[sdiy] OT:? Lissajous

[ニコラス・ケント]

>> Film it with a video camera (ha, ha), expect lots of visible
>> frequency aliasing.

Yes, this is the only way you would be able to record the image.

There are a fair number of people who've modified standard video  
video monitors to display vector based signals with varying results.  
Besides risk of a nasty high voltage shock you still wind up in the  
same place, you don't have a signal you can record (unless you film  
or video tape the monitor) and by and it's probably going to look  
crappier than the scope (unless that's the point)

>
> Temporal aliasing is always a snag. Then there's the variable slew  
> rate
> which changes the brightness...

Strobing issues are usually a problem though if you have the  
flexibility to adjust rates and perhaps try a few cameras you can  
often get improved results.

A few artists have used longer single frame exposures with a film  
camera and animate changes by adjusting the signal input between  
frames. You may be able to get similar results with a digital camera  
that can take a longer exposure by using a tripod and patience ;-)

While on the subject. Has anyone gotten a good quality digital video  
file of a dynamic audio waveform via software? The last time I tried  
I taped the S-Video output from a video card and cropped the good  
part. But I keep wondering if there are any any screen capture apps  
that capture at a fairly high frame rate - like 30fps rather than 5  
or so. Or conversely an audio to waveform graphic plugin for a video  
app. There's one bundled with  After Effects, but it's just animated  
triangle waves.

nick kent