On Wednesday 08 June 2005 23:04, Andrew de Quincey wrote: > > Incidentally, my latest test was to set the tone every 60 seconds in the > > frontend loop. This didn't work though - it still lost the lock, and went > > into the patch I posted earlier and regained it simply by setting the > > tone. > > My mistake - there was a bug in this code which meant it wasn't actually > doing the above. I've corrected it and am waiting to see if it still loses > the lock. Nope - its just lost it and ran the auto-regain-by-setting-tone code. So to summarise my current findings: *) Setting the tone every 60 seconds does not help. *) Setting the tone when the lock is lost causes it to be regained in under 100ms. *) If you don't set the tone/reg0x08 on lock loss, you will never regain the lock. *) The contents of register 0x08 of the stv0299 stay constant. *) It cannot be noise/traffic on the i2c bus changing other registers since the only thing needed to fix the issue is to set register 0x08 again. *) No i2c traffic to the stv0299 besides reading the lock status occurs after the initial tuning attempt. *) Only a few cards are affected. Cards tuned to the same channels on other sites are fine. Cards using the same multiswitch at the same site are fine. *) At a site with the issue, channels can be manually reassigned between cards/machines until a stable situation is found. This is very time consuming though. *) Temperature is unlikely to be a cause. *) This problem occurs across a whole range of stv0299 based cards (we have several vintages of them from the last few years). *) There is no pattern temporally to the lock loss. *) The problem occurs across different multiswitches by different manufacturers. *) The signal is perfect (BER==0) up until the time the lock is lost. *) The problem _may_ affect stv0299 based Twinhan cards as well, but this needs verified. This is sounding awfully like the tone being generated is drifting or stopping completely - due to an unknown cause. Unfortunately I do not currently have the means to measure the tone output during one of these incidents.
