Lec7chap6f04

Lecture 8 / Chapter 6 COSC1300/ITSC 1401/BCIS 1405 10/19/2004
F.Farahmand 1 / 14 File: lec7chap6f04.doc
General Items:
Tests?
Questions?
Anything?
Reading Materials:
Miscellaneous:

What is output?
- A computer processes the data and generates output!
- Also known as Information (or processed data)
- The output type depends on the HW or SW being used
- Viewable, Printable, Audible, …
Output devices
- A hardware device that can convey information to a user
o Display Devices
o Printers
o Speakers, Handsets, etc.
What is the big idea?
Input
(data)
Processor
(generates Inf.)
Video/GraphicsText Audio ?????
Viewable
Viewable – visually orthrough
some physical medium
Audible
Viewable
What is missing?
Viewable

So what about DIGITAL SMELL TEHCNOLOGY?
- Another aspect of Multimedia and Virtual Experience
- Real or laughable? - A very challenging area of research
o Where is the smell coming from?
o How do they generate the smell?
- The Idea: Click & Sniff
- Applications: Another virtual experience; Just imagine:
o Smelling the nature through your computer
o Watching Smelly movies!
o Smell perfumes/food/etc. before you buy them over internet
- Manufacturers
o Trisenx : http://www.trisenx.com/menu.html
?Creating customized fragrances
?60 Primary aromas (odors)
?Uses the computer serial port
o Digisents : Out of business!
o Listening to the music and smelling an odor!
?You can buy it for $50!
- Want to learn more?
o http://www.time.com/time/interactive/technology/smelling_np.html
What about Touching?

Know the difference
- Display Device: Visually conveys outputs such as text and graphics on
a screen
o Information is displayed temporarily (Soft Copy)
- Printers: Generate outputs such as text and graphics on a physical
medium (paper, film, transparency, etc.)
o It generates Hard Copy and it is permanent
Display Devices
- Project text, graphics, video, etc.
- Consists of a Screen housed in the Monitor
- Projection types:
o Distinctive in several ways:
?Technology and cost
?Quality (resolution)
?View ability
?Application
?Power usage
?Ergonomics
- Monochrome Monitors
o Black and white colors
o Sometimes use Gray Scaling (one color but different contrasts)
- Uses different shades of gray from white to black

CRT Monitors
- Cathode Ray Tube – a glass tube with conductive coating
- CRTs are the most common way of displaying images today
o Monitors, televisions
- Cathode is negative – indicating the electrons
- Basic Idea:
o A High-speed beam of electrons flies through the vacuum in the
tube and hits the flat screen at the other end of the tube
o The screen is coated with phosphor, which glows when struck by
the beam
o The generated beam can be “steered” using electromagnetic fields
- Each dot of phosphor consists of Red, Green, and Blue – called a Pixel
- Black color is created when R=G=B=0
- White color is created when R=G=B=255
- Yellow color? RG=255, B=0
What is it with the curvy looking screens? Why not flat?

Field Emission Display (FED)
- Fundamentally similar to CRT: But has several magnetic fields
o A CRT has a single electron source addressing many pixels
o An FED has many electron sources addressing a single pixel
Why do you have two greens?

LCD Monitors
- Liquid Crystal Display
– Strange name (solid or liquid?)
o Invented in 19th
century!
o Sensitive to temperature
o Easy to build!
o Generating color is done by controlling each pixel separately
- Flat-panel display – thus smaller, lower power consumption
- The basic idea:
o The LC is sandwiched between two sheets made of special
materials
o By applying electricity the light passing through it can be blocked
- Resolution is proportional to size
- Some cool applications:
o Calculators, what else?
o Use them as picture frames! Huh?
o Electronic books (would you buy one?)
- Uses ClearType technology
Gas Plasma Monitors
- Flat-panel display devices that use Gas Plasma instead of liquid crystal
- The basic idea:
o By charging the gas, atoms collide and change energy levels ->
generating light!
- The main advantage : We can have a very wide screen
- Each pixel is lit individually
o The image is very bright
o The image looks good from almost every angle

Some basic terminologies:
Response Time: Time it takes to turn a pixel on/off – used for LCD
monitors
Electromagnetic Radiation (EMR): Magnetic field generated by the CRT
monitors
Energy Star Program: Building energy efficient devices
Refresh Rate: Redrawing speed of the monitor (also called scan rate – used
for CRT monitors)
Comparing different technologies:
Characteristic CRT LCD Plasma
Cost Low High
Radiation(EMR) High None None
View ability Very large
Quality Good Very clear All-angles view ability
Power High Low Low
Refreshing and flickering Issue (75 times/s) None (on/off) None (on/off)

