Having briefly considered the question of 'how fast can we send
data', it is immediately apparent that there are two fundamental factors affecting the
information transfer rate on a channel, namely:
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The maximum possible detectable rate of change of waveform or symbol state
The bandwidth of the channel (and any bandwidth limits
imposed by the transmitting and receiving devices) will determine how quickly the
signalling states on the channel can be changed.
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The ability to resolve any number of discrete symbol states
The level of noise in the channel will impose an upper
limit on the number of different unique symbol states that can be correctly resolved
(decoded) at a receiver.
The degree of distortion introduced by the channel will
also limit the number and rate of change of symbol states that can be accommodated with
acceptable performance.
So, if we had a channel with infinite bandwidth, or no noise and distortion, it would
be possible to send the 1000000 bits of information 'instantaneously' well, at the speed
of light anyway.
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