Re: TV to RGB

In <[EMAIL PROTECTED]> [EMAIL PROTECTED] (Mark Zenier) writes:

>In article <[EMAIL PROTECTED]>,
>Susan <[EMAIL PROTECTED]> wrote:
>>Dear All
>> Would it be possible to canabalise an old tv in order to make a cheap
>>TV to RGB convertor ?

   Television folks refer to this as a decoder.

>There was a NTSC (baseband video) to RGB converter project in
>Radio-Electronics or Electronics Now (Same magazine, name change) about
>a dozen years ago that used a now discontinued Motorola decoder chip.
>About the only way to get that chips (TDA3330, I think) would be
>do go digging in the board boneyard, probably a Zenith brand set about
>15-20 years old.

   A friend of mine built that project.  It used a CCD comb filter,
sourced as a replacement part for a tv of the time.  He had a wee
bit of difficulty getting it working.

   Unfortunately, the design was a bit flawed.  The burst loop needed
to be locked in order to seperate chroma properly from the comb filter,
which was clocked by... the burst oscillator.  I wound up modifying
the design to a sampled PLL that gated off sync, like most standard
burst-lock oscillators.

   For the OP, I'd look around for a commercial product, unless
she's interested in doing the design herself, which can be quite
fun.  Otherwise, I'd think someone must have a cheapie decoder out
there that doesn't cost the moon and the stars.  Or look for a used
broadcast decoder, like an old Faroudja, or even an Accom.  These
kick ass, but can also be noisy and might come with their own set
of problems.

-- 
                                        Tim Mullen
------------------------------------------------------------------
Am I in your basement? Looking for antique televisions, fans, etc.
------ finger this account or call anytime: (212)-463-0552 -------