Sound card scope SW with smooth roll mode?

Hello Folks,

Does anyone know of a sound card oscilloscope software that does the following?

a. Windows b. Smooth non-trigger roll mode, no jitter or jerking (very important) c. Can read in from WAVE under Windows d. Scroll rate can be changed, somewhat decent display

The smooth roll mode is most important, where new parts of trace come in at the right and roll off the left. To my surprise a lot of software can't do that.

Oh, and it doen't have to be freeware. I actually don't need a real oscilloscope function but just something configurable that can display a slow signal from DC to 50Hz or so. Would be nice if it could also stream results into a big fat log file.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg
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your soundcard will need modification to work down to DC from your description it sounds like you want a "chart recorder"

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--
?? 100% natural 

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Reply to
Jasen Betts

You can easily analyze soundcard output with sox, i.e. convert to an ascii file of numbers. I've done this for SIGINT circuitry analysis, i.e. put the waveform into spice. [Sox is on windows and linux. It is amazingly powerful if you can handle CLI.]

DC will be a problem.

Reply to
miso

Not sure if sound cards today permit DC input.. years ago they didn't.

Things may have changed since then.

You could experiment with your machine with a variable 1 volt on the input and watch your level meter in the mixer panel, if you have one.

Because of that problem, I made an oscillator with a AM circuit and the reference I was measuring would simply vary the amplitude.

Sound card just did a simple zero crossing decode and the use of some trig like the sine cardinal function get an average peak for a close approximation of the amplitude. Actually, I found that a basic integral function of 3 order samples with a multiplier gave me some good results.

This was a charting app I wrote to record some events over a long period on the PC. I would offer you the software but you need the hardware to go with it.. It does show a scope graph as it is recording.

Jamie

Reply to
Jamie

I know Audacity can do a, c, and d, but I'm not sure about b. There is a suggestion that some version of this is possible at this link

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, but the wishlist at
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still has an entry of

"Smoother Track scrolling on Playback: (22 votes) Keep the cursor in one place but move the track - gives smooth visual playback without continual cursor back and forth"

which would seem to be what you would want for "oscilloscope" mode.

Installer available at

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if you want to try it, but I suspect it may not do what you want.

My next idea would be something like sox converting the audio input into some kind of headerless binary or ASCII format, and then feeding that into gnuplot. I know you could call gnuplot repeatedly and generate a series of static plots; I don't know if gnuplot has an "update plot on new data" mode or not. You would probably want a batch file to set things up and shepherd the data along. (This batch file can probably also take care of your logging IWBNI*, by writing to file in between sox and gnuplot.)

If I were doing it, I'd make it run on Linux first, and then figure out how to move it to Windows; I'm more familiar with Linux and both sox and gnuplot were born on Unix so they work better there. Windows builds of both programs are available, so you don't have to compile them yourself for that platform.

To get Sox and gnuplot, you can visit

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and
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.

The sound card will have DC blocking capacitors in the input that will prevent you from getting all the way to DC. On most of the sound cards I've seen, you can identify them in series with the input jack and jumper around them if you want. I don't know if there is additional highpass filtering in front of the A/D converter.

Is this for your 4-20 mA logging thingy?

Matt Roberds

*It Would Be Nice If. Something that comes in a notch below a requirement, but that sometimes gets randomly promoted to a requirement when you're not looking.
Reply to
mroberds

You'll will have to do a bit coding,

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-Lasse

Reply to
langwadt

Sounds like a job for your labjack?

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George H.

Reply to
George Herold

They usually don't, at least not without a hack. I would already have the DC to 50Hz signal in the PC. In there DC is ok, as Audicity for example has a DC removal routine for this.

That's similar to what I want to do but I need quite some signal processing before the phase detector. Stuff that I was planning to do in the PC.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

I'd not be looking directly at the soundcard input but at a WAVE input which comes from audio processing software.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

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Thanks, Matt, I'll check this out. Audacity itself does not work, I used it a couple days ago. But to record a memorial service onto CD for folks who couldn't attend :-(

Yeah, but I am definitely not a software guru. Else I'd probably program it all in C.

This is only one of many facets of the project, so I am looking for something that won't turn into its own science project :-)

That was someone else. No, this is to record miniscule phase changes in a resonant circuit below 10kHz.

