Amplitude modulated signal generation using a third-order delta-sigma oscillator

A major challenge for the realization of mixed-signal built-in self-test is the generation of analog signals. Not only must the analog sources be reliable and tunable but they should also require the smallest area possible. Delta-sigma oscillators which use a delta-sigma modulator in the feedback loop of a digital resonator were introduced to provide complex communication signals for this purpose. Circuits generating sinewaves and frequency modulated carriers have already been introduced. These designs were based on second-order digital resonators. A third-order highpass delta-sigma oscillator capable of generating amplitude modulated signals is presented. To the best of our knowledge, this is the first reported use of highpass delta-sigma modulation for signal generation