Matsushita Electric Industrial Co., Ltd.

Kabushiki Kaisha Toshiba

Ntt Docomo, Inc.

Panasonic Mobile Communications Co., Ltd.

Toshio Obara

Hidenori Matsumoto

Hisashi Adachi

Takashi Miura

Hiroaki Kosugi

Kaoru Ishida

Toru Matsuura

Hiroyuki Handa

Makoto Sakakura

Naoki Komatsu

Wataru Shimizu

Yasushi Iwata

Youichi Morinaga

Manabu Yamaguchi

Yoshiharu Ishihara

Yoshio Yoshinaga

It is an object of the present invention to suppress an abrupt gain change and smoothly and highly accurately control transmitted electric power even if the transmitted electric power greatly changes when a closed loop control that crosses the threshold value as the detection limit of the transmitted electric power. The transmitted electric power of a self-station is detected to obtain an error between the detected transmitted electric power of the self-station and transmitted electric power set in accordance with a transmitted electric power control bit sent to the self-station from the other station. A buffer unit such as a transmitted electric power deciding part, an error integrating part or the like is provided for preventing the obtained error from greatly changing upon great change of the transmitted electric power when the transmitted electric power is controlled by crossing the threshold value as the detection limit of the transmitted electric power. Thus, an error when the gain of the variable gain amplifier is suppressed.

Wireless communication device having gain error correcting feature

An antenna selection diversity apparatus capable of shortening, when antennas are switched in frame units, a measuring time of antennas and shortening the time of selecting an optimal antenna from among a plurality of antennas on standby. In this apparatus, an antenna selection section () selects one of three antennas as an antenna in actual use for a period of a plurality of frames consecutively according to selection priority stored in an antenna information storage section () and gives an instruction for selecting one of two antennas on standby as an antenna to be measured once at a period of a plurality of frames to an antenna selection switch (). When the reception level of the antenna in actual use measured by a reception level measuring section () falls below the reception level of the antenna to be measured a predetermined number of times consecutively, the antenna selection section () gives an instruction for selecting the antenna to be measured as the antenna in actual use to the antenna selection switch ().

Antenna selection diversity apparatus and reception method

A determining section () and gain variation amount detecting section () detect a period having a possibility of a DC-component offset in an internal circuit of a direct conversion receiver increasing beyond an allowable value due to AGC operation, and during the period, a cut-off frequency of each of high-pass filters (to) is set at a frequency higher than that in general operation, thereby rapidly converging transient responses of signals passed through the high-pass filters, while controlling precisely operation timings of reception power measuring section (), gain calculating section (), gain control section () and circuit power supply control section () composing an AGC loop, whereby the DC offset is prevented from increasing and stable circuit operation is assured. It is thereby possible to achieve further reductions in size and power consumption of a CDMA receiver using the direct conversion receiver.

Direct conversion receiver and DC offset reducing method

It is an object of the present invention to switch bands with a simple structure in which frequency bands can be individually switched respectively in a transmission and a reception and only a receiving part can be switched to another frequency band without disconnecting an upward line during communication. The device of the invention includes an antenna () capable of transmitting and receiving radio waves of first and second frequency bands, a wave separator (), antenna sharing devices (A,B) respectively provided so as to correspond to the frequency bands, transmitting circuits (A,B), transmitting PLL synthesizers (A,B), receiving circuits (A,B) and receiving PLL synthesizers (A,B). A control partcontrols, through a common three-line serial bus, the transmitting PLL synthesizers (A,B), the receiving PLL synthesizers (A,B), a transmitting band switching signal generating circuit () and a receiving band switching signal generating circuit () to individually switch the frequency bands respectively in the transmission and the reception.

Radio communication device that meets a plurality of frequency bands

At the time of ordinary communication, up-mixer combines a signal with a frequency f2 from frequency synthesizer with I and Q signals for transmission that are quadrature modulated in quadrature modulator , down-mixer combines the signal with the frequency f2 with a received signal, then only in the case of receiving a signal with a frequency fr&prime; different from a frequency fr, frequency synthesizer that generates a signal with a frequency f3 different from the frequency f2 is operated, and frequency synthesizer and down-mixer are connected with switch , so that down-mixer combines the signal with the frequency f3 with a received signal. It is thereby possible to switch frequencies fast and with low current consumption in receiving a signal with a reception frequency other than a combination of transmission frequency and reception frequency specified in an ordinary radio system.

