Bill,
> Joe, you could not be more mistaken.
>
> For a mode to be "digital", the states have to represent numbers. In
> your examples which follow your quote above you have taken an analog
> signal and digitized it. That is perfectly ok, but the original signal
> was not numeric. Only your digitized version is truly digital.
You are wrong - it does not matter what the original signal was.
The mode (mode of emission or mode of transmission) is digital
because the signal can take only a limited number of finite states
not the infinite number of states between limits that characterize
an analog transmission.
A "digital" system does not represent only numbers ... it is only
a convenient way of expressing the concept of integers vs. real
numbers. Integers represent a discrete (e.g., "digital") system
while real numbers represent a continuous (e.g., "analog")
system.
> In an analog system the different states are only the presence of
> absence of a signal - no numbers involved.
Wrong again .. an analog system uses not only the presence of
absence of a signal but the characteristics of that signal on
the continuum from off to fully on. In the audio world, that
continuous information is loudness ... in video it is brightness.
> Take two digital characters and multiply them together, then
> divide the result by one of the original characters. You will
> now have the two original characters. Can you multiply two
> Baudot characters together without digitizing them first?
The Baudot characters are already digital a five bit digital
code and you can most certainly multiply two five bit digital
numbers together and divide by one of the two to recover the
other. The start (always a space) and stop bits (always a
mark) are only present to frame the asynchronous data in the
channel.
> You either get it or you don't, Joe.
There is nothing to "get." You simply do not know the basic
difference between digital (discrete) and analog (continuous)
signals. Anything that can be completely described in a finite
number of symbols (whether they are numbers, letters, or arbitrary
designs) is "digital". A transmission method where the "carrier"
(channel state) takes on a finite number of discrete states
is a digital transmission mode.
73,
... Joe, W4TV
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