[mythtv-users] PVR-500 question

Joe Votour joevph at yahoo.com
Wed Aug 31 15:37:31 UTC 2005


Note that I'm talking generically, having worked with
chips that are capable of doing both NTSC and PAL, and
their assorted other hardware bits.  I don't know what
parts a PVR-500 or a PVR-350 use, so this is a generic
explanation.  I don't want to say that it's not
possible, but there's definitely strikes against it
happening.  You're better off buying a proper card for
your region.

For the PAL PVR-500, it might work.  European channels
are 8MHz wide, versus 6MHz on an NTSC system. 
Therefore, the saw filter (assuming there is one, and
it's not done digitally) on the PVR-500 card would be
8MHz.  (The saw filter, by the way basically causes
the signals before and after [frequency + saw/2] to be
clipped).  So, you can get a 6MHz signal through an
8MHz saw filter (though 1MHz on each side could be
crap).

Where I see the problem on the PAL PVR-500 is that
they likely used a tuner chip that is only capable of
locking onto multiples of 8MHz, rather than one that
can lock anywhere (it's a cheaper and more readily
available part).  If, on the other hand, they didn't,
with some software changes, it should be possible to
at least tune to the frequency and receive data. 
S-Video input is also an option, since there should be
no need for the tuner.  The MPEG-2 encoder should be
programmable to receive PAL or NTSC signals, so again,
with (maybe) a software change, you'd be able to have
your PAL PVR-500 work as an NTSC one.

The NTSC PVR-350 working in PAL though, well, I don't
think that's going to happen.  You'd be feeding an
8MHz channel through a 6MHz saw filter (or the
equivalant) which would chop off part of the RF
signal.  Your capture is absolute crap at this point. 
S-Video might work, but that's about it.  Same notes
on the software part, about programming the MPEG-2
encoder to work in PAL mode (if supported).

-- Joe

--- Marty Ravell <mythtv at rave-tech.com.au> wrote:

> I have a mate with an NTSC PVR-350 but who has just
> relocated to Australia
> (PAL land). Any idea if the reverse is also
> possible?
> 
> 
> Regards
> Marty
> 
> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org
> [mailto:mythtv-users-bounces at mythtv.org] On Behalf
> Of Gideon N. Guillen
> Sent: Wednesday, 31 August 2005 8:58 PM
> To: Discussion about mythtv
> Subject: [mythtv-users] PVR-500 question
> 
> I have a question regarding the PVR-500. 
> 
> Will a PAL PVR-500 work with NTSC? I'm in a NTSC
> country, but I saw
> this PVR-500 being sold locally at a very low price.
> The vendor said
> it's the PAL model. I'm just wondering if I can use
> this card for NTSC
> signals (including cable TV). It should be a good
> replacement for my
> existing bttv card that I'm using for MythTV.
> 
> -- 
> Gideon N. Guillen
> gideong at gmail.com
> 
> Take back the web! Download Firefox Today!
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