Introduction
With the growing prevalence of high-frequency circuits, Wi-Fi, Bluetooth, walkie-talkies, mobile phone signals, and various interference frequencies, microphones are increasingly subjected to external noise disruptions. Users often report hearing buzzing, hums, current noises, or other unwanted sounds through their devices.
Common Causes of Interference
Microphones, especially those used in modern digital devices, are prone to interference from nearby high-frequency sources such as Wi-Fi routers, Bluetooth devices, and mobile signals. These sources emit electromagnetic waves that can affect microphone performance, leading to unwanted noise and poor sound quality.
Effective Solutions: Filtering and Shielding
Filtering
Microphones often use filters to block high-frequency interference. These filters are typically passive components like RC (Resistor-Capacitor) or LC (Inductor-Capacitor) circuits that are built directly into the microphone. When high-frequency interference enters the microphone, a small capacitor (C) offers very low impedance to these high-frequency signals, allowing them to bypass to the ground. Meanwhile, the microphone's audio signal has a much higher impedance and is not affected by the interference.
Shielding
Shielding is another effective method to resist high-frequency interference. Most microphones use PCBs (Printed Circuit Boards) with double-sided layers and isolation plates for this purpose. These external electromagnetic fields can be intercepted by the isolation plate, preventing interference from reaching the microphone. Grounded shields and casings are also used to minimize the impact of external noise.
