Em 05-07-2012 14:37, Bert Massop escreveu: > On Thu, Jul 5, 2012 at 5:05 PM, Antti Palosaari <crope@xxxxxx> wrote: >> >> On 07/05/2012 05:16 PM, Mauro Carvalho Chehab wrote: >>> >>> Implement API support to return AFC frequency shift, as this device >>> supports it. The only other driver that implements it is tda9887, >>> and the frequency there is reported in Hz. So, use Hz also for this >>> tuner. >> >> >> What is AFC and why it is needed? >> > > AFC is short for Automatic Frequency Control, by which a tuner > automatically fine-tunes the frequency for the best reception, > compensating for small offsets and oscillator frequency drift. > This is however done automatically on the tuner, so its configuration > is read-only. Aside from being a "nice to know" statistic, getting > hold of the AFC frequency shift does as far as I know not have any > practical uses related to properly operating the tuner. AFC might be useful on a few situations. For example, my CATV operator still broadcasts some channels in both analog and digital. The analog equipment there doesn't seem to be well-maintained, as some channels have frequency shifts or have some other artifacts. Still, analog broadcast is useful for me to test drivers ;) Anyway, adjusting the channel tables to consider that offset shift help to tune them a little faster and/or get a better quality by letting the PLL to work closer to the pilot carrier. Regards, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
