Generally the information is encoded differently in analogue and digital electronics, the method they process a signal is consequently different. All operations that can be performed on an analogue signal such as amplification, filtering, limiting, and others, can also be duplicated in the digital domain. The first electronic devices invented and mass produced were analogue. The use of microelectronics has reduced the cost of digital techniques and now makes digital methods reasonable and cost-effective. There are all some main difference between analogue and digital electronics:
Noise: Because of the way information is encoded in analogue circuits, they are much more susceptible to noise than digital circuits, since a small change in the signal can represent a significant change in the information present in the signal and can reason the information present to be lost. Since digital signals take on one of only two different values, a noise would have to be about one-half the magnitude of the digital signal to cause an error; this property of digital circuits can be exploited to make signal processing noise-resistant. In digital electronics, for the reason that the information is quantized, as long as the signal stays inside a range of values, it represents the same information. Digital circuits use this principle to regenerate the signal at each logic gate, lessening or removing noise.
Precision: A number of factors influence how precise a signal is, mainly the noise present in the original signal and the noise added by processing. See signal-to-noise ratio. Fundamental physical limits such as the shot noise in components limits the resolution of analogue signals. In digital electronics additional accuracy is obtained by using additional digits to represent the signal; the practical limit in the number of digits is determined by the performance of the analogue to digital converters, since digital operations can usually be performed without loss of precision.
Design Difficulty: Digital systems are much easier and smaller to design than comparable analogue circuits. This is one of the major reasons why digital systems are more common than analog. An analogue circuit must be designed by hand, and the process is much less mechanical than for digital systems. Also, because the smaller the integrated circuit (chip) the cheaper it is, and digital systems are much smaller than analog, therefore a digital system is cheaper to produce than an analog.