Simple FM Modulator in LTSpice

Here is a simple FM modulator driven by a staircase voltage.

http://tinyurl.com/25rdzg7

This FM modulator can be used as a signal source for simulating an FM amplifier or other circuit.

NOTE: This modulator was obtained from the LTSpice Yahoo! group. I did not develop this schematic. This schematic was posted by the user "Petzen".