550 results about "Interference wave" patented technology

In a transmitting method, it is possible to avoid influences of adjacent-channel interference to perform communication satisfactorily. In the case of performing transmission with a previously set sending power, the transmission is performed with the set sending power with respect to a channel having the largest sending power. With respect to a channel having the next largest sending power, if its adjacent channel is the determined channel, the transmission is performed such that the sending power is corrected on the basis of the sending power of the determined channel. Thereby, it is possible to prevent the signal-to-interference wave power ratio C/I of the channel from deteriorating due to the leakage signal (interference wave) from the adjacent channel. Thus, it is possible to avoid the influences of adjacent-channel interference to thereby perform communication satisfactorily.

In a FM-CW or CW radar apparatus, when interference components are Contained in channel signals obtained as beat signals from array antenna elements of respective channels, and the interference components result from directly receiving transmitted CW radar waves from an external source, phase shifting is applied to each of the channel signals to shift respective phases of the interference components of the respective channels to a condition corresponding to reception of interference waves from a predetermined direction. The interference components are then eliminated, and reverse phase shifting is applied to restore remaining components of the channel signals to their original phase condition.

The invention relates to a method for eliminating linear regular noise of seismic prospecting and multiple wave disturbance in a self-adapting mode, aiming to provide seismic figures with high resolution for the exploration of oil fields. The method comprises the following steps: transforming seismic data sets in a field according to regular disturbance linear event virtual inclination; subtracting a seismic trace and a noise model trace to obtain a current signal value; determining the receiving probability of the noise by utilizing a probability density function and a threshold value; subtracting the separated noise from an original record to eliminate a regular interference wave; carrying out linear inverse transform on the seismic data to obtain a data set; carrying out linear inverse transform on the record with the regular interference wave being eliminated to obtain a seismic record; and carrying out separate frequency processing and noise suppressing processing. The invention dose not damage the frequency components of effective waves and has the advantages of fast operation speed, good effect for suppressing noise, suitability for pre-stack seismic data and post-stack seismic data, and the like.

An interference wave detecting device comprises a transmitter for converting data to be transmitted from a base station into a radio signal of a predetermined transmission frequency, and for transmitting the radio signal to a mobile station by way of a transmitting antenna, a receiving unit for receiving either of a radio signal lying within a certain reception band of frequencies including a predetermined reception frequency from the mobile station and an interference wave signal lying within a certain transmission band of frequencies including the predetermined transmission frequency, and a controlling unit for causing the transmitting unit to stop transmitting the radio signal of the predetermined transmission frequency in order to detect the interference wave signal, and for enabling the receiving unit to receive the interference wave signal only within a period of time during which the transmitting unit stops transmitting the radio signal of the predetermined transmission frequency to the mobile station.

A sampled beat signal RD is split into a plurality of short-time data SD in the time direction, for each of antenna elements. Interference component frequency of an interference wave is detected from a frequency spectrum of the short-time data SD. A digital beam forming process is performed for the interference component frequency of the interference wave to extract a peak of the electrical power of an azimuth direction and estimate an absolute value of an incoming direction of interference components. Based on the absolute value of the incoming direction of the estimated interference components, a filter for suppressing the interference components is operated to suppress the interference components.

A high frequency signal receiver comprising a variable gain amplifier, a first filter for restricting a bandwidth of an analog baseband signal, an AD converter connected to the first filter, a second filter for restricting the bandwidth of an output of the AD converter, an interference wave detection circuit for detecting the level of an interference wave in the received signal, and a controller for controlling the first filter to have a wide bandwidth when the level of the interference wave is lower than a threshold level, and switching the first filter to have a narrow bandwidth while changing the characteristics of the second filter so as to compensate deterioration of the pass-band of the first filter when the level of the interference wave is equal to or greater than the threshold level.

