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83 results about "Phase cancellation" patented technology

Piezoelectric flat panel loudspeaker with distributed ceramic wafers

The invention belongs to the technical field of loudspeakers, in particular to a thin type piezoelectric speaker with a novel piezoelectric ceramic wafer structure. The thin type piezoelectric speaker structurally comprises a vibration film, piezoelectric ceramic wafers adhered to the vibration film, electrodes on the surfaces of the piezoelectric ceramic wafers, and electrode leading wires connecting the electrodes with an external circuit, and a frame for restricting the vibration film. With the adoption of structure in which an integral piezoelectric ceramic wafer is changed by a plurality of ceramic wafers distributed regularly, the difficulty in the manufacturing process of the piezoelectric ceramic wafers is reduced, the middle-frequency characteristic of the piezoelectric loudspeaker provided by the invention is adjusted, the distortion of acoustic pressure level is reduced, the phase cancellation of middle-frequency sound radiation in the space is reduced and even eliminated, the levelness of acoustic pressure level frequency response curve of the piezoelectric loudspeaker is greatly improved, and the peaks and valleys of the middle-frequency acoustic pressure level frequency response curve can be eliminated under the situation that the parameters are appropriate. Therefore, the tone quality of the piezoelectric loudspeaker is better.
Owner:KINGTONE INNOVATION BEIJING TECH

Open-ended coaxial probe and method for measuring dielectric spectrum property of biological tissues

The invention provides an open-ended coaxial probe and connection cable for measuring a dielectric spectrum property of biological tissues, and a corresponding instrument calibration method according to high-precision and wide-broadband measurement requirements on the dielectric property of in-vitro or in-vivo biological active tissues which are soft, small in volume and irregular in appearance. The open-ended coaxial probe comprises an inner conductor and an outer conductor which are concentrically arranged; the ratio of the radius of the inner conductor to the radius of the outer conductor is 3: 10; polytetrafluoroethylene is filled between the inner conductor and the outer conductor and a plating layer is arranged on the surface of the outer conductor. The connection cable is mainly composed of an N-type connector and a coaxial cable. The probe is calibrated by utilizing a phase cancellation method and is used for measuring the dielectric property of the biological active tissues at 1-200 MHz. Meanwhile, in order to increase the reliability of measured data, a calibration box which is used with the open-ended coaxial probe is provided; and a method for measuring the dielectric property of the biological tissues can be carried out by using the open-ended coaxial probe.
Owner:FOURTH MILITARY MEDICAL UNIVERSITY

Diaphragm perforating type piezoelectric flat speaker

The invention belongs to the technical field of speakers, particularly relating to a thin piezoelectric speaker with a novel diaphragm structure. The structure of the speaker comprises a diaphragm, a piezoelectric ceramic wafer, an electrode, an electrode leading wire and a edge frame, wherein the piezoelectric ceramic wafer is adhered on the diaphragm; the electrode is arranged on the surface ofthe piezoelectric ceramic wafer; the electrode leading wire is connected with the electrode and an outer circuit; and the edge frame is used for restricting the diaphragm. The characteristics of the medium and low frequency section of the piezoelectric speaker are regulated through introducing single holes, single hole arrays, multiple holes, multiple hole arrays and porous symmetrical structureson the rectangular or round diaphragm, thus the distortion rate is reduced; the phase cancellation of medium-frequency range sound irradiation in space is lowered or eliminated; the evenness of the acoustic pressure level frequency response curve of the piezoelectric speaker is greatly improved; even if the acoustic pressure level at the distortion position is improved by above 25db, which is generated by the fact that the voltage applied on the frequency bandwidth of the distortion position is improved by 17 times, so that the sound quality of the piezoelectric speaker is better; and in addition, the rigidity and quality distribution of the diaphragm are improved, thus the output of the acoustic pressure of the speaker at the medium frequency range is obviously increased.
Owner:KINGTONE INNOVATION BEIJING TECH +1

Adjacent harmonic and inter-harmonic separation and measurement method under IEC (international electrotechnical commission) framework

The invention discloses an adjacent harmonic and inter-harmonic separation and measurement method under an IEC (international electrotechnical commission) framework. The method includes the following steps: firstly, performing discrete sampling on a power grid signal; secondly, performing ten-cycle Hanning window addition DFT/FFT (discrete Fourier transform/fast Fourier transform) spectral transformation on a sampling value according to IEC standards so as to obtain a spectrum; thirdly, multiplying the spectrum by rotary phase factors to obtain a new spectrum; fourthly, solving a vector sum of neighboring spectral lines of the new spectrum so as to offset sidelobe interference of rest components on the new spectrum, and solving corresponding frequency, a frequency deviation value and amplitude phase via a spectral line phase cancellation interpolation method; fifthly, rejecting spectrum leakage values of a fundamental component and the rest components at spectral line attention positions on a frequency domain; sixthly, solving a harmonic spectrum value to obtain parameters of h subharmonics, and solving parameters of inter-harmonics adjacent to the h subharmonics. By the method, the problem that the parameters of the two adjacent harmonics and inter-harmonics cannot be measured accurately during limited data asynchronous sampling is solved.
Owner:STATE GRID CORP OF CHINA +2

