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Originally Posted by Proppinupthebar
Or could it be due to the transmission medium in each case ? Not really thought it through have you? A satellite signal has to travel approx 23500Miles to the satellite and then 23500 miles back to earth. Theres a lot of interference in the atmosphere and the signals involved aren't particularly high powered. With the noisy enviroment the transmission method is kept simple. A dish is required to focus the weak signals. QPSK modulation is simple and hence simple to recieve and decode.
DTT using rooftop or indoor aerials has to cope with lots of echos which cause ghosting in the analogue enviroment, hence they use a method which can cope with echoes (reflected signals). COFDM, is thought the best method.
Cable is a relatively noise free enviroment, when terminated properly it doesn't suffer from reflections. Therefore it can use a relatively complicated modulation method (QAM), without the 'echo cancellation' capabilities of COFDM.
So your comments about it being pure greed on the part of broadcasters/manufacturers are cr*p.
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Woah, slooow down ... there's no need to get aggressive about it, we're only talking about set top boxes.
I bow entirely to your knowledge of the technical side of this, I know you work in the industry. But all that aside, are you saying it is not possible for a box to be made that would work with all three? Or that one modulation method could never work perfectly adequately for all three?
I'm afraid that when big corporations with big sales and marketing departments get involved with technology, the outcome is certainly not guaranteed to be in the best interests of the customer. Just look at the ridiculous format war now going on over the various kinds of DVD and CD, or the old VHS/Betamax war, or the way the world ended up with three different colour TV systems. I have no doubt that the various manufacturers can all advance arguments in favour of their own product.