Method and apparatus for frequency measurement and adjustment of monolithic crystal filters
OwnerFranz L. Sauerlandinventor
Life of this patent
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Abstract
Method and apparatus for measuring the characteristic frequencies of a monolithic crystal filter and for adjusting them to predetermined values, based on selectively transmitting two balanced decoupled signals through the filter to an output signal detector for exciting and measuring the characteristic frequencies.
Claims17
A method for measuring up to four characteristic frequencies of a monolithic filter, said four frequencies including symmetric and antisymmetric frequencies and two resonator frequencies, and said method comprising the steps of:
- a. selectively applying two decoupled balanced signals to first and second filter ports of the filter;
- b. transmitting said decoupled balanced signals through the filter to an output signal detector, such that said characteristic frequencies of the filter are selectively excited;
- c. measuring said excited characteristic frequencies at the output signal detector.
An apparatus for measuring up to four characteristic frequencies of a monolithic filter, said four frequencies including the symmetric and antisymmetric frequencies and two resonator frequencies, and said apparatus comprising:
- a. a signal input means for providing two balanced input signals that are decoupled from each other,
- b. an output signal detector, and
- c. switching means for selectively interconnecting the terminals of a monolithic filter with the signal input means and with the output signal detector so as to selectively excite and measure the characteristic frequencies by means of selective signal transmission through the filter and signal detection in the output signal detector.
Dependencies are inferred from the claim text.