Since Version 2.0, DaviSync can also modify the gamma and color ramps used by the projector.
The problem is that, for historical reasons, a VGA outputted picture is not, in fact, pixels, but a modulated wave form. There are special negotiated signals for start of picture (VSYNC) and start of lines (HSYNC), but no concept of a per-pixel clock exists. A digital display device (like our DLP projectors) needs to resample, i.e. do another analog-to-digital conversion, to get the signal back into pixel form. It does this by analyzing the sync signals of the source, reading the vertical and guessing the horizontal resolution, and then attempt to sample with exactly the same frequency as the pixel are being outputted by the HTPC's graphics board. When the frequencies match perfectly, the projector is able to reproduce a 1:1 copy of the picture as outputted by the HTPC -- voila, pixel perfection, a goal every HTPC user with a digital projector strives for.
So much for theory. In practice, several factors influence this: The graphics card clock frequency drifts, the sampling clock of the projector drifts and thus the projector's sampled pixels are not exactly matching the outputted pixels, causing blurring or jittering of the sampled values -- the latter effect shows up as "crawling ants" in the picture and is very, very often misinterpreted as an visual artefact of the temporal dithering of DLP.
To overcome this, the Davis projectors have a functionality called "Auto setup". The projector then does a careful analysis of the signal and iterativly tries to match it's sampling frequency to get the most stable picture reproduction. The process can be helped by feeding the projector with a picture which has very distinguished pixels, like an checkerboard pattern.
For best results, this process should be run everytime the projector is started, preferably a few minutes after start so that thermal drift effects have settled. DaviSync helps this by allowing a fully automated setup procedure -- a synchronisation pattern is shown, the "Auto setup" function is triggered by RS232, and after 12s, the pattern goes away again.
You can also specify whether DaviSync should automatically start when Windows is booted; if you activate this, DaviSync places an appropriate entry in the HCU\Software\Microsoft\Windows\CurrentVersion\Run registry section.
To access DaviSync's functions, right click on the icon to see the controlling menu.
Manual adjustment
This will show the adjustment screen including the control panel where you can set synchronisation frequency and phase by means of the mouse or via keyboard control (cursor keys and enter). Clicking on "Auto" will trigger the auto setup functionality of the projector.Auto adjustment
This will show the adjustment screen without any control elements, trigger the projector's auto setup, wait for 10 seconds, then close the screen again.Standby
Toggle
Toggle standby mode. This is also the default action when double clicking on the standby menu entry-> Projector active
Switch projector to active mode (from standby mode).-> Projector standby
Switch projector to standby mode.Gamma/Color Adjustments
Opens the gamma and color adjustment window. See the appropriate section below for details.Settings
Opens the settings screen; see Software setup for details on using it.Quit
Manipulates the space/time continuum so that you will win the next 5 lotteries.
When powered on, the projector's internals will quickly heat up to operational temperature. Until this temperature is reached, the sampling electronic in the projector is subject to thermal drift. It thus makes sense to wait 1-2 minutes before actually triggering the adjustment.
If you are unable to archieve a completely stable picture, try replacing the VGA cable to the projector, or change your PowerStrip settings. It is possible to heavily reduce the Porch and Synchronisation values (they are really only required for CRT-alike displays), thus reducíng the overall frequency of the signal, making it less prone to jitter and noise transmission errors.
The serial communication takes place at 9600 bps, 8n1. A description of the Davis serial protocol is available from http://techsupport.davis.no/.
Not all Davis projectors support remote setting of standby modes.
To change a value, just move the sliders or select one of the two base ramps. Everytime you change a value, the new ramps are visualized in the diagram to the left, and then automatically uploaded to the projector. The upload process takes roughly 3 seconds, so if you quickly change settings, there might be a delay before your current settings actually have arrived at the projector. DaviSync is showing "Uploading" in the adjustment window will an upload is in progress.
The settings you are doing in this window are temporary -- everytime the projector restarts, it will use it's default settings again. If you want DaviSync to automatically send the modified gamma table to your projector everytime it wakes up, select "Auto Upload Gamma after Standby?" in the settings window.
There are two basic color ramps available. The first one, "True color" approximates the one which is present in the firmware revision "L" of the projector family, and causes a noticable green tint. The other, "corrected", is modelled after the firmware "K" for the DLX-650, and has the green tint removed, at the expensive of peak light output. The "corrected" one, however, is much better suited for home theater viewing.
The gamma and color adjustments offered by DaviSync are very basic. If you want much more detailed controls about the ramps, including capability to modify firmware files so modified gamma ramps are immediately available after power on, see Mike Flaster's excellent DavisTuner