Robert Schlabbach wrote: > From: "Johannes Stezenbach" <[EMAIL PROTECTED]> > > > and AFC is interesting even if there is no sync. > > > > (sync & 2) tests if the carrier has been recovered. > > If we don't have a carrier, then AFC is undefined > > (AFC := difference between given frequency and > > recovered carrier frequency). > > True, the docs say "if the carrier has been recovered". However, the value > of the AFC register seems to reflect where the VES1820 is currently > "looking" for the carrier if it has no sync. And you can see when it gets > "stuck", because it stops changing. Thus, I stand by my statement: The > value of the VAFC register is _interesting_ even if there is no sync.
OK, I print AFC now always, surrounded by [] if the carrier indicator is unset. But the AFC value is only reported by FE_GET_FRONTEND if it is valid according to the data sheet. > > > ((s32)(p->u.qam.symbol_rate * afc) >> 10)); > > > > The calcuation above avoids overflow errors at the expense of some > > loss in precision. > > Unnecessarily so. The maximum symbol_rate supported by the VES1820 is 8.75 > Mbaud. AFC can be -128 maximum. 8.75M * -128 = -1120M -> that'll fit into a > signed 32-bit integer. OK, you're right. Thanks, Johannes -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe linux-dvb" as subject.
