论文部分内容阅读
在整个电视台及播出系统中,如果没有一个精准的时钟作标准,将引起转播时间不准,切播信号混乱等一系列严重的后果,直接影响电视的正常播出,因此精准的时钟系统在播出系统中具有非常重要的作用。以前贵州台采用CCTV场逆程16行基准时间码信号进行解码,作为电视台播出系统的基准时间。原始时间取自西安国家校时中心的超稳定晶振时钟产生的精准时间,传输到北京中央电视台,再由中央台加入16行场逆程信号发送到卫星,各地卫星下行接收站,然后通过光纤传输给播控,在播出系统中最后分配到授时卡。由于中间设备及路程带来的时间差不确定,不可能提供准确的误差数据,因而导致时间不准,误差较大。由于数字转换的需要,这套系统已经关闭。现在贵州台主要采用全球定位系统(GPS授时系统)作为播出系统的基准时间。全球定位系统(GPS)无地区时差、定位精度高,受环境影响小,近来在电视播出系统的应用发展很快,并在传统播出向数字化播出升级中得到广泛应用。
In the entire television station and broadcast system, without a precise clock as a standard, will lead to broadcast time is not allowed, cutting the signal chaos and a series of serious consequences, a direct impact on the normal broadcast television, so the precise clock system at Broadcasting system has a very important role. Previously, Guizhou Taiwan used CCTV field inverse 16-bit baseline timecode signal decoding, as the television broadcast system benchmark time. The original time was taken from the accurate time produced by the ultra-stable crystal clock of Xi’an National Chrono Center and transmitted to Beijing Central Television Station. The CCTV added 16 lines of reverse signals to the satellites and downlinked reception stations of all satellites and then transmitted through optical fiber To broadcast control, broadcast system last assigned to the timing card. Due to the uncertainty of time difference caused by intermediate equipment and distance, it is impossible to provide accurate error data, resulting in inaccurate time and large error. Due to the digital conversion needs, the system has been closed. Guizhou station now mainly uses Global Positioning System (GPS timing system) as the broadcast system benchmark time. Global positioning system (GPS) no regional time difference, high positioning accuracy, less affected by the environment, the recent development in the television broadcast system developed rapidly, and in the traditional broadcast to digital broadcast upgrade has been widely used.