Analog and Digital Signals
A signal is simply an indication of movement of something. It can be current. Light, music or even the heat. Being quite crucial to science, signals have been widely divided into two classes in order to ease out their study. Analog and digital are types of signals that follow different mannerisms in propagating any signal. Signals that follow Analog methodology propagate in such a manner that they can be studied at any instant of time. On the other hand, digital signals can be defined at discrete values which are a whole number.
Analog Signals: It is a continuous wave form which changes smoothly over time. Such signals can be easily generated from the source of information by using an appropriate transducer, e.g. pressure variations in the sound waves can be converted into corresponding current or voltage pulses with the help of a microphone.
A simple Analog signal is represented by a sine wave:The frequency of Analog signals associated with speed or music varies over a range between 20 Hz to 20 KHz.
The range over which the frequencies of signal vary is called bandwidth.
The term base band designates the band of frequencies representing the signal supplied by the source of information
A signal consisting of two or more waves of different frequencies known as a complex Analog signal.Digital signals: A digital signal is a discontinuous function of time. It has only two voltage levels, i.e. either low (0) or high (1). Either of 0 and 1 is known as bit. A group of bit is called byte. A byte comprising 2 bits can give four code combinations, i.e. 00, 01, 10, and 11.The number of code combination increases with number of bits in a byte is given by N = 2x, where, x = number of bits in a byte. The number of binary digits (bits) per second, which describe a digital signal is called its bit rate. Bit rate is expressed in bits per second (bps).
Analog and Digital Signals: The advantages of ANALOG systems are that they can be easily interfaced to the real world, and do not need any type of converts and the speed is not dependent on the clock rate. Whereas the DIGITAL systems are very accurate and has a greater control over resolution and re – configurability and has a predictable and reproducible behaviour. The main difference between Analog and Digital is that we can feel the Analog where as digital is not real and it exists only inside a machine.