Passing a pure sine wave through a non-linear component such as a diode or a transistor produces all of the harmonics of the input signal.
Using a transistor is preferred as it produces and amplifies the harmonics, using a generic frequency multiplier circuit with bandpass filters allows for the extraction of the 1st harmonic of 24.5MHz which is 49MHz.
The 10pF capacitor at the top of the circuit doesn't seem to effect the output frequency much but I believe it is required in a real circuit for it to operate properly.
This Circuit is going to be one part of a complete 49MHz FM Tranceiver for generic audio communication.
