Title :
On the realisation of asymmetric transmission zeros for crystal filter design
Author :
de Barros, M.P. ; Lind, L.F.
Author_Institution :
University of Essex, Department of Electronic Systems Engineering, Colchester, UK
fDate :
10/1/1985 12:00:00 AM
Abstract :
The design of crystal filters with asymmetric amplitude characteristics is considered. A cascadedsection network is synthesised by the factorisation of the lossless chain matrix, in the lowpass (LP) domain. Special elementary sections, each realising a transmission zero on the j¿-axis, are related to the lower-order matrices extracted. These sections contain LP crystal prototypes where the LP motional inductances can present any desired value, so that, after a lowpass to bandpass transformation and impedance scaling, the piezoelectric units of the final crystal filter can possess the same motional inductance. An example is given.
Keywords :
band-pass filters; crystal filters; linear network synthesis; lumped parameter networks; passive filters; poles and zeros; asymmetric amplitude characteristics; asymmetric transmission zeros; cascaded-section network; crystal filter design; impedance scaling; lossless chain matrix; low-pass prototype; lower-order matrices; lowpass/bandpass transformation; motional inductances; piezoelectric units;
Journal_Title :
Electronic Circuits and Systems, IEE Proceedings G
DOI :
10.1049/ip-g-1:19850044
