How to select an Oscilloscope

hey guys Eddie I'll hold here with kiss analog calm if you're still on the fence about buying an oscilloscope because you're not quite sure about some of the specs or parameters which scope to get well I want to see if I can help to solve or answer some of those questions today so let's jump into this first question you may be thinking do I want an analog scope or are these new fandangled digital scopes the way to go well go with digital you can see I have that's where you go I haven't seen or worked with an analog scope in quite some time I think it worked somewhere on a shelf at some place there I've seen one in the lab pretty nice one back in the day I used to actually own that scope so some people may ask well you still need an analog scope around for certain things right and I say no not anymore okay one time I believe that and one time that was true I had at home two scopes Tektronix 2465 I think has around 300 Meg 350 Meg scope and then I had tech times 24 30 that's a digital storage scope those are pretty sweet scopes back in the day but the 24 30 I didn't totally trust it so back then I didn't you know really understand how to fix the problem with the digital scope today I see how they solved it that's deep memory we're gonna talk about that so I used both scopes use price they're over $3,000 now I want to say it so I won't admit that that was like 20 years ago okay 20 plus years today these new digital scopes for weight less money do way more ok so let's talk about that let's see why it's just given analog scopes a little respect and to explain how Tektronix got such a great name and some of the other scope manufacturers well Tektronix they really helped develop oscilloscopes back in the day as a matter of fact they may have been the ones that develop oscilloscopes at least they're right there in the frontier they were making with CRTs right just like your televisions back in those days cathode ray tubes okay big old long tubes so the Scopes for this deep on your bench because that big old tube and the display was like yay big for a nice one what you know see an electrons blasting up into the tube hitting the phosphor brightening it up and giving your display and what they eventually found out how to do was some of the nice analog scope is they had this persistence thing where they could make the image stay there and then slowly fade away because the great thing about an analog scope is it doesn't miss anything ideally right so signal comes in and like goes to the screen analog and it just is written across the screen and there's no digitizing there's no bits so you you know ideally you're not missing anything thing is is you might be zoomed out like this looking at a whole bunch of waveforms trying to detect that anomaly that spike whatever and and you might see it my glitch every so often so that persistence kind of helped capture that well the digital scopes when they develop that this they have storage that they thought hey that persistence it's kind of cool idea so it's kind of like you know they come histograms writer so you can adjust the very building on the persistence how how long you want to stay on your screen then also you can have color and like this thermal kind of tracking thing this thermal histogram I guess so there might be red where it's away from sitting often may be green where it's not so often so that way you can kind of see you know how the waveform is changing so so anyway analog scopes that was the heyday of analog scope well now with digital scopes no more CRTs all that technology all that art that went into making a great CRT that Tektronix are so good at the art it went into making a great trigger all that stuff has been simplified the triggers today are digitized they're almost perfect I mean these images complex waveforms this is a frequency that's has a low frequency modulation and this scope has no trouble triggering on it without it much work at all every once while you see it glitch but come on these I haven't even tried to set this up it just worked so easily I can move this trigger up and down and look at that just so easy easily captures that so yeah triggers are amazing today all the artwork that witness and analog scopes have been perfected that means forget about analog scopes go with the digital you'll be happy now let's talk about digital once you've gone digital you won't go back right so once you've gone digital how do you go to Joe well you want to pick a bandwidth game back the day because scopes for expensive tubes are expensive they offered scopes from five megahertz on up to you know pretty fast gigahertz just pretty darn fast nowadays you can go 5 gigahertz I don't know how fast they go but I think it worked we have one that goes to 5 gigahertz so pretty dang fast anyway point is is they went all the way down to 5 megahertz to nowadays with the digital scopes I think they start a 50 I don't anything getting slower than 50 so 50s respectable bandwidth I've got 200 here just cuz hey I want to go fast I want your videos I just wanted you know coolness effect oh you know by 200 if you know if that's what you want to do but if you if you want to just buy what you need so you can save your money to buy other things I think 50 meg is probably good for most people I think it's good for me I think it worked fine I