# jitter on Panasonic DLP Projector PT-D7500U
**URL:** https://psychtoolbox.discourse.group/t/jitter-on-panasonic-dlp-projector-pt-d7500u/1474
**Category:** Uncategorized
**Created:** [October 29, 2003, 10:26pm UTC](https://psychtoolbox.discourse.group/t/jitter-on-panasonic-dlp-projector-pt-d7500u/1474 "2003-10-29T22:26:42Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@dahliasharon](https://psychtoolbox.discourse.group/u/dahliasharon)
#### Post date: [October 29, 2003, 10:26pm UTC](https://psychtoolbox.discourse.group/t/jitter-on-panasonic-dlp-projector-pt-d7500u/1474/1 "2003-10-29T22:26:42Z")
Hi,
We're experiencing problems running PPTB with this 3-chip DLP
projector, with a sizeable jitter in the onset of stimuli - about
15ms. The same projector works without any jitter when using
programs other than PPTB, such as Presentation. Also, the same
scripts worked without jitter with an older projector. Does anyone
have any idea why PPTB should be having trouble with this high-end
(~$20K) projector? Any possible fixes?
Thanks,
Dahlia.
---
### Author:  [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)
#### Post date: [October 31, 2003, 2:52am UTC](https://psychtoolbox.discourse.group/t/jitter-on-panasonic-dlp-projector-pt-d7500u/1474/2 "2003-10-31T02:52:37Z")
> \> \> We're experiencing problems running PPTB with this 3-chip DLP
> \>\> projector, with a sizeable jitter in the onset of stimuli - about
> \>\> 15ms. The same projector works without any jitter when using
> \>\> programs other than PPTB, such as Presentation. Also, the same
> \>\> scripts worked without jitter with an older projector. Does anyone
> \>\> have any idea why PPTB should be having trouble with this high-end
> \> \> (~$20K) projector? Any possible fixes?
Most likely, the projector has an internal refresh rate of 60 Hz,
and any other video rate passed to it is internally resampled
to 60 Hz. Such resampling can cause visible artifacts in the
display. The solution is to set your video card to drive the
projector at its native 60 Hz. On a Mac, you'd do this
through the Monitors control panel, or some shareware
utility. I'm not sure how you do it on a Win machine, but
it must be possible. My vague memory is that there is
a display control panel ....
DB