[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
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.
Matt