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. The authors present a method to detect noise in signal using SWitching Activity Measurement (SWAM) of Analog-to-Digital Converter (ADC) output.