Fujitsu Corporation

Nobuhide Hachiya

Masahiko Hirao

Kenji Iwai

Kazushige Kishigami

Yasuhiro Murakami

Takashi Tanii

Manabu Murakami

Hiroshi Oikawa

Yusuke Yamamori

Yasuaki Takeuchi

Mikio Hayashihara

Atsushi Kudo

Atsushi Kudou

A power adjustment method includes: measuring output power that is obtained when input power to be amplified in a linear region is input to a power amplifier configured to amplify input power linearly in the linear region and amplify input power nonlinearly in a nonlinear region; deriving a straight line connecting a measurement point corresponding to the measured output power and a boundary point between the linear region and the nonlinear region in a coordinate plane representing input/output characteristics; acquiring information on an approximate equation that is stored in advance in correspondence with the measured output power, the approximate equation representing a relation between input power and output power in the nonlinear region; and storing information on the derived straight line and the acquired information on the approximate equation in a semiconductor integrated circuit provided at a preceding stage of the power amplifier.

Power adjustment method, computer-readable recording medium and power adjustment apparatus

A first signal path has one or a plurality of coils arranged in series, the coils being connected to the output of a first amplifier. A second signal path has the same number of coils as the coils of the first signal path, the coils being arranged in series and connected to the output of a second amplifier. Coupling paths have capacitors and couple the first signal path and the second signal path at both ends of the corresponding coils on the first signal path and the second signal path. A SW controlling unit switches a switch to a contact when a signal is input from the first amplifier and switches the switch to a contact when a signal is input from the second amplifier.

Matching device, transmitting amplifier, and wireless communication device

A first casing and a second casing movably connected to the first casing are provided. PAs amplify a transmit signal. FET switches are provided between the ground and respective transmission paths connecting the PAs and an antenna. When an intermediate voltage is applied, the FET switch has a capacitance according to the applied intermediate voltage. An open or close detection unit acquires the impedance of the antenna corresponding to the positional relationship of the first casing and the second casing. A control unit turns one of a plurality of switches ON and applies the intermediate voltage to the FET switches to achieve a capacitance whereby the impedance of the PA arranged on the transmission path where the switch is ON and the impedance of the antenna are matched based on the impedance of the antenna acquired by the open or close detection unit.

Wireless terminal device

A pre-emphasis control method automatically and appropriately performs the pre-emphasis of each wavelength in a wavelength division multiplexing communications system. Before instructing pre-emphasis for a transmitting unit, the optical power of an optical signal of each channel (wavelength) is increased/decreased by a predetermined value, and it is determined for each channel whether or not the difference between a Q value when the optical power is large and a Q value when the optical power is small, is larger than 0. Depending on the determination, that is, if the difference is larger than 0, then it is determined that the channel belongs to a linear area, and if the different is equal to or smaller than 0, then the channel belongs to a nonlinear area. If the Q value of each channel is to be improved by the pre-emphasis, then the optical power is increased for the channel in the linear area, and decreased for the channel in the nonlinear area.

Pre-emphasis control method in consideration of nonlinear deterioration

Growing community of inventors

Sapporo, Japan

Nobuhide Hachiya