31 results about "Tone burst" patented technology

A non-invasive method and apparatus for monitoring changes in intracranial pressure which removes extracranial effects from the measurements. The method and apparatus can include the supplying of a fixed frequency electrical output to a transducer coupled to the patient's head, thereby generating an acoustical tone burst in the patient's head which generates a first echo and a second echo, the first echo reflecting from a first interface in the side of the patient's head coupled to the transducer, and the second echo reflecting from a second interface at the opposite side of the patient's head. The first and second echoes are received by the transducer which can generate a first electrical signal and a second electrical signal, wherein the first and second electrical signals vary in accordance with the corresponding first and second echoes. The counterbalancing phase shifts required to bring about quadrature between each of the first and second electrical signals and the fixed frequency electrical output can be measured, and values for the change in intracranial distance based on the changes in the counterbalancing phase shifts can be obtained.

Electronic circuitry for high-power, high-frequency excitation of electromagnetic acoustic transducers (EMAT) without the use of a matching transformer is described. This circuit contains a least 4 switching devices such as power Mosfet transistors, arranged in an H-Bridge configuration that are designed to drive various EMATs over a wide range of frequencies. The switching devices can be connected in parallel with respect to the H-Bridge and switched in sequence for greater power output and variety of wave forms. This circuit configuration can provide a many excitation waveforms including, Churp, Hemming window tone burst, rectangular tone burst and Barker Code wave forms.

An improved electronic pulser circuit based on the H-bridge topology is designed for driving the sensor coils of an electromagnetic acoustic transducer (EMAT) to correct the disadvantages of conventional H-bridge pulsers and pulsers that require the use of an output transformer. A plurality of switching devices, primarily power Mosfets, are connected in parallel and augmented with support circuitry to provide improved performance in terms of increased power output, stability, reduced noise and complex output wave forms. This improved design provides for the application of modulated pulses such as multi-pulse, multi-frequency tone bursts of peak power outputs in excess of 20 thousand watts and frequencies in excess of 10 thousand Hertz.

In a positional information detecting device, a tone-burst signal propagating unit causes a tone-burst signal to propagate through a path. The tone-burst signal is composed of a continuous wave train, the continuous wave train including a plurality of cycles of a constant frequency. A detecting unit detects, at a predetermined position in the path, the tone-burst signal propagating through the path every one cycle of the tone-burst signal to measure a propagation delay time based on the detected signal. The propagation delay time represents a period for which the tone-burst signal has propagated through the path. A phase obtaining unit obtains a phase of the detected signal. A positional information obtaining unit obtains positional information associated with the predetermined position based on the measured propagation delay time and the obtained phase of the detected signal.

A communication system and method is utilized to communicate data over an AC power line. Tone burst are superimposed on an AC power signal at predetermined voltage reference levels or at predetermined phase angles to represent bit values. These bit values are represented by either the presence or the absence of the tone burst on the AC power signal. In this manner, control information can be communicated to an apparatus, such as a ballast for a gas discharge lamp.

Apparatus and methods for adaptively, reliably, and accurately measuring the duration of an alerting or other signaling tone. A tone detector in accordance with the principles of the present invention accurately measures a duration of a tone burst (i.e., tone pulse) using a long frame length DFT and a short frame length DFT. Based on information obtained by the short frame length DFT, the long (i.e., standard) frame length DFT may be interrupted and reset to begin a new frame of data synchronized with the start of the next short frame corresponding to the processing by the short frame length DFT to minimize noise in the processing by the long frame length DFT and to greatly improve the resolution of the measurement of the duration of a particular tone to correspond to the lengths of the short frames used by the short frame length DFT. If desired, after a tone is initially detected, the frame length of the short frame length DFT can be iteratively reduced to increase a resolution of the measurement of a tone start time and a tone end time used to determine the duration of the detected tone burst.

The present invention provides a method and system of auditory evoked heart rate variability analysis having advantage of simply analytical process and portability. The disclosed method mainly includes the following steps of: stimulating the auditory system of a person by a sound through a sound transmission device, capturing an electrocardiogram signal of the person, performing analog-to-digital conversion of the electrocardiogram signal, selecting the peaks of the electrocardiogram signal and transforming the qualified peaks to a consecutive peak signal, and performing spectrum analysis to the peak signal in frequency domain, and obtaining the difference of the spectral parameters before and after the evoked sounds. Moreover, the sound further is selected from the group consisting of noise, short tone burst, click, and any other sound with the intensity of 30 dB to 100 dB. By comparing the heart rate variability analysis before or after sound stimulation in order to get the differences, the disclosed method and system of auditory evoked heart rate variability analysis can evaluate a changing index of stimulated autonomic functions.

