Congats on the find and hopefully a full repair.
So often another scope is needed to repair another.
Nothing like keeping your eyes open though for the obvious.
Good call to proceed with the purchase of a DSO, you will marvell at their capabilities.
If what I was told about the limited usefulness of the FFT function in these DSOs is true, I must admit that some of my interest has dissipated. However, who knows, maybe the spectrum analyzer aspect is better now....
to me the biggest problem with modern DSO's is the lack of external clock sync and tools to time align with other acquisition tools.....that baffles me beyond any of the other potential "problems" with these tools...
Not sure what scopes you are looking at specifically, but only the very base low end scopes do not provide a 10Mhz ref in (sometimes out as well) and also a trigger output. Using these two connections should be sufficient to synchronize with other test gear.
to me the biggest problem with modern DSO's is the lack of external clock sync and tools to time align with other acquisition tools.....that baffles me beyond any of the other potential "problems" with these tools...
Not sure what scopes you are looking at specifically, but only the very base low end scopes do not provide a 10Mhz ref in (sometimes out as well) and also a trigger output. Using these two connections should be sufficient to synchronize with other test gear.
He might be referring an external sample clock input. I have a couple of old DSOs which support this.
As far as the trigger outputs on modern DSOs, they seem to have a lot of latency and/or jitter compared to older DSOs which use analog triggering.
I know some Yokogawa units have the true clock in (no re-sampling or modification to the input).....would love to know what other units support this feature.
I know some Yokogawa units have the true clock in (no re-sampling or modification to the input).....would love to know what other units support this feature.
From LeCroy at least the WavePro 7000(A) Series and later offer ext. sample clock input as well, although at the moment I'm not sure if this is standard or part of one of the options.
It might be that some of the other LeCroy scopes (i.e. WaveRunner Series) support it as well, but I'd have to check.
I know the labmasters support true sample clock (ext) ref.
BTW I wound up buying that loaded 64MXi....so i will do some testing on it's external input and see if it is time aligned, to sample accuracy.....would be very cool if it is. Looking forward to playing with the new tool and seeing just what it can do.
We had talked about processor upgrades in the other thread. Do you think the same processors will apply to the MXi?
If this unit works out, I might just replace the other scopes with some new LeCroy units. They are very compelling tools. I had used them in the past, and liked them, but never got very deep into what they can really do. Our conversation in the prior threads, has me really curious if they can live up to their claims....esp. the DEVkit and more advanced feature sets....
Maybe so, but my experience with dome switch computer keyboards has been less than stellar. Of course this may be an apples to orange comparison, but I'd still rather see more robust hardware (for a few bucks more, of course).You don't have a choice. All modern test equipment uses the same kind of switches, from the cheapest DSO, to the most expensive exotic comms analysers. Some examples of these switches are a bit better made, but they are all pretty similar. The biggest problem comes when heavy units need to be moved. Its very common for one or two of the switches to take a big enough hit from the mover that you end up with damage - often a switch ripped right out of the membrane sheet. These can be very costly to fix. You can't go to anyone but the original source for a replacement membrane, and they can charge whatever they like. A short time after production stops the supply of suitable spares will dry up. These are the real issues with membrane switches, not general wear and tear.
As for computer keyboards, your view might be distorted. If you have trouble and open up a keyboard you will find it is a membrane type. However, almost all the ones which don't give trouble are also the membrane type. Only a small quantity of specialised keyboards, like those available from pckeyboard.com, are not membrane ones.
If what I was told about the limited usefulness of the FFT function in these DSOs is true, I must admit that some of my interest has dissipated. However, who knows, maybe the spectrum analyzer aspect is better now....
I'm not sure what you were hoping to get from the FFT engines.
There is a pretty simple way to organize the "useful range" of an FFT: your max frequency will be set by your sample rate, your frequency bins will be set by the maximum window. (Rough approximation)
Example: I have my scope set to 100us/div, with 10 divisions width. My sample rate is set to 800ps/pt (1.25GSPS). Fmax will be 1/2 your sample rate (625MHz) and the bin width will be 1/(10*100uS) = 1kHz which will also set the minimum frequency of the window. Processing 1,250,000 points will take a big chunk of time too.
Dynamic range will also be crap. Most of the 8-Bit ADCs might get 6 bits ENOB. Even with all of the other sampling tricks you can pull, you won't have a very good "noise floor" with the FFT.
