FPGA implementation of FHSS-FSK modulator

This In this paper, we present the Binary Frequency Shift Keying (BFSK) modulator using the Frequency Hopping Spread Spectrum (FHSS) operating in the European band ISM 863-870 MHz. This modulator is intended for short range wireless applications, such as the wireless network sensors. The modulator generates a 7 MHz wide single-sideband, frequency hopped spread spectrum waveform for wireless transmission in the 863-870 MHz. This modulator is designed using the Direct Digital Frequency Synthesizer (DDFS) which enables us to generate BFSK signal with the hopping frequencies. Low power DDFS architecture is presented. It uses a smaller lookup table for sine and cosine functions compared with existing systems using a minimum additional hardware. A DDFS with -88 dBc spectral purity, 41.29 Hz frequency resolution and 10 bits output data for sine function generation is being implemented in an FPGA.