Area-optimized FPGA implementation of a digital FM modulator

An architecture and a prototype implementation of a digital frequency modulator are presented. The system features a direct digital synthesizer with a highly compressed ROM and a low-area Interpolator for the audio input signal. The frequency synthesizer has a spurious free dynamic range of more than 75 dB. The implementation occupies less than 200 configurable logic blocks on a Xilinx XC4000E-series field programmable gate array.