[sci.electronics] RGB video to composite video conversion

josvdb@fwi.uva.nl (Jos van den Berg) (03/26/91)

I need a simple method to convert RGB video (1.00 V p-p) from a Booktree BT101 video DAC into composite video, preferably using only one IC and some off the shelf components.

dmturne@PacBell.COM (Dave Turner) (03/27/91)

In article <1991Mar26.125905.13464@fwi.uva.nl> josvdb@fwi.uva.nl (Jos van den Berg) writes:
>I need a simple method to convert RGB video (1.00 V p-p) from a Booktree BT101 video DAC into composite video, preferably using only one IC and some off the shelf components.

Check the National Semiconductor Special Purpose Linear Devices Databook
for the 

	LM1886 TV Video Matrix D to A
and the
	LM1889 TV Video Modulator

These two along with a suitable sync generator will produce both
composite video and RF channel carrier.

For a sync generator check the RCA Integrated Circuits for Linear Applications
databok for the CD22402 Sync Generator.



-- 
Dave Turner	415/823-2001	{att,bellcore,sun,ames,decwrl}!pacbell!dmturne

andreww@uniwa.uwa.oz (Andrew John Williams) (03/28/91)

dmturne@PacBell.COM (Dave Turner) writes:

>In article <1991Mar26.125905.13464@fwi.uva.nl> josvdb@fwi.uva.nl (Jos van den Berg) writes:
>>I need a simple method to convert RGB video (1.00 V p-p) from a Booktree BT101 video DAC into composite video, preferably using only one IC and some off the shelf components.

>	LM1886 TV Video Matrix D to A

>-- 
>Dave Turner	415/823-2001	{att,bellcore,sun,ames,decwrl}!pacbell!dmturne

NO!!! Not the LM1886! Its got 3 bit digital input for each of R,G,B. I
think there's something a little more suitable in the Motorala Linear
book, or the Phillips TV books. But I couldn't be bothered having a look
for the chip numbers at the moment. Look them up yourself

John West (stealing Andrew's account)
Why do fish eat grapefruit?

andreww@uniwa.uwa.oz (Andrew John Williams) (03/29/91)

andreww@uniwa.uwa.oz (Andrew John Williams) writes:
>think there's something a little more suitable in the Motorala Linear
>book, or the Phillips TV books. But I couldn't be bothered having a look
>for the chip numbers at the moment. Look them up yourself
Sorry about that. I was having a bad day. And all those b****y freshers
playing games on the Mac making it just about impossible to get at the
books. But I've looked them up now...
MC1377 video RGB to NTSC/PAL
MC1374 RF oscillator/modulator and FM sound osc/mod
The Motorola Linear book (or I'd guess the MC1377 data sheet) has an
example circuit using both chips - RGB,sync in, RF out. Just the two
chips and a few resistors/capacitors/those nasty inductor things
I've just had a look at the Philips book, and it seems to be entirely
PAL/NTSC/SECAM decoders, not encoders. But the Motorola chips should do
you.

John West (stealing Andrew's account)
Who was that masked fish?