Austin this was an ILLUSTRATION, not based on an actual D/A - I was using
an illustrative range of 0 -1024mV just to make a point which is valid
whatever range you choose. I could have talked about -3 to +3 V but the
point would have been even more obscure than it already is.
As you point out and as I mentioned, there is no problem introducing an
offset and/or amplification to give any range to a D/A, or to modify
linearity through log pre-amps etc, but it is irrelevant and confusing when
related to my main point.
The detail of voltage ranges is not important to the principle that
determines measurable density ranges, and in fact I don't think linearity
is relevant either.
Julian R
At 01:50 12/01/01, you wrote:
> >Because it is an 8-bit D/A, the lowest level we can read is 2^8 lower than
> >1024 = 1024/256 = 4mV.
>
>The number of bits has NOTHING to do with what voltage it can read.
>Different converters have different voltage ranges, AND the input voltage
>range can be changed via an analog front end to the converter.
>
>Typical converters have a voltage range from +3 to -3 volts, or a 6V swing.
>An 8 bit converter would therefore have 6/256 or .023V or 23mV resolution
>per bit.
Julian Robinson
in usually sunny, smog free Canberra, Australia
