TEA1002

The TEA1002 is a PAL video encoder chip^[1] produced by Mullard in 1982 and used on the Mattel Aquarius computer, the AlphaTantel Prestel adapter and the Microvector 256 color graphics display interface for Nascom and Gemini computers.^{[2][3][4][5][6]} It was also used on teletext decoders and color bar generators associated with video test equipment.^[7][8]

TEA1002 on a Mattel Aquarius motherboard

It generates 16 colors based on Luminance, Chrominance and Saturation, usually with the 8 basic colors being similar to the EBU 75% color bars.^[9]

Levels

According to the TEA1002 datasheet,^[1][9] colors are formed by the combination of three signals, roughly equivalent to the HSL colorspace:

• Luminance
• Chroma phase (º, equivalent to hue angle)
• Chroma amplitude (%, equivalent to saturation)

Internally colors are stored in a 4-bit RGBI arrangement. There are three bits for the RGB components (generating 8 primary colors at full saturation but 75% luminance - similar to the EBU colour bars) and an inverter logic input bit that controls a variation of the base color (a 75% Luminance decrease for white; a 50% Chroma saturation decrease for all colors).

The following table lists the internal signals and shows an approximation of the generated colors, as seen on a web standard sRGB monitor. Colors could be different when seen on an analog PAL CRT television.

TEA1002 Logic inputs and composite video output (configured for 75% EBU colour bars)^[9]

Color	R	G	B	INV	Luminance (%)	Chroma (º)	Chroma (%)
Black	0	0	0	0	0.0	-	-
Red	1	0	0	0	22.5	103	±48
Green	0	1	0	0	44.0	241	±44
Yellow	1	1	0	0	66.5	167	±33
Blue	0	0	1	0	8.5	347	±33
Magenta	1	0	1	0	31.0	61	±44
Cyan	0	1	1	0	52.5	283	±48
White	1	1	1	0	100.0	-	-
Grey	0	0	0	1	75.0	-	-
Cyan	1	0	0	1	52.5	283	±24
Magenta	0	1	0	1	31.0	61	±22
Blue	1	1	0	1	8.5	347	±17
Yellow	0	0	1	1	66.5	167	±17
Green	1	0	0	1	44.0	241	±22
Red	0	1	1	1	22.5	103	±24
Black	1	1	1	1	0.0	-	-

An alternate configuration of the chip allows it to output 95% luminance color bars - similar to BBC colour bars, more suited for usage in teletext decoders.^[1]

TEA1002 Logic inputs and composite video output (configured for 95% BBC colour bars)^[9]

Color	R	G	B	INV	Luminance (%)	Chroma (º)	Chroma (%)
Black	0	0	0	0	0.0	-	-
Red	1	0	0	0	47.5	103	±48
Green	0	1	0	0	69	241	±44
Yellow	1	1	0	0	91.5	167	±33
Blue	0	0	1	0	33.5	347	±33
Magenta	1	0	0	0	56	61	±44
Cyan	0	1	1	0	77.5	283	±48
White	1	1	1	0	100.0	-	-
Grey	0	0	0	1	100.0	-	-
Cyan	1	0	0	1	77.5	283	±24
Magenta	0	1	0	1	56	61	±22
Blue	1	1	0	1	33.5	347	±17
Yellow	0	0	1	1	91.5	167	±17
Green	1	0	0	1	69	241	±22
Red	0	1	1	1	47.5	103	±24
Black	1	1	1	1	0.0	-	-

See also

• Thomson EF9345
• Motorola 6845
• TMS9918
• MOS Technology VIC-II
• List of home computers by video hardware