Comparative Analysis of First-Order, Second-Order, and Fourth-Order Low-Pass Filters in Amplitude Modulation Synchronous Demodulation Systems

Amplitude Modulation (AM) is both a ubiquitous modern communication technology and is used extensively in the low-power Internet of Things (IoT). In real-life settings, noise in a channel, system flaws, and electromagnetic interference are major factor that plagues the quality of communications, and this aspect requires proper filtering in order to obtain sound data recovery. The paper explores the behaviour of filters of different orders in an AM synchronous demodulation system. The simulation model includes the amplitude modulation, additive white and pink noise, phase-locked loop synchronous demodulation, and parallel low-pass filtering. Filter performance under the same system parameters is compared using gain accuracy, phase delay time, signal-to-noise ratio (SNR), carrier rejection ratio, total harmonic distortion (THD), and steady state error. Findings show that superior noise suppression, which enhances signal reliability, is attained at higher-order filters, which are susceptible to phase delay and sensitivity in terms of synchronization.