Difference between a Signal and a Function

  Signal and  Function

   Many Times it seems that a signal and a function are similar in nature but there are a few properties which separate a Signal form a Function.

Function: Function is the relationship between some independent variable to a dependent variable. Independent variable has some domains and dependents variable have ranges for those domains. Functions do not have any Bandwidth. A function is generally predictable i.e. we can express a function with some equations. A strict function is always a single valued variable. That each output is corresponds to one and only one input value.

Signal: Signal is also a relationship of input (independent) variable to output (dependent) variables. Independent variable have domain and dependent variable possess some ranges for those domain. But along with these characteristics a signal must have following characteristics.

•     Randomness: A signal can occur randomly at any instant. More the randomness the signal may contain more the information. It is defined as I =

•     Bandwidth: All the signals have its specific range of frequencies called bandwidth (BW). e.g. Audio signal has a bandwidth of 20 Hz to 20 KHz.