I'll rather look for something that's already there. One method might be to stream it into Excel via VBA.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

Thanks, but that's probably a bit over the head of a hardcore analog or mixed-signal guy like me. However, if nothing else can be found I could contract a local SW guy to "solder it in" for me.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

Tried it, no good so far. The SCADA software that comes with it has very paltry graphics output. It does have roll mode but not really, the refresh rate is so sluggish that the graph moves in chunks.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

in

a

am

what does it need to do? just take data form a soundcard and/or a file?

-Lasse

Reply to
langwadt

in

a

am

Do you need to watch it in real time.. or could you dump it all to a data file and 'sort it out in software'. I think I could even write a program to scroll data across the screen. George H.

Reply to
George Herold

A sine in the sub-10kHz range is placed on a sound card output. This feeds a concoction of caps, inductors and whatnot. Back comes a phase-shifted sine of same frequency. The relative phase shifts are miniscule, sometimes below 1 degree. This is fed back into the PC sound input. In the PC it is digitally band-pass filtered to get noise and other crud out and then phase-detected. And that's where it ends, there are not decent "oscillosscope mode" output functions in most software, regardless whether SCADA or for other markets. I (hopefully ...) can feed this into some other display spftware via the WAVE function in MS-Windows, the one where a device can read audio from some other source instead of the physical sound card jack. Because the sound card data processing is already done at that point.

Well, maybe LabView would do it but they want well over $1k, and a ton more if you want to do some math which I have to. It doesn't have to be free but should be more reasonably priced.

I'd also be willing to buy some reasonably priced (as in a few hundred bucks) DSP demo board and software. But only if the building of signal processing and (good) display blocks into a working system is truly click-drag-and-drop, no code writing. Because I am not a SW guru. SCADA software generally fulfills that requirement but is sorely lacking in proper display modalities.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

It has to be realtime. I probaly could write it as well, just don't have the time to re-learn. It was one of my first projects after I had shelled out north of $300 for the Microsoft C compiler package in 1990 or so. Like today, back then there were no decent roll mode display routines available anywhere. Automation companies said "It can't be done under DOS". So I wrote my own and, of course, it did work nicely under DOS. Had to learn the innards of the Tseng Labs chip (ET4000 or something like that) and then more or less address it directly. But I don't want to do this again.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

John Carmack did the same thing, back in the day. People thought side scroller games were the domain of consoles only (namely, the Nintendo/Famicom at the time). Which did it by hardware sprite generators, which relative to the hardware on an XT, was cheating. Fortunately, standard EGA hardware gives you a shift-the-address-the-screen-reads-from control, making scrolling graphics a cinch. Only have to redraw the edge that scrolled. There was even enough fill rate left over (on the 8086, that is) to, you know, draw blinking lights and monsters and stuff.

I don't know what the intricacies of the Tseng Labs chip were, but I bet it (or a suitable variation) also worked on standard hardware as well. Notwithstanding a suitable definition of "standard".

Not going to argue about not needing to do it again though... after all, that's what DOSBox is for! ;-)

Tim

--
Deep Friar: a very philosophical monk. 
Website: http://seventransistorlabs.com
Reply to
Tim Williams

Almost had it but ... One of the SCADA programs (DAQFactory) can set the refresh to around 10Hz via a systime trick (setting a dummy trace with systime as the x parameter) that was explained to me by their support engineer. Not ideal but smooth enough for most sutuations where nobody has to look at the graph for more than a few minutes. However, there is no default mechanism for grabbing WAVE data from the Windwows environment. Dang!

Somehow hardware is easier. One goes to the wires drawer, gets a wire, strips both ends, solders it in, done. No drivers to write, no DLLs, just a spool of Kester 8806.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

That's because it was improperly implemented for a O-scope operating.

what you're seeing is the complete dump of the buffer at once.. What you should be seeing is a local timer reading from that buffer one pixel line at a time and scrolling the screen to keep it operating smoothly.

Jamie

Reply to
Jamie

With one software (Azeotech DAQFactory) I was able to get that part going. One of their support engineers explained the trick. You have to set up a dummy trace and set the X-axis for that to systime(). That somehow cajoles it into a 10Hz update mode which is better than 2Hz. Not as good as most of my other stuff but at least you can look at the plot for many minutes without getting a headache.

However ... no link to the soundcard or even the winamp (WAVE) whatsoever. That jinxes it for this case.

I am pretty close to doing the whole chebang in hardware.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

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