240 results about "Echo detection" patented technology

The invention relates to an echo detection and self-excitation elimination method for an electromagnetic wave common-frequency amplifying repeater system. By using the method, a relationship among grains of an amplifier, a phase when returned electromagnetic wave signals reach a receiving antenna and the output power of the amplifier in the electromagnetic wave common-frequency amplifying repeater system is discovered. According to the relationship, the magnitude of echo signals can be detected effectively, the output power of the amplifier is improved, the self-excitation of the amplifier resulting from the echo signals is avoided, the requirements on isolations of a forward antenna and a backward antenna are reduced, the system grains are improved, and the coverage area is increased. The method is suitable for all electromagnetic wave common-frequency amplifying repeater systems, such as communication repeaters, data television repeaters and the like.

A method of full-field or “ping-based” Doppler ultrasound imaging allows for detection of Doppler signals indicating moving reflectors at any point in an imaging field without the need to pre-define range gates. In various embodiments, such whole-field Doppler imaging methods may include transmitting a Doppler ping from a transmit aperture, receiving echoes of the Doppler ping with one or more separate receive apertures, detecting Doppler signals and determining the speed of moving reflectors. In some embodiments, the system also provides the ability to determine the direction of motion by solving a set of simultaneous equations based on echo data received by multiple receive apertures.

Techniques for suppressing large echo due to nonlinearity, instable adaptive filter, and so on. An echo cancellation system includes an echo canceller unit, a nonlinear echo detection unit, and a nonlinear echo suppression unit. The echo canceller unit (e.g., an adaptive filter) receives a reference signal and a near-end signal, derives an echo estimate signal based on the reference and near-end signals, cancels a portion of echo in the near-end signal based on the echo estimate signal, and provides an intermediate signal having residual echo. The nonlinear echo detection unit detects for large nonlinear echo in the echo estimate signal. The nonlinear echo suppression unit suppresses large nonlinear echo in the first intermediate signal based on a variable gain, which may be adjusted lower if large nonlinear echo is detected and higher otherwise.

The invention provides a three-dimensional laser radar based on a MEMS scanning micro-mirror and a range finding method in view of the complex structure, the small scanning field of view, and the low refresh rate of a conventional laser radar based on a double-axis MEMS scanning micro-mirror. A single-axis MEMS scanning micro-mirror and an optical component with a one-dimensional amplification function are used in cooperation to realize two-dimensional surface scanning. A photoelectric detector composed of a linear detection unit is used for achieving laser echo detection. The three-dimensional laser radar is simple in structure, large in scanning field of view, and high in refresh rate.

A radar device operates for emitting a detection wave ahead of a vehicle, and detecting objects in response to echoes of the emitted detection wave. A reflector detecting device operates for detecting reflectors among the objects detected by the radar device. The detected reflectors are located along a road. A reflector-row extracting device operates for, in cases where there are a plurality of rows of the reflectors detected by the reflector detecting device in one side of the vehicle, extracting one from among the reflector rows. A road-shape recognizing device operates for recognizing a shape of the road on the basis of the reflector row extracted by the reflector-row extracting device.

An echo detector correlates between an incoming signal an echo signal to determine echo delay. A preprocesssor extracts a characteristic pattern such as a binary pattern derived by thresholding an averaged power of each signal. This pattern is down sampled then used for the correlation, and delay is deduced from peaks in the correlation. Advantages include reduced computational load, or larger correlation window size, because the characteristic pattern is easier to correlate. The quantising can enhance the correlation peaks, and the averaging can limit the number of transitions, to give more robustness to noise. An echo canceller has a coarse echo delay estimator and a fine echo delay estimator. The coarse estimated delay is used to adjust a delay detection range of a fine delay detector having a narrow range. The output of the fine detector is used to adjust or suppress the adaptive echo canceller.

A method and an apparatus are provided in an OFDM receiver for detecting and compensating for long echo. The method comprises a first pilot tone interpolation mechanism and a first window placement to filter a received OFDM symbol, a long echo channel detection coupled with a second pilot tone interpolation mechanism, a pre-echo and post-echo detection wherein the pre-echo condition is associated with a second new window placement, and both pre-echo and post-echo conditions place two time windows around a first peak channel response and a second peak channel response for channel estimation. The long echo is estimated by obtaining power spectra of a subset of subcarriers in one OFDM symbol, performing an inverse Fourier transform on the power spectra and determining the long echo by measuring the time between two peaks in the power profile.

