Patent ID: 7038552

Claim:
A variable frequency oscillator comprising: a variable frequency oscillator core comprising a plurality of capacitors selectively connectable to a resonant circuit so as to control a frequency of the oscillator; an oscillator controller; and an output voltage amplitude stabilization device for maintaining an amplitude of an oscillator output within a predetermined range, wherein the variable frequency oscillator core is controllable to operate in one of a plurality of frequency bands and has a frequency control input responsive to the oscillator controller, and where in order to set a new operating frequency the oscillator controller performs a frequency search to set the output frequency of the oscillator by: a) making an adjustment to the frequency of the oscillator by connecting or disconnecting a capacitor from the resonant circuit of the oscillator; b) adjusting an amplitude of oscillation of the oscillator to attain a target value prior to testing the output frequency of the oscillator to compare it to a target frequency; c) comparing the oscillator frequency with a target frequency; and d) on the basis of the comparison repeating steps a) to c) until an appropriate selection of capacitors to be connected to the resonant circuit has been made.