Digital Technology: Digital TV

The advantage of digital generator speed governor with the advantages of digital television has some similarities. learning the advantages of digital television can help you better understand the advantages of digital speed board :

1 signal -noise ratio and regardless of the number of consecutive process. After the television signal is digitized by a plurality of binary bits to represent the two levels , and thus the continuous process , or after the introduction of noise during transmission , as long as it does not exceed a certain amplitude noise nominal level , the digital signal regeneration, can be able to clear it up , even if a noise level exceeds the rated value , causing the error , you can also make use of error correction coding and decoding technology to rectify them . So , in the digital signal transmission process, not reduce SNR . The analog signal processing and transmission, each may introduce new clutter , in order to ensure that the final output has sufficient SNR , we must offer higher SNR requirements of the various processing equipment. Analog signals require S / N> 40dB, and a digital signal only require S / N> 20dB. Analog signal transmission gradual accumulation of noise , and the digital transmission signal , substantially no new noise , i.e. substantially constant SNR .

2 Digital system can avoid the effect of nonlinear distortion of the system. In analog systems, nonlinear distortion can cause significant damage to the image.

3 digital device output signal is stable and reliable. Only because the digital signal "0", "l" two levels, "l" level as long as the size of the amplitude of the processing circuit may be identified "l" level can, bigger.

4 Digital system is easy to implement signal storage, storage time and independently of the characteristics of the signal. In recent years, LSI (semiconductor memory) development of multi-frame video signal may be stored, thereby completing the analog processing technology can not meet. For example, the frame memory and is used to achieve frame synchronization processing such as format conversion to obtain images of new television special effects. 5 due to the use of digital technology, with a computer can automatically control and adjust the equipment.

6 digital time division multiplex technology to take advantage of the channel capacity, use of digital television signals BOC, vertical blanking time, to achieve a text multiplex broadcast (Teletext).

7 After a digital television signal digitally modulated compressed , can be open broadcast service area of the design ( terrestrial broadcast ) , the probability that the viewer will be great to achieve the "no reception error " ( fat " 0 " received " 0 " fat " l " close " l "), to watch the television image and sound quality is very close to studio quality .

8 It is reasonable to use various types of spectrum resources . In terrestrial broadcasting, digital TV can enable analog TV quot; Disable Channel (taboo channel), but also in the future be able to "single- frequency network " (single frequency network) technology , such as television sets l only use the same one digit TV channels and nationwide coverage. In addition, existing 6MHz analog TV channels can be used to transmit l sets of digital high-definition TV programs or 4-6 sets of high -quality digital conventional television programs, or 16-24 sets and home VHS VCR considerable quality digital TV programs .

9 In the synchronous transfer mode (STM) communications network, can achieve a variety of business "dynamic combination " (dynamic combination). For example, in digital high -definition television , image detail is often less time appear. At this time due to less amount of image data after compression , you can insert other services ( such as a TV program guide , fax, electronic game software , etc. ) , without having to insert a lot of pointless "padding bits".

10. Easy to implement encryption / decryption and scrambling / descrambling technology to facilitate professional applications (including the military), and broadcast applications (especially to carry out all types of fee-based businesses).

11 scalable, scalability and interoperability, facilitate various types of communication channels in particular, asynchronous transfer mode (ATM) network transmission, but also facilitate and computer network connectivity.

12 Can a computer "integration" and constitute a class of multimedia computer systems has become an important part of the future, "National Information Infrastructure" (NII) is. Digital speed signal processing board is also only a "0", "l" two levels, "l" magnitude of the margin level processing circuit as long as possible to identify the "l" level can be, bigger, little bit irrelevant. So many benefits.