigger timing.
Fact that it takes samples sparsely is of no influence to Nyquist.
Real time sampling is same: effective sampling rate is based on effective sampling aperture length, but we can (because technology allows it) take every single sample consecutively in real time. Instead of doing it from thousands of separate trigger events like with repetitively sampling scopes. .
There is a reason nobody cares about repetitive sampling scopes anymore (outside special applications). They are useless for any signal that is not strictly repetitive and autocorrelated..
On your interview question, answer is more than 20 something MS/s. Because you didn't specify you want to down convert RF and extract audio you need to satisfy Nyquist to grab full data...
We are talking about oscilloscopes here, not radio receivers or software radio.... Stop confusing people with ortogonal information...
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