Page "Crystal filter" Paragraph 1

A crystal filter is an electronic filter that uses quartz crystals for resonators.

Quartz crystals are piezoelectric, so their mechanical characteristics can affect electronic circuits.

( see mechanical filter ) In particular, quartz crystals can exhibit mechanical resonances with a very high Q factor ( from 10, 000 to 100, 000 and greater — far higher than conventional resonators built from inductors and capacitors ).

The crystal's stability and its high Q factor allow crystal filters to have precise center frequencies and steep band-pass characteristics.

Typical crystal filter attenuation in the band-pass is approximately 2-3dB.

Crystal filters are commonly used in communication devices such as radio receivers.