Audio Line Noise Suppression for Smartphones

Murata examines how to maintain audio quality while suppressing noise in the internal audio circuits of smartphones. Smartphone audio quality differs by manufacturer as illustrated by the Earphone Audio Distortion Diagram (below), which shows the results of measuring audio distortion (THD + N). Common ferrite beads were used for noise suppression in the internal audio circuits of smartphones with poor THD + N results, but the models that emphasized audio quality used Murata's NFZ series. As the shift toward high-resolution audio continues to advance not only in specialized audio equipment but also in smartphones, audio filters that consider the impact on audio quality will become increasingly important.