[Discuss-gnuradio] Re: usrp_tv_rcv issues

[Nathanael Nerode]

Matteo Campanella wrote:

> Hello folks, here there is an interesting piece about the nice usrp_tx_rcv
> and the status of the art as of now.
> I am sending it to the list with the consensus of Martin.
<snip>

>> A needed add-on is also color-decoding, color-video-sink and
>> audio-decoding.
>> Audio-decoding should be straight-forward because it is just a variation
>> on FM-radio (for PAL-TV)
>> The problem is that you need the full 6Mhz bandwidth to get the color and
>> audio sub-carriers and for most PC-s this is too much for realtime
>> decoding.
Is it perhaps possible to implement some of the decoding in the USRP, so as
not to clog the PC's CPU?  Perhaps a specialized daughterboard?

>> A quick-and-dirty solution could be to use a second channel in the usrp
>> tuned to the audio-carrier with smaller bandwidth.
>> (For color this will not work because you need exact
>> phase-relationships.)
Hmm.  I'm not sure I see this.  If the luminance channel and the color
channel are being digitized through different channels but with extremely
exact timing, can't the phase be kept synchronized for at least a full
line?  The synchronization code should make sure that they're resynced at
the beginning of each line.  Or is there simply not enough exactness in the
timing.

-- 
Nathanael Nerode  <address@hidden>

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