Abstract: A signal generator generates a test signal including a positive signal and a negative signal which have the same amplitude. The signal generator corrects a DC level of the test signal based on a DC offset correcting signal supplied thereto, and supplies the corrected test signal to a frequency converter. An amplitude detector detects the amplitudes of the positive and negative signals of the test signal processed by the frequency converter. A level compressor converts in level the amplitudes of the positive and negative signals which are detected by the amplitude detector, with a gain variable depending on an input level thereto. A comparator compares the amplitudes of the positive and negative signals which are converted in level by the level compressor, with each other. An offset adjuster supplies the DC offset correcting signal depending on a compared result from the comparator to the signal generator.

Abstract: An apparatus includes a test signal generation unit supplying test signals to an orthogonal modulator and a control unit that based on a result of decision by comparison and decision of detection results of a detector detecting envelopes of modulated signals output from the orthogonal modulator responsive to the test signals, derives adjustment values and a compensation value. An estimation means estimates a DC offset and an IQ mismatch of the orthogonal modulator, based on the derived compensation value. The test signals includes a first set including a first test signal (I1, Q1) and a second test signal (I2, Q2) having a predetermined relationship with the first test signal, and a second set of which in-phase and quadrature components have predetermined relationships respectively with in-phase and quadrature components of the first set.

Abstract: A signal processing circuit for compensating for an I/Q amplitude mismatch in which the amplitudes of I- and Q-components of output signals of a quadrature modulator are unequal to or for compensating for an I/Q phase mismatch in which the phase difference between the I- and the Q-components of output signals of the quadrature modulator deviates from 90 degrees.

Abstract: A signal generator generates a test signal including a positive signal and a negative signal which have the same amplitude. The signal generator corrects a DC level of the test signal based on a DC offset correcting signal supplied thereto, and supplies the corrected test signal to a frequency converter. An amplitude detector detects the amplitudes of the positive and negative signals of the test signal processed by the frequency converter. A level compressor converts in level the amplitudes of the positive and negative signals which are detected by the amplitude detector, with a gain variable depending on an input level thereto. A comparator compares the amplitudes of the positive and negative signals which are converted in level by the level compressor, with each other. An offset adjuster supplies the DC offset correcting signal depending on a compared result from the comparator to the signal generator.

Abstract: A test signal, the amplitudes of which are equal in the positive and negative directions, is generated and supplied to a signal processing circuit that performs a frequency conversion. Signals outputted from the signal processing circuit are detected to provide detected signals, which comprise a detected positive signal corresponding to a positive signal of the test signal and a detected negative signal corresponding to a negative signal of the test signal. The level of the detected positive signal is compared with the level of the detected negative signal to output a comparison result that indicates which level is higher. Additionally, an offset correction signal, which causes the level difference between the detected positive signal and the detected negative signal to be within a predetermined range of tolerance, is generated based on the comparison result. Then, an offset correction of the test signal and an externally supplied modulated signal is performed in accordance with the offset correction signal.

Abstract: A continuous processing trap apparatus is capable of increasing the trapping efficiency while maintaining conductance required by a vacuum chamber. The trap apparatus includes an exhaust passage for evacuating a hermetically sealed chamber by a vacuum pump, a hermetically sealed trapping and regenerating casing extending across the exhaust passage and a regenerating passage adjacent to the exhaust passage, and a trap unit movably housed in the trapping and regenerating casing for selective movement between a trapping position connected to the exhaust passage and a regenerating position connected to the regenerating passage. The trap apparatus further includes valve bodies disposed one on each side of the trap unit and supporting seals on outer circumferential surfaces thereof for sealing the exhaust passage and the regenerating passage from each other, and a monitoring mechanism for monitoring whether the seals are functioning normally.

Abstract: The present invention relates-to-a-vacuum pump and a method of starting a vacuum pump. The vacuum pump includes a pump rotor (1) rotatably disposed in a casing (2), and a pump-rotor controller (15) for controlling rotation of the pump rotor (1) in a forward direction or a reverse direction in accordance with a predetermined pattern at the time of starting the vacuum pump.

