What Is TV Airtime?
A telephone terminal device capable of transmitting voice and moving images simultaneously on one telephone line.
- Chinese name
- TV telephone
- Foreign name
- television telephone set
- Applied discipline
- Wired communication
- A telephone terminal device capable of transmitting voice and moving images simultaneously on one telephone line.
TV Telephone Introduction
- The image frame rate of television telephones transmitted by analog circuits is generally about 10 frames per second, with lower resolution. When digital circuits are used for transmission, the transmission rates can be 14.4, 19.2, 64 and 128kbit / s. If it is transmitted on the analog circuit, the data information can be transmitted and received through the modem of 14.4 or 19.2kbit / s. For transmission on the narrowband integrated service digital network, three rates can be used: rate 1. The voice signal is 16kbit / s, and the image signal is 48kbit / s, occupying a total of B channels; rate 2. The voice signal occupies one B channel at 64 kbit / s, and the image signal occupies one B channel at 64 kbit / s; rate 3. The voice signal is 16kbit / s, and the image signal is 112kbit / s. The two signals occupy two B channels.
- The basic functions of a television telephone are to use an automatic telephone to complete dialing and calling, complete image shooting and transmission, and display the other party's image. The use of television telephones can also complete the transmission and display of fax graphics.
- TV telephones are composed of automatic telephones and image devices. The image device part mainly includes a source coding unit, a video composite coding unit, a transmission buffer unit, and a transmission coding unit. In image systems, image compression coding methods are mainly used to meet the requirements of various transmission rates. In addition, in order to adapt to different TV system standards, the source encoder also uses a common intermediate format (QCIF).
- With the gradual development of the integrated service digital network, it has also accelerated the commercialization of television and telephone services. It will become an important part of multimedia communications and will gradually enter millions of households.