The invention provides a tissue viscoelasticity measuring method based on shear wave amplitude and phase detection. An acoustic radiation force excitation probe and an ultrasonic echo detection probe are used for detection at the same time, the acoustic radiation force excitation probe generates push wave beams, tissue generates shear waves at certain frequency, the ultrasonic echo detection probe generates detection wave beams to detect amplitude attenuation and phase change of the shear waves on a propagation path, the elasticity modulus and viscosity coefficient of the tissue are estimated through an amplitude attenuation coefficient and a speed detection value, in other words, the elasticity modulus and viscosity coefficient of the tissue can be quantitatively detected at the same time, precise and rich mechanical parameter information is provided for diagnosis of multiple diseases, the clinical application range of ultrasonic elastography can be widened, and the level of ultrasonic elastography can be improved. The method can carry out detection through the shear waves at one frequency, the system complexity and design cost are reduced, detection efficiency is improved, phase detection noise caused by high-frequency shear waves is avoided, and the accuracy of mechanical tissue parameter detection is improved.

The present invention relates to call voice signal processing, and particularly, to apparatus and method for echo control in parameter domain. The apparatus includes: an echo detection module configured to extract parameter domain characteristic parameters of a far-end output signal and a near-end input signal, respectively, through parameter domain decoding, and detect whether a near-end input signal frame is an echo frame according to the parameter domain characteristic parameters; and a transition module configured to re-quantize the fixed codebook gain, the adaptive codebook gain and an LSF prediction error in the near-end input signal frame when the echo detection module detects the near-end input signal frame as a non-echo frame, and replace the original fixed codebook gain, the original adaptive codebook gain and the original LSF in the near-end input signal frame.

The invention discloses an ultrasonic detection imaging method. The method includes the following steps that first, a stepping motor drives a foldable multi-stage rotating ultrasonic probe, an ultrasonic probe body of the foldable multi-stage rotating ultrasonic probe transmits an ultrasonic signal, and an ultrasonic echo detection signal is collected and transmitted to a detection host; second, a signal processing module positions and calculates the position of the ultrasonic probe body, and position information is transmitted to the detection host; third, the ultrasonic echo detection signal picked by the detection host is imaged through the detection host, image splicing is performed according to the position information, and an image of a detected target is obtained; fourth, an image display displays the image. The invention further discloses a device for implementing the ultrasonic detection imaging method. The device comprises a sucker, the image display, the detection host, a power module, a signal processing module and the foldable multi-stage rotating ultrasonic probe. The device has the advantages of being simple in structure, easy to operate, convenient to control, high in accuracy and the like.

A continuous wave radar Doppler echo detection method comprises the steps: (1) after a baseband signal is sampled, performing N-point FFT operation to obtain a power spectrum curve of a sampling signal, (2) according to a result of gain control (AGC) of a last measurement period, calculating an SNR (signal to noise ratio) threshold of echo detection of this period, (3) judging a working mode, wherein, in a near-zone mode, echo spectrum searching is performed according to a near-zone mode zone division, and, in a far-zone mode, the echo spectrum searching is performed according to a far-zone mode zone division, (4) calculating a speed value according to a detected spectrum position, (5) switching a working mode of a next measurement period according to a speed result, and (6) performing calculation of a gain control (AGC) value according to an acquired time domain signal, and taking an AGC control result as a calculation basis of the SNR threshold of the next period. The method improves the success rate of echo signal detection, and improves the continuous wave radar anti-interference capability.

The invention discloses an intelligent identification method for prestressed concrete beam grouting compactness. According to the method, variational mode decomposition, finite element simulation, support vector machine and other technologies are used, wherein impact echo vibration signals under different working conditions are simulated through finite elements, a support vector machine training sample is constructed by using variational mode decomposition and hilbert transform, and finally the prestressed concrete beam grouting compactness is quantitatively predicted with the trained support vector machine according to an impact echo detection signal. According to the present invention, with the intelligent identification method, the disadvantages of low efficiency, poor precision and the like during the existing impact echo detection process can be effectively overcome, the influence of the human factors in the detection process can be eliminated, and the detection precision and the working efficiency can be improved to the greatest extent.