Method and Apparatus for Treatment of Monofrequency Tinnitus Utilizing Sound Wave Cancellation Techniques

Tinnitus is defined as sound(s) heard by an individual when no external sound it present and often takes the form of a hissing, ringing, chirping or clicking sound which may be either intermittent or constant. According to the American Tinnitus Association, tinnitus affects tens of millions of Americans and many suffer so severely from tinnitus they are not able to function normally on a daily basis. Unfortunately the exact cause or causes of tinnitus are not understood by the medical community and thus many tinnitus sufferers are told by their doctors to “learn to live with if”.
In accordance with novel aspects of Applicant's monofrequency tinnitus patient treatment apparatus and process, phase cancellation effects are achieved by utilizing an externally generated sound which is subjectively selected by the monofrequency tinnitus patient to match in both tone and loudness his or her tinnitus sound. This subjectively selected externally generated sound wave which matches in tone and loudness the patient's tinnitus sound, is either (i) sequentially phase shifted through a plurality of phase shift sequence steps totaling at least 180 degrees or (ii) alternatively is directly phase shifted in essentially a single step motion into a 180 degree, out-of-phase reciprocal, canceling relationship with the patient determined tinnitus tone. The sequential steps of the phase shifted tone or the directly phase shifted tone are applied to the tinnitus patient to effect cancellation or diminishment of the patient's tinnitus.
Owner:CHOY DANIEL S J

Self-adaptation four-port cancellation network structure and self-adaptation cancellation method

The invention discloses a self-adaptation four-port cancellation network structure and a self-adaptation cancellation method. The structure comprises an amplitude-phase cancellation network and a self-adaptation adjusting structure, wherein the amplitude-phase cancellation network comprises a coupler, an adjustable gain amplifier, an analog phase shifter, a power amplifier, a matched load and a attenuator, the aim that the transmitting chain is coupled with part of energy is achieved, amplitude phase adjustment is performed on a coupling signal, then, the amplitude of a received link coupler and the amplitude of a received same-frequency interference signal are approximately equal, the phase of the received link coupler and the phase of the received same-frequency interference signal are approximately opposite, finally, the amplitude of the received same-frequency interference signal is restrained to be on a lower level, and therefore the received channel carrier-to-noise ratio is improved. The self-adaptation adjusting structure comprises a coupler, a detector, a comparator matched load and a gain adjustable amplifier, the amplitude of the received same-frequency interference signal set on a parallel comparator public reference end is restrained to be the target level detection voltage, and a loop self-adaptation adjusting structure can automatically adjust the adjustable gain amplifier and the analog phase shifter in the amplitude phase cancellation network.
Owner:XIAN INSTITUE OF SPACE RADIO TECH

Environment-friendly sound insulation wall for communities

The invention discloses an environment-friendly sound insulation wall for communities. The wall includes a mortise, a sound insulation main body, a tenon and an active noise reduction system; the leftside of the mortise is provided with the sound insulation main body; the sound insulation main body is fixedly connected to the mortise; the left side of the sound insulation main body is provided with the tenon; the tenon is fixedly connected to the sound insulation main body; the internal of the tenon is provided with the active noise reduction system; the active noise reduction system is embedded in the tenon; the surface of the active noise reduction system is provided with a concave-convex noise attenuation board; and the concave-convex acoustical panel is tightly attached to the activenoise reduction system. The active noise reduction system is arranged at the internal, an acoustic wave generator can emit sound waves with an opposite phase and identical frequency and amplitude withregard to noise, so that phase cancellation can be realized, and noise can be radically eliminated; and the soundproof board is provided with the mortise and the tenon, and the mortise and the tenonare connected to each other through an embedded manner, so that the problem of infirm contact of joints can be well solved.
Owner:GUILIN JIAHONG ELECTRONICS TECH CO LTD

Transducer saddle for stringed instrument

A saddle of a multi-stringed instrument includes a highly efficient means of coupling to sensors, vibrations from plucked musical instruments strings. The saddle includes a downwardly extending body portion for mechanically conveying string vibrations to transducers by way of cavities beneath a string saddle that define a vertically compliant area of sensitivity. The vertically compliant area beneath each respective string is mechanically responsive to vertical string motion. These areas couple the strings to transducers mounted within said cavities, and are selectively sensitive to vertical string vibrations from the top of the saddle, beneath the string. The uni-directional sensitivity does not respond to vibratory information from beneath the saddle and is only sensitive from its top or positive Z axis direction. This eliminates the introduction of micro-phonic noise from the body of the instrument in the amplified signal. Isolating the vertical component of the string vibration further maximizes fidelity, clarity of sound and responsiveness. The cavities housing the transducers are arranged in alternating phase relationships to avoid phase cancellation effects between the adjacent transducers. A string saddle kit for a multi-stringed instrument includes multiple string saddle segments each providing a highly efficient means of coupling to sensors, vibrations from plucked musical instruments strings.
Owner:BARBERA RICHARD
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