Abstract: The present invention provides a differential voltage control oscillator including: a parallel resonance circuit in which an inductor circuit, a variable capacitance circuit, and a radio-frequency switching circuit are connected in parallel together; and a negative resistance circuit connected in parallel with the parallel resonance circuit.

Abstract: The present invention provides a voltage controlled oscillator for changing an oscillating frequency in accordance an input control voltage, including a parallel resonant circuit, a negative resistance circuit connected in parallel to the parallel resonant circuit, a first capacitor connected in parallel to the negative resistance circuit, a first current source connected between one terminal of the first capacitor and the negative resistance circuit, and a second current source connected between the other terminal of the first capacitor and the negative resistance circuit. The capacitance value of the first capacitor is set to a value that suppresses a signal with a frequency twice the oscillating frequency at both the terminals of the first capacitor. Each of the first and the second current sources is constituted by a bipolar transistor.

Abstract: A dielectric ceramic composition comprises 100 parts by weight of major component represented by the formula BaO-×{(1-y)TiO2.yZrO2} wherein 3.5≦×≦4.5 and 0≦y≦0.2, and auxiliary components added to the main component. The auxiliary components comprises about 5 to 30 parts by weight, on a ZnO basis, of zinc compound about 0.5 to 6 parts by weight, on a SiO2 basis, of silicon compound, about 0.1 to 3 parts by weight, on an oxide (R2O) basis, of alkali metal compound wherein R is alkali metal, about 0.1 to 7 parts by weight, on a CuO basis, of copper compound, and about 0.1 to 6 parts by weight, on a V2O5 basis, of vanadium compound or about 0.1 to 6 parts by weight, on a Bi2O3 basis, of bismuth compound. This dielectric ceramic composition can be simultaneously sintered together with silver or copper at a temperature of 1,000° C.