Techie question...

[avevale_intelligencer]

We have cable TV, which is ace and brill and all that except when it goes wrong, which is often. My question is this. When I am watching a cable channel, is the image supposed to be semi-pixelated into roughly three-quarter-inch squares? (I say semi, because there is detail inside the squares, but it's very noticeable, especially during fast camera moves in dark bits, that the screen has these gridlines, and I'm sure they shouldn't be there...