had a 40 Meg's scope is my first scope and I don't remember having trouble doing anything or you know not being able to do everything I wanted to do it but and by the way my generator back then on my bench was one or two megahertz bandwidth this one's 10 Meg okay so there's rule of thumb get a bandwidth to the scope that is four times faster or wider bandwidth in the thing you're gonna measure so this is ten megahertz four times out before T Meg so a 50 mega scope could you know see everything that that thing has to offer without changing the you know without any distortion in the output or anything like that so that 4x thing is pretty conservative so I think 2x is just fine so what does that mean just before this scope rolls off and your measurement starts to drop in amplitude the 3 DB point is that is that your corner frequency you say 50 mega or 200 Meg that's where your corner frequency is I think these scopes especially the 50x scopes I have a bet that they go out further than 50 mega before they roll off they want to guarantee the 50 min a probably go out some ways past that anyway 2x the frequency of the roll-off 50 Meg so say 2x at 100 Meg at a hundred mega it'll be 60 B down ok so that means it'll be half the amplitude so if you're reading a 10 volt sine wave a hundred Meg instead of being 10 volt you should probably be reading about flight boats okay so doesn't mean you don't get to see the signal anymore it just means the amplitudes been you know starting to drop off all right so that's the analog bandwidth now the digital bandwidth that's very important with the digital scope is the samples per second how many times its sampling that waveform when it comes in here and it gets converted to to digital from analog to digital how fast does that does I get processed or how many times do you read take a measurement from that and that's the samples how many samples are you taking for that waveform well how many you need Nyquist solve that problem he came up with theorem this says hey if you have two points in a cycle I can but this mathematical formula I can regenerate that that waveform so that's the theory is two points per cycle okay so if you have a 200 mega cope then you want to have two points so that's 400 million samples okay and now this is 1 1 1000 million you know it's a 1 Giga sample well that gets divided down to two channels if I turn it on once I turn it on whether I'm using her or not now the scope is looking at both so it's sampling each side with half of that Giga samples so 500 mega samples 500 mega samples well that is still that's still above the 400 right I think a lot of scope manufacturers are using the 2.5 roll at least so that's where the one gig comes from so you've got at least two point five samples per site okay now if I really want to get all the resolution I possibly can I only need one channel then just turn this off and I get one gig on this guy now if I get the hundred medic I'm still gonna get the one Giga samples because when these guys make these oscilloscopes the firmware all the like you know the board is capable of this one Giga sample they're not gonna make one for each one the GW n stack they will make this 200 megahunter Meg think of 70 Megan at 50 Meg okay and they're all one Giga samples per second hey if you get a 50 Meg's scope you're getting lots of sampling and so your digital bandwidth this is great okay so now you got that covered and most scopes are gonna make sure you know it's one of those things to compare to see how they work if you get say a 50 Meg's scope that has 250 million samples or 500 million samples and you're comparing that to one that says gig one Giga samples well even though it might meet a Nyquist criteria you know the 1 Giga sample sounds better right seems like you might get a better capture with that one so so if that's the trade-off you know it's nice to pay attention these numbers that are important ok so the next important number is deep memory now deep memories the GameChanger no oscilloscopes deep memory there's how many how many of those things can it save so let's say I'm looking at this waveform let's say I'm looking at the ripple of a power supply and these are the spikes the screeching spikes it wouldn't look like this but let's just say it does so then I want to look at lower frequency because I go okay that's what the switching spikes look like but what about my low frequency ripple I want to see what that looks like so I go to this low frequency mode and I go okay now I'm 100 milliseconds per division so this is low frequency and if I saw thing like this I'd go oh okay so I have some low frequency ripple there and I go well I'm wondering what's going on - my switching spikes well with deep memory I can just capture this way for him stop the trigger this this seems captured all that dave is in my memory and then I can go I can zoom in that thing looks just like it did before I zoomed out the bird's eye view and was looking down on on this you know planet I mean that's like having a camera with you know little huts a detail right basically that's deep memory so that's why this digital scope acts like an analog scope go back to that triggering if I see whoa I see a spike there I can set this thing up to trigger on that spike and when it captures it I can scroll over zoom in on it I can go into this mode whoops