Xref: utzoo rec.video:3983 sci.electronics:3567
Path: utzoo!attcan!uunet!husc6!bbn!uwmcsd1!ig!agate!pasteur!ames!amdcad!phil
From: phil@amdcad.AMD.COM (Phil Ngai)
Newsgroups: rec.video,sci.electronics
Subject: Re: Who needs S-VHS? (Was Re: MTS Stereo, Linear Stereo, VHS Hi-Fi)
Message-ID: <22575@amdcad.AMD.COM>
Date: 8 Aug 88 17:45:13 GMT
References: <8808030123.AA21805@jade.berkeley.edu> <983@acornrc.UUCP> <22535@amdcad.AMD.COM> <4721@fluke.COM>
Reply-To: phil@amdcad.UUCP (Phil Ngai)
Organization: Advanced Micro Devices
Lines: 26

In article <4721@fluke.COM> strong@tc.fluke.COM (Norm Strong) writes:
>} How about making a copy of a VHS tape, can you see that? 
>
>The last argument is, of course, an argument for owning 2 VCR's, at least one
>of which is S-VHS.  The results will be pretty close to having two non-VHS
>recorders:  At best, the copy will be identical to the original--which is
>ordinary VHS.  

This is a common belief, that if one of your components is limited to
240 lines of resolution, it doesn't pay to make your others any better
than that. 

It's been a long time but I believe that if you have a series of cascaded
systems, such as a VCR taping off a VCR, that you will lose resolution
even if they are both the same. The relationship is something like

system = 1/sqrt( (1/vcr1)^2 + (1/vcr2)^2)

I believe this works out to 170 lines if you cascade two VCRs with 240
lines of resolution each.

(did I remember my linear systems theory correctly?)
-- 

I speak for myself, not the company.
Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or phil@amd.com