PC Scopes there are quite a number of scopes for the diy would you recomend one?

Depends on what you mean by PC scopes. Do you mean a hardware gadget that interfaces to the PC? Or something that uses your existing sound card?

As the author of Daqarta for DOS (and the upcoming Daqarta for Windows), I can say that sound card systems (like Daqarta) can never be a complete replacement for a benchtop scope, because they have limited sample rates that confine them to audio-range work. However, if you are doing work in this range they can be very useful for things like spectral analysis and synchronous signal averaging for noise reduction. These are things that are available on pricier benchtop scopes, but not on the entry-level models you are likely to find. So one approach is to get a cheap benchtop scope for high-frequency and digital work, and use a sound card system for audio work.

With a sound card scope you can measure audio distortion better than many expensive benchtop units, simply because souond cards have 16-bit ADCs and many high-frequency benchtops and PC hardware add-ons are only 8-bit. It is *so* nice to be able to make tweaks to an amp or oscillator and watch what happens to the distortion as you adjust a pot in real-time.

Another advantage of sound cards is that they make outstanding audio signal generators, both for things like the above distortion measurements, or just general testing. (You may want to check out my free DaqGen for Windows; it's only a signal generator, but it does all sorts of waveforms and modulation tricks.)

One downside of sound cards is that they don't go down to DC. If you don't mind a little wiring job, you can make your own 8-bit "sound card" for Daqarta for DOS that uses the LPTX driver. This circuit is typically a handful of resistors that you plug into the printer port. It goes down to DC and samples at up to 50 kHz.

As far as increasing the input voltage range, you can do that on any scope, either benchtop, PC add-on, or sound card, using voltage dividers.

Best regards.

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

Server Error 500 on the above site. How does one reach it? Thanks, mike

-- Return address is VALID but some sites block emails with links. Delete this sig when replying. . Wanted, PCMCIA SCSI Card for HP m820 CDRW. FS 500MHz Tek DSOscilloscope TDS540 Make Offer Wanted 12" LCD for Compaq Armada 7770MT. Bunch of stuff For Sale and Wanted at the link below. MAKE THE OBVIOUS CHANGES TO THE LINK

site not working !

could you please send me more infor on this scope bob and perhaps if you have any links to other because i am really intrested in this and probably i\\'ll build anyone i find because i am really intrested

regards

what i am mainly intrested is in more info about soundcard scopes their limits and voltages and parrallel port scopes the same info

Sorry, just discovered that after I posted. I am hoping the Web host can fix it soon!

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

It's back up now. Sorry for the inconvenience.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

The Daqarta / DaqGen site is back up. (Sorry for the inconvenience.)

No links there to other sites.

But there's lots of into there on Daqarta, including the complete Help system for the main program, plus each of the drivers. If you go to the downloads page and scroll down a bit to the driver section, you'll find the Help link for the LPTX driver. That has schematics, theory, and construction tips. There's info on how to set it up for desired input ranges.

Note that Daqarta for DOS run only under real-mode, so you need Win9x or earlier; Win2K and XP won't work. (That's why I'm working on Daqarta for Windows!) In general, the LPTX approach is not suitable for Windows, which does not allow real-time operation like DOS does. So there will likely never be an LPTX driver for Daqarta for Windows... sorry!

So, if you have a rel-mode DOS system and would enjoy a bit of construction, this might be a fun project. But it will never compete with a real hardware scope on anything except cost!

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

For low-frequency stuff (