A nonlinear relation between current and voltage for schottky resonant tunneling diode is used. A general form of equation similar to VanDer Pol equation is obtained. A Resonant tunneling diode(RTD) has a negative differential resistance that means when the voltage increases the current decreases. This property is very useful for oscillators manufacture. Nonlinear transmission lines is considered to show that it canbe used in oscillators and to show that it can reshape the sinusoidal signals to othershapes by using OrCad and mathematica programming.