Re: wanted: RGB to greylevel converter

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#20805

From: David Grieve
Date: Fri, 16 Jul 1993 14:16

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G. van Rooij (wswire3@rwa.urc.tue.nl) wrote:
: I have a monitor with 3 bnc inputs: Hsync, Vsync and video. Further I
: have some hardware with outputs Hsync, Vsync, R, G, B.  What I want is
: combining the R, G and B outputs to one video-signal so I can get a
: grey picture instead of only seeing either R, G or B in grey.

The simplest scheme is an emitter follower buffer with an output
impedance of 75 ohms and a resistive summer on the input which
adds R, G and B in the proportions 0.299R + 0.587G + 0.114B.

: The maximum bandwith of the monitor is 120 MHz and preferably, the
: converter can deal with that. 

If video bandwidth to 120MHz is required you might want to implement
the above summation using a video op-amp.  There are several on the
market which boast 100MHz bandwidth.  Look at Elantec, Harris, Maxim or
Analog Devices.  Layout is critical though, if you don't want an
oscillator :-).

: -Guido
: -- 
: ===============================================================================
: WIRE, Wiskundig Ingenieurs Eindhoven  |  wire@win.tue.nl
: PO Box 6421                           |   
: 5600 HK Eindhoven The Netherlands     |

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References: <wswire3.742827713@rwa.urc.tue.nl>

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From: dwg@hpqmola.sqf.hp.com (David Grieve)
Subject: Re: wanted: RGB to greylevel converter
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Date: Fri, 16 Jul 1993 14:16:08 GMT
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