High-definition digital TV transmission technology
HDTV signal transmission mainly has four transmission modes, through (live) satellite transmission, cable TV, terrestrial/mobile wireless digital TV network and IP network TV system, etc., for high-definition digital TV programs covering the whole country, through (live) Satellite broadcasting is the most suitable solution. Correspondingly, they are called HD satellite digital TV, HD cable digital TV, HD terrestrial/mobile wireless digital TV, and IP high-definition network digital TV. among them: This article refers to the address: http:// 1) High-definition digital TV transmitted via satellite For the past decade or more, the European satellite digital television transmission standard DVB-S (ETS 300 421) has been MPEG-2 standard definition video. The standard for digital satellite transmission, the modulation of its data stream adopts four-phase phase shift keying modulation (QPSK) mode, the working frequency is C band and Ku band (such as live satellite, its working frequency is only in Ku band), and is in use. In the MP@ML (main class @primary) format of MPEG-2, the client can achieve CCIR601 studio quality code rate of 9Mbps, and the PAL quality code rate is 5Mbps. A 54MHz transponder can transmit at up to 68Mbps and can be used to multiplex multiple sets of SDTV programs. But as more video content moves to high-definition formats, DVB-S has proven to be a transmission bottleneck in bandwidth allocation. 2) High-definition digital TV transmitted over cable television networks China's cable digital TV has a good foundation, with cable TV network as the transmission medium, and its application range is wide, and its development is also very fast. Digital cable The broadcast television system adopts the European standard DVB-C (ETS 300 429), which has 16QAM, 32QAM, 64QAM (corresponding to a transmission bandwidth of up to 38Mbps), 128QAM (corresponding to a transmission bandwidth of up to 44Mbps) and 256QAM (corresponding to a maximum of 50Mbps). Transmission bandwidth) Orthogonal amplitude modulation and other modulation methods. 3) HD digital TV transmission via terrestrial/mobile wireless The transmission capacity of terrestrial digital transmission is theoretically roughly equivalent to that of cable television systems, but is limited by the permission of the wireless transmission frequency; it can Achieve high coverage of wireless digital TVs in the region. Due to the newer modulation method, 10~12 sets of SDTV programs, or at least 2 sets of HDTV programs can be transmitted in the 8MHz bandwidth, and the transmission cost is low. 4) HDTV HD digital TV transmitted via IP network system IPTV network TV, also known as interactive TV or broadband TV, is a new type of telecom broadband Internet (such as ADSL for Telecom and China Netcom, community 5 cable, etc., or FTTH (fiber to the home) for TV programs. Interactive TV communication format; it integrates various technologies such as Internet, multimedia, and communication, and provides various interactive digital media services including digital TV to home users through Internet Protocol. Internet TV users can pass through at home. Personal computers or "network set-top boxes + ordinary or high-definition TVs" to receive various types of Internet TV programs, not only provide traditional video services and Internet browsing, but also launch new interactive services and support digital TV platforms. Enjoy interactive entertainment and services on an integrated web services platform, such as online transactions, interactive on-demand, TV voicemail and online games, and because of its many channels and content, it can meet a large number of different levels of IPTV users. Demand. In order to transmit high-definition digital TV programs in the IP network system, in addition to real-time MPEG-2/MPEG-4/H.264/AVS high-definition streaming media encoding equipment, it is also necessary to specifically guarantee the transmission bandwidth of the IP network, and it should be guaranteed to have 3 to The 5Mb/s broadband network connection, together with the corresponding IPTV high-definition digital TV receiver set-top box, can watch the HDTV high-definition digital TV program in the IP network. Satellite, cable, terrestrial and mobile wireless digital TV networks can use different modulation methods to transmit digital TV signals. The following table lists the various modulation methods currently or planned to be used according to different common transmission methods. .
Gaming Headset /Gaming Headset With Microphone /Stereo Gaming Headset /USB Gaming Headphones
Features:
1. Popular gaming headset with custom logo with different color
2. Manufacture with competitive price & good quality
3. Excellent sound performance
4. Material:PVC
5. Custom packing design service
6.Use for Fashion Show and Internet bar
Gaming Headset Gaming Headset,Amazing Gaming Headsets,Gaming Headset Ps4,Gaming Headset Usb Shenzhen Greater Industry Co., Ltd. , https://www.szgreater.net