Continuous & Discrete Signals

Continuous signals & those defined over a set of real numbers(R) & discrete signals & those defined for discrete integers(I).
For instance, a signal(a function) having the domain [0,10] is continuous & one having the domain {1,2,3...10} is discrete.

A Continuous Signal can be converted to a Discrete Signal using an Analog-to-Digital Converter(ADC). The conversion consists of a process called sampling.

The sampling process simply samples out values of the signal at certain points seperated by an equal interval called the sampling period. In the above figure, the sampling period would be 3.

A common application of the above process is a Compact Disc(CD) which is simply a signal sampled at 44.1kHz & Quantized at 16 bits/2 bytes.

Analog & Digital Signals Analog Signals are continuous electric signals which arise from non-electric signals. The variable of the converted signal is analogous to the non-electric time varying signal & hence, they are called analog signals. A good example is an audio(speech) signal.

A digital signal, unlike the analog signal, takes only two vales-HIGH or LOW, ON or OFF, 0 or 1, TRUE or FALSE, etc. All computers & other gadgets use digital signals to store information. (The term sometimes also refers to discrete time signals which can also take discrete values other than 0's & 1's)

Based on the above, we may infer that a analog signal is continuous signal & a digital signal is a discrete time signal.

Signals are also classified as...

We then have Deterministic & Random Signals.

A random signal takes random values & at a point on the signal, we cannot determine its value just before it or just after it. However, these values can be easily determined for a deterministic signal. Next Post in this Category >> Signal Operations