Phase correlation doesn’t care about where the location is. The input parameter can be as wide as the image itself, so you could create a either a narrow pattern or a wider pattern with harmonics. The down side of the wide pattern is constant however that same system allows deconvolution (discovery of fundamentals) plus could (inversely) also detect odd behaviour.
If the signals drift then it depends if it’s a constant vector, a cycle pattern or random distribution. The first two are relatively straight forward but a random perhaps searching for a Gaussian distribution (make a Gaussian input then correlate on the result of the initial search) is a little more difficult. Assuming constant linear signals (and phase shift as a linear function).
Non linear - that’s where it becomes complex. You can use the signal over time and search for patterns but I suspect there’s ideas and concepts that can be applied from radar and machine learning.
I forgot to say - the phase correlation is highly resistant to noise.
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Nice
In a digital context you can even hunt for known injected signals (of sweep even), correlate to create a distortion map and then supplement by simply multiplying in too. A rough calibration.
I used the stars in the CCD image as point spread functions, detect the distortion of the lense and also the distortion of the earths atmosphere (small angle of the sky which helps).
A further technique would be super resolution. If you shifted the signal both in voltage level and time base over the ADC, then use the correlation to align the samples interpolated on a 10:1 up sampled grid, you can retrieve data from the signal thus increasing resolution. I use this for detecting objects that my scope and camera could not normally see.
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Be careful of exaggerated claims for scopes bandwidth wise.
Take max samples/second and divide by 20 to 30 to get real bandwidth.
It takes about 25 samples to get a half decent picture on the screen.
Some claim 2 dots is enough ! which is rubbish.
It can maybe extrapolated into a sine but is pretty useless.
Take max samples/second and divide by 20 to 30 to get real bandwidth.
It takes about 25 samples to get a half decent picture on the screen.
Some claim 2 dots is enough ! which is rubbish.
It can maybe extrapolated into a sine but is pretty useless.
10:1 based on previous measurement experience (ie arc second rotation for telescopes). Think three 10p (cent) side by side at over a km away precision and repeatable pointing/tracking accuracy.
I know that 5x is a minimum and for a 24MHz square wave signal. that you're going to need quite a bit of BW. From the reviews and testing the 1104X-E bandwidth is at least 250MHz+. In terms of samples - 1GS/s that's 250MS/sec for a 1:4 so for a 24MHz wave that's ~10 per wave which is good enough, however also the question is - how does the ADC see a dB attenuation at a higher frequency? 8Bit means you're going to quickly find resolution problems between a 0dB signal and an attenuated higher frequency signal when the frontend amp starts being non-linear.
Some of the cheaper '100Mhz' measure way lower. Always best to see at least three reviews where the bandwidth is measured to exhaustion.
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Having made do with an ex university Tektronix 502a with 2 no. differential inputs for 30 years, (and only 1MHz bandwidth!) which in the time honoured fashion had a control for every parameter,
I recently treated myself to a popular Rigol 4 channel digital scope.
On one side the new one uses less power, takes up much less space, makes less noise and is portable (not trolley bound) but I don’t like it. Sure it has better bandwidth and I am beginning to appreciate the one button auto function, but I don’t like the general usability what with all of the twist and press controls that somehow jog on to the next setting requiring you to repeat the action and button presses which lead to sub menus and more button presses, argh!
I am currently on the look out for a nice example of a late tektronix analogue scope, 100 or 60MHz or a Japanese scope of similar era and spec. I have fond memories of our firms’ lab scopes of this type, easy to operate, good quality with a sharp trace. I recall a really nice mains/battery operated Hitachi 20MHz model too, not the last word in sophistication,but nice to use and really handy.
A case of Rose tinted glasses? perhaps and maybe it’s because that’s what ‘I grew up with’ but sometimes you just click with a particular instrument.
I recently treated myself to a popular Rigol 4 channel digital scope.
On one side the new one uses less power, takes up much less space, makes less noise and is portable (not trolley bound) but I don’t like it. Sure it has better bandwidth and I am beginning to appreciate the one button auto function, but I don’t like the general usability what with all of the twist and press controls that somehow jog on to the next setting requiring you to repeat the action and button presses which lead to sub menus and more button presses, argh!