Radio apparatus and transmission/reception method

To provide a power amplifier circuit with a smaller circuit scale and with good characteristics over a wide range of load impedance. A configuration includes: a DC/DC converter which delivers a supply voltage from a battery to a power amplifier according to control commands from a control circuit a directional coupler which outputs a signal from one terminal according to signal waves received by an antenna from a second matching circuit and outputs a signal from another terminal according to reflected waves received from the antenna and detectors and or the like.

Power amplifier circuit, control method for power amplifier circuit, and portable terminal apparatus for mobile communication

A transmission electric power control device includes: a coupler detector electric power amplifier error detection means target value generation means gain variable means control calculation means control calculation parameter generation means modulator control variable addition means transmission electric power control means and transmission electric power designation means In this case, the automatic transmission electric power control feedback loop includes: the coupler detector error detection means control calculation means control calculation parameter generation means transmission electric power designation means control variable addition means and gain variable means When the control calculation parameter in the automatic transmission electric power control feedback loop is made variable according to the transmission electric power designation information and also when the convergence offset value of the loop response characteristic is made variable, it is possible to conduct an electric power control of a high dynamic range, high linearity and high accuracy even if the electric power source control of the electric amplifier is conducted for each transmission electric power and the gate bias control is conducted.

Transmission electric power control device and control method

A transmission power control in a wireless communication, in that based upon transmission power designation information &ldquo;A&rdquo; functioning as a power control target derived from a transmission power designating unit 16, a transmission power error &ldquo;E&rdquo; is detected from a difference between a detection value &ldquo;D&rdquo; of an outputted transmission signal and a power control target value &ldquo;C&rdquo;. This transmission power error &ldquo;E&rdquo; is multiplied by a loop gain &ldquo;G&rdquo; of a feedback loop set by a loop gain setting unit 22 so as to produce a feedback correction value &ldquo;F&rdquo;. The transmission power control is carried out based on the feedback correction value &ldquo;F&rdquo;. Furthermore, a suitable bias voltage &ldquo;J&rdquo; is outputted from a bias voltage producing unit 17 in response to the transmission power designation information &ldquo;A&rdquo; so as to reduce power consumption, and also, a gain variation of a power amplifier 13, which is caused by this bias current control, is compensated by a gain variation compensating unit 26 in response to the transmission power designation information &ldquo;A&rdquo;.

Wireless communication apparatus and transmission power control method in wireless communication apparatus

Power amplifier, power control method for power amplifier, and communication equipment

In the radio equipment in which necessary absolute precision of the transmit power can be assured while keeping the power variable amount precision in transmit power adjustment and the transmit power control of wide dynamic range and high linearity also is requested. The transmit power controlling method in the radio equipment, and the recording medium, when the transmit power is adjusted by detecting the error based on difference between the detected value which is obtained by detecting the transmit signal of the radio equipment and the detected value of the transmit signal when it is transmitted by the designated transmit power to be transmitted, then calculating the correction value by multiplying this error by the predetermined gain, then generating the control amount based on the correction value, and then re-setting the gain in transmit power amplification based on the control amount at a predetermined timing, the predetermined gain can be set such that an amount of change in the transmit power to be adjusted based on the control amount can be suppressed in the allowable range requested for an amount of change in the transmit power to be adjusted based on the reference value of the transmit power control, which is generated based on the designated transmit power.

Radio equipment and transmit power controlling method for the same

A transceiver circuit with a heterodyne receiver circuit is provided. Output signals of first and second local oscillator 103, 104 are mixed by a local frequency converter 105. An output signal of the converter 105 passes a filter 106 and inputs a modulator 111 of a transmitter circuit 101 as well as a first frequency converter 122 of a receiver circuit 102. The second local oscillator 104 comprises a frequency synthesizer whose output signal varies for a transmission or a receiving mode. The output signal of the second local oscillator 104 also inputs the second frequency converter 124 of the receiving mode. A reference frequency of the second local oscillator 104 is set higher than a frequency step between communication channels so that a quick switching of the frequency is performed. Thus, the transceiver circuit of this invention is suitable for a compact size and hardly generates unwanted spurious components at transmission mode.

Transceiver circuits for TDMA system with variable frequency second

A handy image data filing apparatus is disclosed, which is made up of a hand scanner as an image data reading device and an IC memory card as an image data storing medium. Image data on an object such as a name card is read by the hand scanner, and filed into the IC memory card. The read data is stored into the IC memory card, together with ID data for identifying the image data to be stored. The ID data is used for retrieving the image data later, and is entered from a keyboard. For retrieval, ID data corresponding to the desired image data is entered from the keyboard. The image data is specified by the ID data entered, and displayed by a liquid crystal display device.

Growing community of inventors

Kawasaki, Japan

Toshio Obara