Patent ID: 8183943

Claim:
An oscillator comprising: a signal line that has a voltage applied portion to which a power supply voltage is applied and propagates a traveling wave according to application of the power supply voltage, the length from the voltage applied portion to at least one end being based on wave length of the propagated traveling wave; a maintaining unit that maintains a standing wave generated in the signal line according to the traveling wave propagated by the signal line; an output unit that outputs a signal having an oscillation frequency using the standing wave maintained by the maintaining unit; a plurality of potential changing electrodes each including a facing portion, which faces the signal line and of which the potential changes to the ground potential; and a controller that adjusts the oscillation frequency of the signal output from the output unit by increasing the number of potential charming electrodes where the potential of the facing portion becomes the ground potential when the oscillation frequency of the signal output by the output unit is increased, and by decreasing the number of potential changing electrodes where the potential of the facing portion becomes the ground potential when the oscillation frequency of the signal output by the output unit is decreased, wherein the controller changes a potential of the potential changing electrodes to a ground potential in the sequence starting from the potential changing electrodes close to the position of the voltage applied portion of the signal line or the position away from the voltage applied portion by integer times as long as the 1/2 wavelength of the traveling wave when the controller increases the number of potential changing electrodes where the potential of the facing portion becomes the ground potential.