That may not have anything to do with the projector. The software driver is simply waiting for the next vertical retrace interval before sending the data. Even though vertical retrace is an "archaic" concept originally necessary for CRT displays (you had to wait for the electron beam to sweep back to the top of the display), all cards provide this signal for compatibility. If you have a relatively modern video card you can probably get around this by disabling the vertical retrace in the driver configuration.
Our DLP/DVI system is similar. It has a rise time of about 5 ms and practically no jitter, but the software always waits for the next "retrace". It's usually no problem because it's consistent.
Maarten van-Casteren wrote:
> Actually, one of the main problems with our current projector
> is the lag: it only shows the input with a delay of two frames,
> which at 60Hz is about 34ms. We would want something that
> is a bit faster. A higher frame rate would also be nice, but the
> main thing is the input lag.
>
> Maarten
>
> -----Original Message-----
> From: Discussion list for international MEG community [mailto:[log in to unmask]] On Behalf Of Tom Holroyd (NIH/NIMH) [E]
> Sent: 14 November 2012 17:45
> To: [log in to unmask]
> Subject: Re: [megcommunity] LCD screen in MEG chamber
>
> We use this Panasonic projector. It goes up to 85 Hz, though we usually run it at 60 Hz.
> It works well.
> http://www.projectorcentral.com/Panasonic-PT-D3500U.htm
>
> You need to buy a non-standard lens to project onto a small screen at a short distance properly, see the "throw distance" calculator:
>
> http://www.projectorcentral.com/Panasonic-PT-D3500U-projection-calculator-pro.htm
>
> Beth wrote:
>> We are hoping to accomplish the same thing here in our MEG. We would like to have refresh rates >75Hz with visual stims sent from Matlab using the Psychtoolbox. This is quite difficult with the standard LCD monitor and our LCD projector. Does anyone have a setup for refresh rates of 85Hz? What type of DLP monitors are being used successfully for MEG vision studies?
>>
>> Beth
>
--
The white knight is talking backwards.
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