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Electronics Forum / Basics / July 2008a PC Based Oscilloscope?
Hello, My company wants to buy an oscilloscope. The scope that meets our needs is around $7,000. I am sure we can save much money if we buy a PC-based unit, like Picoscope. Do you have experience with PC based scopes? Do you recommend them for serious work? Thanks > Hello, > > My company wants to buy an oscilloscope. The scope that meets our needs is around $7,000. I am sure we can save much money if we > buy a PC-based unit, like Picoscope. Do you have experience with PC based scopes? Do you recommend them for serious work? > > Thanks You left out a vital part of information, what do you need the scope for? What kind of requirements do you have? M We are developing a board with a DSP, some logic, and some analog circuitry. The scope will be used to debug the circuit, make sure signals are clean, make sure timing is correct. We should get a 4-channel 350 MHz scope, yet these start at $7,000. So, I thought maybe a PC-based scope would do the job for less money. I do not know, I never used PC-based scopes. >> Thanks > > You left out a vital part of information, what do you need the scope for? > What kind of requirements do you have? > > M > We are developing a board with a DSP, some logic, and some analog circuitry. > The scope will be used to debug the circuit, make sure signals are clean, > make sure timing is correct. We should get a 4-channel 350 MHz scope, yet Those are things you need to think about before you even commit to making a board. The scope won't help you if you do major mistakes in the design from the start. You need to simulate stuff before, never mind the scope. > Hello, > [quoted text clipped - 4 lines] > > Thanks No, more so if you need a $7000 scope. Look on ebay if your that short of cash. > Hello, > [quoted text clipped - 4 lines] > > Thanks Which Picoscope are you looking at: http://www.picotech.com/oscilloscope-specifications.html At $11,990.00 or $2,390.00, the price or specs are better with the $7,000.00 scope, which ever scope that is. donald I am sorry, I did not understand what you are telling me. > Which Picoscope are you looking at: > [quoted text clipped - 4 lines] > > donald > I am sorry, I did not understand what you are telling me. Please do not remove attributions. Those are the initial lines that say "Whozit wrote". In addition avoid losing all quotations from previous messages by top-posting. Your answer belongs after (or intermixed with) the quoted material to which you reply, after snipping all irrelevant material. See the following links: <http://www.catb.org/~esr/faqs/smart-questions.html> <http://www.caliburn.nl/topposting.html> <http://www.netmeister.org/news/learn2quote.html> <http://cfaj.freeshell.org/google/> (taming google) <http://members.fortunecity.com/nnqweb/> (newusers)  Signature[mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section. ** Posted from http://www.teranews.com ** > > I am sorry, I did not understand what you are telling me. > [quoted text clipped - 16 lines] > > ** Posted fromhttp://www.teranews.com** Yet another "content free" post. Ugh. >>> I am sorry, I did not understand what you are telling me. >> [quoted text clipped - 3 lines] >> (or intermixed with) the quoted material to which you reply, after >> snipping all irrelevant material. See the following links: ... snip ... > Yet another "content free" post. Ugh. Without which many newbies would never learn the basic rules for Usenet use. Your addition did nothing to improve the newsgroup and was totally useless. Signature[mail]: Chuck F (cbfalconer at maineline dot net) [page]: <http://cbfalconer.home.att.net> Try the download section. ** Posted from http://www.teranews.com ** >>>> I am sorry, I did not understand what you are telling me. >>> Please do not remove attributions. Those are the initial lines [quoted text clipped - 9 lines] > Usenet use. Your addition did nothing to improve the newsgroup and > was totally useless. Yours (CBFalconer) added nothing to the topic at hand either. Thank you Mother Falconer. donald >>>>I am sorry, I did not understand what you are telling me. >>> [quoted text clipped - 11 lines] > Usenet use. Your addition did nothing to improve the newsgroup and > was totally useless. Educating newbies may be pointless; the following appeared in comp.dcom.telecom regarding major ISPs yanking nntp services: > Verizon has pulled all but the "big8" hierarchies plus the vz newsgroups. A > lot of people are up in arms, as alt.