A good digital oscilloscope?
in [Design]
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From: Joerg on 9 Dec 2009 20:12 Jamie wrote: > Joerg wrote: > >> krw wrote: >> >>> On Tue, 08 Dec 2009 14:36:53 -0500, Spehro Pefhany >>> <speffSNIP(a)interlogDOTyou.knowwhat> wrote: >>> >>>> On Tue, 08 Dec 2009 10:28:27 -0800, John Larkin >>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>> On Mon, 7 Dec 2009 22:21:43 -0600, "Tim Williams" >>>>> <tmoranwms(a)charter.net> wrote: >>>>> >>>>>> "Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote >>>>>> in message news:oFhTm.36236$kY2.31856(a)newsfe01.iad... >>>>>> >>>>>>> My Tek 485 serves me well. I do have a small assortment of >>>>>>> digital scopes for portable use to gather basic data and road >>>>>>> trip testing how ever, I find that my 485 still gives me nice >>>>>>> results at the bench as long as I don't need live digital storage. >>>>>>> It's the only scope I have that I can take full advantage of my >>>>>>> active >>>>>>> Fet probes when I need them. >>>>>> >>>>>> 486 is on my Wish List. And 2465. Yessss, my preciousss.... >>>>>> >>>>>> >>>>>> Tim >>>>> >>>>> I love our TPS2024. 200 MHz, and all four channels and the trigger >>>>> input are fully floating. Wanna clip the probe ground lead onto the >>>>> source of a fet that's flailing 400 volts off ground? No problem. >>>>> >>>>> John >>>> >>>> Shame about that antediluvian CF card slot that can't write to even a >>>> 2G card. 8-( >>> >>> >>> Beats waiting 3 minutes to write to floppy. >>> >> >> >> But wouldn't you think a scope of this day and age would come with a >> USB stick slot? I mean, it's been years now ... >> >> Mine did :-) >> > And to add to that, my recently acquired DDS function generator (Rigal > DG1022) does have a USB host on it. > Hell, even their low end Rigal scope has a USB host on it..(DS1052E) > > http://www.tequipment.net/RigolDS1052E.html > > Check those out.. > > Makes a greate xmas gift for that starter ;-) > Pretty announcer on there, too :-) But wait, $600 for a Christmas gift? Ain't that a bit over the top? As a kid I had to work for stuff like that. For example at a meat factory until I had the $400 for my first used and pretty banged up HW100 transceiver. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jamie on 9 Dec 2009 21:47 Joerg wrote: > Jamie wrote: > >> Joerg wrote: >> >>> krw wrote: >>> >>>> On Tue, 08 Dec 2009 14:36:53 -0500, Spehro Pefhany >>>> <speffSNIP(a)interlogDOTyou.knowwhat> wrote: >>>> >>>>> On Tue, 08 Dec 2009 10:28:27 -0800, John Larkin >>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>> On Mon, 7 Dec 2009 22:21:43 -0600, "Tim Williams" >>>>>> <tmoranwms(a)charter.net> wrote: >>>>>> >>>>>>> "Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote >>>>>>> in message news:oFhTm.36236$kY2.31856(a)newsfe01.iad... >>>>>>> >>>>>>>> My Tek 485 serves me well. I do have a small assortment of >>>>>>>> digital scopes for portable use to gather basic data and road >>>>>>>> trip testing how ever, I find that my 485 still gives me nice >>>>>>>> results at the bench as long as I don't need live digital storage. >>>>>>>> It's the only scope I have that I can take full advantage of >>>>>>>> my active >>>>>>>> Fet probes when I need them. >>>>>>> >>>>>>> >>>>>>> 486 is on my Wish List. And 2465. Yessss, my preciousss.... >>>>>>> >>>>>>> >>>>>>> Tim >>>>>> >>>>>> >>>>>> I love our TPS2024. 200 MHz, and all four channels and the trigger >>>>>> input are fully floating. Wanna clip the probe ground lead onto the >>>>>> source of a fet that's flailing 400 volts off ground? No problem. >>>>>> >>>>>> John >>>>> >>>>> >>>>> Shame about that antediluvian CF card slot that can't write to even a >>>>> 2G card. 8-( >>>> >>>> >>>> >>>> Beats waiting 3 minutes to write to floppy. >>>> >>> >>> >>> >>> But wouldn't you think a scope of this day and age would come with a >>> USB stick slot? I mean, it's been years now ... >>> >>> Mine did :-) >>> >> And to add to that, my recently acquired DDS function generator (Rigal >> DG1022) does have a USB host on it. >> Hell, even their low end Rigal scope has a USB host on it..(DS1052E) >> >> http://www.tequipment.net/RigolDS1052E.html >> >> Check those out.. >> >> Makes a greate xmas gift for that starter ;-) >> > > Pretty announcer on there, too :-) > > But wait, $600 for a Christmas gift? Ain't that a bit over the top? As a > kid I had to work for stuff like that. For example at a meat factory > until I had the $400 for my first used and pretty banged up HW100 > transceiver. > Today's kid standard, $600 is nothing! anything less, they throw it back at ya! I supported my 2 sons while they were in technical college. Between the toys and "I must have this" wasn't cheap! After they graduated, a lot of it never came home. Strangely got lost some where or, it was beat up and most likely not working properly any more.. And for what it's worth, neither one of them ended up in careers using that knowledge. The oldest still lives with me, soon to be 28 doing a job totally unrelated with no ambition to upgrade!. Sort of sounds like the new age of Obama is already in my home!
