Re: Apple GPUs now 2 generations out of date?

In article <45GdnUVRIbXRNWzanZ2dnUVZ_tCrnZ2d@xxxxxxxxxxx>,
"Hasta La Vista" <noemail@xxxxxxxxx> wrote:

"Timberwoof" <timberwoof.spam@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:timberwoof.spam-0B2365.12564930032008@xxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <GIOdna0uAsyMLXLanZ2dnUVZ_hadnZ2d@xxxxxxxxxxx>,
"Hasta La Vista" <noemail@xxxxxxxxx> wrote:

"Timberwoof" <timberwoof.spam@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:timberwoof.spam-3CCDD1.08064330032008@xxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <aPCdncKTH4UfFHLanZ2dnUVZ_uuonZ2d@xxxxxxxxxxx>,
"Hasta La Vista" <noemail@xxxxxxxxx> wrote:

Discrete voltage levels from 0 to 255 are *not* binary numbers.

No, they're not. But they are digital, not analog.

That's wrong.

No it's not.

If you have one signal and its information is expressed as
a variation in voltage or current for more levels than two (1 or 0)
then
it is analog,

That's wrong. It doesn't have to be binary to be digital.

There were early computer systems that tried to use more than two
voltage levels to represent things, but that turned out to be more
trouble than it was worth,

That's true.

so it's safe to say that digital means, at
the basic level, binary.

That's untrue.

Show us a definition anywhere that defines a electrical signal of an
arbitrary number of discrete voltage levels as "digital", Edwin...


Unless you want to quibble, of course.

No, unless you want to be correct.

even if it came out of a digital-to-analog converter and
happens in some 2^n levels.

Digital to analog converters don't output discrete levels.

Oh, yes, they do. They cannot do otherwise. In fact, you're about to
contradict yourself...

No, Digital to Analog Converters change digital into analog, which means
continously varying levels.

Analog is
continuously variable. It doesn't come in steps. That's why D to A is
only an approximation. There's no way to know the level that was missed
between the steps. It can only be approximated from the levels each step
represent.

There. You contradicted yourself.

No I didn't.

A DAC works by assigning a specific voltage to each input bit. Usually
the voltage for each bit is 2^m/2^n * Out where m is the number of the
bit and n is the total number of bits and the least significant bit is
numbered 0 and Out is the desired maximum output voltage. In an 8-bit
DAC, that's 256 discrete values for the output. With a 16-bit DAC,
that's ~65k values.

You have a DAC confused with an ADC.

No, he doesn't.


http://en.wikipedia.org/wiki/Analog-to-digital_converter

"The resolution of the converter indicates the number of discrete values it
can produce over the range of analog values. The values are usually stored
electronically in binary form, so the resolution is usually expressed in
bits. In consequence, the number of discrete values available, or "levels",
is usually a power of two. For example, an ADC with a resolution of 8 bits
can encode an analog input to one in 256 different levels, since 28 = 256.
The values can represent the ranges from 0 to 255 (i.e. unsigned integer) or
from -128 to 127 (i.e. signed integer), for example, depending on the
application."

There may be an RC circuit (that means resistor-capacitor, not
radio-controlled) in the output to filter out the square-wave component
added by the time- and level-quantization error, and create a smoother
waveform. But either one can be used directly to drive an analog device
such as a speaker of a pixel.

No, that's an analog output that can not be applied to directly control a
pixel in a digital display.

Yes, it can.

The pixels in a LCD display consist of two electrodes in which the
voltage between them is controlled by a single transistor. A single
transitor cannot decode a binary signal, it can only amplify a voltage
level.

You can apply an waveform to the raster circuits of an LCD and it will
happily drive the pixels (assuming you provide voltages in the
appropriate basic range).

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."
.

Relevant Pages

  • Re: Symbol Grounding Problem (attn: Vend)
    ... require independent variables to be rationals. ... Just like, in a PC, the voltages on the wires are really analog, but it's ... easiest to understand the device as "voltage less than 1V means the digital ... You still seem to be stuck on simulation, where the discrete approximation ...
    (comp.ai.philosophy)
  • Re: Apple GPUs now 2 generations out of date?
    ... >>>>> to provide that voltage range for the full input range. ... >>> The final feed to a pixel is analog, ... I defined digital as levels in discrete steps, ...
    (comp.sys.mac.advocacy)
  • Re: Apple GPUs now 2 generations out of date?
    ... >> A digital value for a certain color is the same across video cards. ... > current level for the pixel element. ... > to provide that voltage range for the full input range. ... You described an analog input. ...
    (comp.sys.mac.advocacy)
  • Re: Apple GPUs now 2 generations out of date?
    ... That's claiming a digial input uses an analog signal, ... voltage to actually drive the pixels. ... Each pixel has its own discrete range of steps that are ... In discrete steps, not a continuously variable analog, Gimp. ...
    (comp.sys.mac.advocacy)
  • Re: Apple GPUs now 2 generations out of date?
    ... In any video system, even a digital-input monitor, there's an ... to provide that voltage range for the full input range. ... You described an analog input. ... The brightness of each pixel in a digital system are ...
    (comp.sys.mac.advocacy)
Loading