47 results about "Continuous wave interference" patented technology

For suppression of continuous wave interferers at, e.g., up to four interferer frequencies (f₁, f₂, f₃, f₄) in a GNSS receiver base band circuit a raw digital signal is, in a band stop unit (21), shifted, by a first mixer (31a), by the negative of the first interferer frequency (f₁) in the frequency domain whereupon the continuous wave interferer is suppressed by a band stop filter (30a), a linear phase FIR filter with a suppression band centered at zero, e.g., a filter subtracting a mean over previous subsequent signal values from the actual signal value. After further shifting of the shifted digital signal by the negative of the difference between the second interferer frequency (f₂) and the first interferer frequency (f₁) the shifted digital signal is again filtered by an identical band stop filter (30b) and so on. After the last filtering step the shifted digital signal is shifted back to its original position in the frequency domain to provide a filtered digital signal which corresponds to the raw digital signal with narrow interferer bands centered at the interferer frequencies (f₁, f₂, f₃, f₄) suppressed.

A method for processing weak indoor signals in presence of cross-correlation or continuous wave interference and associated GPS receiver are provided. The method comprises providing a two-dimensional delay-Doppler accumulated power pattern having a plurality of accumulated powers corresponding to frequency and time; for a predetermined frequency, determining an average value of accumulated powers of the two-dimensional delay-Doppler accumulated power pattern over a plurality of times; and subtracting the average value from the accumulated powers used in determining the average at the frequency over the plurality of times to generate a delay-Doppler accumulated power pattern with suppressed interference effect.

The invention provides an open-loop detecting circuit for a frequency modulated continuous wave optical fiber gyroscope based on phase comparison, belonging to the technical field of an optical fiber gyroscope. The open-loop detecting circuit comprises an analogue pretreatment part and a digital domain treatment part, wherein the analogue pretreatment part comprises a band-pass filtering module, a shaping module, a multiplier, and an AD (Analogue/Digital) pretreatment part; the digital domain treatment part comprises an AD collector and an FPGA (Field Programmable Gate Array) programming module; and the AD pretreatment part comprises a low-pass filter and an AD head amplifier. The invention provides the open-loop detecting circuit for the frequency modulated continuous wave optical fiber gyroscope based on the phase comparison. The novel frequency modulated continuous wave interference type optical fiber gyroscope is quantitatively detected by detecting a phase difference of two paths of signals, so that the influence on phase difference detection, caused by frequency modulation period and amplitude variation, can be removed. The common-mode error of the optical fiber gyroscope can be restrained well in a differential detection manner.

The invention relates to the field of sanitary navigation and location and discloses a continuous wave interference signal estimator, an estimation method, a remover and a removing method. A digital phase-locked ring is adopted to detect the frequency or sine wave and amplitude of a continuous wave interference signal, a continuous wave interference estimation signal can be obtained easily, so that the continuous wave interference estimation signal can be removed conveniently. The digital phase-locked ring is a common circuit, FFT conversion and FFT reverse conversion are not required to be conducted on time domain signals received by a global navigation satellite system (GNSS) in real time, and complex technologies such as the FFT conversion and the FFT reverse conversion are avoided. The problem in the prior art that a continuous wave interference frequency point needs to be known in advance is solved. Further, a frequency band of a radio frequency front end output signal is divided into a plurality of sub frequency bands, the plurality of sub frequency bands can be processed respectively, hardware achieving difficulty is further reduced, and the processing speed is increased.

An anti-jam receiver for coordinating with a frequency hop jammer includes a receiver assembly for receiving a spread spectrum signal, and a processor for removing an undesired signal from the spread spectrum signal. The processor utilizes an anti-jam algorithm in the frequency domain. The processor has an update interval during which frequencies that have been identified with undesired signals are removed from the spread spectrum signal. The frequency hop jammer has a hop interval during which a jamming signal is transmitted at a constant frequency. By coordinating the update interval of the processor with the hop interval of the frequency hop jammer, the frequency hop jammer appears to be a continuous wave jammer to the anti-jam receiver, while appearing to be a broadband jammer to other anti-jam systems that are not coordinated with the hop interval of the frequency hop jammer.

