Annoying "mosaic" in digital-to-analog TV conversion

[kx250rider]

Here where I live, we're forced to use CATV since we don't get any air signal; not even radio or satellite. The walls of the canyon are too steep to get line of sight to any DSS satellites. Our cable company, Comcast, is changing over to digital and we got a Motorola digital receiver (free).

When I watch anything on a new digital channel, I see a mosaic breakup of the picture for a split second each time the scene changes. I mean the same as how they distort the face of a child or a license plate sometimes on the news. Also, the sound track is off-sync with the picture by a slight amount. I'm not sure if this problem is an anomaly of watching digital TV through a converter box on an analog set, but it's really annoying! Annoying enough that I shut it off.

I sure hope this isn't how we will all be watching TV on our analog sets in a few years! Any opinions welcome...

Charles