Arrangement for providing improved linearization of the voltage-frequency characteristic of a resonant circuit having a voltage-variable capacity diode

Claim 1

An improved, more linear frequency modulator circuit for a high frequency oscillator having a structure forming a cavity and a transistor operatively positioned in said cavity for causing high frequency oscillations therein, said frequency modulator comprising: a. a modulator housing attached to said oscillator structure, said modulator housing having an elongated cylindrical opening therein that extends through a part of said oscillator structure to operatively connect with said oscillator cavity; b. an elongated conductor coaxially positioned in said cylindrical opening and insulatingly supported therein with one end of said elongated conductor positioned in said oscillator cavity and with the other end of said elongated conductor positioned adjacent its respective end of said cylindrical opening, said elongated conductor having a length that is substantially one-third wavelength long at the frequency of oscillations of said oscillator; c. a probe connected to said one end of said elongated conductor for coupling said elongated conductor to oscillatory energy in said oscillator cavity; d. a voltage-variable capacity diode mounted on said other end of said elongated conductor; e. means for connecting one electrode of said voltage-variable capacity diode to said other end of said elongated conductor and the other electrode of said voltage-variable capacity diode to said respective end of said cylindrical opening; f. and a direct current circuit connected to said elongated conductor between its ends and to said modulator housing for applying a modulating signal To said voltage-variable capacity diode, thereby modulating the frequency of said cavity oscillations in a more linear manner.