[linux-dvb] Re: The drivers and HTV

[Dennis Noordsij <dennis.noordsij@wiral.com>]

> >What do you use for tuning/zapping? Are you sure that your zapping
> >application keeps the frontend file descriptor opened? Your report sounds
> >like if the demodulator gets powered down...
>
> I use VDR 1.1.25 for tuning. I found the problem to be the PWM value saved
> to the card. I changed PWM manually to 0x45 which gives me the best results
> and now QAM64 channels work fine but QAM128 channels don't tune every time,
> I quess I'll have to experiment with the register values to see if I can
> find something better for my system.

Hi Markko,

I have the same revision Siemens, and also the HTV network :-) so let me see! 
I have to say it works perfectly for me, although QAM_128 is very sensitive 
to signal quality, like if I wiggle the antenna cable I can "see" the 
results, but not so for QAM_64 channels. 

Locking is immediate and has not yet failed me once, no matter which 
transponder. Tonight hopefully I will have time to isolate any changes to the 
official driver that make a difference.

I have the inversion hardcoded for the way the card is routed. Zigzag 
disabled, frequency bending can be on or off because the AFC can correct 
about 425kHz either way.

Note: I found an interesting PDF application note about using the successor of 
the ves1820, tdaXXXX (have to find the link, sorry), in a demo board which 
uses the CD1516 tuner also. It mentiones over and over the IF of that tuner 
is 36.125 MHz. 

- div = (freq + 36250000 + 31250) / 62500;
+ div = (freq + 36125000 + 31250) / 62500;

When all is said and done, both cards use an unmodified PWM value (straight as 
read from the EEPROM), with only register 1 for QAM_128 modified. As this 
appears to be a threshold value, it's probably not that critical. I've tried 
from 95 to 106, all work OK.

I will let you know what works for me, maybe I'll send you my driver as-is and 
see if it works for you!

Cheers,
Dennis



-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe linux-dvb" as subject.