The major difference between digital and analog transmission is the transmission capacity or the bandwidth required for each system. For example, for an average NTSC video signal, analog signals can work on a very low bandwidth of about 4.5 MHz having a data rate of 143.2 Mb/s. At the same time, a digital video transmission may require a large bandwidth of about 74.25 MHz with a 1485 Mb/s data rate. For digital transmissions, advanced single-mode optical fiber can easily make these higher data rates accessible for longer distances while conventional copper coax cannot perform at these levels of data rates at all.
One more important difference between the digital and analog transmission is the device’s ability to recover the transmitted signal. In case of analog systems, to reconstruct the transmitted signal at the receiver end, some adjustment is required. This is because analog modulation is variable in behavior. At this point, you can judge the simplicity of digital system as it used binary format to encode the signals which can be easily reconstructed. Digital signals can include larger information that allows any transmission error to be corrected at the receiver’s end. It makes digital transmission systems better over analog since they can eliminate the effect of noise.
Digital technology makes use of sampling to record, transmit and reconstruct the data. For instance, when a digital music system records the original waveform, it samples the music at a rate of thousands times per second. It is about 44,000 times per second for a CD recording. It means it records 44,000 numbers per second. The more the number of sampling per second, the better will be the quality of the signals. At the time of reconstruction, original waveforms are produced at a rate of one bit at a time at lightning speed.
A digital system delivers the reconstructed signals as the exact copy of the original signals without any disturbance and noise.