sorry yeah take out roll mode and then I go to ok it's captured the data I think so now I can switch this and see this little dark area here this wait for it comes for that little spot right there so I can zoom in or zoom out see it's getting wider I don't know if you can see that or I can zoom back in ok so that's a deep memory anyway deep memory very important ok so get out zoom mode that's how you can make when these scopes look like an analog scope now let's say you have a scope at one Meg samples this this scope happens have 10 Meg sampler sorry this one has 14 mega points that's the deep memory 14 Meg ok if you only had 1 Meg you have build cap shot much stuff it kind of digitized it I call it you it almost captures spot here here here it almost looks like a sine wave when you try to zoom in I did a video on the top Kent scopes under $300 they were not deep memory so they're the best scopes I think he can get before he get into the next level which is scopes app deep memory and the number one option I had there you know this is my less my I'm opinion of course but the number one spot had one mega points well that doesn't sound like much compared to 10 but it's not too bad some of the new scopes now being brought out by the big-name companies it cost a lot a whole lot more than even this one they're marketing them by giving them away and they're trying to make a big splash and say hey look at our new low-cost scopes those scopes they they I think they compare closer to those 300 our scopes say the ones one mega points yeah I think that's what they kind of I think that's where they come in one mega points so not deep memory so those 300 make you know the non deep memory digital scopes I would consider those entry-level scopes even though they have amazing you know everything else pounds awesome you just can't do what I was showing you here but you know you can get around that you just have to not go out you can't just go out and look at a whole bunch of data points and you know if you have a whole bunch of cycles like this you just may miss some things okay so that's one thing about those all right well anyway that's important some deep memory okay now the next thing that goes along with that is what's this gold has captured all this memory and it's processed then it's put it on the screen well it's gonna go do it again it's gonna go do it again it doesn't really do it continuously it has to go capture it and do it so that's capture rate and that capture rate is very important these cygnets have crazy fast capturing they're respected a hundred thousand frames per second that's just you know a hundred thousand times a second they're doing that that's just nuts and I'm sure that's in a certain mode that do that but that's just crazy they can even do that a lot of these other scopes I'm not sure if this one is 40 or 80 something like that maybe 60 somewhere around there that is still really good okay now if you think about those old a hand lock scopes and I just think about this putting this video together is they have this beam of electrons that they shoot across the screen you know speed of light mysterious speed of electrons but then they did actually have to and go back and forth right so I'm not sure how long it took to cross maybe maybe the super super faster probably was but still it's kind of the same kind of thing even then in that mode it's it's having to rewrite so it's kind of a capture rate right it's probably super fast I have no idea how fast it did that so let's just go back and just make sure we got it down we got the bandwidth the samples per second the deep memory 10 mega more is what you want this one has 14 it's divided up into two channels seven and seven okay unless I don't have this one on then I get all 14 on this one then then there's a capture rate those those are the parameters that will give you really good confidence that you're capturing your signal I think those are the main critical pieces now the siglent has something that's kind of unique most scopes go down to 1 millivolt per vision these sig lets go down to 500 micro volts per division so they have one extra stop so that's that's kind of interesting and they're all 8-bit you know pretty much all you scopes are 8-bit now there is this old one scope that you know come out that's got 14 bit up to 14 bit it kind of changes the bandwidth and some other things when it goes into those high debt load captures but it does have that capability and what that does is it gives you more resolution in the steps because that's a digital number of steps you can slice your signal into so okay well anyway the main thing was where those other things I was talking about the capture rate and so on and all these other things are kind of niceties kind of coolness things things that can improve the performance under certain things there's a decode where you can read buses you know like I squared C land can you are those kind of things and there they come they're listed is not for the signal but they come standard you know they just give them to you and even the raikou is start to give them throw them into but so anyway there's some there's some other features like that there's multimeters you can get added function generators and even the power supply I think GW in tech you they even offer a power supply option so there's another options