Re: Apple II Video Generator

[Kevin <kevin@hackaday.com>]

> I understand, but NTSC monitor does not provide sufficient information how square wave is converted into luma and chrominance waves.
> I will discuss chrominance later.  Let's talk about luma.  NTSC monitor is supposed to show only five colors in monochrome.  Five colors are black (0%), dark gray (25%), gray (50%), light gray (75%), and white (100%).

I have no idea where you got that from, NTSC (more specifically RS170) is a analog waveform, you can have any value from 0-100%, which effects how brightly a point on the screen goes, it could be 74.372132823912732% or 0.3892371278239283729382732%, analog is effectively infinite amount of points 

> The NTSC monitor is supposed to use luma by recognizing the percentage between 0% and 100%.

yes, so whats happens when the device producing the signal can only spit out 0 or 100% and nothing between?

> Let's talk about 16 colors.

lets not, luminance only effects how bright a pixel glows and has nothing to do with color unless you add in another signal to define colors, then it determines how bright that color will glow, but its still greyscale, it has no idea what a color is 

NTSC color is a serious PITA, but RS170 monochome is dead simple, so I suggest you start there and add in color later, thats the way it was developed.