Following on from Joergs DTV aerial discussion I did a few empirical measurments on the signal strength and quality metrics on my set - a Panasonic 32" 100HZ LCD. The DVD Tuner is an earlier Panasonic chipset and gives a similarly abrupt transition between Q=10 and Q=rubbish.
The results on UK DVT signals are as follows
Signal Quality Notes Level
10 10 perfect
8 10 perfect
7 10 perfect
6 10 perfect
5 10 OK some glitches per hour
4 7 just about OK
4 6 unwatchable
So there is a very sharp transition between quality 10 that is fully error corrected and Q=6 which is unwatchable. This is with natural signal degradation from a heavy rainstorm.
It all seems a bit too digital. I would expect the quality metric to fall to zero for an image that is fundamentally unwatchable with bit errors in every block rather than 6. Below signal level 4 was useless.
I used an attenuator to find out if with a steady lower level signal there was a different result. And not surprisingly there was.
Signal level 4 with a passive attenuator in fine conditions still gives Q=6 but the picture is basically OK with the odd rare glitch.
It seems like the quality measures used only work on lab attenuated signals rather than naturally degraded noisy ones in the real world during heavy rainfall :(
Anyone else care to share the stats off their set (wet and dry)?
Regards, Martin Brown
** Posted from