9992 results about "Echo signal" 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.

An apparatus is provided for suppressing an echo signal included in a measured signal corresponding to a measured sound. In the apparatus, the measured signal and a reference signal in a time domain are transformed into a frequency domain, and calculated for obtaining each value of a ratio and a correlation between the measured signal and the reference signal in the frequency domain. With executing a comparison of the values of the ratio and the correlation, a coefficient is derived, where a product of the coefficient and the measured sound in the frequency domain gives an estimated value of the echo signal. The echo in the measured signal is suppressed with subtracting the estimation of the echo signal from the measured signal, respectively in the frequency domain.

Multiple microphone noise suppression apparatus and methods are described herein. The apparatus and methods implement a variety of noise suppression techniques and apparatus that can be selectively applied to signals received using multiple microphones. The microphone signals received at each of the multiple microphones can be independently processed to cancel echo signal components that can be generated from a local audio source. The echo cancelled signals may be processed by some or all modules within a signal separator that operates to separate or otherwise isolate a speech signal from noise signals. The signal separator can include a pre-processing de-correlator followed by a blind source separator. The output of the blind source separator can be post filtered to provide post separation de-correlation. The separated speech and noise signals can be non-linearly processed for further noise reduction, and additional post processing can be implemented following the non-linear processing.

A speech processing apparatus which, in the process of performing echo canceling by using a pseudo acoustic echo signal, continuously uses an impulse response used for the previous frame as an impulse response to generate the pseudo acoustic echo signal when a voice is contained in the microphone input signal, and which uses a newly updated impulse response when a voice is not contained in the microphone input signal.

The fouling state of a polymeric membrane within the high pressure housing of a spiral wound or a hollow fiber membrane module is determined. An ultra sonic transducer positioned with its emitting face in physical engagement with the outer surface of the housing is pulse energized by a pulser / receiver device. A membrane echo signal is detected by a receiver of the pulser / receiver device. A reference echo signal indicative of a fouled or an unfouled state of the membrane is compared to the echo signal to determine the membrane fouling state. The echo to reference comparing step can be based upon comparing amplitude domain signals, comparing time-domain signals, comparing combinations of amplitude domain and time-domain signals, and comparing transformations of amplitude domain and time-domain signals. A clean or a fouled reference echo can be provided from a clean or a fouled membrane and then stored for use during a liquid separation process, or a clean reference echo signal can be obtained on-line from a second transducer whose echo signal is derived from an area of the membrane known to remain relatively unfouled during the liquid separation process, or a clean or fouled reference echo signal can be provided for later use during a cleaning process or during a liquid separation process. Multiple transducers and a switching network can sample the fouling state at different positions within the membrane module.

An anti-interfering method of short-range FMCW radar includes designing a set of pseudo-random code according to occasion of radar, distributing different pseudo-random code to different radar operated at different area, applying different pseudo-random code to modulate frequency start-point of FM emission signal for the same radar on each cycle, making frequency-mixture on received echo signal by utilizing emission signal, using filter to filter off interference signal and applying FM signal processing means to treat reserved usable signal for obtaining object distance and speed information in high resolution.

A system monitors and characterizes internal elasticity of a blood vessel to detect abnormality. A catheter system for heart performance characterization and abnormality detection, comprises an ultrasound device for emitting ultrasound wave signals within patient anatomy and acquiring corresponding ultrasound echo signals. A signal processor processes the ultrasound echo signals to, determine a signal indicating displacement of a tissue wall over at least one heart cycle and identify a displacement value in the displacement signal. The displacement value indicates a tissue wall displacement occurring at a point within a heart cycle. A comparator compares the tissue wall displacement value with a threshold value to provide a comparison indicator. A patient monitor, in response to the comparison indicator indicating the tissue wall displacement value exceeds the threshold value, generates an alert message associated with the threshold.

A method for measuring a mechanical property of a subject includes using an ultrasonic transducer to apply ultrasonic vibration pulses to a vibration origin in the subject in an on-off time sequence in order to impart a harmonic motion at a prescribed frequency to the subject, and when the vibration pulses are off, using the same transducer to apply ultrasonic detection pulses to a motion detection point and to receive echo signals therefrom in order to sense the harmonic motion on the subject at the motion detection point. From the harmonic signal information, a harmonic signal is detected and a characteristic such as amplitude or phase of the detected harmonic signal is measured. The mechanical property is calculated using the measured characteristic using for example a wave speed dispersion method.

A repeater for re-transmitting uplink and downlink signals in a wireless network. The repeater uses antenna cross-polarization, signal cancellation and digital processing techniques to reduce or eliminate coupling of echo signals between the receive and transmit antennas of the downlink and uplink signal paths in the repeater.