From: Joerg on 9 Dec 2009 21:59 Jamie wrote: > Joerg wrote: > >> Jamie wrote: >> [...] >>> http://www.tequipment.net/RigolDS1052E.html >>> >>> Check those out.. >>> >>> Makes a greate xmas gift for that starter ;-) >>> >> >> Pretty announcer on there, too :-) >> >> But wait, $600 for a Christmas gift? Ain't that a bit over the top? As >> a kid I had to work for stuff like that. For example at a meat factory >> until I had the $400 for my first used and pretty banged up HW100 >> transceiver. >> > Today's kid standard, $600 is nothing! anything less, they throw it > back at ya! > Sad. We don't have kids but if we did I'd teach them frugality. Just like my parents did with me. Have it all - get it all, that can easily lead them into a life beyond their means. Or in plain American, credit card debt. Yeah, many of my classmates had those cool Bonanza chopper bicycles and I didn't. But I didn't die from not having one :-) > I supported my 2 sons while they were in technical college. Between > the toys and "I must have this" wasn't cheap! > A friend/client has this license plate frame: My daughters and my money go to the University of ... > After they graduated, a lot of it never came home. Strangely got lost > some where or, it was beat up and most likely not working properly any > more.. > > And for what it's worth, neither one of them ended up in careers using > that knowledge. The oldest still lives with me, soon to be 28 doing a > job totally unrelated with no ambition to upgrade!. > But they may still have learned something valuable from it. > > Sort of sounds like the new age of Obama is already in my home! > Kids moving back in with their folks is almost normal these days. Every other neighbor has them, and usually two or even more. I'll never really understand that. I love my parents but couldn't imagine living with them now (unless they needed that for medical or old age reasons). -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: George Herold on 10 Dec 2009 09:58 On Dec 8, 3:29 pm, qrk <SpamT...(a)spam.net> wrote: > On Tue, 8 Dec 2009 06:11:02 -0800 (PST), George Herold > > > > > > <ggher...(a)gmail.com> wrote: > >On Dec 7, 2:56 pm, qrk <SpamT...(a)spam.net> wrote: > >> On Sun, 06 Dec 2009 20:29:24 -0800, John Larkin > > >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > >> >On Sun, 6 Dec 2009 22:18:04 -0600, "Tim Williams" > >> ><tmoran...(a)charter.net> wrote: > > >> >>I never was too impressed with digital scopes. None of them have nearly > >> >>enough buttons, so you spend all your time wading through menus. The Rigol > >> >>I've used (don't remember the number) has awful menus, they are not always > >> >>quite what they say they are, and they take forever to go away. > > >> >>Some digital scopes have better refresh than others. The HP (Agilent??) > >> >>54622D's in all the labs at school here work fairly well, though at least > >> >>two button presses are required to reach any given menu option. Refresh is > >> >>okay, though still chunky on slower sweeps (>1ms/div). > > >> >>My impression of the cheapass Tek TDS's (the thin rectangular ones) is > >> >>similar to the Rigol. > > >> >>I'm most familiar with my Tek 475, but it would be nice to have storage, > >> >>single sweep* and averaging. One of those intermediate scopes, the ones > >> >>with analog AND digital, they're perfect for everything. > > >> >>*Just because it's an analog scope doesn't mean you don't get storage or > >> >>single sweep type readings, it just means it takes more setup. This > >> >>photograph was taken with a 10 second exposure, capturing three photoflash > >> >>discharges: > >> >>http://webpages.charter.net/dawill/Images/Photoflash_Discharge2_sm.jpg > > >> >>Tim > > >> >I like my TDS2012. I rarely use an analog scope any more. > > >> >John > > >> I find that I use an analog scope (Tek 465) for analog stuff. Can't > >> get a feeling for noise issues with a digital scope. For pulse > >> amplifier stuff and when you need arithmetic, digital is the way to > >> go. > > >> -- > >> Mark- Hide quoted text - > > >> - Show quoted text - > > >Not sure what sort of noise you are looking at, but I love my digital > >scope for looking at noise. The trick I use is to trigger right