PROBLEM TO BE SOLVED: To provide a radio communication equipment that conducts communication with a communication system corresponding to a change in channel. SOLUTION: A separate section 109 separates an output signal from a demodulation section 108 into received data and an OK signal or an NG signal, provides an output of the received data and an output of the OK signal or the NG signal to a transmission system changeover decision section 110. The transmission system changeover decision section 110 stores the number of times of receiving the OK signal or the NG signal, decides whether or not revising a transmission system depending on the frequency of reception of the OK signal or the NG signal and outputs an instruction as to whether or not the transmission system is to be revised to a transmission system changeover control section 111. The transmission system changeover control section 111 controls a transmission frame generating section 102, a modulation section 103, a transmission wireless section 104 and an antenna multicoupler section 105 to instruct a buffer 101 to output transmission data for re-transmission when the revision of the transmission system is required according to the instruction from the transmission system changeover discrimination section 110. COPYRIGHT: (C)2001,JPO

Radio communication equipment and radio communication method

A wireless communication apparatus is capable of improving communication efficiency by reducing the amount of control information transmitted. A channel quality information extraction section extracts CQI's from a received signal. An allocation control section allocates subcarriers for every communication terminal apparatus and selects a modulation scheme in such a manner that required transmission rate is satisfied for each communication terminal apparatus based on required transmission rate information, etc. and CQI's for communication terminal apparatus of each user. A required subcarrier number determining section decides the number of subcarriers allocated to every communication terminal apparatus so as to satisfy the required transmission rate for each communication terminal apparatus. A required subcarrier number information generating section generates information for the number of subcarriers allocated to every communication terminal apparatus. A subcarrier allocation section allocates packet data to selected subcarriers. Modulating sections adaptively modulate packet data allocated to each subcarrier.

Wireless Communication Apparatus and Wireless Communication Method

An analog/digital gain control device avoid some of the requirements associated with the nature of a closed-loop AGC circuits and which meets the remaining requirements without much difficulty uses an analog to digital conversion method that increases the number of effective ADC bits by compressing the baseband input analog signal using a logarithmic circuit. After the compressed analog signal is converted into a digital signal, a digital anti-log process or look-up table (LUT) is used to expand the digital signal back to the original linear scale. The word size of the output of the anti-log process is larger than the input word size due to the nature of the anti-log function. To reduce the word size of the digital signal an open loop normalization technique can be applied.

Gain control method and apparatus

A multilayer filter comprising a first dielectric layer (2101a) having a first shield electrode provided on one major surface, a second dielectric layer (b) having a resonator electrode provided on the one major surface, a third dielectric layer (2101c) having a bond electrode provided oppositely to a part of the resonator electrode on the one major surface, a fourth dielectric layer (2101d) having a second shield electrode provided on the one major surface, a fifth dielectric layer (2101e) where at least the one major surface is exposed to the outside, and a ground electrode (2108) provided on the other major surface of the first dielectric layer and/or the one major surface of the fifth dielectric layer, characterized in that the first ground electrode and the first shield electrode are connected electrically through a via hole (2109) made in the first dielectric layer.

Multilayer electronic part, multilayer antenna duplexer, and communication apparatus

An apparatus and method for OFDM demodulation establish symbol synchronization to minimize between-symbol interference even under an environment where multipath occurs. An incoming signal is an OFDM signal including a transmission symbol structured by a valid symbol period and a guard interval, and a predetermined synchronization symbol is included in the OFDM signal for every transmission frame. A correlator calculates how a signal generated by a synchronization symbol generator and the OFDM signal are correlated. A correlation calculator then calculates a correlation therefrom. An integrator integrates the calculated correlation by the guard interval. A timing determination device determines symbol timing from the integrated correlation. An FFT window generator outputs operation timing for Fourier transform from the determined symbol timing. Based on the signal outputted from the FFT window generator, the apparatus for OFDM demodulation extracts a signal in the valid symbol period from the transmission symbol for demodulation.

Apparatus and method of OFDM demodulation

PROBLEM TO BE SOLVED: To highly accurately compensate DC offset existent in the base band of modulation and demodulation systems by adding circuits at a minimum. SOLUTION: This device is provided with a switching part 102 for switching a reference signal and a base band signal, an adder 103 for compensating the DC offset of the modulation system by inputting the output of the switching part 102, a quadrature modulation part 106 for modulating a signal, for which the output of the adder 103 is converted to analog, to a carrier frequency, a distributor 108 for distributing a modulation signal, a switch 109 for turning on/off passage with one distributed signal as a feedback modulation signal, a quadrature demodulation part 110 for performing the quadrature demodulation of the feedback modulation signal, an adder 113 for compensating the DC offset of the demodulation system by inputting a signal, for which the quadrature demodulation signal is converted to digital, and a DC offset estimating part 114 for estimating the DC offset of the modulation and demodulation systems while using the reference signal and the output of the adder 113 so that high- accuracy DC offset compensation is enabled.

