Answer:

A filter that passes frequencies between two designated cut-off frequencies and attenuates all other frequencies is called a band pass filter. It is designed to allow a specific range of frequencies to pass through while attenuating frequencies outside this range.

Band Pass Filter:
A band pass filter is a type of electronic filter that allows a certain range of frequencies to pass through while attenuating frequencies below and above the desired range. It is characterized by two cut-off frequencies, namely the lower cut-off frequency (fL) and the upper cut-off frequency (fH). Frequencies below fL and above fH are attenuated, while those within this range are allowed to pass through.

Frequency Response:
The frequency response of a band pass filter is a graph that represents the filter's behavior across a range of frequencies. It shows the magnitude response (gain) and phase response of the filter. In the case of a band pass filter, the magnitude response is high within the passband (between fL and fH) and decreases significantly outside this range.

Applications:
Band pass filters find applications in various fields, including telecommunications, audio processing, signal processing, and image processing. Some common applications include:

1. Audio Equalization: Band pass filters are used in audio systems to select specific frequency ranges for equalization purposes, such as boosting or attenuating certain frequencies.
2. Wireless Communication: Band pass filters are used in wireless communication systems to select specific frequency bands for transmission and reception, allowing efficient use of the available frequency spectrum.
3. Biomedical Signal Processing: In medical devices, band pass filters are used to extract specific frequency components from physiological signals, such as electrocardiogram (ECG) or electroencephalogram (EEG) signals.
4. Image Processing: Band pass filters are used in image processing applications to enhance or extract specific frequency components from images, such as edge detection or image sharpening.

Conclusion:
In summary, a band pass filter is a type of electronic filter that allows a specific range of frequencies to pass through while attenuating all other frequencies. It is characterized by two cut-off frequencies and finds applications in various fields including audio processing, wireless communication, biomedical signal processing, and image processing.