The present invention provides a marine BDS (BeiDou Navigation Satellite System) receiving device in-band and band edge continuous wave interference threshold determination method. The multi-system navigation signal simulation source is employed to generate satellite signals, a radio-frequency signal generator is employed to generate interference signals, satellite signals and interference signals are transmitted to a signal combination unit through radio-frequency cables to perform channel combination, and the combination signals are transmitted to a marine BDS receiving device through the radio-frequency cables to determine the interference threshold. The marine BDS receiving device in-band and band edge continuous wave interference threshold determination method is not influenced by other undesirable unknown radio-frequency interferences of the external environment so as to accurately measure and estimate the space attenuation of signals.

The invention belongs to the field of broadcasting television network two-way transmission health monitoring, and relates to an up channel noise intelligent recognition method of a broadcasting television access network. The method comprises acquiring the real-time spectral data of the up channel of a NGB (next generation broadcasting) network; classifying the main noise of the up channel of the NGB network to thermal noise, narrow-band continuous wave interference, and wide-band pulse interference, selecting some fields from the real-time spectral data of the up channel of the NGB network, and determining the type of the main noise of each field; extracting the characteristic value of a plurality of frequency points of each field; constructing a three-layer BP (back propagation) neutral network; training the BP neutral network by using LM (levenberg-marquart) algorithm to obtain a neutral network model for intelligently recognizing the noise of the up channel of the NGB network; and effectively determining the noise type of the newly-inputted real-time spectral data of the NGB up channel by the neutral network model. The up channel noise intelligent recognition method provided by the invention has a fault diagnosis accuracy of 85% or above, and has high practical value.

The invention discloses a narrowband interference resisting system and a narrowband interference resisting method based on adaptive signal processing. The narrowband interference resisting system based on the adaptive signal processing is located at the front end of a digital baseband, performs filtering processing on a digital intermediate frequency signal received by the narrowband interference resisting system based on the adaptive signal processing, and outputs the signal to the digital baseband after interference of the signal is filtered out. The narrowband interference resisting system based on the adaptive signal processing comprises a power spectrum estimation module of an interference signal, an interference reference signal generation module and an adaptive signal processing module. The narrowband interference resisting method based on the adaptive signal processing is directed at narrowband noise and continuous wave interference, and used to accurately detect, track and filter the interference signal. According to the narrowband interference resisting system and the narrowband interference resisting method based on the adaptive signal processing, useful signal components are retained to the utmost on the premise of filtering out the interference signal.

The invention relates to a receiving device. The receiving device comprises a radio frequency; an interference elimination unit which is used for receiving the first signal from the radio frequency and outputting a second signal; a baseband; an interference detection unit which is used for detecting whether continuous wave interference exists in the first signal and/or the second signal; an interference elimination control unit; when the interference detection unit detects that continuous wave interference exists in the first signal and/or the second signal; the interference detection unit sends detected continuous wave information to the interference elimination control unit; the interference elimination control unit processes the information of the continuous waves to obtain a first local oscillation frequency; the interference elimination unit is used for eliminating interference according to the received first local oscillation frequency; and the frequency of the continuous wave isshifted to zero center frequency, the interference elimination unit outputs a third signal, the interference elimination control unit performs continuous wave interference judgment according to the third signal, and if the judgment result is that continuous wave interference exists, the interference elimination unit eliminates the continuous wave interference in the first signal according to thethird signal and outputs a second signal.

The invention discloses a communication method and system capable of resisting continuous wave interference. The method comprises the following steps: step S110, a sending end generating a training sequence with start signaling information as a signaling sequence, and marking it as C1; performing time frequency transformation on the signaling sequence C1, obtaining a control frame head, and marking it as C2; and at the same time, generating a sub signal frame to be transmitted; step S120, the sending end multiplexing the control frame head C2 and the sub signal frame to form a signal frame group; and step S130, the sending end sending the signal frame group after the signal frame group is processed. According to the communication method and system capable of resisting the continuous wave interference, under the condition that there is no additional system cost, the signal processing of a receiving end is simple and efficient, high robustness is maintained under quite high continuous wave interference, and the communication performance of the communication system in an extreme transmission environment is further improved.