The invention provides an electromagnetic ultrasonic metal material thickness measurement method, which belongs to the field of metal material thickness measurement. The electromagnetic ultrasonic metal material thickness measurement method aims to avoid problems of low efficiency of electromagnetic ultrasonic energy conversion, unfixed occurrence moments of peak points of electromagnetic ultrasonic echoes and low thickness measurement accuracy. The specific electromagnetic ultrasonic metal material thickness measurement method comprises the steps that: an electromagnetic ultrasonic emitting tone burst pulse string and an electromagnetic ultrasonic receiving echo pulse string each comprises pulse signals of two or more kinds of frequencies, each pulse string comprises N1 consecutive pulse signals of frequency f1, N2 consecutive pulse signals of frequency f2, ...and Ni consecutive pulse signals of frequency fi, and N1 is greater than or equal to 1, N2 is greater than or equal to 1, and Ni is greater than or equal to 0; the time of a first cyclic wave cyclic wave initial zero-crossing point A or an initial peak point B of the pulse string of frequency f1 is obtained according to sequences of emission time and reception time, the time interval between the time of the first cyclic wave cyclic wave initial zero-crossing point A or the initial peak point B and the time of an initial emission point is the ultrasonic transmission time, and the thickness of metal materials is obtained through calculation. The electromagnetic ultrasonic metal material thickness measurement method is used for detecting thickness of metal materials.

Systems and methods for measuring phase dynamics and other properties (e.g. intracranial pressure) are disclosed. For example, the system may generate a reference waveform and a measurement waveform using digital synthesizers, each waveform having an identical constant frequency but also a relative phase shift. Next, system may send a tone-burst, via a transducer, into a sample (e.g. a skull or a bonded material), and then receive a reflected tone-burst in response. Then, a phase difference between the received tone-burst and the measurement waveform may be determined with a linear phase detector. Next, the phase shift of the measurement waveform may be adjusted, by the determined phase difference, such that there is no longer any phase difference between the received tone-burst and the adjusted measurement waveform generated by the appropriate digital synthesizer. A similar adjustment may occur after subsequent tone-bursts, allowing accurate monitoring of continuously variable phase relationships.

An apparatus to produce acoustic cavitation by controlling cavitation events in a liquid insonification medium utilizing a waveform to excite a transducer with a series of bipolar inharmonic tone bursts having medium recovery intervals between respective bursts so that the medium repeatedly recovers from cavitation events between bursts. The apparatus may be used to clean a semiconductor wafer, to de-coat a painted surface having, to induce a chemical reaction, and/or to provide recycled paper made from inked paper de-inked by cavitation. Cavitation events are generated using a transducer and a waveform generator, e.g., square wave tone bursts, to excite the transducer with a signal controlled in frequency, burst repetition rate, duty-cycle and/or amplitude, e.g., utilizing bursts having a frequency between 500 KHz and 10 MHz, and a duty cycle between 0.1% and 70%.

The invention discloses a method for playing a sudden sound in a digital interface of a musical instrument. In the method, a corresponding timing device is set for each channel in advance; property, generate an open channel event according to the property of the burst sound, and execute the open channel event, open the channel corresponding to the event, and play the burst sound on it; at the same time, the system will set the duration in the burst sound property to Send it to the timing device corresponding to the burst sound channel; when the duration ends, the timing device sends a closing instruction to the corresponding channel to close the channel. In the present invention, by setting a corresponding timing device for each channel, after the user generates a burst sound, the system controls the closing of the opened channel through the timing device, which solves the delay problem of burst sound playback and improves the burst sound quality. playback effect.

Various methods of performing ultrasound contrast assisted therapy are provided. One such method includes delivering a plurality of microbubble-based ultrasound contrast agents to a target area and disrupting the microbubble-based ultrasound contrast agents by delivering tone bursts of ultrasound to the target area. The oscillation of the microbubble-based ultrasound contrast agents can be achieved by delivering ultrasound tone bursts of greater than 5 acoustic cycles with a pulse repetition frequency of between 0.01 and 20 Hz, with pressure greater than 0.3 MPa.