50 results about "Signal Repression" patented technology

A system for processing radio frequency (RF) signals includes a searcher and a plurality of Cluster Path Processor (CPPs). The searcher detects a maximum signal energy level and position of at least one of a plurality of individual distinct path signals in a signal cluster of a first information signal, wherein at least a portion of the plurality of individual distinct path signals is received within a duration of a corresponding delay spread. The sampling position is used as a starting sampling location by the plurality of CPPs, including a first information signal CPP and a second information signal CPP. Fine sampling positions of the plurality of CPPs are based upon channel energy estimates for the plurality of individual distinct path signals. CPP outputs are employed to produce channel estimates, which are themselves used in subsequent equalization operations. Sampling positions may change over time in order to satisfy alignment criteria.

The invention discloses an anti-spoofing-attack method and system applied to a satellite navigation system. The method comprises the following steps: S1) capturing and processing satellite signals, and obtaining code Doppler information and carrier wave Doppler information of the satellite signals; S2) carrying out consistency detection on the code Doppler information and the carrier wave Doppler information to obtain a consistency comparison result; and S3) judging whether the satellite signals are spoofing signals, sending alarm information if the satellite signals are spoofing signals, and sending current code phase position and carrier wave frequency information to a preset tracking loop if the satellite signals are not spoofing signals. The method and system in the invention not only can judge whether the spoofing signals exist in the received signals, but also can judge which signals are the spoofing signals and which signals are real signals, that is, the second layer can be reached; and the method and system have spoofing signal suppression function and also have strong anti-spoofing capability.

A flip-angle calculating unit calculates a flip angle of a fat-suppression pulse by inputting scanning parameters read from a scanning-parameter storage unit based on scanning conditions set by a scan-condition setting unit and a desired fat-suppression level, into a predetermined computing program. A control unit suppresses fat signals to a desired level by performing irradiation of a fat-suppression pulse having the calculated flip angle and application of a spoiler gradient magnetic field onto a scan target portion of a subject by controlling a gradient magnetic-field generating unit and a transmitting-receiving unit, and further performs irradiation of an RF pulse and application of a gradient magnetic field in accordance with a predetermined pulse sequence, thereby detecting water signals and suppressed fat signals as MR signals. An image-data creating unit creates image data by reconstructing the MR signals.

A target object detection device is provided. The device includes a transmitter for transmitting at least one transmission wave in a predetermined azimuth, an echo signal receiver for receiving echo signals of the transmission waves, an echo signal suppressor for suppressing levels of the echo signals corresponding to sampling positions, a target object detector for detecting the target object(s) based on the level-suppressed echo signals, a first updater for comparing amplitude level(s) of echo signals of sampling positions, with the threshold that is set in association with the first distance, and determining to update the values with a new threshold and a new suppression value, and a second updater for comparing amplitude level(s) of echo signals of sampling positions, with the threshold that is set in association with the second distance, and determining to update the values with a new threshold and a new suppression value.

The present invention discloses a method and a system for noise reduction of a ground penetrating radar B-scan image based on EEMD and permutation entropy. First, a ground penetrating radar two-dimensional B-scan image signal is obtained, and then each obtained B-scan image signal is subjected to noise reduction to obtain the B-scan image signal of the channel after the noise suppression signal, and finally the signal after each channel is recombined to obtain a noise-suppressed two-dimensional B-scan image signal; for any one B-scan image signal, the method for denoising includes: performing EEMD decomposition on the B-scan image signal of the channel to obtain K IMF components arranged from high frequency to low frequency; calculating arrangement entropy values of each IMF component; and selecting an arrangement entropy value not greater than a preset value IMF components to reconstruct, and obtaining the signal after denoising. The invention solves the signal mode aliasing problem existing in the EMD decomposition and can effectively reduce the noise.

