What are the disadvantages of transmitting data as digital data instead of analog data?
Digital data requires greater bandwidth on a transmission line than analog data. Consider a simple wire-loop carrying signal between a transmitter and receiver: if the signal is analog, the voltage on the line can be almost anything, and that voltage has “semantic value” — i.e. you could have the range from 0 to 10 volts be divided up in one-volt increments, and declare that 3 volts represents the number 3, and that the presence of 3 volts for 1 millisecond constitutes a single “word” of data. If your time units are consistent, that same bit of data would take 4 times as long to send with a binary 1/0 signalling scheme, because you would need to send 1010 – 4 bits. This is basically why digital TV and radio have taken so long to make it to the consumer world: analog packs more information into less “space”. Also, the processing circuitry for analog signals is much simpler — a crystal radio can be constructed by a Boy Scout with a few simple components. No way is the Boy Scout manual
