oscillator problem...

hi..
i designed a basic transistor oscillator circuit with input and output matching networks...when i simulated the circuit in microwave office, i am not getting oscillations at the output port. for the oscillations, am i need to provide pulses to the transistor at starting? if yes, where can i place the pulse triggering on circuit?

hi there

It mite help if we could see your circuit so that we could give an informed answer :)

Dave

u do not need any input for Oscilator to oscilate,actully the only reason to oscilate is noise.
first of all, u shuold be sure that ur simulator is not in ideal mode and niose is partisipate in calculations.

You could just ramp up the power supply or have one current pulse at the crystal input (for instance 1uA, 1ns).

I don't know the simulation capabilities of microwave office, but with classical circuit simulators, e.g. SPICE, noise is not considered in transient simulation. As a result, an oscillator will generally not oscillate without introducing a startup pulse or an initial condition different from equilibrium. The latter is more easy, because it's done by just writing a number, e.g. a capacitor initial voltage. Also skipping the initial operation point solution can achieve the same.