Call me a curmudgeon, but I'd be more concerned about having a scope that is primarily a scope and not a gimmick box that happened to start life as a scope.
He also described how these modern DSOs implement the FFT spectrum analyzer function (or at least how many of them used to do it). I was blown away when he said most have no calibration for this function -- IOW, no freq scale. He also said they have no means to adjust the freq scale. It sounded like he was describing more of a toy than anything else when it comes to the FFT aspect. He did mention that they get better all the time, so that it's possible that the latest units might have a more worthwhile and useful FFT capability -- but I suppose he wasn't sure of the current state of the art.
The issue here may be that many DSOs do not apply the correction factors needed to produce a calibrated output making them difficult to use in place of a spectrum analyser. This EDN article discusses it:
http://www.edn.com/electronics-blogs/the-practicing-instrumentation-engineer/4427466/DSOs-and-noise-
http://www.edn.com/electronics-blogs/the-practicing-instrumentation-engineer/4427466/2/DSOs-and-noise-
If what I was told about the limited usefulness of the FFT function in these DSOs is true, I must admit that some of my interest has dissipated. However, who knows, maybe the spectrum analyzer aspect is better now....
You get what you pay for. The Rigols all have very poor FFT which only uses a few hundred points, and I'd assume (haven't checked if the figure is out there) that Siglent SDS1000/2000 scopes use similar low numbers which they do because their processing is dog slow.
Really old DSOs often use something around the 10kpts mark which, while being much better than modern day Rigols, is still too little, and scopes like the TDS700 Series (which at that time was their highend model) use somewhere around the 100kpts which is where FFT starts to become actually useful, but since these scopes are really old (close to 20 years) and their processing is very slow as well.
Honestly, if you want good FFT then you should have a look at a LeCroy scope. Even the now roughly 20 yrs old 9300 Series could use up to 6Mpts for FFT (although of course the processing is also slow by today's standard due to their age). But the later scopes (i.e. WaveRunner LT) have much faster processing, and with the EMM or WAVA option use the full available sample memory for FFT. They also show signal phase, which most scopes don't.
A Spectrum Analyzer is of course much better for analyzing the RF spectrum than any scope, but you do pay a lot for that. FFT in a good(!) scope however can often be more than good enough.
Congats on the find and hopefully a full repair.
So often another scope is needed to repair another.
Nothing like keeping your eyes open though for the obvious.
Good call to proceed with the purchase of a DSO, you will marvell at their capabilities.
If what I was told about the limited usefulness of the FFT function in these DSOs is true, I must admit that some of my interest has dissipated. However, who knows, maybe the spectrum analyzer aspect is better now....I think the FFT feature on my old Tek TDS2012 can be useful. It does require a degree of sympathy for its limitations but you can do useful stuff with the FFT feature that is impossible on the analogue 465.
I've used it to look at two tone IMD levels from an RF amplifier or from a receiver/detector demod output and it can be used to look at the frequency response of noise. It's pretty quick when used for all of the above tasks as long as you don't expect too much in the way of precision and you can learn to spot and ignore any unwanted alias terms that creep onscreen. Of course, for some of the above AF based tasks it can be outclassed by a PC soundcard but sometimes it's quicker to just press the FFT button on the scope and make a casual measurement...
I am considering an HDO8000. The extra resolution seems VERY beneficial for the type of work I do.
Thanks for the tips on processor, HDD and potential mistakes I could make. I remember we talked about cloning the drive and hidden volumes. I will try to use shadow protect to do a full image, and then see if I can clone the drive using some of my favorite utilities. So I will look into that Pentium-M and some RAM upgrades (might not really need them?)
I plan on doing full reviews and tear-downs of the unit I got. There is a real lack of information and support on the net. I think it would possibly help some folks to know more about these scopes, and how far ahead of the curve they were/are.
I assume from your experience, there is no SATA on board the MOBO? I have a few tricks to try and remedy that, but need to clone those volumes first. Would hate to turn this scope into a doorstop.....
I am considering an HDO8000. The extra resolution seems VERY beneficial for the type of work I do.
The HDO8k is great, and I guess 8 channels might be a benefit for your work, too.QuoteThanks for the tips on processor, HDD and potential mistakes I could make. I remember we talked about cloning the drive and hidden volumes. I will try to use shadow protect to do a full image, and then see if I can clone the drive using some of my favorite utilities. So I will look into that Pentium-M and some RAM upgrades (might not really need them?)