In an echo suppressing apparatus suppressing from a near-end input signal acoustic echo signals caused by a far-end signal, an estimated-echo path characteristic is multiplied by a far-end signal to produce an estimated-echo signal for each frame, and frames of the estimated-echo signals thus obtained are stored in an estimated-echo signal storage. A delay amount estimator calculates the total of differences between the near-end input signal and each estimated-echo signal thus stored, and determines the amount of frame delay having its total of differences minimal. A delay estimated-echo signal calculator uses the amount of frame delay to read out an optimum frame and near frames respectively preceding and following the optimum frame and to calculate a corrected, delay estimated-echo signal. An echo suppressor uses the estimated-echo signal thus corrected to suppress the acoustic echo signals from the near-end input signal.

The invention discloses a crossroad non-motor vehicle and pedestrian position detection method based on special-purpose short-distance communication. The method comprises the following steps: disposing a road side special-purpose short-distance communication unit and a roadbed computer unit at a crossroad turning area, wherein the road side special-purpose short-distance communication unit and the roadbed computer unit are connected; the road side special-purpose short-distance communication unit obtaining crossroad area wireless signal data frames; and by taking the data frames as input signals, performing real-time signal spectrum analysis, window function weighing and multipath signal inhibition processing through the roadbed computer unit such that time sequence based non-motor vehicle and pedestrian position detection in the crossroad turning area is realized. The method provided by the invention has the advantages of being free of space-time change influences, effectively utilizing the wireless signal resources of the crossroad area, and improving the safety grade of a crossroad.

A radio frequency (RF) transceiver includes an RF transmitter that generates an outbound RF signal at a carrier frequency that is based on a transmitter local oscillation. An RF front-end receives an inbound RF signal that includes a desired signal component that is based on the outbound RF signal and that includes an undesired signal component. The RF front-end includes a first RF combiner module that attenuates the undesired signal component to produce a desired RF signal. A down conversion module generates a down converted signal from the desired RF signal based on a receiver local oscillation. A receiver processing module generates inbound data from the down converted signal. A frequency control module controls a frequency of the transmitter local oscillation and a frequency of the receiver local oscillation, based on an interference rejection signal, to control the attenuation of the undesired signal component.

The invention provides a photoelastic modulation measurement system. A reference signal is introduced into the photoelastic modulation measurement system; the reference signal contains information of demodulation deviation of a photoelastic modulator on a polarization state; and data noise caused by the deviation of a modulation state of the photoelastic modulator is curbed through the reference signal.

An OFDM transmitter and a signal processing method thereof are provided. An OFDM transmitter includes a FEC unit for coding data of transmitting stream(TS); a frame format unit inserts pilot signal or transmitting parameter signal (TPS) or null signal into coding TS data and inserts pilot signal or TPS into coding TS data; an inverse discrete Fourier transformer inverse-discrete-Fourier-transforms the coded data which the null signal has been inserted into OFDM signal of time domain; a GI (guide interval) inserting unit inserts a GI into an OFDM symbol outputing from the IDFT unit; a synchronous insertion unit inserts PN sequence into each OFDM signal of GI which having GI inserting unit; a PAL suppression filter removes PAL component from OFDM symbol outputing from the synchronous insertion unit, or transmits the OFDM symbol without filtering; a pulse shaping filter for filtering OFDM signal outputing from the PAL suppression filter, or filtering OFDM signal outputing from the synchronous insertion unit; a RF upconversing unit for upconversing OFDM signal after filtering into radio frequency.

The invention discloses an electromagnetic spectrum umbrella cover radio frequency domain self-interference suppression method and system. The method comprises: a first signal conversion module converting a signal entering through a first input end of a communication receiver and sending the converted signal to an interference signal reconstruction module; the interference signal reconstruction module compensating the local reconstruction interference signal from four dimensions of frequency, time, amplitude and phase, and performing power divider compensation and combiner compensation on thecompensated reconstruction interference signal according to the influence; and the second signal conversion module inputting the compensated signal to the second input end of the combiner through theoutput end of the communication receiver and the amplifier. The invention provides an effective processing architecture for the received radio frequency signal, and the self-interference radio frequency signal can be suppressed within the dynamic range of a receiving channel, so that the saturation of the receiving channel is prevented. The self-interference suppression of the umbrella cover is not limited by the type of a communication signal, the system can be combined with any existing communication link, and is high in compatibility.