CHAPTER 6 OUTPUT WHAT IS OUTPUT: Data that has been processed into a useful form called information. 1. Hard copy -- Printed 2. Soft copy -- Displayed on screen 3. Other types – Audio + Video TYPES OF OUTPUT 1. Reports 2. Graphics 3. Audio output 4. Video output DISPLAY DEVICES 1. CRT Monitors: Cathode-ray tube 1. Monitor size: length from one diagonal corner to the other of the casting 2. Viewable size: size of the actually viewing area, a 21-inch monitor may have a 20” view area 3. Resolution: Sharpness and clearness i. Pixel: (picture elements) single point (dot) in an electronic image ii. Resolution: # of horizontal pixels * # of vertical pixels, e.g., 800*600, 1024*768 4. Refresh rate: the # of times per second that the pixels are recharged. The higher the rate, the less it flickers. 5. Dot pitch (dp): the distance between the centers of adjacent pixels. The smaller the dp, the clear the display 2. Video cards: convert digital signals to analog video signals for CRT monitors 1. Color depth: # of bits used to represent color. 8 bits: 256 colors, 24 bits: 16M colors, 32bits: 4G colors 2. Resolution: max. resolution the card can handle. 3. Flat Panel Displays 1. Liquid Crystal Display (LCD): produce sharp and flicker-free displays i. Geared to specific resolution: 15-inch: 1024*768, 17-inch: 1280*1024 ii. Normally refresh rate is not an issue iii. Response time: the time in us that is takes to turn each pixel on or off iv. Brightness (nits); the higher the nits, the brighter the display 2. Gas plasma displays: use a different technology for larger and higher quality displays 3. HDTV (high definition TV) i. Regular analog TV: 520*400 pixels ii. HDTV: 1920*1080 pixels using digital signals IMPACT PRINTERS: print by striking a mechanism against a inked ribbon that contacts the paper 4. Dot matrix printers Small dots form characters graphics (9-pin or 24-pin heads, 300-1100 char/min) 5. Band printers High-speed printers using continuous-form paper (3000 lpm (lines per minute)) NONIMPACT PRINTERS: print without actually striking the paper Resolution (dots per inch) and Speed (pages per minute) 1. Ink-jet printers: Spray tiny drops of ink onto the paper (300-2400 dpi color, 2-8 ppm) 2. Laser printers: Operates much like a copy machine (240-2400dpi, 4-12ppm for PCs) 3. Thermal printers: (thermal transfer printers) Transfer color inks from ink sheets onto the printer surface 4. Plotters: Produce high-quality line drawings OTHER OUTPUT DEVICES 1. Speakers and Headsets: Audio ouput 2. Data projectors take the computer image from a monitor to a large screen. 3. Facsimile (fax) machine and Fax modem Used to transmit and receive an image of a document over a phone line