3 edits | System modifies same ATSC signal as regular OTA digital TV I wondered why they just didn't have devices use the same OTA digital TV ATSC signals used by the new DTV systems. After all, my laptop can pick up OTA DTV using a USB stick from Hauppauge(WinTV).
But while on the move, signal errors make the regular DTV std signals hard to watch. So, the ATSC standards group modified the A/53 std and came up with A/153 std. The new mobile std has extra error correcting mechanisms built-in. The downside is that all the laptops, netbooks, mobile phones will need new chipsets and/or adapters to be on sale before anyone will be able to watch the new service. »www.omvc.org/about-mobile-dtv/standards/
»www.omvc.org/_assets/docs/about/OMVC_FAQ.pdf
»www.omvc.org/objects/docs/ATSCMo···2-08.pdf
The ATSC Mobile DTV service shares the same RF channel as the
standard ATSC broadcast service described in ATSC A/53 (“ATSC
Digital Television Standard, Parts 1 – 6”). The mobile system is
enabled by using a portion of the total available 19.4 Mbps
bandwidth and utilizing delivery over IP transport. Just think of the new mobile DTV as adding another sub-channel(10.1, 10.2, 10.M) to the existing OTA DTV signal transmitted by a TV station.
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| All these sub channels just mean less bandwidth for the main HD channel which can result in reduced picture quality and increased pixelation. Im sure this mobile channel doesn't make much difference, but it seems some stations have a lot as it is. One of our local stations has the main channel (cbs), and thewb, and 24/7 weather. |
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| said by cooldude9919:All these sub channels just mean less bandwidth for the main HD channel which can result in reduced picture quality and increased pixelation. Im sure this mobile channel doesn't make much difference, but it seems some stations have a lot as it is. One of our local stations has the main channel (cbs), and thewb, and 24/7 weather. That is a problem. The new mobile signal(not likely to be HDTV) will eat up another 1 mbps of the 19.4 mbps of a std DTV channel. With all these sub-channels, the main HDTV primary channel loses quality.
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Sammer
join:2005-12-22
Canonsburg, PA | Each TV market that chooses this really needs an additional channel (shared by broadcasters) with distributed transmission to solve the bandwidth and other problems. |
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recnepsPremium
join:2006-06-24
Whitby, ON Reviews:
 ·TekSavvy Cable
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| Good idea.
A single transmitter could provide 20 channels of 1mbps each.
As you're only operating one transmitter, you can also just crank up the power and serve a very large area.
Some of the ATSC stations in Toronto are only a couple kilowatts of power (compared to the megawatt analog stations that they had)
So imagine a full megawatt ATSC transmitter's range..  |
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Sammer
join:2005-12-22
Canonsburg, PA
1 edit | said by recneps:A single transmitter could provide 20 channels of 1mbps each. As you're only operating one transmitter, you can also just crank up the power and serve a very large area. Some of the ATSC stations in Toronto are only a couple kilowatts of power (compared to the megawatt analog stations that they had) So imagine a full megawatt ATSC transmitter's range.. Because there would be some overhead I doubt that 20 Mpeg-4 subchannels would be practical but a half dozen broadcasters with a subchannel or two each would probably work out. Also MPH is very well designed for distributed transmission (multiple low power transmitters) and could probably cover an area better than with a single large transmitter. MPH should also have fewer receptions problems than regular ATSC. |
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