Low power noise detection circuit utilizing switching activity measurement method

Noise often limits the performance of transmitted signals and degrades signals quality. Moreover, stochastic nature of noise makes it difficult to predict, and hence, is hard to detect. In hardware implementation, the reduction of noise can only be optimized in the baseband where complex and intensive computation is executed using digital signal processors (DSPs). Although analog pre-filtering is applied at receiver front-end to reduce interferences, fractions of noise still exist due to non-ideality of the device. We present a method to detect noise in signal using switching activity measurement (SWAM) of analog-to-digital converter (ADC) output. Simulation results show that switching activity of digital outputs varies with different signal-to-noise ratio (SNR) values where high SNR value leads to low switching activity. A noise detection unit (NDU) is implemented and is synthesized using AMS 0.35 μm/3.3V CMOS standard library. The result shows minimum overhead where NDU occupies only 774 equivalent 2-input NAND gates and consumes only 978 μW of power. With advantage of small complexity and power usage, NDU is attractive to be used in ADC-based systems and noise prone devices in order to detect noise and leads to further signal improvement.