Modulation/demodulation device

PROBLEM TO BE SOLVED: To provide a low-loss electrode for high frequency circuit, for which a surface effect is reduced, for a circuit such as a transmission line or resonator to be used in a high frequency area. SOLUTION: Concerning structure, plural metal films 11-13 on which high frequency currents flow, dielectric films 21-22 for separating he metal films 11-13 and connection conductors 31-32 for connecting the plural metal films 11-13 are provided and the metal films 11-13 and the dielectric films 21-22 are mutually laminated. Since the plural metal films 11-13 are electrically connected by the connection conductors 31-32 at the peripheral edge part or central part of metal films 11-13, the high frequency current flows while being distributed to the plural metal films 11-13. Thus, the electrode for high frequency circuit, for which the concentration of currents onto the surfaces of metal films is relaxed and the loss in the high frequency area is reduced in comparison with an electrode composed of a single metal film, is provided.

Electrode for high frequency circuit, transmission line and resonator using the same

PROBLEM TO BE SOLVED: To improve accuracy in the estimation of frequency offset quantity and amplitude distortion quantity between a transmitter and a receiver in the case of performing sub-synchronous detection on the side of demodulation and to improve the bit error rate characteristics of a carrier wave power-to-noise power ratio concerning a pilot symbol inserting system to be used for radio communication and a radio communication system using the same. SOLUTION: Concerning the system for periodically inserting a pilot symbol into a multi-level modulating system of >=8-adic, a signal point 102 of the pilot symbol is located at a position which is different from a point to become a maximum amplitude, of a signal point 101 of the multilevel modulating system so that the signal point amplitude of the pilot symbol is made greater than the maximum signal point amplitude of the multilevel modulating system of >=8-adic without affecting a peak-to-average transmitting power ratio. Thus, accuracy in the estimation of frequency off set quantity and amplitude distortion quantity between the transmitter and the receiver in the case of performing sub-synchronous detection on the side of demodulation is improved and the bit error rate characteristics of the carrier wave power-to-noise power ratio are improved.

Radio equipment and transmitting method

PROBLEM TO BE SOLVED: To provide a small filter which has the satisfactory damping characteristic with small loss in a high frequency area and also has the stable characteristic against its external environment. SOLUTION: This filter has a specific structure where the input/output coupled circuits 102-103 are connected to a ring resonator 101 with a distance of 1/4 ring length secured between them and accordingly the discontinuity is caused in terms of an electromagnetic field at a position 107 that is symmetrical to the coupling points 105-106 of the circuits 102-103. Then a negative resistance circuit using a distributed coupling line 104 connected to a ring resonator line and a transistor is added to connect together two modes orthogonal to each other in the resonator 101. Thus, a two-stage filter is constructed by a single resonator so that a small plane filter is obtained. Furthermore, the satisfactory damping characteristic is attained for the plane filter since a damping pole is produced at a place near a passing band.

Dual mode filter

PROBLEM TO BE SOLVED: To suppress the drop in data transmission quantity by periodically inserting a PSK modulation system into a multivalued modulation system of more than 8 values and making it perform as a role of a pilot symbol at the same time as the data transmission by using a PSK modulation symbol. SOLUTION: An orthogonal baseband modulating part 12 inputs a transmission digital signal 11 and outputs an in-phase component 13 and an orthogonal component 14 of a transmission orthogonal baseband signal. A transmitting radio part 15 converts them into a transmission signal 16 and transmits it from an antenna 17. A receiving radio part 22 inputs a receiving signal of an antenna 21 and outputs an in-phase component 23 and an orthogonal component 24 of a receiving orthogonal baseband signal. An amplitude distortion quantity estimating part 25 and a frequency offset estimating part 26 input the components 23 and 24, and output an amplitude distortion quantity estimating signal 27 and a frequency offset quantity estimation signal 28. A quasi- synchronous detecting part 29 inputs the components 23 and 24 and the signals 27 and 28, performs quasi-synchronous detection and outputs a receiving digital signal 30. COPYRIGHT: (C)1999,JPO

守一佐川

Papers

Modulation/demodulation device

Electrode for high frequency circuit, transmission line and resonator using the same

Radio equipment and transmitting method

Dual mode filter

Modulation system and radio communication system using the same

守一 佐川

Papers

Modulation/demodulation device

Electrode for high frequency circuit, transmission line and resonator using the same

Radio equipment and transmitting method

Dual mode filter

Modulation system and radio communication system using the same

守一佐川