An AM signal in SPICE

Look in the special function lib. The last 4 items all the way down the list.

Select modulator add two signal sources.

Right click the modulator and add the two descriptors.
Mark= ?????
Space= ?????
The ?????= your desired frequency.Be sure to put both are your signal will be distorted.

V1 is the amplitude of the envelope.
V2 is the modulating signal. Set its DC offset, amplitude and frequency.
Q is an AM signal you just built.