up > >at the top of the noise. Then I put the scope in average mode and you > >get an image that looks like the auto correlation function. My > >colleague has dubbed this the Quasi auto- correlation function, > >Quacf for short and of course pronounced quaff. (Ahh, nothing like > >a good beer.) If you ask for the FFT of this trace you get a much > >better picture. But Ive become very good at reading quacfs. > > >George H. > > I deal with high gain amplifiers (80 dB gain, around 256 channels per > system) sitting in a sea of noise. Trying to pick out switching power > supply noise, digital noise, AM & FM radio transmitters, and ground > loop noise from other equipment is difficult with digital scopes since > the structure of the noise is lost. I'll revert to frequency domain > (usually a swept analyzer) to pick out the offending frequency if it's > from a switcher, clock or radio station, but logic noise doesn't show > up well in the frequency domain. The sweep rep rate of digital scopes > is better than days of yore, but still not as good as a 30 year old > 465 which puts digital scopes at a disadvantage when looking at noise > structure. Plus, the alias factor of digital scopes is misleading - so > much so, that I'll use one of my analog scopes to figure out what the > real waveform looks like so I can set up the digital scope or > understand why I'm seeing odd looking signals. > > Not that I'm anti-digital scope, I just like using the tool that makes > the task at hand easier to deal with. > > -- > Mark- Hide quoted text - > > - Show quoted text - Hmm, sounds like you may be looking at higher frequencies than I am. (Above a 10MHz?) I'm using a TEK TDS 2022 with 2 GS/s. and don't have any aliasing issues at frequencies below 10 MHz. The averaging function on the digital scope is a nice feature. If you trigger higher and higher on the noise you can 'see' smaller interfering signals... but it's a bit of a losing proposition. The scope triggers less and less frequently and it takes longer to build up an image. George H.
From: Jan Panteltje on 10 Dec 2009 10:52
On a sunny day (Tue, 08 Dec 2009 18:18:50 -0800) it happened John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in <j52uh51k3lbcia4ol0lj4n63f0qpacm1se(a)4ax.com>: Many decennia ago, and this also touches on that Tek patent for input isolation that uses a modulated carrier via a transformer, I had a big Philips tube color TV. I also had their first video recorder, a tape recorder with 1/2 inch tape IIRC. As tube TVs in that time has no mains isolation, chassis always live, Philips provided a little box with that recorder, it consisted of a 38 MHz (or there about, basically TV IF) video modulator. The box went into the TV, connected to the IF via a relay IIRC, and provided it with a floating video + audio input. That was one thing, and predated the Tek patent by say, it was from 1968, Tek's applied 2002, makes 34 years YES THIRTY FOUR YEARS. But now the clue, as related to this. To display some waveforms on that big color TV screen (well 61 cm was big in that time), I designed a little circuit, it looks like this: ftp://panteltje.com/pub/TV_scope_img_1679.jpg What is does is create a dot on the TV screen that can be moved in X and Y direction. the 2 window comparators compare the H and V ramp against an X and Y DC voltage. The size of the dot is set by the width of the windows, so a square dot. When you only use the V comparator, you would get a horizontal line displayed on the TV as set by the Vpos pot. If you put a *signal* on the Vpos pot, you would see the waveform as with a 64 uS timebase... So, if you tested signals that were related to the TV H sync, the display would be rock solid. I used BFY90 transistors to make fast window comparators, and you cloud easily see the spikes on the output of a TTL gate in a 500 kHz signal (is 32 x 15625 Hz). Beautiful, and if course that Philips IF modulator box provided the needed 100% isolation :-) So, Tek people, here is your prior art, the Philips recorder was the LDL 1000. And here is my prior art to use it as a scope, think I could produce some witnesses who did see it in operation in my place. KIllall patent trolls kill kill kill kill kill kill kill |