Color bar generator - Page 1
Forum section: electronics / projects

author: leblanc
author_rank: Regular Contributor
timestamp: October 30, 2015, 05:06:07 pm
content: I am looking for a cheap and easy way to generate an NTSC video + audio. I will be using this in a semi-automated manufacturing test.A simple color bar + 1kHz tone would be perfect.B&K 1257 does pretty much exactly what I need (http://www.bkprecision.com/products/video-cable/1257-portable-ntsc-generator.html), but I'd prefer an IC that I can put on a "tester" board. Maybe something like an NTSC encoder IC that has a test mode.

author: cpuerror
author_rank: Regular Contributor
timestamp: October 30, 2015, 08:05:08 pm
content: I would just get a dvd player with a test dvd. You can download the dvd images from places like avsforum.

author: German_EE
author_rank: Super Contributor
timestamp: October 30, 2015, 09:51:33 pm
content: A scrap PC with a video card that has NTSC out. Download your color bars as a tiff for best accuracy.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 31, 2015, 12:03:59 am
content: You're a bit late to the game if you want NTSC output from a chip, but maybe this:http://www.averlogic.com/AL128.asp?

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 31, 2015, 04:04:09 am
content: How about a Parallax Propeller?

author: bktemp
author_rank: Super Contributor
timestamp: October 31, 2015, 07:32:33 am
content: I tried to use a averlogic ic some years ago, but even the output from their demo boards didn't look good and they were unable to find the source code for the demo board. A bit unprofessional. Unless you want to sign NDAs, wait some weeks to get all the information and then have too much time fiddling around and guessing what each setting actually does, I can not recommend the averlogic parts.As already been said, specialized ics for composite video signals are pretty much obsolete. Today everything is integrated into the main asic. About 10-15 years ago there were many nice parts, some of them had an integrated test mode like BT864, BT865, BT868, BT869. They only need a clock and some i2c settings to enable the test pattern and they output a PAL or NTSC signal. If you can find them, they are easy to use and provide a good quality signal if you add a filter at the output.

author: Scrts
author_rank: Frequent Contributor
timestamp: October 31, 2015, 10:20:40 pm
content: This chip can output color bar:http://www.analog.com/media/en/technical-documentation/data-sheets/ADV7170_7171.pdfHowever, I don't think it will do audio.

author: Richard Crowley
author_rank: Super Contributor
timestamp: October 31, 2015, 10:48:53 pm
content: There are lots of old-school analog composite video test generators on Ebay.Probably not worth trying to roll your own with the glut of old gear going begging.Audio is a separate signal and can be easily generated even with a 1-transistor oscillator.Or with a 555 chip. Or something more sophisticated as required.

author: bitslice
author_rank: Frequent Contributor
timestamp: October 31, 2015, 11:10:37 pm
content: Just look on ebay under video broadcasting, they use colour bar signals as part of equipment testing and you can pick up amazing kit for the cost of an IC.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 31, 2015, 11:36:50 pm
content: Quote from: bktemp on October 31, 2015, 07:32:33 amSame here. Years ago I did a hobby project:RGBIto VGA upconverter with AL250. Got there 95%, but couldn't figure out how to get the color LUT working. It should be so simple, all I ever got waspurplesandgreens.I didn't get great answers from their tech support and the datasheet was pretty short for something like this.I always figured it was because I suck at software.