An ultrasound imaging system with pixel oriented processing is provided in which an acoustic signal is generated, echoes from the acoustic signal are received at a plurality of receiving elements to obtain echo signals that are then stored, a given pixel is mapped into a region of the stored signals, the mapped region of the stored echo signals is organized into array for the given pixel after which the array is processed to generate a signal response for the given pixel to obtain acoustic information for the given pixel. The system can be implemented entirely on plug-in cards for a commercial PC motherboard. The system and method can be implemented for pixel-oriented or voxel-oriented image processing and display, eliminating intermediate data computations and enabling extensive use of software processing methods. Advantages include improved acquisition of signal dynamic range, flexible acquisition modes for high frame rate 2D, 3D, and Doppler blood flow imaging.

The invention relates to an ultrasonic imaging system for elasticity measurement. The ultrasonic imaging system comprises a probe, an ultrasonic imaging device, a controlling and processing device and a display device, wherein the probe comprises a low-frequency oscillation driving device for generating oscillation and forming a shearing wave propagating from human body surface to tissues, and an ultrasonic transducer array for sending an ultrasonic signal to the tissues and receiving an ultrasonic echo signal; the ultrasonic imaging device is used for driving the ultrasonic transducer array to send the ultrasonic signal and receive and process the ultrasonic echo signal according to loaded imaging parameters; the controlling and processing device is used for controlling the low-frequency oscillation driving device and the ultrasonic imaging device to process the ultrasonic echo signal so as to obtain a two-dimensional ultrasonic image and elasticity information of the tissues; and the display device is used for displaying the two-dimensional ultrasonic image and the elasticity information. The system and elasticity measuring method can simultaneously obtain the two-dimensional ultrasonic image and the elasticity information of the tissues, thereby improving clinical diagnosis accuracy; and the probe can realize precise positioning under the guiding of the two-dimensional ultrasonic image without considering displacement compensation, thereby improving convenience and accuracy of tissue elasticity measurement.

A real-time radar surveillance system comprises at least one land-based non-coherent radar sensor apparatus adapted for detecting maneuvering targets and targets of small or low radar cross-section. The radar sensor apparatus includes a marine radar device, a digitizer connected to the marine radar device for receiving therefrom samples of radar video echo signals, and computer programmed to implement a software-configurable radar processor generating target data including detection data and track data, the computer being connectable to a computer network including a database. The processor is figured to transmit at least a portion of the target data over the network to the database, the database being accessible via the network by at least one user application that receives target data from the database, the user application providing a user interface for at least one user of the system.

A repeater for re-transmitting an incoming RF signal comprising: a first antenna array for receiving the incoming RF signal; a second antenna array for transmitting an outgoing RF signal; and a transceiver for down-converting the incoming RF signal to a down-converted signal, processing the down-converted signal, and up-converting the processed signal to produce the outgoing RF signal. The first antenna array is cross-polarized with respect to the second antenna array. The repeater also comprises an echo processor for attenuating in the down-converted signal an echo signal associated with the outgoing RF signal. The echo processor delays transmission of the outgoing RF signal in order to minimize the echo signal.

The battery charging pad comprises a moving mechanism 13 that moves the transmitting coil 11, and a position detection controller 14 that detects the position of a device housing a battery 50 and controls the moving mechanism to move the transmitting coil in close proximity to a receiving coil 51. Pulse signals are supplied to a plurality of position detection coils 30 from a pulse generator 31, and the echo signals are a result of coil excitation by the pulse signals. The battery charging pad position detection controller 14 detects the position of the receiving coil 51 and moves the transmitting coil 11 in close proximity to the receiving coil 51, and the position detection controller 14 detects the position of the transmitting coil 11 and moves the transmitting coil 11 to the reference position, or it moves the transmitting coil 11 in close proximity to the receiving coil 51.

A method for measuring a mechanical property of a subject includes using an ultrasonic transducer to apply ultrasonic vibration pulses to a vibration origin in the subject in an on-off time sequence in order to impart a harmonic motion at a prescribed frequency to the subject, and when the vibration pulses are off, using the same transducer to apply ultrasonic detection pulses to a motion detection point and to receive echo signals therefrom in order to sense the harmonic motion on the subject at the motion detection point. From the harmonic signal information, a harmonic signal is detected and a characteristic such as amplitude or phase of the detected harmonic signal is measured. The mechanical property is calculated using the measured characteristic using for example a wave speed dispersion method.

