92results about How to "Improve reception characteristics" patented technology

Either one of a transmission terminal connected to a transmission filter and a receiving terminal connected to a receiving filter is a balanced type terminal, and the other is an unbalanced type terminal. The transmission filter and the receiving filter includes surface acoustic wave resonators or film bulk acoustic resonators. The balanced type terminal is connected to a longitudinal mode coupled surface acoustic wave filter.

An OFDM transmitter transmits an OFDM signal by a frame having a plurality of transmission symbol periods constituted of an effective symbol period for transmitting an information bit and a guard interval. The OFDM transmitter includes a guard interval length decider configured to decide a guard interval length in accordance with a feedback signal from an OFDM receiver; and a guard interval length changer configured to change a guard interval length in each transmission symbol period, in accordance with a decided guard interval length without changing a frame length.

When cancelling interference in a radio communication device for repeatedly decoding/receiving a spatially multiplexed signal, if a symbol of erroneous judgment is contained or if an error factor caused by a propagation channel estimation error or hardware error (carrier frequency error, sampling frequency error) is contained, reception characteristic is degraded by an interference signal component. The radio communication device (100) includes an error estimation unit (13) for estimating an error of a replica signal during interference cancelling and a weighting unit (14) for weighting likelihood information for a spatially multiplexed signal which is demultiplexed and multiplexed after the interference cancelling. Accordingly, even if an error of the replica signal during interference cancelling is contained, it is possible to obtain preferable reception characteristic.

A constant output signal can be achieved by controlling a gain variable amplifier 2 based on a level of an output signal which is derived by variably amplifying a receiving signal S1 (input signal). An AGC output signal S11 is detected by a detector circuit 3, then a detected voltage signal S7 is converted into a digital signal by an A/D converter 4 to output it to a CPU 5. Then, the CPU 5 generates a control signal S8 based on the detected voltage signal S7, then an A/D converter 6 converts the control signal S8 into the analogue signal, and then the signal is sent out to the gain variable amplifier 2 to execute gain control. At this time, an RSSI detector portion 9 detects an RSSI signal S10 corresponding to a transmitting signal level from the receiving signal S1, and then the CPU 5 sends out the control signal S8 stored at the time of preceding execution of the gain control when the RSSI signal S10 is reduced below a predetermined threshold value S12. In the weak received electric field strength, the control voltage for the gain variable amplifier is prevented reduction, and the proper automatic gain control can be made possible to thus achieve the good receiving characteristics.

When switching to a path whose directivity changes greatly or a path with a widely different propagation delay, transmission is performed for both directivities for a certain period of time. Then, transmission is performed for one directivity. When the switching of transmission directivities is controlled, this allows correct reception of signals and prevents instantaneous interruption due to loss of synchronism even if transmission is performed by switching to a path with a widely different propagation delay.

Radio receiving apparatus comprises antennas, radio units adjusting gains of received signals, and outputting the adjusted received signals, respectively, converters converting the adjusted received signals into digital signals, selector device which selects several of the digital signals, combination of the selected digital signals exhibiting good receiving characteristic, controller which determines the gains and outputs single control signal included in information of the determined gains to certain radio units, the certain radio units being included in the radio units and connected to certain converters of the converters which output digital signals included in the selected combination, weight calculator which calculates weight for each of the selected digital signals to enhance the receiving characteristic if the controller outputs the single control signal, synthesizer which synthesizes, into synthetic digital signal, digital signals obtained by multiplying each of the selected digital signals by the weight, and demodulator which demodulates the synthetic digital signal.

An on-vehicle antenna system which offers a superior receiving performance, by suppressing reception of reflected/scattered waves coming from inside of the vehicle's cabin; these reflected/scattered waves being an adverse factor which deteriorates signal receiving performance of an antenna. The antenna system is installed at glass pane portion of a vehicle with direction (12) of the greatest radiation pattern (11) directed towards ahead (14) of the vehicle from boundary plane (10) containing power supply portion (9), while direction (13) of the smallest radiation pattern (11) towards behind (15) of the vehicle. The above-configured antenna system can suppress those waves reflected/scattered in the vehicle cabin from being received; as the result, it demonstrates improved characteristics.

The present invention provides a receiving antenna coil capable of realizing both improvement in the reception characteristic and miniaturization. In a receiving antenna coil, at least one of an X-axis winding core part and a Y-axis winding core part is formed in a plurality of bars. While increasing occupancy of the winding core parts (the X-axis winding core part and the Y-axis winding core part) in a region in the XY plane surrounded by a Z-axis receiving coil, the length of the winding core parts can be assured long. Further, since the X-axis winding core part and the Y-axis winding core part are provided in the same plane, the height of the core is suppressed, and the dimension of the entire receiving antenna coil can be suppressed.

A mobile communication terminal includes an interference rejection combining processor for obtaining a received signal vector with regard to each of multiple resource elements and for calculating receiving weights so as to suppress influence to a desired beam of electric wave sent from the desired base station by other beams, on the basis of the received signal vectors; a non-interference-rejection receiving weight calculator for calculating receiving weights so as not to suppress influence to the desired beam by other beams; a signal separator for separating a signal destined for the mobile communication terminal from signals destined for other mobile communication terminals; and an interference rejection combining determiner for determining whether the receiving weights to suppress influence by other beams or the receiving weights calculated by the non-interference-rejection receiving weight calculator should be used for signal separation by the signal separator, on the basis of an index representing a relationship between reception quality of a desired downlink transmission signal and reception quality of an interfering signal.

An adaptive antenna reception device is disclosed in which a directional beam having excellent reception characteristics can be quickly and easily obtained from the start by selecting an initial beam direction of signal processors that are to begin determination of weight that uses time averaging based on the reception quality and the arrival direction in which the reliability is high for an incoming wave that is received in each signal processor in which sufficient averaging time has been secured. An arrival direction detection unit detects the arrival direction of an incoming wave that is received in each signal processor from weight that is determined by each signal processor in which at least a prescribed time interval has been secured for the averaging time for finding a time average. A SIR measurement unit finds the reception quality of a signal of an incoming wave that is received by weighting and synthesizing in each signal processor in which at least a prescribed time interval has been secured for the averaging time. An information collection/selection processor, based on each arrival direction and each reception quality in each signal processor in which at least a prescribed time interval has been secured for the averaging time, selects the initial beam direction in signal processors that are to begin determination of weight using time averaging.

A cell phone antenna switching circuit includes a plurality of built-in antennas which perform radio transmission/reception. This circuit includes reception level measuring sections and an antenna switching section. The reception level measuring sections measure the reception levels of the corresponding built-in antennas. The antenna switching section always automatically selects an antenna whose reception level is high during a standby period, and selects an antenna with good antenna characteristics depending on a function during speech communication. A cell phone antenna switching method is also disclosed.

A radio receiver including a reception processing system that uses a discrete-time frequency conversion to acquire a signal having a sampling rate corresponding to a local frequency, wherein the reception characteristic is improved when the reception processing system is applied to a system having a wide reception channel band. The radio receiver (100) comprises a discrete-time frequency converting part (130) that uses a local frequency signal to sample a received signal in a discrete-time manner, thereby performing a frequency conversion and a thinning process to output a discrete-time analog signal of a sampling rate in accordance with the local frequency; an A/D converting part (150) that quantizes the discrete-time analog signal to a digital value to output a received digital signal; a channel selection filtering part (161) that uses a tap coefficient value to perform a digital filtering process of the received digital signal; and a frequency response characteristic correcting part (162) that generates the tap coefficient in accordance with the sampling rate.