Question

any idea about linear systems...??? how can we identify whether a given signal is linear or non-linear..???

Answer 1

Linear systems are those who are having their output response linearly (means the the output to input ratio will have linear relationship). for general ex. take graph and when you plot x*y or x+y you will get an liner straight line (mostly straight lines are linear) but if you try x^2 or Y^2 then you will get curve in 1st and 2nd quadrant (i.e nonlinear response). usually liner system are having func in first order (ex:ax+by) and non liner (ex:ax^2+y) systems has func in higher orders, logs and exponents. (note: when to take y=|x| or y=x^n where n is even number then your output will be always positive irrespective of the input this is causing the system to be an nonlinear)