Techniques of performing acoustic echo cancellation involve providing a bi-magnitude filtering operation that performs a first filtering operation when a magnitude of an incoming audio signal to be output from a loudspeaker is less than a specified threshold and a second filtering operation when the magnitude of the incoming audio signal is greater than the threshold. The first filtering operation may take the form of a convolution between the incoming audio signal and a first impulse response function. The second filtering operation may take the form of a convolution between a nonlinear function of the incoming audio signal and a second impulse response function. For such a convolution, the bi-magnitude filtering operation involves providing, as the incoming audio signal, samples of the incoming audio signal over a specified window of time. The first and second impulse response functions may be determined from an input signal input into a microphone.

A system for monitoring the condition of elongate structural elements, for example, railway rails, and a method of designing and manufacturing the system is disclosed. The method includes identifying and selecting suitable modes of propagation and signal frequencies that can be expected to travel large distances through an elongate structural element; designing a transducer that will excite the selected mode at the selected frequency; numerically modelling the transducer as attached to the elongate structural element; validating the transducer design by analysing a harmonic response of the selected mode of propagation to excitation by the transducer, and manufacturing one or more transducers for use in the system.

Methods and systems disclosed herein use acoustic energy to determine a gap between a wafer and an integrated circuit (IC) processing system and/or determine a thickness of a material layer of the wafer during IC processing implemented by the IC processing system. An exemplary method includes emitting acoustic energy through a substrate and a material layer disposed thereover. The substrate is positioned within an IC processing system. The method further includes receiving reflected acoustic energy from a surface of the substrate and a surface of the material layer disposed thereover and converting the reflected acoustic energy into electrical signals. The electrical signals indicate a thickness of the material layer.

Methods and systems disclosed herein use acoustic energy to determine a gap between a wafer and an integrated circuit (IC) processing system and/or determine a thickness of a material layer of the wafer during IC processing implemented by the IC processing system. An exemplary method includes emitting acoustic energy through a substrate and a material layer disposed thereover. The substrate is positioned within an IC processing system. The method further includes receiving reflected acoustic energy from a surface of the substrate and a surface of the material layer disposed thereover and converting the reflected acoustic energy into electrical signals. The electrical signals indicate a thickness of the material layer.

Detection of gas characteristics, especially the detection of the gas composition, the temperature and/or humidity of a gas, by measuring the speed of sound with a sound sender and a sound receiver both mounted on common structure. A method for determining the humidity of the scavenge air of an internal combustion engine. A speed of sound based gas sensor arrangement adapted to measure gas characteristics, especially the gas composition, the temperature and/or the humidity of a gas, including a sender, a receiver and a signal processing unit. The speed of sound is determined by driving the sender and receiver at different operation cycles in order to differentiate between the different travel times of the sound through the gas and the common structure of solid material.

A method for the measurement of the speed of sound in a gas suitable for the determination of gas characteristics, especially the composition of the gas, the temperature and/or the humidity of the gas, and a speed of sound based gas sensor arrangement adapted to measure that gas characteristics comprising sound sending means and sound receiving means and signal processing unit. A sound sender is used as sound sender and a first sound receiver and a second sound receiver as sound receiving means, all three of them being arranged such that the travel distance of the sound provided by the sender to the first receiver is different from the travel distance of the sound provided by the sender to the second receiver. Further the arrangement includes the signal processing means connected with the sender and the receivers which operate the sender and determine gas characteristics, especially the composition of the gas, the temperature and/or the humidity of the gas, from the different signals provided by the first and the second receiver.

A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.

A system and method directed to inspecting a high density polyethylene pipe. The system includes a pipe inspection tool that is positioned about a fused polyethylene pipe joint. The inspection tool may include search units, a pipe carriage, a pulser and a phased array testing instrument programmed to adjust an amplitude response signal from the search units based on a vertically established time corrected gain curve. The inspection tool is rotated around the high density polyethylene pipe joint while propagating acoustical waves at various patterns and angles through the polyethylene pipe joint. Prior to the joint inspection, the inspection tool is calibrated using a calibration tool which includes a block having an array of equal sized bores positioned along different axis' through the block's depth. The block is constructed of the same material type and grade as the pipes that were fused together to form the polyethylene pipe joint.

According to one embodiment, a control method includes setting a transmission angle of an ultrasonic wave to a standard angle. The control method further includes transmitting an ultrasonic wave at the set transmission angle and detecting an intensity of a reflected wave from an object. The control method further includes calculating a tilt angle based on a gradient of the intensity. The tilt angle indicates a tilt of the object. The control method further includes resetting the transmission angle based on the tilt angle.

Systems and methods are disclosed for conducting an ultrasonic-based inspection. The systems and methods perform operations comprising: receiving a plurality of scan plan parameters associated with generating an image of at least one flaw within a specimen based on acoustic echo data obtained using full matrix capture (FMC); applying the plurality of scan plan parameters to an acoustic model, the acoustic model configured to determine a two-way pressure response of a plurality of inspection modes based on specular reflection and diffraction phenomena; generating, by the acoustic model based on the plurality of scan plan parameters, an acoustic region of influence (AROI) comprising an acoustic amplitude sensitivity map for a first inspection mode amongst the plurality of inspection modes; and generating, for display, a first image comprising the AROI associated with the first inspection mode for capturing or inspecting the image of the at least one flaw.