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From: mph@rover.UUCP (Mark Huth)
Newsgroups: comp.sys.amiga,comp.sys.misc
Subject: Re: Tuner for Monitor
Message-ID: <471@rover.UUCP>
Date: Tue, 18-Aug-87 18:34:11 EDT
Article-I.D.: rover.471
Posted: Tue Aug 18 18:34:11 1987
Date-Received: Fri, 21-Aug-87 06:54:18 EDT
References: <3561@ihlpg.ATT.COM> <948@bsu-cs.UUCP> <464@rover.UUCP> <1527@ukecc.engr.uky.edu>
Reply-To: mph@rover.UUCP (Mark Huth)
Distribution: na
Organization: Motorola Microcomputer Division, Tempe, Az.
Lines: 61
Xref: mnetor comp.sys.amiga:7544 comp.sys.misc:763

In article <1527@ukecc.engr.uky.edu> agollum@ukecc.UUCP (David Herron aka Admiral Gollum) writes:
>In article <464@rover.UUCP> mph@rover.UUCP (Mark Huth) writes:
>>>In article <3561@ihlpg.ATT.COM>, rre@ihlpg.ATT.COM (Velveteen Rabbit Corps) writes:
>>> [He's looking for a tuner for his monitor]
>>> 
>>There has been a lot of netnoise concerning "tuners" that can be connected to
>>the Amiga monitors.  Most of the recommendations that I have seen relate to
>>RF to RF types of boxes.  These will not work with the Amiga RGB/Composite
>>Monitor (1080?), as there is no way that these cheap little cable boxes produce
>>a composite video (or, drool, RGB) output.  The output from the VCR is a
>>composite video output, no RF involved.  There are RF to composite boxes 
>>available, but one needs to be careful about getting the right thing.  These
>>tend to be known as component TV, and are generally not as inexpensive as the
>>cable converters.
>>
>>Mark Huth - I speak for myself
>
>Don't listen to this man.
>
>These doohickeys being discussed *do* put out composite video (I believe
                                   ^^ some do, some don't - just be careful
is all I'm saying.

>I've seen ads for RGB versions as well)--what good would a tv tuner
>be if it emitted an RF signal?  You'd need a tv to watch it!

That is precisely the point - many, but not all cable type boxes simply do
a block conversion.  Those types will not work.
>
>I saw the one Service Merchandise carries (and which someone else already
>mentioned)--they had it hooked to a Commodore 1902 monitor--don't remember
>if it was composite or RGB.
>
> ...
>Kenneth Herron
Perhaps we could listen more closely to each other and avoid flames over 
terminaology that is far from universal.  For instance, I have a Sony tuner at
home that converts RF to the IF frequency.  It is very good as a tuner - if
what you want is to replace the RF front end of a TV.

A tuner is tunable (assuming we speak English).  The RF portion is usually
a hetrodyne converter of some sort which converts the RF channel to a fixed IF
frequency.  The IF stages are very frequency selective and produce a modulated
signal at a fixed frequency.  This signal is then processed by video
demodulators, color-burst separators, audio channel demodulators, sync
separators, etc.  Composite video signals contain baseband luminance (light
intensity) chrominance (sp?) (color information) and video sync (timing)
information.  Of all the stages mentioned above, only the RF hetrodyne front
end is actually tunable by the consumer (as opposed to using tuned circuits
which are factory aligned).  

Various products called tuners in the market place may include little or
all of the signal processing to produce a demodulated video and audio signal.

Disclaimer - while I have tried to be accurate, space prevents a complete
treatment of TV signals.  Do not attempt to use the above information to
construct a television set in you home.  Don't try this at home kids - go
do some research first.

Mark Huth - I speak for myself
seismo!noao!mcdsun!nud!rover!mph