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Detecting the high def TV for the Google Lunar X Prize.
Yes. *OP said "near real time," which I take to mean "OK to drop some frames," like the satellite video phones the reporters use from the boondocks. *Thus, high-def can be confined to a lot lower bandwidth if you don't mind seeing compression artifacts as each frame is being built on the screen. I have a contemporary example: *KABC-DT, Channel 7 Los Angeles is high-def on 7-1 AND high-def on 7-2, with a service called Living Well. *Seehttp://livingwell.tv/Welcome.html. Living Well is apparently getting a skimpy bitshare, as compression artifacts are obvious, especially on scene changes and motion, whereas ABC programming on 7-1 is just beautiful. *Living Well is very good, sharp HD, but you can see details being "painted in" for a quarter-second after a scene change. There's a fairly complex trade. For a lunar mission, the scene is going to be pretty static, just shifted. (not like there's a baskeball team doing a fast break in the field of view), so it should compress well, given a suitable algorithm. The challenge is that compression (especially good compression) takes computational power. So you have a tradeoff: do you spend you joules on compressing the images and radiate less RF energy, or do you compress less, and use a bigger power amp. There's also a mass tradeoff.. big amp or big antenna. The big antenna needs more accurate pointing, which increases complexity. Or the trade of frequency selection, higher frequency means more antenna gain, but usually lower efficiency in the PA and higher NF in the receiver end, as well as higher probabiliity of weather related fading. And even there, because Moore's law means that semiconductor technology is always advancing, the tradespace is shifting towards more processing (because it gets cheaper in size, weight, power, while power amps are pretty much at the physics limits) This is, of course, "rocket science".. or more properly, spacecraft system engineering. It's straightforward, for the most part, but non- trivial. Pick your requirements, define the tradespace(s), try configurations and see what happens. |
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