Concept of Transfer Function

       In any system, first the system parameters are designed and their values are selected as per the requirement. The input is selected next, to see the performance of the designed system. This is shown in the Fig.1.

       Now performance of the system can be expressed in terms of its output as,

             Output = Effect of system parameters on the selected input

        .^..   Output = Input x Effect of system parameters,

       This effect of system parameters, role of system parameters in the performance of system can be expressed as ratio of output to input. Mathematically such a function explaining the effect of system parameters on input to produce output is called transfer function. Due to the own characteristics of the system parameters, the input gets transferred into output, once applied to the system. This is the concept of transfer function. The exact definition of the transfer function is given in the next section.