The invention discloses a vehicle-mounted millimeter-wave radar moving target recognizer. The vehicle-mounted millimeter-wave radar moving target recognizer is characterized in that the recognizer is a frequency synthesizer; a frequency agility continuous signal is modulated into a pulse signal and then is processed into a millimeter-wave signal by up-conversion; after being amplified by a power amplifier, the millimeter-wave signal is transmitted out; an antenna receives a radar echo signal back to a circulator and then the signal is transmitted into a frequency mixer; a high-frequency echo pulse and constant-amplitude high-frequency voltage generated by a high-stability local oscillator are mixed and the signal is reduced to a middle frequency and then is processed by a middle-frequency amplifier; the middle-frequency signal is directly sampled by an A / D (Analogue / Digital) conversion module; after being sampled, echo signals of a whole pulse string are stored into a storage unit; and information of targets, such as quantity, speed and direction, is measured by a signal processing unit and then is transmitted to an alarm executing unit. With the adoption of the structure, the vehicle-mounted millimeter-wave radar moving target recognizer has the advantages that 1 the distance measuring precision and the angle measuring precision of a moving target are improved; and 2 excessive hardware does not need to be added and the production cost is lower.

An ultrasound system is provided comprising an ultrasound probe having a 2D matrix of transducer elements transmitting a continuous wave (CW) Doppler transmit signal into an object of interest. The CW transmit signal includes a dither signal component and the probe receives ultrasound echo signals from the object in response to the CW transmit signal. The probe generates an analog CW receive signal based on the ultrasound echo signals. An analog to digital (A / D) converter converts the analog CW receive signal to a digital CW receive signal at a predetermined sampling frequency and a processor processes the digital CW receive signal in connection with CW Doppler imaging.

The ultrasound diagnostic apparatus, ultrasound image generation apparatus and method transmit ultrasound waves to a subject into which a puncture tool is inserted, receive reflected waves reflected from the subject and the puncture tool, and generate echo signals of time-sequential frames based on the received reflected waves, and generate an ultrasound image of the subject based on the generated echo signals. These apparatus and method generate a differential echo signal between time-sequential frames from the echo signals, perform a tip detection process based on the differential echo signal to thereby detect at least one tip candidate including a tip end of the puncture tool, highlight a tip candidate of the puncture tool detected to thereby generate a tip image, and display the tip image of the highlighted puncture tool so as to be superimposed on the generated ultrasound image.

An apparatus and method for determining the density and fluid-type of a fluid flowing in a capillary tube, the velocity and viscosity of a blood sample flowing in a capillary tube, the erythrocyte sedimentation rate (ESR) of a blood sample after flow has been brought to an abrupt stop in a capillary tube, and / or the zeta sedimentation rate (ZSR) of a blood sample after flow has been brought to an abrupt stop in a capillary tube. These measurements are accomplished by directing a waveform pulse, such as an ultrasound pulse, at a pre-determined frequency transversely across the capillary tube and sample fluid, and by determining the flight of time of the pulse through the capillary tube and sample fluid and / or the Doppler shift of the echo signals reflecting off cells moving forwardly or transversely within a flowing, or stationary, blood sample.

The search / detection apparatus modulates a carrier signal by a modulation signal, generates a probe signal for detecting the location of a target, and receives the probe signal reflected by the target as an echo signal. Then, the search / detection apparatus detects the existence of an interference signal other than the echo signal from the received signal and modifies the parameter of the modulation signal and / or carrier signal.

A system comprising a transmitter element creating an interrogation signal and transmitting the interrogation signal and a receiver element receiving a reflection signal of the interrogation signal and combining the reflection signal and a feedback signal to cancel at least a portion of radio frequency echo signals in the reflection signal.

Multiple microphone noise suppression apparatus and methods are described herein. The apparatus and methods implement a variety of noise suppression techniques and apparatus that can be selectively applied to signals received using multiple microphones. The microphone signals received at each of the multiple microphones can be independently processed to cancel echo signal components that can be generated from a local audio source. The echo cancelled signals may be processed by some or all modules within a signal separator that operates to separate or otherwise isolate a speech signal from noise signals. The signal separator can include a pre-processing de-correlator followed by a blind source separator. The output of the blind source separator can be post filtered to provide post separation de-correlation. The separated speech and noise signals can be non-linearly processed for further noise reduction, and additional post processing can be implemented following the non-linear processing.

