rbt@sftig.UUCP (R.Thomas) (09/03/85)
> Inputs: RGB analog and sync signals, digital > RGBI, NTSC composite. > > Jere M. Marrs > Tektronix, Inc. OK. I give up. Will somebody please explain what the difference between the various color input types are. What is the difference between RGBI digital, RGB analog, and NTSC composite, and all the rest. (The Apple RGB Color card produces something called XRGB, what's that?) Thanks for any light you can shed! Rick Thomas ihnp4!attunix!rbt
ron@brl-tgr.ARPA (Ron Natalie <ron>) (09/04/85)
> OK. I give up. Will somebody please explain what the difference between the > various color input types are. What is the difference between RGBI digital, > RGB analog, and NTSC composite, and all the rest. (The Apple RGB Color > card produces something called XRGB, what's that?) > RGB ... red, green, blue. A separate wire for color signal. There may be a separate sync signal or it may be overlaid on one of the color signals. RGB analog is just that. The Sony profeel monitors put schmidt triggers on the RGB inputs which shape them into either zero or one values. NTSC is what your TV set use (nick named Never The Same Color). It is the method of composing all the colors into a single video signal that is also compatible with Black and White monitors. They do this by making the primary signal the black and white intensity, and then have some side signals for the color. Look up "color" in Foley and Van Dam. -Ron
peterh@tekgvs.UUCP (Peter Hildebrandt) (09/06/85)
In article <577@sftig.UUCP> rbt@sftig.UUCP (R.Thomas) writes: >What is the difference between RGBI digital, >RGB analog, and NTSC composite, and all the rest. (The Apple RGB Color >card produces something called XRGB, what's that?) > >Thanks for any light you can shed! > >Rick Thomas >ihnp4!attunix!rbt TTL or RGB digital refers to a video source of three signals, RED, GREEN, and BLUE, each of which has a digital signal level (0 or 5 Volts). RGBI digital adds a fourth bit, INTENSITY, which is also a digital signal. Hence, RGB digital gives eight colors, whereas RGBI digital produces 16. RGB analog is also a video source consisting of three signals, RED, GREEN, and BLUE, but in this case, the signals are analog voltages from 0 to 1 volt. With analog RGB, you can theoretically get an infinite number of colors on the screen, but most analog systems are limited by the size of the digital to analog converter inside. NTSC composite is standard composite video, combining the red, green, and blue signals into one. Most video cassette recorders output NTSC composite. NTSC video is usually output through a RCA phono jack on microcomputers. Generally, the signal quality is degraded when the signals are combined for NTSC video, and therefore, any kind of RGB is preferable. Peter Hildebrandt Tektronix Laboratories