Optimized periodic sigma-delta bitstreams for analog signal generation

This paper describes a new method to generate analog signals with high precision at very low hardware complexity. This method consists in reproducing periodically a portion of the bitstream output of a sigma-delta modulator. This technique utilizes less hardware than conventional analog signal generation methods and does not require a multi-bit DAC. An optimization routine which increases the quality of the signals is presented and signal generation examples are given. The design of a Dual Tone Multi-Frequency generator implemented using an FPGA is also presented