Euroquartz Ltd

Custom crystal filters, overview of capability. BAND PASS FILTERS Narrow Band Pass Crystal Filters Narrow band pass crystal filters are designed to pass a narrow frequency band and reject all other frequencies. The maximum band width using fundamental mode crystals is 0.3% of the centre frequency and is 0.03% when using third overtone crystals. Frequency range 1.0MHz to 100.0MHz. Intermediate Band Pass Crystal Filters The maximum bandwidth of this range of crystal filters is 2.0% of the centre frequency. Frequency range 1.0MHz to 100.0MHz. Linear Phase Crystal Filters To avoid distortion and ringing due to group delay it is necessary to have a flat time-delay characteristic. The group delay of a highly selective filter, varies considerably within the pass band. This introduces distortion into digital and low noise transmission signals. These problems can be overcome by specifying a Linear phase crystal filter. Frequency range 1.0MHz to 180.0MHz. SPECIALIST CRYSTAL FILTERS Comb Filter Banks A comb filter bank is made up of a number of crystal filter elements which are used to divide a particular frequency spectrum into discrete elements. Frequency range 1.0MHz to 100.0MHz. Band Reject Filter A band reject filter is a narrow band device which will reject a single frequency from a spectrum of frequencies

Design considerations when specifying custom filters: specifying the pass band, stop band, phase response, group delay, packaging etc.

Customer specified centre frequency Any Fo between 55MHz to 1600MHz Customer specified bandwidth No NRE design charges Low Insertion Loss Low Impedance Small Group/Phase Delay Smaller batch sizes at low cost Specimen Helical filter specification: 815.0MHz, 3 Pole