You don't need them, the scope is fine as it is. It does help if you do a lot of processing, though.
I wouldn't bother cloning the original drive, there's nothing special on it (aside from the calibration data of course). Just save the cal data and you're safe. If required just use a generic Windows XP Pro CD and install from there, and then download software 7.3.0.9 and 7.4.0.9 from the LeCroy site.QuoteI plan on doing full reviews and tear-downs of the unit I got. There is a real lack of information and support on the net. I think it would possibly help some folks to know more about these scopes, and how far ahead of the curve they were/are.
Nice! Just a word of warning, though: the connectors which connect the Front End to the Aquisition Board are really very fragile. They are the only real weak point in these scopes. If you ever find that a channel only shows noise or a very distorted signal, and at the same time the trace jumps back into the middle after turning the vertical offset, then you should check these connectors. When this happens they usually only need resoldering, but in some cases they need replacing.QuoteI assume from your experience, there is no SATA on board the MOBO? I have a few tricks to try and remedy that, but need to clone those volumes first. Would hate to turn this scope into a doorstop.....
No SATA, just IDE. It's also 44pin, which means the cable is 40 conductor (there are no 80 conductor 44pin cables as far as I know) which means the UDMA133 chipset is limited to UDMA33 only. But that isn't much of a problem for a scope.
Cheap Chinese 44pin EIDE to SATA bridges work fine (just be careful with the space), and allow the use of modern 2.5" SATA drives. You could also use one of those SSHDs (hard drive with SSD cache), although I doubt it will bring any noticable benefit (on the other hand, these drives are dirt cheap). Just forget about SSDs in this scope.
CPU, RAM and hard drive are the only alterations I would consider doing on such a scope, though. Don't forget that if you break something LeCroy will fix it, but it probably won't be cheap.
With my limited home shop budget, it sounds like I need to revisit to used market. Thamks for the tips.
Thanks again for all of your insights.
I might not mess with the unit at all. If it works fine, no need =)
I will clone the entire volume as a safety precaution. I did notice LeCroy is still giving limited support on the MXi.
I agree that the SSD isn't going to really show much benefit, across an old bus master. No point, and the potential issue of corruption we had discussed (XP has no garbage collertion/trim and also will try to initiate defragmentation). Those items can all be dealt with and "turned off", but it's hardly worth the hassle, to see no benefit.
I will try and make a few cables here. I if am successful, i would be happy to send you one (token of appreciation for all of your help and effort).
Are the connections in the front surface mount or flying leads? Hope they aren't aging flat flex.
Thanks again for all of your insights.
You're welcome! It's a nice change from the strong Rigol/Siglent/Hantek focus in this forumQuoteI might not mess with the unit at all. If it works fine, no need =)
I will clone the entire volume as a safety precaution. I did notice LeCroy is still giving limited support on the MXi.
The MXi went out of sale in 2009, which means it is still fully supported until 2016. After that there is limited support based on "best effort", which means that some boards might no longer be available as spare part and will be repaired instead.
Realistically I'd expect that you'll be able to get this thing repaired until at least 2020. LeCroy still repairs the 9300 Series, and this went out of sale around 1998.QuoteI agree that the SSD isn't going to really show much benefit, across an old bus master. No point, and the potential issue of corruption we had discussed (XP has no garbage collertion/trim and also will try to initiate defragmentation). Those items can all be dealt with and "turned off", but it's hardly worth the hassle, to see no benefit.
I will try and make a few cables here. I if am successful, i would be happy to send you one (token of appreciation for all of your help and effort).
Thanks for the offer, but I guess shipping is going to kill it.
Just thank me by doing a review of your scopeQuoteAre the connections in the front surface mount or flying leads? Hope they aren't aging flat flex.
The Front End connectors are SMD mounted hard connectors. I guess they could be replaced with some good flex cables should they ever fail, though.
