Crystal FiltersCrystal filters are electronic filters that use a crystal resonator to selectively pass or reject signals of a specific frequency or frequency range. These filters are commonly used in radio frequency (RF) and microwave applications, where they are used to select the desired signal from a mix of signals. Crystal filters are known for their high selectivity and stability, as well as their low loss and low temperature drift. They are also relatively small and inexpensive, making them a popular choice in a wide range of RF and microwave applications. Crystal filters are typically used in conjunction with other filtering and amplification components, such as amplifiers, mixers, and oscillators, to form a complete RF or microwave system.