Re: [Discuss-gnuradio] ( An attempt ) to run GNURadio on WinTV : )

[Hew How Chee]

Hi Jim,

 

Can't remember that clearly, but the idea is to get the 2nd sound IF of the TV/FM tuner capacitively to one of the ADC inputs. The IF pin is one of the TV/FM tuner output pin. (It might not be available in all tuner module). I removed the existing circuit that was attached to this IF pin, in my case, I just need to removed a 0 ohm resistor. I also resisitively divide the IF pin output voltage just enough so that it does not exceed CX23881 voltage level. This step might be redundant since I do not have a oscilloscope to measure the IF pin voltage swing.

 

The sine came from a program written for Palm Pilot. Looking back at the code, I guess its about 2k. You can inject the tone direct to the composite video in and use the CX built in multiplexer to select this input.

 

 

Regards,

Hew

Jim Perkins <address@hidden> wrote:

> Hew,
> Do you recall what the hardware mods were?  I'm wondering if  I can clean up card with caps here and there.  I looked at your sine wave data.  I low pass filtered it and got rid of most of that garbage.  The tone is at 1890 Hz as far as I can tell.  How did you generate that tone and what was the center frequency?  Where did you inject the tone?
>  -Jim
>
> Hew How Chee wrote:
> > Hi Jim,
> >
> > The card I use last time is PV-TV304P+ (REV .2B) with FMRC (FM and Remote Control) . The chipset used is CX23881. The card from newegg.com is using CX23883. Can't tell it is compatible or not. The data I got is 8 bit unsigned. Didn't try out 10 bit since I was quite dissapointed by the noise in the 8 bit
> >  digitized signal. Nevertheless, it is still possbile to digitize the 10.7 MHz FM IF with hardware mods.
> >
> > Note that the source code at http://www.geocities.com/how_chee/cx23881.htm can't compile and run in Linux kernel 2.6 and is not hooked up to GNURadio. It was developed using Knoppix Live CD 3.4 running kernel 2.4.x.
> >
> > Best regards,
> > Hew

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