OUTPUT
OUTPUT
The Many Uses of
Computing and
Communications
Output Hardware
Hardcopy : Hardcopy refers to printed output Softcopy : Softcopy refers to data that is
shown on a display screen or is in audio or voice form.
Output Devices
Display Screens
Printers, plotters, multifunction, and
microfilm / fiche devices
Audio-output devices Video-output devices
Display Screen: CRT
A CRT, for cathode-ray tube, is a vacuum tube used as a display screen in a computer or video display terminal. Images are represented on the screen by individual dots or “picture elements” called pixels. A pixel is the smallest unit on the screen can be turned on and off or made different shades.
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Display Screen : Flat-panel Displays
Flat-panel are much thinner, weigh less, and
consume less power. Thus, they are better for portable computer.
Substances between plates --- LCD and gas plasma
– LCD consists of a substances called liquid crystal, the molecules of which line up in a way that
alters theirs optical properties. As a result, light --- usually backlighting behind the screen --- is blocked or allowed through to create an image .
– Gas plasma display is like a neon bulb, in which the display uses a gas that emits light in the
presence of an electric current.
Arrangement of transistors --- active-matrix or
passive-matrix
Flat-panel monitors
Flat-panel monitors
Screen Clarity
Resolution: The clarity or sharpness of a display
screen is called its resolution; the more pixels there are per square inch, the better resolution. E.g., 640x480, 800x600, 1024x768, 1280x1024, 1600x1280.
Dot pitch : Dot pitch is the amount of space between
the centers of adjacent pixels, the closer the dots, the crisper the image. E.g., .24mm, .27mm.
Refresh rate : Refresh rate is the number of times per
second that the pixels are recharged so that their glow remains bright. Typical ranges from 50Hz to 150Hz.
Monochrome Versus Color Screen
Monochrome Versus Color Screen
Monochrome : Monochrome display screens
display only two colors --- usually black and white, amber and black, or green and black.
Color : Color display screens can display
between 16 and 16.7 million colors, depending on their type.
Text Versus Graphics :
Character-mapped : Character-mapped
display screens display only text --- letters, numbers, and special characters.
Bitmapped: Bitmapped display screens
permit the computer to manipulate pixels on the screen individually rather than as blocks.
Video Display Adapters
Video Display Adapters
A video display adapter, also called a graphics
adapter card, is a circuit board that determines the resolution, number of colors, and how fast images appear on the display screen.
– VGA: VGA, for Video Graphics Array, will support 16 to 256 colors, depending on resolution.
– SVGA: SVGA, for Super Video Graphics Array, will support 256 colors at higher resolution than VGA.
– XGA: XGA, for Extended Graphics Array, support up to 16.7 million colors at
Hardware Output : Printer
Hardware Output : Printer
Desktop Versus Portable Printers:
– Desktop printers
– Portable printers: transportable versus ultraportable
Impact Versus Nonimpact Printers:
– Impact Printers • Dot-matrix – Nonimpact Printers • Laser printers • Inkjet printer • Thermal printer
Impact Printers
An impact printer forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon. The right is a
Inkjet Printers ( 噴墨印表機 )
Inkjet printers spray small, electrically charged droplets of ink from four nozzles through hotels in a matrix at high
Page Description
Languages
• A page description languages describes the shape and position of letters to the printer. Two common page description languages:
• PostScript
Laser printer ( 雷射印
表機 )
A laser printer uses the principle of dot-matrix printers in creating dot-like images. However, these images are
created on a drum, treated with a magnetically charged ink-like toner (powder), and then transferred from drum to paper.
Hardware Output : Plotters
Hardware Output : Plotters
Pen plotter : A pen plotter is designed so that
paper lies flat on a table-like surface (flatbed
plotter) or is mounted on a drum (drum plotter). Between one and four pens move across the
paper, or the paper moves beneath the pens.
Electrostatic : An electrostatic plotter uses
electrostatic charges to create tiny dots on special treated paper. The paper is then run through a developed to produce the images, which may be four-color.
Thermal plotter : A thermal plotter uses
electrically heated pins and heat-sensitive paper to create imaged.
Plotters
Plotters
Multifunction Technology:
Multifunction Technology:
Printer that
do more than print
Multifunction machines combine several
capabilities, such as printing, scanning, copying, and faxing, all in one device.
Computer Output Microfilm/fiche is computer
output produces as tiny images on rolls/sheets of of microfilm.
Audio-output Devices
Voice-output devices: Voice-output devices
convert digital data into speech-like sounds. Two types of voice-output technology:
– Speech coding uses actual human voices
speaking words to provide a digital database of words that can be output as voice sounds.
– Speech synthesis uses a set of 40 basic speech sounds (called phonemes, the bases of all speech in English) to electronically create any words.
Sound-output devices: Sound-output devices
produce digitized sounds, ranging from beeps and chirps to music.
視訊會議
Video-output Devices
Videoconferencing and video editing:
Videoconferencing is a method whereby people in different geographical locations can have a
meeting --- and see and hear one another --- using computer and communications.
HDTV: HDTV(High-definition television) is a
television system that features enhanced video and crisp, clear picture using digital transmission.
Virtual-Reality and Simulation
¤ Headgear:The headgear has two small video display screens that create the sense of 3-D.
¤ Glove:The glove has sensors
that collect data about your hand movements.
¤ Software:Software gives the wearer of this special headgear and glove the interactive sensory experience.
Virtual reality (VR) is a kind of computer-generated artificial reality that projects a person into a
Robots
Robots
A robot is an automatic devices that performs functions ordinarily ascribed to human
beings or that operates with that appears to be almost human
Robots
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Creative Output :
Creative Output :
The Manipulation of Truth in Art &
The Manipulation of Truth in Art &
Journalism
Journalism
Preview & Review :
Users of information
technology must weigh the effects of the
digital manipulation of sound, photos, and
video in art and journalism. Manipulation of Sound Manipulation of Photos(right picture) Manipulation of
The Future of Output
Preview & Review : On the horizon are better,
cheaper, and lager display screens; higher-fidelity audio using wave-table synthesis and
three-dimensional sound; and real-time video using
digital wavelet theory. 3-D technology is bringing three-dimensionality to computer displays and, through VRML (Virtual Reality Markup language)
software, 3-D ”virtual worlds” to user of the World Wide Web.
Display Screens
: Better & Cheaper
