Analog and digital

  1. Analog and Digital Signals
    There are two different methods of sending an electronic signal from A to B.
    ANALOG signals are continuous, and can take any value. DIGITAL signals encode
    values into binary numbers. As a binary number is made up entirely from 0’s and 1’s,
    it may be transmitted in the form of electronic on/off pulses (on =1, off =0). When
    these pulses are received, they are processed. A digital signal is made up of discretely
    variable physical quantities.
    Whilst these two types of signal both transmit information in electrical voltages, they
    each have their advantages and disadvantages. In recording audio signals, analog
    systems are useful, because they can give a faithful electronic representation of a
    complex waveform. However, because of the need for amplification of the electronic
    signal, ‘noise’ can be added along the signal path. This noise is due to unavoidable
    electron activity in the circuitry. Unfortunately, there is no easy way to get rid of
    noise from the original signal. Consequently, the noise (audible as a ‘hiss’) is added to
    the signal with each stage of transmission.
    A digital equivalent to this system would sample the sound wave at selected intervals
    and transmit the values that correspond to the sound wave in binary code. The digital
    representation of the sound wave could then be moved around or processed within the
    system without picking up any additional noise. Although the electron (noise) activity
    is still taking place, whenever the digital signal is repeated, during each stage of the
    transmission, the noise can be omitted.
    Analog Signal Digital Signal
    Accurate reproduction of signal needs
    extra work
    Very immune from noise
    Suffers from noise and distortion Output is accurate but can have errors
    from the sampling process
    Simple technique Complicated but can operate at long

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