* is gone. So, look before you leap. [quoted text clipped - 6 lines] > this has fallen dramatically in recent years. The kids all want HTML, > wireless doo-dads and easy answers; newsgroups just aren't "hip." Michael (from comp.dcom.telecom): >>"The kids all want HTML, wireless doo-dads and easy answers; newsgroups just >>aren't "hip." You'll find those kids on Google Groups, you know? The main benefit of delivering discussions via NNTP rather than through a "web board" interface is the much greater efficiency (far fewer bytes transferred per message -- so much snappier, regardless of the connection type) and the significant feature of having filtering performed on the client side using however fancy of a filter you'd like to use rather than on the host side using what's almost always a very, very limited set of options (e.g., just try getting Google Groups to not display posts from a particular other NNTP server!). Most "hard core" development still takes place on straight mailing lists of Yahoo! groups anyway -- the Linux guys alone have thousands of them. > I am sorry, I did not understand what you are telling me. You seem to be hung up on price. The picoscopes are ( see link) much higher or much lower then the $7,000. You have yet to mentioned which $7,000 scope you are looking at, so we can not compare the specifications of it with the picoscope devices. So, I ask outright, which scope are you looking at for $7,000. donald >> Which Picoscope are you looking at: >> [quoted text clipped - 4 lines] >> >> donald Talal Itani TOP-POSTED: >I am sorry, I did not understand what you are telling me. People who use Outlook Express to read newsgroups should read this: http://www.google.com/search?q=cache:I4NVjCO2JKIJ:www.torrens.org.uk/SitePhil/Ne tiquette.html+*-*-*-*-inferior+published+proper+do.not.properly.mark.quoted.text +top.post+Micro.oft.programs+QUILA+Outlook.Express+official+do-not-*-use-Micro.o ft-programs+average+Netiquette+Richard.Torrens+dry+top.posting&strip=1#quila This page tells you what *you* have to do MANUALLY to compensate for that TERRIBLE software: http://www.google.com/search?q=cache:jA9I9kln6pkJ:www.usenet.org.uk/ukpost.html+ quoting+proper.attribution+use-a-standard-*-character+outlook.express+*-*-*-befo re-*-quoted-text+default+Trim+*-a-test-post+move-*-cursor-to-*-bottom-*-*-*-*+un able#ss3.1 Outlook Express has MANY, MANY flaws: http://groups.google.com/group/sci.electronics.design/browse_frm/thread/a7e80116 4cadb331/f82cdc06a0dca6b7?q=*-triple-extension-*+easy-to-create+execute-*-code+e xploited+Outlook-Express+zzz+*-no-longer-safe-*-*-*-*-*-*-*-*-*+exploit+vulnerab ilities+qq-qq+uu+exploiting http://groups.google.com/group/microsoft.public.windowsxp.general/browse_frm/thr ead/3e63579968f70adc/3bac48809895403a?q=SUCKS+trivial+get.a.real.news.reader+dif ficult+poor.design+outlook.express+Other-news-readers-*-*-*+OutlookExpress+OE.us ers+worth.every.penny http://groups.google.com/group/comp.lang.python/browse_frm/thread/b4d82899afb755 38/88c279033a6828dc?q=zz-zz+*-*-*-real-news-reader+skip.leading.hard.tabs+helpin g+Outlook.Express&fwc=2 http://groups.google.com/group/alt.support.depression/browse_frm/thread/deabc672 d1976c4/b20bb0a866d51d93?q=*-*-*-*-*-*-*-*-*-worse-than-OE+zzz+*-*-*-*-surprised -and-delighted-at-*-*-real-news-readers-*+broken.sig.dash+incapable+Outlook.Expr ess > Hello, > > My company wants to buy an oscilloscope. The scope that meets our needs is > around $7,000. I am sure we can save much money if we buy a PC-based unit, > like Picoscope. Do you have experience with PC based scopes? Do you > recommend them for serious work? I don't really like them, no matter what the spec. It ties up a PC, for one thing. It makes it super non-portable. Just too many 'bits' floating about. SignatureDirk http://www.transcendence.me.uk/ - Transcendence UK Remote Viewing classes in London >Hello, > >My company wants to buy an oscilloscope. The scope that meets our needs is >around $7,000. I am sure we can save much money if we buy a PC-based unit, >like Picoscope. Do you have experience with PC based scopes? Do you >recommend them for serious work? I've used Picoscope but I think they are crappy. There is no peak-detection which makes high frequency signals dissapear at low sweep rates. The number of sweeps (screen updates) is around 3 or 4 per second. Way too slow. And their software crashes every now and then. SignatureProgrammeren in Almere? E-mail naar nico@nctdevpuntnl (punt=.) > >Hello, > [quoted text clipped - 12 lines] > Programmeren in Almere? > E-mail naar nico@nctdevpuntnl (punt=.) I have also used the PicoScopes. The update is not as the other poster says, I think I have like at least 50 times per second.( on a USB 1.0 connection) That being said, some of the SW is buggy. But I live with that. The great thing is that my 12bit scope can be programmed and I can then use it for a test system also and even better when it is connected to the PC the documentation of measurements are a charm. Also the FFT is quite good Regards Klaus >I have also used the PicoScopes. The update is not as the other poster >says, I think I have like at least 50 times per second.