Abstract: A vacuum pump has a casing having an inlet port and an outlet port, and a pair of confronting pump rotors which are provided inside the casing and synchronously rotatable for drawing in a gas from the inlet port and discharging the gas from the outlet port. A motor for rotating the confronting pump rotors is a permanent magnet motor having a stator and a motor rotor. The motor rotor has an iron core and permanent magnets disposed within the iron core.

Abstract: A trapping apparatus traps solid substances converted from reaction products contained in exhaust gases discharged from a process apparatus by a vacuum pump. The trapping apparatus has a trap member for contacting the exhaust gases and trapping reaction products contained in exhaust gases, and a trap housing (1) accommodating the trap member (4) therein. The trap housing has an inlet port (2) for introducing exhaust gases, and an exhaust gas space (3) connected to the inlet port and having an increased cross-sectional area in the direction in which exhaust gases flow in. The trap housing has a flow passage defined therein for passing the exhaust gases in the exhaust gas space and then changing the direction of the exhaust gases so as to flow from the exhaust gas space substantially perpendicularly to the trap member so as to pass the exhaust gases through the trap member while in contact therewith.

Abstract: A continuous processing trap apparatus is capable of increasing the trapping efficiency while maintaining conductance required by a vacuum chamber. The trap apparatus includes an exhaust passage for evacuating a hermetically sealed chamber by a vacuum pump, a hermetically sealed trapping and regenerating casing extending across the exhaust passage and a regenerating passage adjacent to the exhaust passage, and a trap unit movably housed in the trapping and regenerating casing for selective movement between a trapping position connected to the exhaust passage and a regenerating position connected to the regenerating passage. The trap apparatus further includes valve bodies disposed one on each side of the trap unit and supporting seals on outer circumferential surfaces thereof for sealing the exhaust passage and the regenerating passage from each other, and a monitoring mechanism for monitoring whether the seals are functioning normally.

Abstract: A continuous processing trap apparatus is capable of increasing the trapping efficiency while maintaining conductance required by a vacuum chamber. The trap apparatus includes an exhaust passage for evacuating a hermetically sealed chamber by a vacuum pump, a hermetically sealed trapping and regenerating casing extending across the exhaust passage and a regenerating passage adjacent to the exhaust passage, and a trap unit movably housed in the trapping and regenerating casing for selective movement between a trapping position connected to the exhaust passage and a regenerating position connected to the regenerating passage. The trap apparatus further includes valve bodies disposed one on each side of the trap unit and supporting seals on outer circumferential surfaces thereof for sealing the exhaust passage and the regenerating passage from each other, and a monitoring mechanism for monitoring whether the seals are functioning normally.

Abstract: A screw-type dry vacuum pump comprises a rotor having a screw thread thereon for exhausting a gas through rotation, a casing for housing the rotor therein, a reduced portion provided in the casing, and an enlarged portion provided on a discharge end of the casing. The reduced portion forms a slight gap between the outer circumferential surface of the rotor and the inner surface thereof. The enlarged portion forms a larger gap between the outer circumferential surface of the rotor and the inner surface thereof.

Abstract: A continuous processing trap apparatus is capable of increasing the trapping efficiency while maintaining conductance required by a vacuum chamber. The trap apparatus includes an exhaust passage for evacuating a hermetically sealed chamber by a vacuum pump, a hermetically sealed trapping and regenerating casing extending across the exhaust passage and a regenerating passage adjacent to the exhaust passage, and a trap unit movably housed in the trapping and regenerating casing for selective movement between a trapping position connected to the exhaust passage and a regenerating position connected to the regenerating passage. The trap apparatus further includes valve bodies disposed one on each side of the trap unit and supporting seals on outer circumferential surfaces thereof for sealing the exhaust passage and the regenerating passage from each other, and a monitoring mechanism for monitoring whether the seals are functioning normally.