The invention discloses a gain-variable trans-impedance amplifier integrated circuit for a pulse laser range finder echo receiver, belonging to the technical field of integrated circuit design. The integrated circuit is based on the CMOS integration technology, a narrow pulse photo signal generated by a photoelectric detector is converted into a voltage signal via a current buffer and a difference trans-impedance amplifier, the voltage signal is attenuated by an R-2R resistance attenuating network according to a given attenuation times input by digital control, is amplified to a certain amplitude by a broadband voltage amplifier and is in buffer output by an output buffer. The invention has the advantages of realizing single chip integration for a multi-functional module circuit in the existing pulse laser range finder, improving the integrated level of a receiving circuit, lowering batch production cost for the system and being favor of realizing the multi-element laser echo detection at a high integration level.

The invention provides an ultrasonic range-measuring circuit system, which comprises a drive circuit, an ultrasonic probe, an echo signal detection circuit and a singlechip, wherein the singlechip provides a starting signal for the drive circuit, the output end of the drive circuit is connected to the ultrasonic probe, an echo detection signal of the ultrasonic probe outputs to the echo signal detection circuit, the output end of the echo signal detection circuit is connected to the singlechip, the echo signal detection circuit can be used for rectifying the echo detection signal, and fully converting a negative signal into a positive signal, so that the conversion ensures that the ultrasonic echo signal is more precisely detected and the ultrasonic range-measuring precision is further improved, and meanwhile, an ultrasonic echo sine signal is subjected to full positive conversion so that the frequency of the ultrasonic echo sine signal is increased by one time, thus ultrasonic echo is more favorably subjected to frequency selecting and signal processing.

Echo detection and monitoring systems and methods are provided. According to the invention, the outgoing and incoming voice bearer channels of a voice communication are monitored. The outgoing and incoming signals are time aligned, and measures are then taken to determine whether echo is present in the signal. In accordance with an embodiment of the present invention, the outgoing signal is fed through an adaptive filter.

In a sonodynamic treatment apparatus including: a first ultrasound radiating unit for radiating diagnostic ultrasound; a second ultrasound radiating unit for radiating treatment ultrasound; an echo detection unit for detecting an ultrasound echo; a diagnostic controller for radiating the diagnostic ultrasound with the first ultrasound radiating unit and detecting the ultrasound echo corresponding the diagnostic ultrasound; an echographic controller for processing an echographic image on the basis of the detected ultrasound echo; and a treatment controller for radiating the treatment ultrasound with the second ultrasound radiating unit, radiation of the treatment ultrasound with the second ultrasound radiating unit is controlled to have a predetermined exposure duration and a predetermined pause duration of the treatment ultrasound, and the echographic image is generated on the basis of the ultrasound echo during the pause duration of the treatment ultrasound exposure with the diagnostic image generator. The treatment ultrasound may be weakened after detection of a bubble generated by the treatment ultrasound.

The invention relates to the technical field of ultrasonic flaw detection, and in particular relates to an ultrasonic flaw detection defect location method and an ultrasonic flaw detector. The ultrasonic flaw detector comprises an echo detection circuit, wherein the echo detection circuit is connected to an ultrasonic probe; the ultrasonic probe is fixedly connected to a support; the support is provided with a reference substance linking along with the ultrasonic probe. The first shortest distance from the ultrasonic probe to a welding seam remote side line is obtained by utilizing the reference substance, and positional information of a reflection point relative to a welding seam cross section, namely the position of a flaw relative to the welding seam cross section, can be directly obtained by contrasting the first shortest distance from the ultrasonic probe to the welding seam remote side line with a second shortest distance from the ultrasonic probe to the reference substance and then matching with the depth of the reflection point, so that the detection workload of site flaw detection is reduced, the dependence on subjective judgment of operators is reduced, and the error rates of flaw position misjudgment and characteristic misjudgment are reduced.

A method for detecting and processing echo signals comprises detecting reflections of a transmitted signal as echo signals, obtaining digital magnitudes representative of an envelope of the echo signals over time, applying the digital magnitudes to a plurality of data storing cells, estimating a signal threshold by accumulating the digital magnitudes from a predetermined number of reference window cells at each side of a predetermined cell-under-test in the plurality of data storing cells and multiplying the resulting accumulated signal by a predetermined first weight factor, thus obtaining an estimated signal threshold, comparing the threshold with the signal stored in the predetermined cell-under-test in the plurality of data storing cells, thus reducing chances of false detection.