A DS-CDMA (Direct Sequence-Code Division Multiple Access) multi-user interference canceller cancels interference waves of a plurality of users. The DS-CDMA includes a variable gain controller for comparing reception characteristics of reception signals received from the plurality of users prior to interference cancellation processing with reception characteristics upon the interference cancellation processing and evaluating a comparison result, and controlling gains prior to baseband decoding of the reception signals so as to maximize improvements of the reception characteristics of the reception signals on the basis of an evaluation result. A CDMA multi-user system using the above canceller is also disclosed.

Provided is a cyclic shift sequence generation method which can prevent coming of an interference wave into a desired wave detection window even if a cyclic shift sequence has a high mutual correlation in different bandwidths, thereby improving a channel estimation accuracy in a base station. In this method, a cyclic shift sequence number to be allocated to a cell is decided in advance. Moreover, when the cyclic shift amount between cyclic shift sequences allocated in cells is Δ1 and the cyclic shift amount of the cyclic shift sequences allocated between the cells is Δ2, Δ1 and Δ2 are made different when generating a cyclic shift sequence.

The invention discloses a method and a system for resisting dense forwarding type defraud interference of an airborne radar, and the resistance of dense forwarding type defraud interference is realized through an interference scout module and an interference filter and elimination module. Interference scout is used for carrying out the PD (probability of defraud) treatment on data received by a radar; the CFAR (constant false alarm rate) detection is carried out on data in a clear area; a detection result direction of arrival is estimated; an interference direction of arrival is estimated with combination of the detection result of a plurality of wave positions. In the interference filter and elimination treatment, a sum beam pointing to the interference direction is formed according to an interference scout result; the sum beam pointing to the interference direction is used as an auxiliary passageway, an existing space passageway is used as a main passageway, the method of GSC (gain scheduling control) is adopted to filter and eliminate interference, and the channel covariance matrix of the interference is estimated according to an interference sample selected from the clear area. By adopting the method and the system, the difficult problem of inhibition on dense forwarding type defraud interference is solved, the dense forwarding type interference is fundamentally filtered and eliminated, false alarms caused by the dense forwarding type interference are reduced, adverse effects on a CRAR detection threshold and the STAP (space time adaptive processing) performance are eliminated, the detection performance of a radar target is improved, the system is simple and easy to realize, and an engineering application value is provided.

Based on a received signal y(t) received by a radiating element of an array antenna including the single radiating element and a plurality of parasitic elements, an adaptive controller calculates and sets a reactance value of a variable reactance element for directing a main beam of the array antenna in a direction of a desired wave and directing nulls in directions of interference waves so that a value of an objective function expressed by only the received signal y(t) becomes either one of the maximum and the minimum by using an iterative numerical solution of a nonlinear programming method.

Disclosed are a radio communication terminal device, a radio communication base station device, and a radio communication method which can prevent input of an interference wave peak into a detection window of a cyclic shift sequence allocated to a local cell and improve the channel estimation accuracy in a base station. A frequency serving as a reference is set for a transmission band width of all the cells and respective terminals in which frame synchronization is established. By using the frequency as a reference point, a phase rotation addition unit (110) of a reference signal generation unit (108) adds a phase rotation corresponding to a frequency difference δ; between the transmission band of the reference point and that of the reference signal to a ZC sequence as a reference signal in the frequency region. The ZC sequence to which the phase rotation is added is multiplexed with transmission data in a multiplexing unit (114) and a multiplexed signal is transmitted from a transmission RF unit (115).

A conventional method of controlling the passband of a filter involves an increase in cost for a chip due to a large area of a detection circuit for determining the level of an interference wave. The present invention utilizes a result obtained by detecting the amplitude level of a signal with an automatic gain control circuit to appropriately control the passband of a filter. The amplitude level of all the signals including a desired wave and an interference wave is detected by utilizing the automatic gain control circuit to thereby control the passband of a filter on the basis of the result.