Abstract: A continuous processing trap apparatus is capable of increasing the trapping efficiency while maintaining conductance required by a vacuum chamber. The trap apparatus includes an exhaust passage for evacuating a hermetically sealed chamber by a vacuum pump, a hermetically sealed trapping and regenerating casing extending across the exhaust passage and a regenerating passage adjacent to the exhaust passage, and a trap unit movably housed in the trapping and regenerating casing for selective movement between a trapping position connected to the exhaust passage and a regenerating position connected to the regenerating passage. The trap apparatus further includes valve bodies disposed one on each side of the trap unit and supporting seals on outer circumferential surfaces thereof for sealing the exhaust passage and the regenerating passage from each other, and a monitoring mechanism for monitoring whether the seals are functioning normally.

Abstract: A vacuum pump has a casing having an inlet port and an outlet port, and a pair of confronting pump rotors which are provided in the casing and synchronously rotatable for drawing in a gas from the inlet port and discharging the gas from the outlet port. A motor for rotating the confronting pump rotors is a permanent magnet motor having a stator and a motor rotor. The motor rotor has an iron core and a permanent magnet disposed within the iron core.

Abstract: A continuous processing trap apparatus is capable of increasing the trapping efficiency while maintaining conductance required by a vacuum chamber. The trap apparatus includes an exhaust passage for evacuating a hermetically sealed chamber by a vacuum pump, a hermetically sealed trapping and regenerating casing extending across the exhaust passage and a regenerating passage adjacent to the exhaust passage, and a trap unit movably housed in the trapping and regenerating casing for selective movement between a trapping position connected to the exhaust passage and a regenerating position connected to the regenerating passage. The trap apparatus further includes valve bodies disposed one on each side of the trap unit and supporting seals on outer circumferential surfaces thereof for sealing the exhaust passage and the regenerating passage from each other, and a monitoring mechanism for monitoring whether the seals are functioning normally.

Abstract: A screw-type dry vacuum pump comprises a rotor having a screw thread thereon for exhausting a gas through rotation, a casing for housing the rotor therein, a reduced portion provided in the casing, and an enlarged portion provided on a discharge end of the casing. The reduced portion forms a slight gap between the outer circumferential surface of the rotor and the inner surface thereof. The enlarged portion forms a larger gap between the outer circumferential surface of the rotor and the inner surface thereof.

Abstract: A screw type dry vacuum pump having dual shafts is disclosed, whereby the process gas is transported through three compartments, a gas admittance pump section, a central drive motor section, and a gas discharge pump section. By placing the drive motor in the center of the pump, it becomes possible to design a pump having the dual shafts supported only at one end, thus enabling to mount the rotors at the free ends of the pump which are closed with end plates which can be removed easily for servicing the pump sections. Synchronous operation of the dual shaft pump by magnetic coupling enables to lower power consumption and to extend the range of operable pressures.

Abstract: The transverse tooth profile of a screw rotor which meshes with a companion screw rotor is defined by a tooth root circular arc, an outer circumferential circular arc, and two curves interconnecting the tooth root circular arc and the outer circumferential circular arc. One of the curves is defined by a trochoid curve generated by a point on an outer circumferential surface of the companion screw rotor. Alternatively, the curve may comprise two curve segments, and one of the two curve segments comprising a tooth tip arc which is defined as an arc having a radius of curvature equal to or smaller than the difference between a radius of curvature of the outer circumferential circular arc and a radius of a pitch circle of the tooth profile, and the other of the two curve segments comprising a curve connected to the tooth root circular arc and determined by a curve generated by the tooth tip arc of the companion screw rotor.

Abstract: The transverse tooth profile of a screw rotor which meshes with a companion screw rotor is defined by a tooth root circular arc, an outer circumferential circular arc, and two curves interconnecting the tooth root circular arc and the outer circumferential circular arc. One of the curves is defined by a trochoid curve generated by a point on an outer circumferential surface of the companion screw rotor. Alternatively, the curve may comprise two curve segments, and one of the two curve segments comprising a tooth tip arc which is defined as an arc having a radius of curvature equal to or smaller than the difference between a radius of curvature of the outer circumferential circular arc and a radius of a pitch circle of the tooth profile, and the other of the two curve segments comprising a curve connected to the tooth root circular arc and determined by a curve generated by the tooth tip arc of the companion screw rotor.