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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/Graphics Text Audio

?????

Viewable Viewable – visually or through

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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