( on a USB 1.0 >connection) >That being said, some of the SW is buggy. But I live with that. The >great thing is that my 12bit scope can be programmed and I can then >use it for a test system also and even better when it is connected to >the PC the documentation of measurements are a charm. > >Also the FFT is quite good I have cought a 16-bit picoscope, I believe those were cancelled later. The cool thing is I can do FFT with good dynamic range and this has been very usefull a few times. Where does the noise come from? Fire up the FFT and you clearly see where it sits at. Also check poScope, this is incredibly cheap and does some usefull stuff as well, such as serial protocol analysis (I2C etc). Also a logic analyzer, signal generator etc. I'm just not sure how fast as this is probably AVR based. If you ask me I'd get a nice analog standalone scope, 200-300MHz and a PC based for those rare protocol debugging issues. Sometimes a brain fart prevents you from seeing a very obvious bug and they help save long hours. M > Hello, > [quoted text clipped - 4 lines] > > Thanks They just aren't convenient, ideally, you want something small so it can easily be moved from lab to lab to thermal chamber etc. battery powered is even better. >Hello, > >My company wants to buy an oscilloscope. The scope that meets our needs is >around $7,000. I am sure we can save much money if we buy a PC-based unit, >like Picoscope. Do you have experience with PC based scopes? Do you >recommend them for serious work? I've used a few different PC based scopes and some regular Tektronix standalone scopes as well. The PC based scopes are fine as long as you understand their limitations and are prepared to work around them. Advantages of PC based scopes: - Low cost - Smaller box - Much larger screen - Longer recording length (on some models) - Easy saving & exporting of the captured waveforms Disadvantages: - Slow screen updates - No peak detection on the cheaper models - Might limit your choice of PC operating system - Not very portable One model that I have used is this one: http://www.dynoninstruments.com/products_elab080.php It's a DSO, logic analyzer, and waveform generator all in one. It's only 80 MS/s but for $500 you can't expect much more. I've actually found myself using the digital waveform generators on this thing quite often. > One model that I have used is this one: > http://www.dynoninstruments.com/products_elab080.php > It's a DSO, logic analyzer, and waveform generator all in one. > It's only 80 MS/s but for $500 you can't expect much more. I've actually > found > myself using the digital waveform generators on this thing quite often. Thanks, this is nice, yet I wished it had a higher sampling rate. Are you aware of any others? >> One model that I have used is this one: >> http://www.dynoninstruments.com/products_elab080.php [quoted text clipped - 5 lines] > Thanks, this is nice, yet I wished it had a higher sampling rate. Are you > aware of any others? Most low to medium end PC based DSO's are all a similar sample rate, i.e. a few hundred MHz. Because they all use off-the-shelf FPGA's and memories in their design, and that's about as high as you can go cheaply. When you start talking 1GS/s+ you are into the high end domain of the big manufacturers of professional oscolloscopes. Agilent make a PC based DSO that might suit you if you *really* want a PC based scope: http://www.home.agilent.com/agilent/product.jspx?nid=-536902447.774929.00&cc=US& lc=eng 200MHz, 1GS/s, 32Mpoint memory, $1600 Stop being cheap, you *need* at least one real bench scope for your lab, even if it's a lower end mixed signal scope like a Rigol: http://cgi.ebay.com.au/RIGOL-DIGITAL-Oscilloscope-DS1102CD-100M-COLOUR-LCD_W0QQi temZ150261816918QQihZ005QQcategoryZ45008QQrdZ1QQssPageNameZWD2VQQcmdZViewItem Dave. I realize it's an old conversation, but... What's involved in building a simple 50 MHz oscilloscope? I have a spare Xilinx Spartan DSP board, and an unused LTC 105 MSps A/D chip in the part box. The board's 125 MHz clock is different enough from the sampling rate, I think, to jitter the trigger point for meaningful averaging. It seems almost too simple. Aside from a low noise amp, what am I missing? The board has a VGA port, 128 MB 5ns DDR2, and tons of I/O. >>> One model that I have used is this one: >>> http://www.dynoninstruments.com/products_elab080.php [quoted text clipped - 23 lines] > > Dave. > I realize it's an old conversation, but... > [quoted text clipped - 4 lines] > averaging. It seems almost too simple. Aside from a low noise amp, what > am I missing? The board has a VGA port, 128 MB 5ns DDR2, and tons of I/O. Just code :) And a variable gain pre-amp/attenuator, if you want a useful Volts/Div dynamic range. -jg > What's involved in building a simple 50 MHz oscilloscope? I have a spare > Xilinx Spartan DSP board, and an unused LTC 105 MSps A/D chip in the part > box. The board's 125 MHz clock is different enough from the sampling rate, I > think, to jitter the trigger point for meaningful