The ultrasonic apparatus for a diagnosis and therapy includes: a first ultrasound probe, a second ultrasound probe, and an ultrasound exposure apparatus for exposing ultrasounds for a phase shift, diagnosis, and therapy, respectively; an echo detection device for detecting an ultrasound echo; control parts for the phase shift for causing the shift in an ultrasound contrast agent by exposing the ultrasound for the shift through the first device, and for the diagnosis for detecting the shift of the agent, using the echo detected by the detection device, corresponding to an exposure of the ultrasound for the diagnosis by the second device; a difference calculation device for calculating a difference over time of the shift detected by the control part for the diagnosis; a device for positioning for deciding a target position where the difference is produced; and a control part for the therapy for exposing the ultrasound for the therapy to the decided target position through the exposure apparatus.

The invention relates to a target classification identification method for a Doppler frequency transformation radar. A main procedure of the method is as follows: firstly, through radar echo detection and trace point agglomeration processing, a center point of target echoes is found and a plurality of target data which can be used for meeting a processing condition are extracted; a target radial speed is used to carry out Doppler frequency compensation on target data which meets the processing condition; autocorrelation processing, frequency transformation processing and enhancement processing are carried out through the compensated data and frequency components of the target data are estimated; and at last, threshold segmentation and classification processing are carried out on an enhanced result and whether a target is a helicopter target or a sea-surface target is judged finally. The method has the characteristics of allowing engineering realization, being great in identification effect and being sea-clutter resisting in a specific degree, and a helicopter accuracy reaches more than 85%.

The invention provides a correlated encryption transmission device and method of an underwater optical image. The device comprises an optical image reconstruction platform and an underwater optical detection platform, wherein the optical image reconstruction platform comprises a submarine sound signal receiving module and a correlated computation module; the underwater optical detection platform comprises a center control module, a structured light illumination module, an optical echo detection module and an acoustic transduction emission module. The method comprises the following steps: S1, emitting the detection light to irradiate an underwater target object to perform correlated imaging processing; receiving a light echo signal, modulating and then sending to an acoustic channel to be transmitted; S2, receiving an acoustic channel signal, demodulating and performing correlated computation processing to obtain an underwater target object image. The device provided by the invention not only can maintain the high resolution of the optical imaging, but also can increase the underwater transmission distance of the optical image, the communication rate is improved, and the remote transmission of the optical image is realized.

In the oil industry, the acoustic sounding method is a well-known technique for taking the depth measurements of particular attributes of an oil well or borehole. The method involves sending a short, sharp, clear, loud bang sound down a borehole, normally between the inside wall of the borehole casing, commonly referred to as the annulus and the outside of the production tubing string, and recording the echoes generated. One device for generating the sound needed in the acoustic sounding method is an air or gas pressurized chamber which is discharged at or near the wellhead of the borehole. The sound being generated by this device, commonly known as an acoustic generator, comes from the energy released by the equilibration of the different gas pressures. The current invention is an acoustic generator and its control unit that uses several new and novel features to improve the quality of the sound generated and echoes detected in the acoustic sounding method such as a microphone and microphone unit design for more efficient and effective echo detection.

The invention provides a train collision avoidance system based on acoustic echo detection and a collision avoidance method thereof, relates to the technical field of track traffic and aims at solving the technical problem of the safety of a train running in a tunnel. The train collision avoidance system comprises an acoustic emission device, an acoustic receiving device and a signal control processing device. The collision avoidance method comprises the steps of utilizing an acoustic emission device to emit an acoustic detection signal to the front of the train, utilizing the acoustic receiving device to receive an echo of the acoustic detection signal reflected from the front of the train, analyzing the received echo of the acoustic detection signal, calculating the size of a front obstacle and a distance between the front obstacle and the train according to receiving-emitting time difference between the acoustic detection signal and the echo, the acoustic transmission speed and the train running speed and then judging collision risks of the train according to calculated results. The train collision avoidance system based on the acoustic echo detection and the collision avoidance method are especially suitable for application in urban metro lines.

The invention relates to the field of voice communication, and discloses a residual echo detection method and apparatus. In the invention, according to a voice spectrum statistical characteristic, within a frequency range with a voice signal-to-noise ratio, an average coherent coefficient of several frequency ranges is utilized to replace a conventional full-frequency range average coherent coefficient as a residual echo detection statistical amount. Since in a frequency range with quite low voice energy, the voice signal-to-noise ratio is quite low, a coherent coefficient is greatly influenced by noise; however, in a frequency range with quite high voice energy, the voice signal-to-noise ratio is quite high, and the coherent coefficient is less influenced by the noise. Therefore, the interference resistance of the full-frequency range average coherent coefficient is lower than the frequency range with the quite high voice energy, so that in actual application, the detection method of a selected frequency range can be provided with a quite high interference resistance capability. At the same time, since the calculation of the full-frequency range average coherent coefficient is unnecessary, the complexity of the detection method is greatly reduced.

