Krystaly, Hradec Králové, a.s.
 

Terms, Definitions and characteristics

Basic definition
The filter is the passive four-terminal network, transmitting (or retenting) the defined frequency band.

Course of attenuating characteristic of the filter

Other terms and definitions
Title Symbol Definition
Nominal frequency fo [MHz] Indicates the nominal center frequency of the band-pass or the nominal stop frequency of a band-stop filter
Poles [--] The number of poles of the transfer function
Nominal bandwidth
(Pass band)
B1 [kHz] Minimal bandwidth of the pass-band at the attenuation A1 [dB]
Stop-bandwidth B2, B3 [kHz] Separation of frequencies between the relative attenuation of filter shall be equal to, or greater than, a specified value
Insertion loss L [dB] The logarithmic ratio of the power delivered to the load impedance before insertion of the filter to the power delivered to the load impedance after insertion of the filter
Pass-band ripple R [dB] Difference between the maximum value and the minimum value of attenuation within the pass-band B1 [kHz] of the filter
Alternate attenuation A3 [dB] Attenuation in a frequency range far outside of the pass band
Spurious response A4 [dB] Minimum attenuation caused by extraordinary response in the stop-band. Spurious response usually appears at higher frequency than the center frequency
Group delay distortion Δt [ µs ] The difference between the maximum and minimum group delay within the pass-band (B) unless otherwise specified
Terminating impedance Zt
Rt // Ct
[ Ω // pF ]
Either of the impedances presented to the filter by the source or by the load

Reference
For more information about the crystal filters can be obtained from the following technical standards:
EN (IEC) 60 368-1, Piezoelectric filters of assessed quality - Part 1: Generic specification

 
 
 

KRYSTALY 

Hradec Králové, a.s. 
Okružní 1144 
500 03 Hradec Králové 3 
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