----- Original Message ----- From: "John Willkie" <johnwillkie@xxxxxxxxxx> > Hmmh.. were those old computer displays monochrome (one dot per pixel) or > color (three dots per color)? When you mention dot pitch, were you talking > about pixel pitch or dot pitch? In a color CRT, there is only one hole or slot in the shadow mask for every three color triad or stripe. The red, blue, and green guns approach the shadow mask at slightly different angles, so that each gun only "sees" it's own color phosphors. Dot pitch is simply the spacing between the holes or slits in the shadow mask. If you want to get really picky about CRT resolution, look at the color stripe spacing at the extreme left and right edges versus the center of a 16x9 CRT. Due to the angle of the beam at the extreme edges, the spacing between color triads or strips are greater than in the middle. Even though the image is made up of dots in the case of a color triad shadow mask CRT, or stripes in the case of an inline shadow mask CRT, there is no relationship between one color triad and one 'pixel.' Each of the three color guns are modulated in intensity by an analog amplitude signal, and it is the beam spot size and frequency response of the amplifiers that determines how many triads are illuminated per 'pixel.' Likewise, counting the number of color stripes across the face of an inline gun CRT will tell you the theoritical maximum number of 'pixels' that can be reproduced, but the actual number will be smaller due to beam spot size and video amp response. In fact, with a computer display, given two CRT monitors with identical resolution the one with the higher 'dot pitch' will give the crisper display, precisely because there is more than a single color triad illuminated by one computer 'pixel.' In a monocrome CRT or in a three CRT projector, there is no shadow mask. Without a shadow mask or color phosphor triad to rely upon, the idea of a CRT having a 'pixel' falls apart altogether. It is simply the upper frequency limit of the video amplifiers' ability to turn the beam on and off that determines resolution. ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.