you can get so you want to know what your options are where you can upgrade to so that's something to be aware of if you want to upgrade all right now if your site's digital and analog scopes digital scopes are really broken into I think three types of scopes there's the digital scope the basic digital storage scope and some people call that the DSO the digital storage scope oscilloscope and then there's the if I would've got this this add-on this would have given me 16 channels of digital reading this would have turned the scope into essentially a logic analyzer and then it would have been an analog scope plus a digital you know a logic analyzer and then would have sixteen lines across here with clock waveforms or whatever data you know that kind of stuff bunch of digital stuff not really a digital guy but I would add sixteen channels coming across here and it would build I could turn it into a logic analyzer I didn't go for that so if you're interesting maybe possibly upgrading that's something to think about so think about you know what's upgrades okay so the basic DSO they call that a mixed signal oscilloscope so that's a MSO type scope and then there's the EM deal mixed domain this one's an oscilloscope or a spectrum analyzer so that's pretty cool that's way cool for an analogue Ike so that's why I got this scope and this one has four channels so that's the other thing to consider if you want G channels or four channels I I suggest getting four channels I think if you get a 50 Meg for channel scope with deep memory I imagine you finding a wave that wave form that you're like oh shoot I wish I had a 100 mega 200 bag you know I I just think that if you know if you're working to a budget then if you go if you just jumped into that I don't think it's one of those things where you would go a year later down the road going aw shoot you know I wish I would have got you know the better scope because I don't I don't think you'd not ever noticed that you I don't think you'd ever notice that you're being limited by something now you know there's engineers that do have things that they have to deal with and if you're one of those guys you know you who you are and you know what scope you need but for those that don't know you probably don't need it I do power supplies audio stuff and switching power supplies might go to five megahertz the fastest ones I've dealt with and they might have some oscillation serene on the switching edges that might be in the tens of twenty thirty Meg's but I haven't had a problem capturing anything I hopefully this answers a lot of questions you might have had about oscilloscopes okay now the other thing to be aware of when you're looking at the scope of the screen size these are ATM screens a lot of those scopes are have seven inch screens eight inch are pretty big 7-inch seems to be a good a good big size standard that I see on a lot of scopes ranging from four to you know six hundred dollars this scope is around 560 and it has an eight inch but it has two channels but then against 200 Meg and you can get the X - that has four channels for around I think it's just under 500 bucks with a couple of things I want to touch on about the screen as you see this segment I have this bar down here and this bar across here I can't get rid of those like it's just bars that are there the Reiko has the same kind of thing as a bar on this side of bar on this side has menus on both sides has buttons that run down both sides so screen size and how the scope uses the screen I think GW just knocks out the park on things hey guys hey I had a technical difficulty audio went out on my mic and so I am going to summarize what to look for in your next oscilloscope look for the bandwidth I think 50 megahertz will be great I don't think you should worry about you know hey it's the low end I think 50 megahertz would be just great if you can afford it do the hundred or 200 the Giga samples per second compare that with the scopes you're looking at you want to have at least two times two and a half times whatever the frequency is times your channels so one Giga sample is going to be divided by the two so let's say I have two hundred megahertz to challenge that's 400 megahertz and then times two and a half so that gives me 1 Giga sample okay so bandwidth frequency deep memory that's the game changer that's really the big deal guys so look for that 10 mega points or better is deep memory not one mega point one mega points is a really good $300 scope okay so I have a video on that like I said the capture rate capture rate with deep memory scopes I think you're gonna be fine because if you have deep memory they're gonna make sure you have at least enough but just it's a number to compare right and also I think that's a number where depending on which mode you're in and all that kind of stuff people who can claim different numbers but Signet claims 100,000 pretty high number 100,000 frames per second GW in stick I forget what it is right now but I go GW some of the other ones they're like 40 60 80 thousand frames a second I won't be concerned with that but it is a number to compare although I think it's a hard apples to apples comparison actually because I'm not sure what mold they use what mode of operation they used they come up with that so anyway I think deep memory is the game changer and then after all