The invention discloses a method for calculating the farthest detection distance of a Gm-APD laser radar. The method comprises the following steps: 1, acquiring echo intensity by using a laser radar equation; 2, obtaining the triggering probability of each time interval of the Gm-APD laser radar; 3, acquiring simulation data under different statistical frame number conditions by using a Monte Carlo method; 4, echo parameters are obtained through a signal detection method according to the Gm-APD trigger probability curve obtained in the step 2 and the simulation data obtained in the step 3; and5, calculating echo detection probability and confirming optimal parameters of the system. The Gm-APD performs optimal argumentation on parameters such as laser parameters and optical aperture underthe condition that the index parameters are determined, so that the laser radar system realizes optimal power consumption and volume on the premise of meeting the indexes, and has a very important promotion effect on further engineering of the Gm-APD laser radar.

The invention discloses a radar photoelectric linkage system. Radar equipment is used for performing echo detection on a target in a radar detection region, a direction adjustment equipment is used for adjusting a detection direction, photoelectric equipment is used for acquiring an image signal in a field region, cloud equipment is used for adjusting an acquisition angle, and a data processing sub-system is used for acquiring an echo detection signal and an image signal, resolving the echo detection signal and / or the image signal to achieve identification of an invasion target and sending a control instruction to the direction adjustment equipment and the cloud equipment so that the invasion target is continued in the radar detection region and / or the field region. The detection directionof the system can be automatically or manually adjusted according to actual application scene and detection demand, so that the expanded application of the direction detection region of the system ismet, and the direction application rate of the radar is effectively improved. Moreover, the invention also provides a control method of the radar photoelectric linkage system having the advantages.

A method of measuring the thickness of a bonding layer using an acoustic signal. The method is accomplished by applying sound waves to the layered object that cause primary and secondary echoes to be reflected from different interfaces; detecting and digitizing the echoes to produce a digital time series that is processed to remove noise; using filtering the time series with a filter matched to the main echo; locating the time position and magnitude of the maximum value of the filtered time series; time shifting and scaling the main echo using the obtained time position and magnitude; subtracting the primary echo transform model to obtain a cleaned time series; filtering the cleaned time series using a filter matched to the secondary echoes; locating the time position of the maximum value of the secondary echo filtered time series; from The transit time is determined from the difference between the time locations of the primary and secondary echoes; and the bond bond thickness is determined, which is equal to half the measured transit time multiplied by the velocity of the sound wave or pulse in the bond bond.

The invention relates to a sub-microsecond multipath synchronization triggering method. The method comprises steps that when a triggering pulse generated by an apparatus reaches an action end, an echo signal will returns to the output end of an original signal along the path the same as that of the original signal; and through detection and analysis of the apparatus, detection and estimation of transmission delays of the triggering signal are finished. The invention also discloses a sub-microsecond multipath synchronization triggering device. According to the invention, based on the same-path echo detection technology, the device and the method have a detection function of the signal transmission path delays and are capable of achieving real-time monitoring of path delays of the triggering signals; in the triggering method, based on the maximum tolerance principle, by use of the delay compensation technology, high precision synchronization of triggering signals at the acting moment is achieved; and effects caused by difference of multiple transmission paths can be effectively avoided without ensuring that the signal transmission paths are symmetrical highly.

The embodiment of the invention provides an echo suppression method and an echo suppression device. Echo in a complex network environment can be suppressed by using a unified method. The echo suppression method comprises the following steps of: determining the current network transmission mode, executing echo detection corresponding to the current network transmission mode on a far-end signal and a near-end signal; and according to the detection result of the echo detection, starting an echo suppression mode corresponding to the current network transmission mode to suppress the echo in a near-end signal. The method provided by the embodiment of the invention can be adapted to diversified network environments, and is free from continuously adding new processing procedures due to variation of the network transmission mode, for example, adding an encoding procedure and a decoding procedure, and the like, so that resources are saved, and the network transmission performance can be improved.