Different criteria for "broad" have
been applied in different contexts and at different times. Its origin is in
physics, acoustics, and radio systems engineering, where it had been used with
a meaning similar to "wideband".[1][2] Later, with the advent of digital
telecommunications, the term was mainly used for transmission over multiple
channels. Whereas a passband signal is also modulated so that it occupies
higher frequencies (compared to a baseband signal which is bound to the lowest
end of the spectrum, see line coding), it is still occupying a single channel.
The key difference is that what is typically considered a broadband signal in
this sense is a signal that occupies multiple (non-masking, orthogonal)
passbands, thus allowing for much higher throughput over a single medium but
with additional complexity in the transmitter/receiver circuitry.
The term became popularized through the 1990s as
a marketing term for Internet access that was faster than dialup access, the
original Internet access technology, which was limited to 56 kbit/s. This
meaning is only distantly related to its original technical meaning.
भिडियो हेर्न तलको बक्स भित्र क्लिक गर्नुहोस
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