A bandpass filter is an electronic device that allows signals within a specific frequency range to pass through while blocking signals outside that range. It is commonly used in audio processing, telecommunications, and radio broadcasting to isolate desired frequencies and reduce noise. These filters are characterized by their lower cutoff frequency and upper cutoff frequency, defining the bandwidth of frequencies that can pass. Bandpass filters can be implemented using various components, such as resistors, capacitors, and inductors, or through digital signal processing techniques in software applications.