A fishfinder is provided for identifying with high precision a single fish under the ship and for measuring the length of the fish precisely. An operator of the fishfinder is assisted to grasp the depth and the length of the fish. A fishfinder transmits an ultrasound pulse having a high carrier frequency and an ultrasound pulse having a low carrier frequency by means of a pulse transmission and reception device at predetermined time intervals. A single fish echo is determined and tracked for a plurality of transmission intervals of ultrasound pulses emitted into the water. A target strength of single fish is measured based on the signal strength of a low carrier frequency echo signal from the single fish. The length of the fish is measured based on the target strength. A fish mark is displayed on the screen of an indicator, with the size of the fish mark depending on the fish length.

A FM-CW radar system comprises a frequency modulated continuous wave digital generator that produces both in-phase (I) and quadrature-phase (Q) outputs to orthogonally oriented transmitter antennas. A linearly polarized beam is output from a switched antenna array that allows a variety of I-and-Q pairs of bowtie antennas to be alternately connected to the transmitter and receiver. The receiver inputs I-and-Q signals from another bowtie antenna in the array and mixes these with samples from the transmitter. Such synchronous detection produces I-and-Q beat frequency products that are sampled by dual analog-to-digital converters (ADC's). The digital samples receive four kinds of compensation, including frequency-and-phase, wiring delay, and fast Fourier transform (FFT). The compensated samples are then digitally converted by an FFT-unit into time-domain signals. Such can then be processed conventionally for range information to the target that has returned the FM-CW echo signal.

Methods and apparatus for echo cancellation in a system having a speaker and a microphone are disclosed. The speaker receives a speaker signal x(t). The microphone receives a microphone signal d(t) containing a local signal s(t) and an echo signal x1(t) that is dependent on the speaker signal x(t). The microphone signal d(t) is filtered in parallel with first and second adaptive filters having complementary echo cancellation properties relative to each other. A minimum echo output e3(t) is determined from an output e1(t) of the first adaptive filter and an output e2(t) of the second adaptive filter. The minimum echo output has a smaller energy and less correlation to the speaker signal x(t). A microphone output is then generated using the minimum echo output e3(t).

A radar apparatus includes an antenna that receives echo signals, each of the echo signals being a radar signal reflected by one or more objects; a Doppler-frequency acquirer that acquires Doppler frequencies at each range bin from the received echo signals; a direction correlation power-value calculator that calculates direction correlation power values for respective combinations of the Doppler frequencies and at least one of a distance to the one or more objects and an arrival direction of the echo signals, each direction correlation power value indicating a strength of a corresponding echo signal; and a normalized direction correlation-value calculator that calculates, for the respective combinations, normalized direction correlation values, each normalized direction correlation value indicating a probability of the arrival direction of the corresponding echo signal.

A method and apparatus is set forth for accelerating the total acoustic echo cancellation convergence time in a microphone array full-duplex conferencing system with beamformer. The invention is based on sequentially switching the beamformer to untrained sectors during periods of far-end speech activity and performing real-time cancellation of far-end echo signals from the near-end signals to consecutively adapt and store filter coefficients for the echo canceller corresponding to each sector.

A FM-CW radar system comprises a frequency modulated continuous wave digital generator that produces both in-phase (I) and quadrature-phase (Q) outputs to orthogonally oriented transmitter antennas. A linearly polarized beam is output from a switched antenna array that allows a variety of I-and-Q pairs of bowtie antennas to be alternately connected to the transmitter and receiver. The receiver inputs I-and-Q signals from another bowtie antenna in the array and mixes these with samples from the transmitter. Such synchronous detection produces I-and-Q beat frequency products that are sampled by dual analog-to-digital converters (ADC's). The digital samples receive four kinds of compensation, including frequency-and-phase, wiring delay, and fast Fourier transform (FFT). The compensated samples are then digitally converted by an FFT-unit into time-domain signals. Such can then be processed conventionally for range information to the target that has returned the FM-CW echo signal.

In a high-resolution flow mode, a diagnostic ultrasound apparatus and a diagnostic ultrasound method that provide an image of blood flow or perfusion is provided with higher sensitivity and high resolution, which makes it possible to precisely observe the presence of fine blood vessels. In this apparatus, by scanning means (81 to 83), with a ultrasound pulse having a wideband frequency characteristic transmitting at least two times in the same direction within an object, a cross section to be imaged therein is scanned to obtain an echo signal at each time of transmission. By processing means 84, highpass filtering or differential processing is performed with rows of data in the time axis direction of an echo signal acquired at each sample location in the cross section, so that signals from blood flow are extracted. By producing means 85, the processed signals are produced into data of luminance or power. This data is displayed by displaying means 86 as a high-resolution color (flow) image or grayscale flow image indicative of blood flow or perfusion.