Signal processing system with baseband noise modulaltion chopper circuit timing to reduce noise

摘要

A signal processing system utilizes chopping modulation technology to remove 1/f and other baseband noise from a baseband of a signal of interest. Chopping modulation and demodulation circuitry use direct and cross-over switches to modulate low frequency noise, such as 1/f noise, out of a signal baseband. Chopping circuits are particularly useful with low frequency baseband applications such as audio applications. In one embodiment, the direct switches coupled to respective input and output terminals of a differential amplifier have nonoverlapping conduction phases with cross-over switches coupled to the terminals of the differential amplifier. Additionally, the direct switches coupled to the respective input and output terminals have different duty cycles with respect to each other, and the cross-over switches coupled to the respective input and output terminals of the differential amplifier have different duty cycles with respect to each other to reduce noise transfer to an output of the system.