| Patent application number | Description | Published |
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| 20080231129 | Spindle apparatus - In a spindle apparatus for a machine tool, a spindle is supported on a housing by support-purpose bearing devices, and is rotated by an electric motor, and a tool is attached to a tool attaching portion formed at a distal end of the spindle. A radial magnetic bearing for vibration suppressing purposes which includes a plurality of electromagnets is provided around the tool attaching portion of the spindle. A plurality of radial displacement sensors for detecting a displacement of the tool attaching portion in radial directions are provided around the tool attaching portion. There is provided an electromagnet control unit for controlling the electromagnets of the radial magnetic bearing on the basis of outputs of the radial displacement sensors so as to support the tool attaching portion in a predetermined position. | 09-25-2008 |
| 20090009018 | Magnetic bearing unit - Displacement data of axial position targets measured by axial displacement sensors is transmitted to a first main spindle elongation computation section, which then computes elongation of a main spindle between the axial position targets. The computation result is transmitted to a second main spindle elongation computation section, which then computes elongation of the main spindle between one of the axial position targets provided on the side of a tool and the tool. The computation result is transmitted to an axial position control section. The axial position control section changes the power to be supplied to axial magnetic bearing parts, thereby controlling the axial position of the main spindle so that the axial position of the tool becomes constant. | 01-08-2009 |
| 20090042479 | Grinding apparatus and method of controlling grinding apparatus - A grinding wheel formed on an outer peripheral surface with a grinding surface is attached to a grinding wheel spindle supported by axial active magnetic bearings and radial active magnetic bearings in a noncontact manner axially and radially and rotated by an electric motor. A casing is axially positioned and then is radially moved and a ground part of a workpiece is ground. Before the casing moves radially and the grinding wheel comes in contact with the workpiece, the stiffness value of the radial magnetic bearings is set to an initialization value lower than a value at the usual grinding time and after the grinding surface of the grinding wheel comes in contact with the workpiece, the stiffness value of the radial magnetic bearings is set to a value higher than the initialization value for grinding the workpiece. | 02-12-2009 |
| Patent application number | Description | Published |
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| 20090323515 | OFDM TRANSMITTTER AND OFDM RECEIVER - In an environment with large transmission delays, use of an OFDM transmitter which includes: a pilot/data allocator for allocating pilot/data symbols on OFDM symbols and an OFDM receiver which includes: an antenna for receiving the OFDM signals sent out from the antenna of this OFDM transmitter; a ratio unit for frequency transforming the OFDM signals received as RF signals to baseband signals; a frequency offset estimate for estimating an offset value; and a frequency offset corrector for performing frequency compensation by the amount of the frequency offset, improves data transmission efficiency while reducing interference of data between sub-carriers to prevent degradation of reception characteristics by performing appropriate frequency offset correction. | 12-31-2009 |
| 20110003551 | TRANSMITTER, RECEIVER, TRANSMISSION METHOD, AND RECEPTION METHOD - A transmitter which communicates with a receiver. The transmitter includes a null subcarrier allocation unit which allocates a null subcarrier based on a priority and a signal. The priority is for allocating a null subcarrier to each subcarrier. The priority is a ranking predetermined with the receiver. The signal is allocated to each subcarrier. The transmitter includes a transmission unit which transmits the signal using the subcarrier allocated by the null subcarrier allocation unit as the null subcarrier to the receiver. | 01-06-2011 |
| 20110038398 | COMMUNICATION SYSTEM, TRANSMITTER, RECEIVER AND COMMUNICATION METHOD - A transmitter communicating with a receiver, the transmitter including: a first hopping sequence generation unit which generates a hopping sequence whose hopping subcarrier interval is less than or equal to a predetermined threshold value based on a cell ID; a first reference signal pattern generation unit which generates a reference signal pattern based on a reference signal basic pattern including a predetermined known signal sequence and the hopping sequence generated by the first hopping sequence generation unit; an arrangement unit which arranges the reference signal and a data symbol in a predetermined position within the symbol, based on the reference signal pattern generated by the first reference signal pattern generation unit; and a signal transmission unit which transmits the symbol having the reference signal and the data symbol arranged by the arrangement unit to the receiver. | 02-17-2011 |
| 20110116438 | COMMUNICATION SYSTEM, RECEPTION DEVICE, AND COMMUNICATION METHOD - A communication system includes a reception device and at least one transmission device. The transmission device includes: a signal transmission unit which transmits at least one unicast signals and a multicast signal to the reception device. The reception device includes: a plurality of signal reception units which receive at least one the unicast signals and the multicast signal from the transmission device; a first control unit which receives the unicast signals from the transmission device using all of the plurality of signal reception units when only the unicast signals are received; and a second control unit which receives the unicast signals from the transmission device using some of the plurality of signal reception units, and simultaneously receives the multicast signal from the transmission device using another signal reception unit of the plurality of signal reception units, when the unicast signals and the multicast signal are received. | 05-19-2011 |
| 20110217961 | COMMUNICATION SYSTEM, BASE STATION DEVICE, MOBILE STATION DEVICE, AND COMMUNICATION METHOD - A communication system includes a unicast base station device, a multicast base station device, and a mobile station device. Before receiving information concerning a multicast service, the mobile station device transmits, to a position register server, identification information identifying a reception area in which a multicast service is provided. When receiving incoming call information indicating that information concerning a unicast service has been received, the multicast base station device transmits the incoming call information to the mobile station device. The mobile station device receives the incoming call information even while receiving the information concerning the multicast service. | 09-08-2011 |
