Model VG1
Video Test Generator
NTSC or PAL

This extremely low cost, video generator produces a complete color composite video signal. The video pattern is a full field 7 bar pattern (EIA type color bars) or the unit can be adjusted to provide any full field color desirable even color black. The output video level is adjustable to a nominal 1V p-p into a 75 ohm load. This design has a sync generator, video pattern generator, color encoder and power supply sections. The encoder section can be used alone for converting computer video graphics in the CGA mode to composite color video. Jumper connector sites are available on the circuit board for a external, Red, Green and Blue TTL level signals. Test points are available for both vertical and horizontal sync and many other signals. This project is a great educational tool also.

FEATURES

The video generator supports either NTSC, the US video standard, or PAL the European standard. The video standard selection is accomplished by configuring two jumpers, two crystals and two capacitors.


The printed circuit board is high quality doublesided with plated through holes, two sided solder mask and component ID silk-screen. The board size is 5.3" H x 7.0" W. If the application requires minimum space and a external power supply is available, only the video generator section of the circuit board is necessary and has the dimensions of 2.7" H x 7.0" W. All input and output connector locations are provided in the small area for this option.

Specifications:

Video Pattern: Full field 7 bar standard color bars from left to right, gray, yellow, cyan, green, magenta, red and blue.

Subcarrier NTSC: 3.579545 MHz +/- 50 PPM Adjustable +/- 10 Hz

Subcarrier PAL: 4.433618 +/- 50 PPM Adjustable +/- 10 Hz

Composite Video Output: Output video level is adjustable to a nominal 1V P-P into 75 ohm load. Negative Sync.

Sync Timing NTSC: Horizontal frequency 15718 Hz. H sync width 3.98 uS. Vertical frequency 59.87 Hz. Vertical Sync width: 190 uS. Sync timing tolerance +/- 5%. (note: H sync is not locked to subcarrier).

Sync Timing PAL: Horizontal frequency 15625 Hz. H sync width 4 uS. Vertical frequency: 50 Hz, Vertical Sync width: 192 uS. Sync timing tolerance: +/- 0.5%. (note: H sync is not locked to subcarrier).

Power Requirements:




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