1. signal filtering: In audio processing and communication systems, low-pass filters can remove unnecessary high-frequency noise or signals and only allow low-frequency signals to pass.
2. Frequency selectivity: The low-pass filter can selectively allow signals in certain frequency ranges to pass and block signals in other frequencies according to its designed cutoff frequency.
3. Signal shaping: In some applications, a low-pass filter can be used to shape the signal to make it smooth in time domain.