I’ve decided to post some patches that attempt to bring some consistency across the ATSC demodulator drivers in the signal strength reporting mechanism.
If we use the lgdt330x driver as an example, signal strength is calculated as a percentage from SNR up to 35 dB. Why up to 35 dB? As indicated in the comments inside the drivers:
Calculate strength from SNR up to 35dB Even though the SNR can go higher than 35dB, there is some comfort factor in having a range of strong signals that can show at 100%
The behavior of the code in this tree gives you a nice feeling of “100%” strong signals when using digital cable, but the reading is less than attractive when tuning ATSC over the air.
Personally, I would prefer to see a better representation used for signal strength here, although I believe that it is more important to bring some sort of conformity to these drivers, first. DVB-T / DVB-C / DVB-S remain untouched for now. More changes will come later on.
If you’d like to experiment with these changes, feel free to use the patches in this tree:
http://kernellabs.com/hg/~mkrufky/atscdemod
All comments, including both positive and negative feedback, are welcome.