Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Ntt Docomo, Inc.

Panasonic Mobile Communications Co., Ltd.

Hidenori Matsumoto

Toshio Obara

Takashi Miura

Atsuhiko Hashigaya

A transmission power control apparatus which reduces the number of steps required for adjustments of the transmission power control apparatus and performs transmission power control with high accuracy in a wide dynamic range. The apparatus has a first variable amplifying circuit () with the resolution of 1 dB and a second variable amplifying circuit () with the resolution of 0.1 dB, where a correction value calculating section () calculates a correction value to compensate for deterioration in the accuracy of transmission power caused by a change in environment due to frequency characteristics and temperature characteristics and another correction value to compensate for error in transmission power, a transmission power calculating section () calculates transmission power obtained by correcting with the correction value specified transmission power to output to a communicating party based on the received signal, and a first set value calculating section () and a second set value calculating section () calculate gain values to set on the first variable amplifying circuit () and second variable amplifying circuit () based on the corrected transmission power, respectively.

Transmission power control device

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

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

A demodulating circuit contains an electric field level detector for detecting an electric field strength from a received modulation signal, comparators to for outputting electric field strength information PS, a detector for outputting a detection signal corresponding to a modulation signal, both a low-pass filter and a digital filter for removing a noise component from the detection signal, and a data comparator for comparing the detection signal with a reference voltage to output a digital signal. This demodulating circuit further includes a control circuit for controlling a cutoff frequency used in a digital filter , an output voltage amplitude of the detector , and the reference voltage of the data comparator in accordance with both the electric field strength information PS and control condition information PC saved in an EEPROM and supplied from a CPU , and also a judging circuit for judging the digital signal at preselected timing to produce a demodulation signal.

Growing community of inventors

Kanagawa, Japan

Hidenori Matsumoto