Abstract: An crystal resonator includes a first oscillating circuit that oscillates a crystal resonator at a first frequency, a first impedance adjusting circuit that adjusts an impedance of a first oscillating system including the crystal resonator and the first oscillating circuit, a second oscillating circuit that oscillates the crystal resonator at a second frequency that is different from the first frequency, a second impedance adjusting circuit that adjusts an impedance of a second oscillating system including the crystal resonator and the second oscillating circuit, and a controlling circuit that controls the first impedance adjusting circuit and the second impedance adjusting circuit.

Abstract: An crystal resonator includes a first oscillating circuit that oscillates a crystal resonator at a first frequency, a first impedance adjusting circuit that adjusts an impedance of a first oscillating system including the crystal resonator and the first oscillating circuit, a second oscillating circuit that oscillates the crystal resonator at a second frequency that is different from the first frequency, a second impedance adjusting circuit that adjusts an impedance of a second oscillating system including the crystal resonator and the second oscillating circuit, and a controlling circuit that controls the first impedance adjusting circuit and the second impedance adjusting circuit.

Abstract: A differential oscillator includes a resonator, a differential amplifier circuit, and a filter. The filter is disposed in parallel to the resonator and the differential amplifier circuit. The filter has a first resonance frequency in the first resonance mode and a second resonance frequency in the second resonance mode. The filter has a lower impedance at one frequency in one of the first resonance frequency and the second resonance frequency than an impedance at one frequency at another in the first resonance frequency and the second resonance frequency. The differential oscillator has a negative resistance at a frequency at which the impedance of the filter is higher while the differential oscillator does not have a negative resistance at a frequency at which the impedance of the filter is lower among the first resonance frequency and the second resonance frequency.

Abstract: A differential oscillator includes a resonator, a differential amplifier circuit, and a filter. The filter is disposed in parallel to the resonator and the differential amplifier circuit. The filter has a first resonance frequency in the first resonance mode and a second resonance frequency in the second resonance mode. The filter has a lower impedance at one frequency in one of the first resonance frequency and the second resonance frequency than an impedance at one frequency at another in the first resonance frequency and the second resonance frequency. The differential oscillator has a negative resistance at a frequency at which the impedance of the filter is higher while the differential oscillator does not have a negative resistance at a frequency at which the impedance of the filter is lower among the first resonance frequency and the second resonance frequency.

Abstract: A low-noise voltage controlled oscillator is provided, to improve a phase noise characteristic and widen a frequency variable range. The low-noise voltage controlled oscillator is configured so that an oscillation element and a capacitor 2 are connected in series between a collector C and an emitter E of a transistor 1, capacitors 3 and 4 are connected in series between the collector C and the emitter E, an electrical potential between the capacitors 3 and 4 is applied to a base B of the transistor 1; a one-port circuit 6 is provided between the collector C and the capacitor 4; and a capacitor for correction 5 is connected in parallel with the capacitors 3 and 4. The one-port circuit 6 includes a tuned circuit provided with a variable capacitor adjusting a capacity thereof smaller and an inductor adjusting a value of inductance larger so as to set a value of impedance relatively large.

Abstract: A low-noise voltage controlled oscillator is provided, to improve a phase noise characteristic and widen a frequency variable range. The low-noise voltage controlled oscillator is configured so that an oscillation element and a capacitor 2 are connected in series between a collector C and an emitter E of a transistor 1, capacitors 3 and 4 are connected in series between the collector C and the emitter E, an electrical potential between the capacitors 3 and 4 is applied to a base B of the transistor 1; a one-port circuit 6 is provided between the collector C and the capacitor 4; and a capacitor for correction 5 is connected in parallel with the capacitors 3 and 4. The one-port circuit 6 includes a tuned circuit provided with a variable capacitor adjusting a capacity thereof smaller and an inductor adjusting a value of inductance larger so as to set a value of impedance relatively large.

Abstract: Novel GalNAc&agr;2,6-sialyltransferases P-B1 and P-B3; GalNAc&agr;2,6-sialyltransferase genes encoding the above GalNAc&agr;2,6-sialyltransferases P-B1 and P-B3; and an extracellularly releasable protein catalyzing GalNAc&agr;2,6-sialic acid transfer which comprises a polypeptide portion as being an active domain of the GalNAc&agr;2,6-sialyltransferase P-B1 or P-B3 together with a signal peptide are provided. Also provided is a process for preparing a sialyltransferases which enables efficient recovery of a sialyltransferase expressed in a large quantity in microorganisms.

Abstract: Novel GalNAc .alpha. 2,6-sialyltransferases P-B1 and P-B3; GalNAc .alpha. 2,6-sialyltransferase genes encoding the above GalNAc .alpha. 2,6-sialyltransferases P-B1 and P-B3; and an extracellularly releasable protein catalyzing GalNAc .alpha. 2,6-sialic acid transfer which comprises a polypeptide portion as being an active domain of the GalNAc .alpha. 2,6-sialyltransferase P-B1 or P-B3 together with a signal peptide are provided. Also provided is a process for preparing a sialyltransferases which enables efficient recovery of a sialyltransferase expressed in a large quantity in microorganisms.