Subscribe to:
Post Comments (Atom)
Welcome to Television Broadcast Technologies Blog Spot! This blog is created to allow members of the linkedin.com Television Broadcast Technologies Group to share ideas, news and concerns related to the television broadcast industry. With more than 1,100 members world-wide, I encourage everyone to participate on this site.
5 comments:
Hello,
The most important diference is the power supply fraquency wich is 50Hz in Europe and 60Hz in US an some Asian countries. With as a result a refresh rate for the pictures of 25 or 50 pictures per second in Europe and 30 or 60 pictures per second for US people. In fact the last one is 29.95 frames pes second due to inexact frequency. The soots are made with the frequenties to avoid beating frequency against the local lights when using tungsten bulbs.
Regards
Hi!
There are ATSC for NA, DVB-T for Europe and ISDB-T for Japan. Major differences are demodulation technologies used. There are many players in different DTV space.
Best,
Since the very onset of DTV technology, I am curious as to why one global standard has not been agreed upon. I understand the situation with power in different regions of the world, as well, the different frequency blocks available for over the air transmission. I do not understand why we need a vast array of demodulation technologies and why a global DTV standard can not be created. Please Help?
It is not only a matter of mains frequencies; when a new standard is developed, different factors are taken into account:
- how much money the implemantation will cost;
- what it is the TV broadcasting situation at the moment (that it is strongly related to the point above);
- how much strong it is the willingnes of the country(ies) to drive the market.
All the American, European and Japanes standard use MPEG-2 (moving to AVC/MPEG-4) as compression coding with slight differeneces in each implemantation, but when you think to the actual transmission of the content, the USA had to save their investment in big TV transmitter and they decided to use a modified Vestigial modulation (so to be able to reuse their analog Vestigial transmitters), Europe has a lot of mountains, so reflections were the main concern, and the OFDM has been used, Japan decided that they needed to do something better and developed their standard that is a real improvement of the European DVB standard.
Bye
Paolo
thanks for your post Paolo!
Post a Comment