You can digitize and lossily compress an NTSC signal significantly without losing much detail; that's why I call it redundant. Compression removes redundancy.

You can digitize and lossily compress an NTSC signal significantly without losing much detail; that's why I call it redundant. Compression removes redundancy. In ATSC the tradeoff between compression and error correction is such that a noisy channel is far more likely to cut out or otherwise be unusable than it would have been in NTSC.