Re: Comparison of laptop audio output and function generator

On Fri, 28 Sep 2007 12:06:29 GMT, NoSpam@xxxxxxxxxxx (Bob Masta)
wrote:

On Thu, 27 Sep 2007 19:11:12 -0000, MRW <mr.whatever@xxxxxxxxx> wrote:

Hi Bob,

I'm actually using DAQARTA to generate the tones from the laptop. :-)
I'm using an older version, though.

I'll see if I can take a picture of the signal when I have access to
the oscilloscope again.

Thanks!


The old DaqGen (just the signal generator
portion of Daqarta as a stand-alone program) had
problems with some video accelerators, which could be
fixed by reducing the video acceleration settings in Windows
Control Panel. I haven't noticed or heard of that with
Daqarta for Windows, but that could be simply due
to newer video systems finally having their act together.
Might be worth a quick test with Control Panel.


Following up on the above: There is actually a
dead-simple test: While the sound is running in Daqarta, hit the
Pause button to stop the display, but not the sound.
If the problem goes away, you can be pretty sure that
it was a graphics acclerator problem. I just checked
the upcoming Daqarta version on my old 200 MHz Win95
system, and it does indeed have a stuttering problem
at max acceleration. (In fact, I had long ago set it back
to "Basic Acceleration" to solve this problem on an
earlier version. No change in graphics performance that
I could see, though I'm not a gamer.)

To change the setting in Win9x, go to
Start - Settings - Control Panel - Display - Settings -
Advanced Properties - Performance.
Set the Harware Acceleration slider over to one
position from the left, which will say "Basic Acceleration".

On WinXP I've never seen any problems even at max
acceleration, but the procedure is pretty much like
above:
Start - Control Panel - Display - Settings - Advanced
Once you click Advanced, things get more iffy. The
system I just checked had hardware acceleration under
Troubleshoot, which is *not* the same Troubleshoot
you see on the Settings page.

The reason for the conflict, especially on older systems,
was that graphics card makers often released a
"no holds barred" ultimate performance driver that
locked out other system processes in order to squeeze
the highest *graphics* performance ranking in reviews.
Then after people bought the cards and found (too late!) that
they had these other problems, the card maker could
release a driver upgrade that toned down the performance
a smidgeon but played nicely with everybody else.

So if you have sound problems, and you find graphics
too slow for gaming or whatever using Basic Acceleration,
check on the Web for a driver upgrade for your graphics card.

Best regards,



Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
.