Displaying on the computer monitor
- The computer sends the signal to a video card then to the monitor
- The monitor and the video card must be compatible
o Agree on a set of standards:
o Analog or digital
o Color depth: Number of bits to store information on each pixel
o Resolution: Number of dots per inch (dpi)
o Memory: Needed to store information about each pixel (color
resolution)
- Obviously, higher color depth and resolution require more memory
- Typical video standards: VGA, SVGA, Beyond Supper VGA
Video Card Monitor
Digital signals Analog signals
Basic standard:
- Resolution
- Number of colors and
color depth
- Connections
Basic standard:
- Resolution
- Number of colors and
color depth
- Memory
Computer

A little about TVs:
- Most TVs expect analog signals (analog broadcasting)
- To receive computer signals we must convert digital signals from the
computer into analog
- Signals must be converted to meet NTSC standard (National Television
Standards Committee)
- HDTV:
o Expects digital signals
o Much better clarity and details
o lifelike pictures
- 720 or 1080 lines of resolution compared to the 525 lines
o Supports digital surround sound system
o Offers Interactive TV features!
525 Scan
lines –
refresh every
1/30 sec
500 dots

Printers:
- Output device that produces text, graphics, etc. on a physical medium
- Generates a hard copy: printout
o Portrait or landscape orientation
- Types:
o Impact: Physical contact with the paper
o Non-impact: Uses spaying, heat, pressure, etc.
- Printer speed:
o In terms of characters per second (cps), lines per sec (lps), page per
sec (pps).
o Resolution (600 to 2400 dpi or more – dots per inch)
- Higher resolution -> better magnification ability
Impact Printers:
- Dot matrix printer: prints by striking the ink ribbon
o Uses continuous-form paper
o Speed is based on cps
o Noisy and produces Near Letter Quality printouts)
- Line printers
o High-speed impact printer
o Prints one line at time
o Some support font size and style
- Braille Printer
o Outputs information in Braille onto paper
Non-impact Printers:
- Ink-jet Printers: print by spraying tiny drops of liquid (still dots!)
o Produce letter quality
o The resolution is based on the number of dots per inch
o How is the color dried? – through some sort of a heating device

o They can print on anything! Photo-papers, glossy, etc.
- Laser Printers
o High-speed high quality non-impact printer (600-2400 dpi)
o Offers high resolution
o Also called page-printers (stores the entire page)
o Support page-descriptive language (PDL) such as PostScript
o Typically very fast (19-50 ppm)
o Have large memory (16MB per page with 600 dpi resolution!)
o Need a toner and works with a laser beam
- Thermal Printers
o Generates images by electrically heated pins against heat-sensitive
paper
o Not a very good quality
- Portable Printers
o Small lightweight printers
o Can be based on different technologies (Ink-jet)
o Many use USB ports (no power cord required)
- Plotters
o Sophisticated printers to produce high quality printouts
Speakers and Headsets:
- Examples: Speakers, Headsets, sub-woofer
- What about subwoofers?
o Tweeter, Woofer, Midrange Driver
- Different technologies:
o Vacuumed sealed (Acoustic) , Bass Reflex, Dipole passive radiator
(bi-directional)

o
Other output devices:
- Fax Machines:
o Scans a document and converts it into digital data
- Transmits the image over telephone line (analog)
- Receives the incoming analog signal
- Converts the data into digital image
- Then prints or stores a copy
- Fax modem:
o Sending electronic documents (such as a word document) as faxes
o Multifunctional Devices: Printer, scanner, copy machine, fax
machine all-in-one
Data projector
- Takes the image from the computer and projects it onto a large screen
- Basic types: LCD or DLP (Digital Light Processing Projector)
o LCD: Uses its own light source to display
o DLP: Offers sharper and brighter image; use tiny mirrors
Want to get free-online fax (eFax): http://home.efax.com/

Terminals:
- A device that performs both input and output
- Types of terminals
o Dumb terminals:
- No processing power; transmits, receives and display the
information only
- Such as a Host terminal
o Intelligent terminals:
- Has some memory and processing capacity
- Also called programmable terminals
o Special purpose terminals
- Perform specific tasks (cash register, bar code reader, ATM)
- Types:
? Point-of-sale terminals: Records purchases remotely
? Automated teller machine: Self-serving banking machine

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