Information, Education and Communication: Television


Definitions:

Television is an electronic system of transmitting still and moving images with accompanying sound over a wire or through space. The system employees equipment that converts light and sound into electrical waves and reconverts then into visible

Light rays and audible sound. The most common type of transmission is broadcast or open circuit television where programmes are radiated to any viewer within range of the station. This is the type of transmission used by commercial and some educational stations. The other type of system, frequently found in schools and colleges, is the closed circuit television system which limits distribution of an image and sound to receivers directly connected to the origination point by coaxial cable or microwave link.

Characteristics:

There are many books and manuals that cover the technical aspects of television.

The simple closed circuit system is a good place to start. A vidicon camera with lenses and a television receiver connected to the camera by a wire constitutes a basic system. To add sound, an audio-video mir (a device which combines the video signal from a TV camera and the audio-single from a microphone and impresses them on a carrier signal for transmission in closed circuit system) is added. Sometimes a separate sound system consisting of a microphone, amplifier, and speaker can be used. The addition of a videotape recorder permits the recording and instant playback of audio and video images.

Videotape packages are now available as separate systems. These packages include a camera with lenses, a videotape recorder, a television receiver, a microphone, and associated electronic equipment and cables. Prices for the basic systems begin at approximately $1000.

When closed circuit systems are extended from one or two locations to many locations on a college campus or in a school system, further modifications of the system must be made. If the closed circuit feature is to remain, the signals have to be carried by coaxial cable (often leased from the telephone company) to each location where TV receivers are installed. Another alternative is the use of low power(2500 megahertz band) transmission or microwave transmission. These wireless systems permit the distribution of four signals simultaneously from point to point on a direct light of slight.

When a broadcast station goes into operation, the entire system is multiplied many fold. There are cameras and film And tape sources for origination of the programmes ; there are the audio and the video systems; and there is the transmitter, usually a separate installation with the transmitter tower adjacent. Signals are sent from the transmitter location. Any standard receivers in the broadcasting area are able to pick up the signals.

A further extension of the wireless space-to-space transmission of signals is the use of satellites which pick up Signals from one location and send them to distant locations.

Advantages:

Many of the advantages of other audio-visual media also apply to television:

  1. It offers a means for providing a common base of experience for all who see a given programme at the same time.
  2. It brings to the classroom people, places, and events, that could not otherwise be seen
  3. Live television-the launching of a space vehicle, the address of the President, or the final game of the world saris-adds the dimension of immediacy to events.
  4. The preconditioned learner comes to school as a confirmed TV consumer. The use of TV in instruction can capitalize on this acceptance and help him to become a more critical viewer.
  5. The reality and concreteness of the visual images are as present in TV as in other audio-visual media.
  6. Specialized personnel are often available on TV or videotape, Schools that cannot locate or afford special teachers of elementary foreign languages, for example, can extend the talents of one teacher to many students by television. Very often the teacher who is using TV becomes part of a teaching team which includes the TV teacher, the subject supervisor, and many of the classroom teachers. As teachers use television, many learn new techniques and ideas from the television teacher. This is a major fringe benefit, a type of in service training.
  7. The widespread use of videotape now permits programmes to be recorded and used when they are most appropriate. Portable videotape equipment can easily be brought to classrooms and laboratories for recording the performance of individuals or groups; these learners are able to analyze their efforts when the videotape is played back.


Limitations:

  1. One of the primary problems of broadcast TV is scheduling. If a teacher does not use a programme when it Is broadcast (or re-broad-cant), it is lost. Consequently, some teachers do not use TV because of timing, or some have used it at inappropirate times simply because it was available and they wanted their students to view the programme. The decreasing cost of videotape recorders now permits recording of pertinent programmes for playback at an appropriate time.
  2. Even on large classroom model TV receivers(21 and 24) students may have difficulty in seeing detailed images in large rooms.
  3. While there have been genuine attempts to use the visual aspect of the medium, too often instructional TV programmes are images of teachers talking. As more teachers gain more experience with the medium and as more is learned about what makes good TV instruction, the quality of programmes can be expected to improve.
  4. The very familiarity of TV sometimes contributes to habits of inattentiveness and passivity. Students do not know how to learn from TV. They often reject it, especially in the secondary Schools and colleges, since it appears to be a further step toward depersonalization.
  5. Some teachers perceive TV as a threat, since another teacher is taking over when the TV set is on. Some teachers fear that they are being replaced.