| 摘要 |
1,187,283. Waveguide crystal mountings. STANDARD TELEPHONES & CABLES Ltd. 12 May, 1967, No. 22147/67. Heading H1W A crystal mount comprises a waveguide section which is dimensioned such that all modes are evanescent at the operating frequency. The capacitative susceptance of a crystal unit 1 mounted directly or indirectly in the section is tuned out by the inductive susceptance of the length l 2 between the unit and the short-circuited end of the section. The section is matched to the impedance of the source by means of an adjustable capacitative susceptance (screw 7) whose value is the conjugate of the input inductive susceptance. The length l 1 is such that the input conductance is equal to the source conductance. A full mathematical treatment is given in the Specification. The screw 7 may form the last in a series of susceptances which provide a band-pass filter. |
