A novel method to generate binary frequency shift-keying (BFSK) radio frequency (RF) signals in optical domain is proposed. In the proposed system, an optical short pulse train is converted into super-Gaussian RF pulses with high frequency based on optical pulse shaping by two Mach-Zehnder fiber interferometers (MZIs). And the generated RF signals are coded using a fast electro-optic switch. By properly designing the MZIs, BFSK RF signals with desired code pattern and modulation index can be generated. A theoretical model for describing the system is developed, and the generation of BFSK RF signals in millimeter-wave regime is demonstrated via simulations.