[linux-dvb] Re: tuning problems wih dvb-kernel

["Robert Schlabbach" <robert_s@gmx.net>]

From: "Holger Waechtler" <holger@convergence.de>
> Some of the VES1820 based cards have the I/Q wires between
> PLL/Synthesizer and Demodulator swapped, so you don't know in advance
> whether INVERSION_OFF is really INVERSION_OFF or not.

Then the driver should detect the hardware type and makre sure that
INVERSION_OFF really results in the entire card being "inversion neutral".
We've actually had this discussion before... :)

I don't think a "try&error" method at runtime is the proper solution to
this.

> If I remember correctly the Hauppauge cards designed by Technotrend
> and the old Siemens cards have the exactly opposite setting.

I have both a Siemens-Cable card as well as a TechnoTrend budget DVB-C card
(0x1004, with ALPS TDBE2 tuner) and they both work the same - the INVQ bit
has to be SET for the card to be inversion neutral (the tuner spectrally
inverts the signal by using a PLL frequency ~36MHz above the target RF).

i.e. for those two cards:

INVERSION_OFF -> SET INVQ bit in CONF
INVERSION_ON  -> CLEAR INVQ bit in CONF

Regards,
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany



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