How Can I Simulate FM Modulation in Pspice?

[Superhawk]

Hello all,

I am an Electrical Engineering student and I currently building a small, simple, FM Transmitter. I would like to be able to simulate this in pspice but I have had no luck. I can get a sinusoidal output, and gain, but no Frequency Modulation. Does anyone know of a good pspice tutorial. I am not very proficient with pspice, but I want to learn. I have looked around the internet with no luck. Any help would be greatly appreciated.

Ron

 

[rayjohn01]

Pspice

How you approach this depends on What you are trying to simulate , First are you just representing a block schematic or actual circuitry.
Second are you dealing with digital modulation or analogue .
in spice it is easy to switch between two sources one at f1 and the next at f2 the switches can be driven by some audio rate signal.
However there are sinusoidal Fm sources in spice if that's what you want .
If you are dealing with circuitry then you will have to build (models ) of the actual oscillators and modulation means such as varactors .
I am afraid unless you have the full Spice software the help is somewhat skimpy and you have to be very inventful as to how to set something up.
Remember that Spice deals Either with the frequency domain i.e AC
analysis or the time domain i.e. transient analysis -- so to set up a modulation scenario you need to set things up in time .
I cannot be of more help unless I know exactly what you are trying to do
If you are looking at simple data transmission at amateur allowed levels of power (by FCC ) then you hardly need more than a couple of transistors
with a varactor modulated Xtal oscillator -- however to simulate such in Spice is quite difficult (not impossible ) .
Ray.