I am currently on the look out for a nice example of a late tektronix analogue scope, 100 or 60MHz or a Japanese scope of similar era and spec. I have fond memories of our firms’ lab scopes of this type, easy to operate, good quality with a sharp trace. I recall a really nice mains/battery operated Hitachi 20MHz model too, not the last word in sophistication,but nice to use and really handy.
A case of Rose tinted glasses? perhaps and maybe it’s because that’s what ‘I grew up with’ but sometimes you just click with a particular instrument.
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Bumping up this thread again instead of starting another.
Short version, looing to buy my first Oscope. Will used for some Pass diy 2 projects predominantly. Should only need 2 channels and stay with the audio frequency range. Trying to keep the budget at or below $500.
I've read just about every thread in the last couple of years on this topic. I'm about to make the plunge and order a Siglent SDS1104X-E. Any reason to do otherwise? About the only thing I've considered is the Keysight EDUX1052A but I believe the consensus seems to that unless you are willing go much further up the Keysight line the Siglent is a better option at this price point.
Short version, looing to buy my first Oscope. Will used for some Pass diy 2 projects predominantly. Should only need 2 channels and stay with the audio frequency range. Trying to keep the budget at or below $500.
I've read just about every thread in the last couple of years on this topic. I'm about to make the plunge and order a Siglent SDS1104X-E. Any reason to do otherwise? About the only thing I've considered is the Keysight EDUX1052A but I believe the consensus seems to that unless you are willing go much further up the Keysight line the Siglent is a better option at this price point.
if you just need a nice, inexpensive, old fashioned analog scope for basic audio, you'd be hard pressed to do better than a Hitachi V-665A in good condition. Because of all the low priced digitals being sold, you can probably find these for <$100.
i'm speaking from experience - i purchased a new one in the 1980s as my first scope, it's still going strong and continues to earn it's place on my bench alongside some fancier ($$) products. at some point, i'll hand it off to my grandson (if I don't croak first
)mlloyd1
Hi,
I certainly wouldn´t go for the entrylevel Keysight stuff, neither Oszi nor other stuff.
First, the B-Brands offer more for Your money. A 1104X-E is imho clearly superior to the EDUx in almost every aspect.
Over at the eevblog You can find an increasing number of threads dealing with buggy-up-to-almost-unuseable KS devices. Now all digital measurement devices seem to enter the market with more or less buggy firmware and the company with a good record of updating the firmware would be my favorite.
But secondly KS recently anounced that they won´t offer service to consumer buyers any more, but just professionals (however a ´professional´ may look like in their eyes). They changed their business model to ´We happily sell You our buggy stuff, but then f****off, or open up a business and buy expensive Keysight Care service options´.
jauu
Calvin
I certainly wouldn´t go for the entrylevel Keysight stuff, neither Oszi nor other stuff.
First, the B-Brands offer more for Your money. A 1104X-E is imho clearly superior to the EDUx in almost every aspect.
Over at the eevblog You can find an increasing number of threads dealing with buggy-up-to-almost-unuseable KS devices. Now all digital measurement devices seem to enter the market with more or less buggy firmware and the company with a good record of updating the firmware would be my favorite.
But secondly KS recently anounced that they won´t offer service to consumer buyers any more, but just professionals (however a ´professional´ may look like in their eyes). They changed their business model to ´We happily sell You our buggy stuff, but then f****off, or open up a business and buy expensive Keysight Care service options´.
jauu
Calvin
I don't think you'll go far wrong with the 1104X-E.
Digital scopes may not last as long as an analogue but like all digital, the speed at which the market moves results in improvements at a faster rate. Good for businesses but for the DIYer perhaps less so as a business model.
I'm happy with the 1104X-E overall. Even with the 8bit limitations. Scopes like the Discovery 3000 (with inbuilt AWG and running 14bit with lower MSPS) are starting to push up in the audio market but at 2x the cost for a 4 channel model, it's still expensive. The software provides a massive amount of options but that's what you'd expect for a 50MHz 14bit scope + 14bit AWG weighing in at $1200 and still needing a PC with grunt plus a screen.
Signal Path does a great teardown and review (if you've not seen this guy - this is one YouTuber that knows his stuff):
When my Philips analogue scope annoyed me enough becaue of the failing power supply (common), I bought a Tektronix digital scope.