The invention discloses an airborne radar unintentional interference suppression method in a complex interference scene. The method comprises the steps of allowing an airborne radar to receive distance-pulse domain echo data; judging whether asynchronous short pulse interference exists or not by adopting an interference detection method based on time-frequency domain characteristics, and eliminating the asynchronous short pulse interference by adopting a time-domain trapped wave interference suppression method; performing two-dimensional Fourier transform on the distance-pulse domain echo datato obtain distance frequency-Doppler two-dimensional frequency domain echo data; judging whether narrowband continuous wave interference exists or not by adopting a narrowband continuous wave interference detection method, and if so, suppressing the narrowband interference by adopting a frequency domain notch method; and carrying out inverse Fourier transform on the echo data in a distance frequency dimension. According to the method, various forms of unintentional interference of narrow-band continuous wave interference and asynchronous short pulse interference can be effectively suppressedat the same time, and the radar target detection performance is improved.

The invention relates to a nonlinear frequency modulation pre-calibration method of a semiconductor laser, and belongs to the technical field of optical frequency modulation continuous wave interference measurement. A deviation between a practical position and an ideal position of an extreme point of the interference signal waveform in each modulation period in the time axis is tested to determinethe magnitude of frequency modulation nonlinearity of the semiconductor laser, position of a point corresponding to the laser modulation signal waveform in the time axis is translated according to the deviation, the calibrated laser modulated waveform is obtained by sectional interpolation or nonlinear fitting, and frequency modulated continuous wave interference linearity of the semiconductor laser is calibrated. According to the method, computer aided detection can be used, the optimal modulated waveform is obtained by repeated iteration, the nonlinearity calibration precision is improved,and the method can be applied to different frequency modulation continuous wave interference measurement systems based on the semiconductor laser to improve the measuring precision.

The invention relates to the technical field of satellite navigation and signal processing, in particular to a single-antenna Beidou satellite signal wavelet decomposition anti-interference algorithm. The single-antenna Beidou satellite signal wavelet decomposition anti-interference algorithm comprises the following steps: firstly, decomposing medium-frequency signals by using Meyer wavelets to obtain signals of all frequency bands; secondly, by comparing energy of the decomposed signals of all frequency bands, detecting a frequency band range of narrowband interference noises, and by attenuating the coefficient of the frequency band range to which the interferences belong, reconstructing signals to remove the narrowband interferences. Experimental simulation proves that by the single-antenna Beidou satellite signal wavelet decomposition anti-interference algorithm, narrowband continuous wave interference can be resisted under the condition of a single antenna, and the sensitivity of a receiver can be increased by about 5 dB; in allusion with characteristics of a single-antenna intelligent terminal, the modern signal processing method is provided based on wavelet decomposition-reconstruction to remove interferences.

The invention discloses an amplitude normalization method of frequency modulated continuous wave interference signals, which is used for correcting the interference signals. The interference signals are corrected into equal-amplitude oscillation signals with constant amplitudes, and meanwhile, the frequency and phase attributes of the interference signals are not changed. The method comprises thesteps of sampling the interference signals and converting the interference signals into digital signals; carrying out amplitude demodulation on the interference signals according to a PI characteristic of a semiconductor laser; and carrying out adaptive gain on the signals according to effective values of the interference signals to obtain the equal-amplitude oscillation interference signals withthe constant amplitudes. According to the method, the amplitudes of the interference signals are not influenced by factors such as current modulation of the semiconductor laser, a detection distance and the like; and the stability of a frequency modulated continuous wave interference system and the precision of carrying out phase discrimination on the interference signals can be improved.

The invention provides a digital frequency-modulation continuous wave interference laser driving and signal processing method and circuit. The method is characterized by firstly, periodically readingdriving signal waveform data by a microprocessor through using a table look-up method, converting into an analog signal by a DAC, after being amplified by an amplification circuit, passing through a voltage-controlled current source so as to drive a semiconductor laser to generate a laser; then, converting an interference signal formed by the laser after passing through an interferometer into an electrical signal by a photoelectric detector, filtering and removing a noise via a preprocessing circuit, and converting into a periodic digital signal synchronized with the modulation period of a driving signal by the ADC; and finally, acquiring the frequency or the initial phase of a frequency modulation interference signal by the microprocessor according to the digital signal in the same periodthrough a digital phase discrimination algorithm. Through certain circuit implementation, the method and the circuit are compared with an analog frequency-modulation continuous wave interference laser driving and signal processing method and circuit, laser linear frequency modulation is easily acquired, the laser is prevented from being damaged, and high precision and large dynamic range measurement are realized.