those things oh and FFT let's not forget that one mega points is awesome the Signet X - G Series has it the GW insect has it and I'm gonna do a video on the top best scopes for around $500 I'm gonna try to post that today and those scopes I'll point out which ones but this one here the X has the 16000 16384 I think so what the number is anyway 16000 pretty darn good so that's good some of the other scopes maybe even the same price range they're they're quite a bit lower and the resolution is pretty obvious I think once you get 16,000 that's pretty good 1 million is awesome those are the things you want to compare alright because FFT I'm going to show videos why that's useful how to use it and it and it's just an awesome thing that people don't use like myself because it just hasn't been available in scopes every day until lately now by the way the scopes I use at work there are tens of thousands of dollars I think 17 grand 20 grand are the scopes I'm using and and I don't think you're missing out with these scopes at all not at all so alright after you decide on those things then if you're a digital guy and you're gonna do a lot of digital signal stuff you might want to make sure you have that option okay so make sure that you have upgradeable options or you know buy it when you get the scope so I'll point that on this next video but anyway 16 channels is what I could have got here with the Plus version the x+ that's the MSO mixed-signal digital and like so decide if you need that if you want an MBO mix domain frequency a spectrum analyzer with your so scope this MBO series from GW and stick no one can touch it just that's why I bought one is like those are things to think about if you want a function generator that might be something you might want look at that option there's a Wi-Fi option that might be kind of a nice thing and there's other things like DM you know both multimeter and then a power supply GW in sec offers a power supply well I guess if you want a scope that does everything on your bench so you don't need a lot of instruments then you know so those are the kind of personal things you have choices you have to make and and then usability is it okay that if you have for you know if you have a 4 channel is it okay that if you have the buttons down one side that you have to select what channel you want to move around and control and then have one set of controls for those four channels a lot of these scopes have that these days so I really like this separate controls I like them lined up like this so personal preference this decode option by the way I mentioned that a lot of this scope Sigma it's been giving it away for a long time my goal is starting to give it away Rygel has thing they call advanced triggering so if you see that you go WOW advanced reading but really it's the same as a siglent it's just an option they used to have but but you can compare those things if you want but so now right goes throwing in the vamps triggering the deep memory option which really is a bigger memory actually and the decode option just try and think there's something else to throw it in but they're throwing that stuff in now signal it's been doing it for a while it's trying to think of it anything else I'm missing that one yeah oh the theme about the display it might have already talked about a little bit but the display these are eight inch screens a lot of the scopes are seven inch screens seven inch if you weren't comparing it to this would seem kind of large now the one thing that takes where your screen if you notice this border here in this border here if I put the 7 inch here that's pretty much what I have left over so really if I had a GW with a 7 inch which is gonna be one of the options I'm going to throw out in the subject video it would actually be as big as this 8 inch screen the reason why because I can't get rid of these menu buttons ok on the GW gets sick you know I can get rid of them I can turn on this guy and I can hit this and turns on this menu that I can turn it off turn it off and I can reclaim my screen so the GW n stack actually uses their inches much better than the ribose or the Sigma Sigma it's I think okay because right go has buttons on both sides and they have menu a bar on both sides so that's something just to look at when you're when you're shopping look at the images that they show you because I'll show you a lot of images capturing different things you can see what I'm talking about okay besides the main critical parts you know the deep memory part that's important as far as capturing your signal the screen size all these other things are they're kinda like bonuses on top of what the silicon is meant to do so alright I think I've covered that so hey guys thanks for watching give me a thumbs up if this is useful helpful for you just right down there thumbs up I helps up actually so alright thanks guys thanks for watching

Channel: Kiss Analog

Views: 50,596

Keywords: Rigol, Siglent, OWON, GW Instek, Instek, Rigol oscilloscope, Siglent Oscilloscope, OWON oscilloscope, GW Instek oscilloscope, how to choose an pscilloscope, whats the best oscilloscope, deep memory, first oscilloscope, oscilloscope for bigginner, oscilloscope for biginer, tektronix, keysight, hantek, oscilliscope review

Id: r-NjuDN4oAc

Length: 31min 38sec (1898 seconds)

Published: Sun Mar 24 2019