Multimedia is the combination of several forms of communication. It may include text, video, photographs, spoken words, and music. Technology Interactions
Electronic Communication • Information is sent and received using electronic devices such as radios, music players, and computers. • Electronic communication can use analog or digital signals or a combination of both. • Analog communication uses a continuous, varying signal. • Digital communication uses separate, distinct signals in the form of binary code.
Waves • A wave is a disturbance that transfers energy from one place to another. • Sound travels in waves through many materials (media): solids, liquids, and gases. • Light also exhibits wave motion. Light does not need any medium; it can travel in a vacuum.
Measuring Waves • Wavelength is the distance between the peaks of any two waves. • Frequency is the number of waves passing a fixed point per second. • Amplitude is the height of the wave.
Radio • Like light, radio waves are a form of electromagnetic radiation that can travel through the atmosphere, cables, or even in space. • Radio is an example of audio communication. • To create a radio signal, sound waves must be converted into electromagnetic waves.
Radio Broadcasting: Creating the Program • Performers work in soundproof studios. Microphones change their audio (sound) energy into electrical energy. • Engineers work at an audio console in the control room to combine and mix sounds from various sources.
Radio Broadcasting: Transmitting the Program • After mixing, the signals are sent to a transmitter. • The transmitter combines the program signals with carrier waves that “carry” the program signals away from the transmitter.
AM and FM • In AM radio transmission, the amplitude (strength) of the carrier wave changes. • In FM broadcasting, the frequency of the carrier wave changes. • AM broadcasts can travel longer distances than FM. • FM broadcasts are usually of better quality than AM.
Satellite Radio • Satellite radio uses digital signals. • Radio programs are produced in ground stations and transmitted to a satellite in orbit about 22,000 miles above the earth. • The satellite bounces the signals back to satellite radio receivers on earth. • The digital signal produces very good sound quality, like the sound of a CD.
Digital Music Players • Digital music players use either a solid-state memory chip or miniature hard drive to store music. • Music is usually loaded in a digital music player by connecting it to a computer. • Music stored in digital music players is usually compressed (reduced) in a format such as MP3 so that it requires less memory.
Television • Television combines audio and video communication. • Television broadcasting uses essentially the same methods as radio broadcasting. • Today, three of every four homes receive their television signals by cable or satellite rather than from broadcast signals.
Planning a TV Program • The producer hires a writer to prepare a script and a director to turn the script into a TV program. • Storyboards are frequently used to plan TV programs, especially prerecorded programs. • Storyboards include sketches that show video to be shot, text for dialogue, and what types of camera shots are needed.
Producing a TV Program • Together, the producer and director usually hire the “talent” – anyone who will actually appear on camera in the program, such as actors or news anchors. • Directors decide which of several cameras is selected for specific shots. • Camera operators, sound technicians, and engineers run the actual equipment.
Broadcasting a TV Program • Live broadcasts are usually news shows or sporting events. • Most other programs are prerecorded and broadcast later. • TV broadcasts send video as AM signals and sound as FM signals.
Aperture and Speed • High-quality cameras—digital or film—control the amount of light that enters the camera by the following two methods: • The size of the opening that lets the light in—the aperture setting • The amount of time that light is let into the camera—the shutter speed
Digital Video • Digital video and still cameras both use a CCD, or charge-coupled device, to change light into an electrical signal that can be recorded. • Video cameras actually record a series of still images that move quickly enough to create the illusion of motion.
The Internet • The Internet is a global network of computers. • The World Wide Web (WWW) is the graphical portion of the Internet. • Web pages are frequently multimedia. They may include any combination of text, video, photographs, drawings, and sound.
Multimedia Production • Steps in creating a multimedia presentation: • Planning • Designing • Gathering material • Digitizing • Producing • Delivering