Xref: utzoo rec.photo:2280 rec.video:3261 sci.electronics:2712
Path: utzoo!mnetor!uunet!husc6!mailrus!tut.cis.ohio-state.edu!bloom-beacon!gatech!ncsuvx!mcnc!unccvax!dya
From: dya@unccvax.UUCP (Edison Carter)
Newsgroups: rec.photo,rec.video,sci.electronics
Subject: Re: Video inversion (build w/ chips, cheap sources of)
Message-ID: <944@unccvax.UUCP>
Date: 6 Apr 88 16:28:11 GMT
References: <637@nunki.usc.edu> <1155@ssc.UUCP>
Distribution: na
Organization: Univ. of NC at Charlotte, Charlotte, NC
Lines: 32
Keywords: chips, cheap boxes

In article <1155@ssc.UUCP>, markz@ssc.UUCP (Mark Zenier) writes:
> In article <637@nunki.usc.edu>, cyamamot@nunki.usc.edu (Cliff Yamamoto) writes:

> > can't find anything on it.  I'm interested in building (or locating a cheap
> > source of) video inverters.  ...

> The uA733 and NE592 are 50-100 mhz video amps that are cheap $1 - $1.50


     The Elantec EL-2020 operational amplifier is a current mode op
amp which has excellent video performance.  It can drive two 75 ohm
lines to 2 v p-p  with no problem.  It is about $ 5.50.

     Its primary advantage over the NE 592 are an order of magnitude
better differential gain and phase performance, and a much lower 
component count (say, 2 resistors, Vcc and Vee, and the chip) for
inverting gain.  It is also much more stable than the 592, or the
Plessey SL541 (yukkk) or the NE 5539 (a nice video amp, but a mean
oscillator).  You could get the EL 2020 to work nicely in a breadboard.

     Still another possibility (for crudity, anyway) is using a TL 084
and a 74LS221 to do your gating timing, etc.  The last thing you'll
need is an FET switch.  Make it an Analog Devices ADG 201.  The TL 084
doesn't make such a bad sync separator, and at unity gain inversion,
won't be gross for home use. You might want a real comparator, though,
to drive your gate (you want to preserve the burst and sync, I think).

     Maxim supposedly has some really neat stuff, too.


David Anthony
WLQV Detroit