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Re: [Discuss-gnuradio] Amateur television ATV

From: Matt Ettus
Subject: Re: [Discuss-gnuradio] Amateur television ATV
Date: Wed, 26 Apr 2006 13:25:40 -0700
User-agent: Thunderbird 1.5 (X11/20051201)

Lamar Owen wrote:
> On Wednesday 26 April 2006 14:03, Matt Ettus wrote:
>> Matteo Campanella wrote:
>>> hello, In the case of atv, as I believe the passband of the signal is
>>> way too large for the throughput of usrp usb, are there any special
>>> techniques/tricks to achieve some sort of result?
>> I believe that most ATV is AM (almost 12 MHz) instead of VSB (6 MHz).
>> If that is true, then you could do an AM demodulation in the FPGA pretty
>> easily.  You would tune the picture carrier to the center of the
>> passband.  Of course, the TVRX filters are only 6 MHz wide, so you'd
>> lost the high frequency content of the signal, and probably the sound
>> carrier.
> If it's true DSB AM, then just tune to one side, filtering out one sideband, 
> and treat it as single sideband.  Would want to watch out for aliasing, of 
> course, from the rejected sideband.  Unless you're real good, and set it so 
> that the aliased sideband folds into the passband perfectly... :-)  the 
> sidebands are, after all, identical in AM.

If you do what I suggested you don't have to tune exactly because you
can do an AM detection.


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