An OFDM receiver 1 receives an OFDM signal. The OFDM signal is composed of a useful symbol period for transmitting a signal relating to data and a guard interval period for transmitting a signal that is the same as part of the signal transmitted in the useful symbol period. An interference wave cancel circuit 18 cancels a narrow-band interference wave component relating to a narrow-band interference wave from the OFDM signal, and outputs the OFDM signal from which the narrow-band interference wave component has been canceled, as a cancel signal. The correlation detection circuit 20 calculates a correlation between a cancel signal output from the interference wave cancel circuit 18 and a cancel signal which has been delayed by the useful symbol period delay circuit 19 by the useful symbol period.

An adaptive antenna apparatus includes antenna elements. One of the antenna elements has an electrical length L1 larger than λ/2, and equal to or smaller than a predetermined upper-limit wavelength, where λ is a wavelength of a radio signal. Another antenna element has an electrical length L2 equal to or larger than a predetermined lower-limit wavelength and equal to or smaller than λ/2. A controller adaptive-controls the adaptive antenna apparatus to form a radiation pattern of the adaptive antenna apparatus including a plurality of nulls substantively in a direction of an interference wave by adjusting at least one of an amplitude and a phase of each radio signal received by the first and second antenna elements.

The invention discloses a method for detecting the quality of a large-diameter tubular pile at a low strain. A plurality of acceleration sensors are arranged on the top of the tubular pile; a central angle corresponding to two adjacent acceleration sensors is 90 DEG; central angles between exciting points and all the acceleration sensors are 45 DEG or 135 DEG; acceleration responses are obtained through the measurement of the acceleration sensors, and speed responses are obtained through acceleration response integrals; an average value is obtained by superposing the speed responses obtained through the measurement at all measuring points to obtain an average speed response curve; and the integrity of a pile body is determined according to the obtained average speed response curve. By the method, a plurality of sensors are use for multipoint measurement, so that the propagation law of stress waves along the circumferential direction of a pile wall can be obtained, and the influence of a three-dimensional effect is eliminated; and due to the adoption of the average speed response curve, the problem of high-frequency interference waves can be completely solved, and the excitation of the points which form an angle of 45 DEG or 135 DEG with the acceleration sensors is better than the conventional excitation of the points which form an angle of 90 DEG with the sensors. The method for detecting the quality of the large-diameter tubular pile is easy to operate, convenient to implement, low in measurement cost, high in measurement accuracy and high in efficiency.

A satisfactory reception environment is secured efficiently regardless of a degree of the traffic intensity. A pilot power control unit is provided to a base station radio unit. The pilot power control unit controls a desired wave power-to-interference wave power ratio of a pilot signal to stay at a preset value. More specifically, upon receipt of a multiplex wave from a multiplexing unit, the pilot power control unit computes a desired wave power-to-interference wave power ratio of a pilot signal. Then, the pilot power control unit transmits a command signal to a coder to change a transmission power value of the pilot signal in an amount corresponding to a difference between the computed desired wave power-to-interference wave power ratio and a set desired wave power-to-interference wave power ratio.

In a cellular telephone provided with a receiving circuit of a direct conversion type, a passive low-pass filter is arranged between a mixer for an I-channel and a base band circuit for removing interference waves of or above a channel next to a channel neighboring to the I-channel, and another passive low-pass filter is arranged between a mixer for a Q-channel and the base band circuit for removing interference waves of or above a channel next to a channel neighboring to the Q-channel. Since the low-pass filters for removing the interference waves of or above the channel next to the neighboring channel are of a differential type, the circuit scale can be small, and the power consumption is small. Since the interference waves are removed by the passive low-pass filters and the active low-pass filters, only the desired channel can be reliably received.

A tuner has a dual AGC function, and frequency-converts an input signal into an IF signal. An orthogonal detector calculates a complex signal from the IF signal. A demodulator demodulates a digital signal from the complex signals. An error corrector corrects the error of the digital signal. A signal level detector calculates a level judgment signal from the IF signal. A demodulation level detector detects a signal level of a demodulation signal on a desired band from an output signal of the demodulator. When a demodulation level judgment unit generates a judgment signal representing an influence from interference waves in adjacent channel affecting on a signal on the desired band from the demodulation signal, a control signal generator feeds back a gain control signal to the tuner in accordance with the judgment signal.