[linux-dvb] Re: tt dvb-c 2.1 and signal quality

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

From: "Torbjörn Jansson" <torbjorn.jansson@mbox200.swipnet.se>
> I tried changing the pwm, but from some of the replies I got to my mail
> I got the impression the pwm didn't do much good on TT cards.

It doesn't. PWM only affects the Siemens DVB-Cable card.

> The AFC is almost always -4

I get the same AFC on my TT budget DVB-C, you cannot get it better than
this. The tuner has some weird IF centre frequency (35.9something MHz),
which cannot be evenly divided by the PLL step size of 62.5kHz.

This card is a mystery to me anyway:

- the VES1820 is connected to a 57.84MHz oscillator and thus expects an IF
centre frequency of 36.15MHz (oscillator/1.6)

- the TDBE2 tuner has a builtin downconverter (the TDBE1 doesn't), which
downconverts the output signal to 5MHz, however the VES1820 cannot take a
downconverted signal...

- you have to add a frequency offset of 35.9375MHz to calculate the PLL
frequency; no idea how that fits in with the 36.15MHz IF centre the VES1820
expects

This doesn't really make sense :(

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



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