The invention relates to the technical field of signal processing and analysis, in particular to a rapid phase discrimination method of a frequency modulation continuous wave interference signal. Themethod comprises the following steps of rapidly calculating initial phase of the frequency modulation continuous wave interference signal, performing high-speed demodulation on the displacement of a target or physical quantities (temperature, pressure and the like) related to the displacement, and improving the precision and dynamic characteristics of a frequency modulation continuous wave interference system. The invention provides a rapid phase discrimination method of the frequency modulation continuous wave interference signals. The wave crest and trough of the interference signal are firstly positioned, and phases of multiple characteristics in the interference signal is calculated, and the initial phase of the interference signal is calculated through the phases of the characteristicpoints. The method disclosed by the invention is rapid in phase discrimination speed, strong in practicability, and capable of improving an applicable range on the target movement speed by the high-frequency continuous wave interference system; and meanwhile, the method cannot be influenced by the strength modulation ad nonlinear frequency modulation of the laser, and the phase discrimination precision is high.

The invention provides an intermediate frequency signal amplitude measurement method and device based on pulse width counting, which can be applied to any motion sensing radar sensor chip and module. According to the Doppler velocity measurement radar sensor chip, a pulse counting method with a fixed time period is used for measuring the output pulse width of a comparator, the method can be used for judging effective dynamic radar triggering, power frequency interference and other interference are prevented, and the duty ratio of a signal is measured through the method. The method can detect the amplitude of a non-continuously existing electric signal without an analog-to-digital converter, can eliminate the interference of continuous waves with constant amplitude, and is theoretically suitable for any analog quantity measurement equipment which needs to measure the signal amplitude.

The invention relates to a contact laser interference displacement sensor and a measuring method, which overcome the problem that large-size and high-precision parts cannot be directly measured in theprior art, and realize the precision measurement of the large-size and high-precision parts. The contact laser interference displacement sensor comprises a sensor shaft sleeve, a hollow measuring rodis arranged on the sensor shaft sleeve through a rolling pair fixed at the front end of the sensor shaft sleeve, a measuring body and a reflector are sequentially arranged at the front end of the measuring rod, a collimator is arranged at the rear end of the sensor shaft sleeve and connected with an optical fiber, and the optical fiber is connected with a frequency modulation continuous wave interference signal processor. The front end and the rear end of the measuring rod are provided with a front limiting block and a rear limiting block respectively, and the front limiting block and the rear limiting block are in threaded connection with the measuring rod.

The invention discloses a secondary quantization method of a satellite-borne receiver and the satellite-borne receiver, aiming at the defects of a time domain anti-interference technology, amplitude amplification is carried out on a baseband signal subjected to down-conversion, and then a high order is intercepted, so that the secondary quantization method can adapt to the stability of anti-interference in a large dynamic range; meanwhile, the method ingeniously and effectively suppresses the pulse interference while suppressing the continuous wave interference, is a zero-resource-consumption method for the pulse interference, is low in cost and easy to implement, and can effectively solve the problems of useful signal loss, large resource consumption and complex logic judgment caused by a time domain anti-interference technology.

The invention discloses a tunable anti-interference pulse self-check detection circuit which comprises a coupling circuit, a detector diode, a filter capacitor, a load resistor, a blocking capacitor, a grounding resistor and an operational amplifier comparator. The coupling circuit is used for extracting the sent self-checking pulse signal; the detector diode, the filter capacitor and the load resistor form a charging and discharging loop used for converting the radio frequency signal into a voltage analog signal; the blocking capacitor, the grounding resistor and the operational amplifier form a filter circuit which is used for filtering a direct current level formed by a continuous wave interference signal at the front end of the blocking capacitor and only detecting and amplifying a coupled input pulse radio frequency signal, and the pulse width and amplitude of the pulse signal change along with the adjustable resistor; according to the invention, self-checking pulse signals with different pulse widths and different amplitudes can be detected, so that external clutter interference, other interference and the like can be resisted.