CRT Size - Although manufacturers measurements will vary, these measurements are ACTUAL tube measurements corner to corner of the projection (raster) area.

Chassis Controls - Analog chassis projectors use manual "pots" for convergence, image sizing, shift, etc.  With the newer digital convergence feature, convergence is done from the control panel or infrared remote control.  This gives you the ability to stand at the screen and more accurately set up the focus and alignment of the CRT's. Digital convergence units also may have memories for different inputs and aspect ratios.  These can then be changed with the push of a button on the remote.

Peak Lumens - Lumens relate to the amount of energy (light) that's coming from the CRT.  It describes the potential of the projector, but little of the actual brightness you will get on screen.  The brightness depends on many factors.  The most important being the screen size and material as well as ambient light conditions. For more information click here.

Scan Rates and HDTV -  The ability of a projector to display HDTV depends on its scanning capability. For example for a projector to line double standard NTSC signals (480i at 15.75khz horizontal) from DVD, VCR or cable/ Satellite  to 480p, requires 31.5 Khz of horizontal scan rate and enough bandwidth to handle twice the picture information. HDTV at 1080i requires a horizontal rate of 33.75 Khz and 50 Mhz bandwidth.  720p requires a horizontal rate of 45 Khz with 50 Mhz bandwidth. 

Inputs - As listed above V = standard composite video, usually a BNC connector on projectors (takes a $2 Radio shack connector to convert back to RCA). S = S-video in its usual form. R = RGB in either a DB type plug or 5 separate RGBHV BNC type connectors. C = Component video.  Any values in ( ) are available with an optional input board.

Point Convergence - A feature of a digital chassis where after doing a rough convergence you can fine tune various areas of the image for a tighter alignment