[TechAssist] Re: Interesting VCR info
- From: "J Silverman" <greentron@xxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 15 Nov 2004 14:08:13 -0500
Both systems used azimuth recording to reduce the luminance pickup from
adjacent tracks. Beta shifted the chroma phase by 180 degrees from an
adjacent track. VHS shifted the chroma each horizontal line by 90 degrees
from the previous one. There was no guard band between tracks on either
system. The VHS chroma adjacent track pickup rejection just did not work as
well as the Beta chroma adjacent track pickup rejection, which resulted in a
"busy" background in the VHS picture. Some brands filtered out some of the
video high frequencies to get rid of the busy background and then emphasized
the remainder to sharpen up the picture detail. This caused a "outline"
effect on vertical lines in the picture. I have a Sanyo Beta Hi-Fi and a VHS
at home and watch the Beta every once in a while to remind me how much
better the picture looked.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
Fax/Phone 864 232 3889
mail to: greentron@xxxxxxx
----- Original Message -----
From: "Hoyt's TV" <hoytstv@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, November 15, 2004 12:51 PM
Subject: [TechAssist] Re: Interesting VCR info
> When I went to the Philips camcorder school in Joisey, back around 1984,
> Jerry Kent told the story this way:
>
> Sony refused to license it's system to the other companies, so the other
> companies got together and came up with the Video Home System as a group.
>
> The basic difference between it and the Sony system is that the heads were
> polarized 180 degrees apart to be able to legally call it a different
> system. This caused a slight deterioration of picture quality which was
not
> noticeable to most people.
> Kind of like the guy who insisted he could tell the difference between his
> Hi Fi phono with the cartridge that was capable of 20,000 hz and one with
a
> 15,000 hz system. When he probably couldn't hear much above 10,000 hz
> anyway, on a hearing test.
>
> When the need to get more than 2 hours on a tape became obvious, there was
a
> problem with print through when they made the tape thinner to get more
feet
> on the reel. So they slowed down the tape speed which cut the guard space
> between tracks to zero. This was a problem with BETA since both tracks
were
> polarized the same, the head could read spillover from the adjacent track.
> In VHS however it didn't read the adjacent track because of the opposite
> polarization. This became an immediate unexpected advantage for the VHS
> system.
>
> Later it was discovered they could slow down the VHS even more to get 6
> hours on a tape without seriously hurting the picture quality. Even though
> this caused the tracks to actually overwrite each other a small amount, it
> was not a problem due to the opposing polarization.
>
> So what was originally a disadvantage, became a terrific market advantage
in
> the long run.
>
> Sony basically allowed greed to cut their own throat.
>
>
> Russ Hoyt
> Hoyt's TV
>
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