averaging. It seems almost > too simple. Aside from a low noise amp, what am I missing? The board has a > VGA port, 128 MB 5ns DDR2, and tons of I/O. That certainly builds a decent simple 'scope (and the amp doesn't even have to bet that low noise!). To compare with contemporary off-the-shelf offerings you need... -- A large amount of software to create a nice GUI, control the time base, make measurements, do FFTs, display cursors, etc. Overall implementing the software will probably take longer than implementing the hardware. -- Decent triggering abilities. "Edge" and "level" are easy, but most scopes today also do video triggering, serial protocol triggering, missed/runt pulse event triggering, etc. Additionally, getting the display data to precisely line up from one trigger to the next requires the ability to reset your clocking system on a trigger event or some fancy software and a high-speed timer to figure out when the "real" trigger event happened and shift the ADC's data (in time) accordingly. Without this, you'll always have (upwards of) one sample time worth of jitter on your signals -- many dirt cheap digital 'scopes do suffer from this problem. -- Some "smart" interface to the probes, if desired. Thees days all Tek and Agilent scopes have a little serial protocol used to interrogate the "fancier" probes so that the probe can tell them what scale and units to use (e.g., "This is a current probe, it produces 100mV/Amp.") -- Connectivity to the outside world via USB, Ethernet, or (very old school) RS-232 to save/print traces, data, etc. ---Joel > I realize it's an old conversation, but... > [quoted text clipped - 4 lines] > too simple. Aside from a low noise amp, what am I missing? The board has a > VGA port, 128 MB 5ns DDR2, and tons of I/O. A "simple" oscilloscope is easy, real easy, as you suspect. Buffer/amp + ADC + memory + basic sample control + PC interface + a few lines of code to display samples. Making it more useful on the other hand is much more work. You need wide range input attenuators and amps plus triggering and protection stuff. Lots of switching control stuff involved too. The control side gets more complicated with pre/post triggering, buffering and other niceties. A decent DSO project involves a lot of software, and this is where many of the cheap Chinese PC based DSO's fall down. BTW, 50MHz analog bandwidth is going to need a lot more than 105MS/s to be useful in single shot mode. Been there, done that quit a few times. Dave. >> One model that I have used is this one: >> http://www.dynoninstruments.com/products_elab080.php [quoted text clipped - 5 lines] > Thanks, this is nice, yet I wished it had a higher sampling rate. Are you > aware of any others? I have a SDS 200A from softDSP. The windows software is crap. The FFT feature is basically unusable. The triggering is unreliable. The claim of a 200MHz bandwidth is blather, they do 'statistical sampling', which is basically adding in some random jitter to the sample clock and correlating it somehow. OTOH, the unit is small enough to go with your laptop in the same case, and is useful therefore as an onsite scope. It can store a fairly large buffer, and allows the possibility of doing things like line monitoring with a very slow signal (like 1s per division). It was also very cheap, less than $1k. I'm not sure I'd buy it again. It does have an SDK (for $200 extra) that allows the possibility of doing special kinds of monitoring with a custom display. $0.02 Regards, Bob Monsen > I have a SDS 200A from softDSP. The windows software is crap. The FFT > feature is basically unusable. The triggering is unreliable. The claim of [quoted text clipped - 14 lines] > > $0.02 Thanks Bob. I will stay away from that unit. >>> One model that I have used is this one: >>> http://www.dynoninstruments.com/products_elab080.php [quoted text clipped - 27 lines] > Regards, > Bob Monsen In other words, it's a paper weight to be used at the site as things are blowing around! http://webpages.charter.net/jamie_5" >One model that I have used is this one: >http://www.dynoninstruments.com/products_elab080.php >It's a DSO, logic analyzer, and waveform generator all in one. >It's only 80 MS/s but for $500 you can't expect much more. I've actually found >myself using the digital waveform generators on this thing quite often. That's good to know, Tom. I recently purchased one of those to supplement my ol' reliable Tek 2235 for my hobbyist work, but haven't had a chance to really shake it out yet. From the little bit I've played with it, it looks pretty good, although it will never totally replace my Tek. I now need to figure how to best integrate it into the sort of work I do. The logic analyzer adds new capability to my bench, which pleases me immensely. I'm hoping that it will make my micro experiments easier and my time more productive. Tom |
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