RF output DOES NOT equal Composite!!!!

From: Andreas Freiherr <Andreas.Freiherr_at_Vishay.com>
Date: Thu Jun 20 11:10:33 2002

Yes! About SCART connectors, ...

Tony Duell wrote:
>
> 1) It doesn't make particularly good contact with the socket. Often it
> comes half-out and you lose video or something

Even while plugging one in, I always end up with an uncertain feeling
about the connector being seated properly.

> 2) It is in no sense a constant-impedance connector. I am a great
> believer in sending video signals along 75 ohm cable fitted with 75 ohm
> connectors, and terminating the input with 75 ohms (any other impedance
> would do as well, provided it's constant, and all parts have the same
> characteristic impedance). SCART would seem to be a source of signal
> reflections

And it does not provide any shields between the audio and video signals,
so I'd expect cross-talk. Although they are spaced pretty far apart, the
relatively large spades might make nice coupling capacitors...

> 3) Have yuo ever tried to wire one of those infernal plugs? Particularly
> if you're using all the pins?

What sort of cable do use to fit into the strain relief when using all
pins? - The cable should also have different runs for video (impedance
matched), audio (low capacity), and data lines (just well shielded), all
with separate grounds... - Once I find a suitable cable, I might try,
but I think soldering will be the easier part. (I did make my own
Ethernet transceiver cables years ago. AUI provides very limited space
in the connector shell, too.)

I think SCART intended to be a non-proprietary bus for complete
video/HiFi systems, easy to install for people who don't know the
different between an input and output jack/socket: I have heard people
talk about the "line input" of a CD player, for example. Well, you can
put a connector in there, yeah!

Whenever possible, I also prefer more specific connectors (and, yes, BNC
for video and RCA or even XLR for audio would certainly do well), and I
usually have no trouble telling from where to where a cable needs to go,
so SCART doesn't really seem to be made for me.

Many cheap TV sets and satellite receivers have SCART connectors around
here, but my A/V receiver (Onkyo TX-DS939, for those familiar with them)
has none at all. It prefers gold-plated RCA and other connectors,
obviously for a good reason.

--
Andreas Freiherr
Vishay Semiconductor GmbH, Heilbronn, Germany
http://www.vishay.com
Received on Thu Jun 20 2002 - 11:10:33 BST

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