* It survived only a few weeks: the input range is 35 volt, so with a 1:10 probe they supply, it can handle 350V. Of course I once in a while did not use 1:10 and maybe that was the reason so the scope died. It got all kinds strange screens, moire effects. Luckily Farnell gave me the money back.
I now bought a refurbished analog Tektronix drom 1970: there is still a factory repairman here in Holland who does that - sort of as a hobby.
* It survived only a few weeks: the input range is 35 volt, so with a 1:10 probe they supply, it can handle 350V. Of course I once in a while did not use 1:10 and maybe that was the reason so the scope died. It got all kinds strange screens, moire effects. Luckily Farnell gave me the money back.
I now bought a refurbished analog Tektronix drom 1970: there is still a factory repairman here in Holland who does that - sort of as a hobby.
In my opinion, it depends on the application. Do you mostly view analogue or digital signals?
An analogue CRT is a better choice for viewing small signals, as the low-end digital ones have visible quantisation noise from the 8-bit ADCs that they use. Unfortunately, there are very few people who repair CRT scopes, in the event of damage. The electricity consumption is also higher due to the tube display.
I suggest that you get a refurbished analogue scope for small money if you're a hobbyist. However, if you happen to be a company / professional, get a 12-bit digital scope from Agilent / Tek / Lecroy etc. Some of these also come with active probes and fully differential inputs, CAT-III rating etc.
Lastly, I would not recommend feeding test signals into the soundcards etc. that are designed only for small, band-limited inputs.
An analogue CRT is a better choice for viewing small signals, as the low-end digital ones have visible quantisation noise from the 8-bit ADCs that they use. Unfortunately, there are very few people who repair CRT scopes, in the event of damage. The electricity consumption is also higher due to the tube display.
I suggest that you get a refurbished analogue scope for small money if you're a hobbyist. However, if you happen to be a company / professional, get a 12-bit digital scope from Agilent / Tek / Lecroy etc. Some of these also come with active probes and fully differential inputs, CAT-III rating etc.
Lastly, I would not recommend feeding test signals into the soundcards etc. that are designed only for small, band-limited inputs.
Exactly what I had read here, too bad KS has gone down that road. The amount of electronical projects that novices/amateurs are doing at their homes continues to increase daily. Seems like an odd time to alienate a customer base.
I suspect products like the Discovery are the future. If they added in distortion analysis you have a nice product package and how many of use don't have a computer sitting next to use as we are working on projects. Not to mention the ease to update products like that via software.
I think you are both correct, for my purposes a nice rehab 2ch analogue scope would be great. The issue for me is the logistics of finding one. I don't live near a large city where there is likely a brick and mortar store. Does anyone have a suggested online site you trust or ebay dealer that you would trust? The draw to the new digital scopes is a warranty and return policies if purchased from a reputable dealer if something goes wrong.
That's interesting. I visited the Keysight website but didn't see an announcement like this. Can you provide a link or a reference?
Hi,
it is afaik in their 'terms and conditions for sale'. You may visit the eevblog ... there's an active thread 'Keysight officially lost the plot...' in the Test Equipment section about this theme providing exactly which paragraph.
There are also posts and other threads from actual 'victims' of this new politics.
jauu
Calvin
it is afaik in their 'terms and conditions for sale'. You may visit the eevblog ... there's an active thread 'Keysight officially lost the plot...' in the Test Equipment section about this theme providing exactly which paragraph.
There are also posts and other threads from actual 'victims' of this new politics.
jauu
Calvin
Thanks, Calvin. The reason I asked is that I was considering buying the EDUX1052G model (with built-in Bode plot capability). A technician friend of mine (who owns an electronics repair shop) has a higher-end DSOX model with this Bode plot function and he really likes it. But he would qualify as a "professional" so this new Keysight service policy would not affect him.
I'll check out the other forums. Thanks again for the information.
I'll check out the other forums. Thanks again for the information.
Buying these online can be tricky, especially if they're used ones. I think it's best to try finding out where the local polytechnics and colleges beside you get theirs from and follow the leads. That way you would also find out where servicing is carried out, if something goes wrong later on.