Commissariat a L'energie Atomique

Lionel Geynet

Emeric De Foucauld

The voltage controlled oscillator comprises an oscillating system wherein two variable capacitors are alternately connected. The capacitances of these two capacitors vary respectively in the same direction as the voltage that is applied thereto and in the opposite direction. Replacing one variable capacitor by the other is performed automatically when the output frequency of the oscillator reaches a predetermined switching value. It is thus possible to divide an operating frequency band of the oscillator into at least two parts in which the frequency varies alternately in the same direction as the control voltage of the oscillator and in the opposite direction. Switchable fixed capacitors can be connected in the oscillating system, either when one variable capacitor is replaced by the other or by means of a command, to make the oscillator switch from one frequency band to a lower band.

Voltage controlled oscillator

The voltage controlled oscillator comprises an amplifier and an oscillating system comprising an inductor and a first and second variable capacitor connected in series, each having a capacitance varying according to its control voltage. The capacitance of one of the variable capacitors varies in the same direction as its control voltage and the capacitance of the other variable capacitor varies in the opposite direction to its control voltage. A capacitor having a fixed capacitance can be connected in series or in parallel with the first and second variable capacitors. The first and second variable capacitors are preferably formed by transistors, respectively of PMOS and NMOS type. An additional series of additional first and second variable capacitors can be connected in parallel with the first and second variable capacitors.

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Fontanes, France

Lionel Geynet