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QAM gets explained in quick-and-dirty fashion

Darren Murph

If you've noticed, quite a few Comcast users have been grumbling over the quality of their HD programming recently, and they're attributing the artifacts / compression to the squeezing of three high-def channels onto a single QAM. Granted, delving into technical aspects typically isn't our bag, but given the constant talk of HD Lite, we figured it prudent to pass along a rough 'n dirty explanation that details why cramming more than two HD channels onto one QAM is a bad idea (in the consumer's eye). Quadrature amplitude modulation, as it's formally known, equals 6MHz of bandwidth, which equals 38.8Mbps of broadband data, which equals thousands of voice conversation, which equals "enough" space for two to three HD nets. Granted, just because three will fit doesn't mean things will look as good as if only two were allocated to one QAM. Quite frankly, we're just scratching the surface in this space, but hit up the read link if you're itching to know more.

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