Maybe so, but my experience with dome switch computer keyboards has been less than stellar. Of course this may be an apples to orange comparison, but I'd still rather see more robust hardware (for a few bucks more, of course).You don't have a choice. All modern test equipment uses the same kind of switches, from the cheapest DSO, to the most expensive exotic comms analysers. Some examples of these switches are a bit better made, but they are all pretty similar. The biggest problem comes when heavy units need to be moved. Its very common for one or two of the switches to take a big enough hit from the mover that you end up with damage - often a switch ripped right out of the membrane sheet. These can be very costly to fix. You can't go to anyone but the original source for a replacement membrane, and they can charge whatever they like. A short time after production stops the supply of suitable spares will dry up. These are the real issues with membrane switches, not general wear and tear.
As for computer keyboards, your view might be distorted. If you have trouble and open up a keyboard you will find it is a membrane type. However, almost all the ones which don't give trouble are also the membrane type. Only a small quantity of specialised keyboards, like those available from pckeyboard.com, are not membrane ones.
I use computer keyboards which incorporate great mechanical switches made by Cherry. Beautiful feel, long life, and while more costly than rubber dome style products, they don't break the bank. However if all modern DSOs use the same switch types, of course this falls out of my decision tree. Thanks for the input re this....
With my limited home shop budget, it sounds like I need to revisit to used market. Thamks for the tips.
He also described how these modern DSOs implement the FFT spectrum analyzer function (or at least how many of them used to do it). I was blown away when he said most have no calibration for this function -- IOW, no freq scale. He also said they have no means to adjust the freq scale. It sounded like he was describing more of a toy than anything else when it comes to the FFT aspect. He did mention that they get better all the time, so that it's possible that the latest units might have a more worthwhile and useful FFT capability -- but I suppose he wasn't sure of the current state of the art.
The issue here may be that many DSOs do not apply the correction factors needed to produce a calibrated output making them difficult to use in place of a spectrum analyser. This EDN article discusses it:
http://www.edn.com/electronics-blogs/the-practicing-instrumentation-engineer/4427466/DSOs-and-noise-
http://www.edn.com/electronics-blogs/the-practicing-instrumentation-engineer/4427466/2/DSOs-and-noise-Thanks for this....
He also described how these modern DSOs implement the FFT spectrum analyzer function (or at least how many of them used to do it). I was blown away when he said most have no calibration for this function -- IOW, no freq scale. He also said they have no means to adjust the freq scale. It sounded like he was describing more of a toy than anything else when it comes to the FFT aspect. He did mention that they get better all the time, so that it's possible that the latest units might have a more worthwhile and useful FFT capability -- but I suppose he wasn't sure of the current state of the art.
The issue here may be that many DSOs do not apply the correction factors needed to produce a calibrated output making them difficult to use in place of a spectrum analyser. This EDN article discusses it:
http://www.edn.com/electronics-blogs/the-practicing-instrumentation-engineer/4427466/DSOs-and-noise-
http://www.edn.com/electronics-blogs/the-practicing-instrumentation-engineer/4427466/2/DSOs-and-noise-Thanks for this....This article is referring to measuring noise with a DSO. Is that your application?
A DSO will display FFT peaks calibrated in both frequency and amplitude, and the frequency scale (you mean span & center?) is adjustable. To get the best results you have to select an appropriate sampling speed in the time domain for the signal of interest, and you need to be cognizant of FFT aliasing issues.
What does he mean by it's "not calibrated"?
I know the labmasters support true sample clock (ext) ref.
Indeed. If I come around I can check my 64Xi and LT264M tonight.
Update: Checked my LT264M, and as expected even this old scope offers external sample clock input (TTL, ECL and 0V, 50ohms or 1Mohms switchable).
I was told that the freq span in FFT mode would always effectively be equal to the bandwidth of the scope. So in my case, the span would be 100 MHz -- not very useful if I'm looking for the harmonic content of some audio device. Furthermore, I heard that the spectrum display is not calibrated either in freq or in amplitude. Sounds like this may not have been completely accurate -- but close?
LeCroy scopes easily outclass Agilent, in terms of triggers and operators.
LeCroy scopes easily outclass Agilent, in terms of triggers and operators.Statements like that are just fan boy garbage. LeCroy supply a variety of scopes sourced from different places, each with the qualities the developing company gave it. A generic statement about the qualities of LeCroy scopes is meaningless.
LeCroy scopes easily outclass Agilent, in terms of triggers and operators.Statements like that are just fan boy garbage. LeCroy supply a variety of scopes sourced from different places, each with the qualities the developing company gave it. A generic statement about the qualities of LeCroy scopes is meaningless.