High definition television or HDTV refers to very high resolution imaging. In simple terms – the moving images on your television screen. If you had to break that down each second would contain approximately 24 frames. Each frame is an image. Each image contains pixels. Now the higher the number of these pixels used the clearer would be the image. HDTV works on the principle of providing the best possible image or moving images to the viewer. Today because of advanced technology like digital broadcast and video compression, we have seen the demise of analogue HD systems which was the standard system that was in use.
Back in 1973, the International Telecommunication Union of the United Nations dealt on developing and agreeing upon various standards with regard to HD systems. In fact the ITU had its radio sector called the ITU-R was expressly involved in developing Analogue HDTV. The ITU-R’s primary aim was to create a global awareness for this technology but soon it was discovered that these would not fit into the broadcasting bands which would be available to home users. From here on the focus was then of the different standards like MPEG-1. Later broadcast companies, consumer electronic companies and other regulatory bodies came together to form the DVB organization which would be involved in agreeing upon specifications which would be formally recognized by the ETS.
One of the earliest HD systems was developed by Japan known as MUSE which is a method of encoding was first worked upon in the late 70’s. This was a dot-interlaced digital video compression system that used modulation of the analog to transmit the rays in order to deliver high definition signals into the homes of consumers. Japan started broadcasting this analogue high definition signal known as Hi-Vision into homes in the late eighties. MUSE as a compression system would ‘fold’ a 200 MHz signal into 8.1 Mhz and therefore this reduced the burden on the bandwidth. It was also the start of the 16:9 aspect ratios becoming a more prevalent standard at the time. This particular aspect ration continued its presence into the 2000s with more and more development on HD systems to become more efficient carriers and reduce bandwidth usage at the same time.
At the time Japanese broadcaster NHK was using MUSE to send HDTV signals into viewer homes. But even with the various limited standardizations of HD that took place in the subsequent years it was not considered a success. This can be attributed to various economic reasons. NHK’s MUSE for instance required more than four times the bandwidth in comparison to a standard definition broadcast. There were efforts made to reduce the burden on bandwidth but even with the shrinkage of the same to twice that of SDTV did not prove to be adequate as there was the matter of distribution. Seven broadcasters would have to share on channel on a daily basis if they wanted to use even this compressed format of the technology. Japan is the only country which has successfully done a public broadcast using analog HDTV. The demise of analogue HD systems in Japan eventually happened in October 2007.
