59 results about "Harmonic method" patented technology

Provided are a scalable wide-band speech coding/decoding apparatus, method, and medium. An input wide-band speech input signal is first divided into a low-band signal and a high-band signal. The divided low-band signal is then coded using a code excited linear prediction (CELP) method. The divided high-band signal is coded using a harmonic method. A signal representing a difference between a synthetic signal obtained from the low-band and the high band, and a signal input to the low-band and the high-band is then coded using a modified discrete cosine transform (MDCT) method. The coded signal is then multiplexed. The multiplexed signal is then output. Accordingly, high quality speech can be achieved for all layers.

The invention relates to a method and a device for testing the thermal physical property of a solid material with an independent probe by using a harmonic method. The device comprises the independent probe, a pressure adjusting part, a torque measuring part and a harmonic measuring unit, wherein the independent probe is positioned between two identical samples to be tested to form a sandwich structure and is arranged parallel to a sample fixing table; the pressure adjusting part is positioned and pressed on the upper end face of the first sample to be tested; the sandwich structure is arranged on the sample fixing table; the torque measuring part is sleeved on one end of the pressure adjusting part; the harmonic measuring unit is electrically connected with the independent probe; and a torsion value and contact thermal resistance between the independent probe and the two samples to be tested are fitted and calculated according to a harmonic measurement principle. In the test, the sandwich structure is arranged on a lug boss of the sample fixing table, the pressure adjusting part is adjusted until the torsion value is displayed to be the optimal torsion value, and then the thermal conductivity coefficient and the thermal diffusivity of the sample to be tested are tested by the harmonic method. Differences among thermal conductivity values of the samples to be tested under the condition of a plurality of torsion values smaller than the optimal torsion value are measured and calculated for obtaining the contact thermal resistances between the samples to be tested and the independent probe under the condition of the plurality of torsion values.

The invention discloses a gradient coil design method in a nuclear magnetic resonance system. The method comprises the following steps of: establishing a mathematical relation between a field expansion harmonic component and a cylindrical surface current distribution harmonic component under a spherical coordinate system based on a current distribution harmonic component coefficient capable of generating a specific target field through solving; combining the traditional harmonic method with a target field method; and introducing a simulated annealing algorithm to optimize and obtain the global optimum current distribution. The gradient coil design method can be used for designing a self-shielding gradient coil with cylindrical surface current distribution and optionally restraining the coil length, and ensures excellent linearity while the higher coil efficiency is achieved through comprehensively considering a plurality of design indexes. Since the gradient coil design method is optimized by utilizing a global search algorithm-simulated annealing algorithm, a global optimum design result is ensured. Meanwhile the position information of the actual distribution of a current lead is directly output by the design result, therefore, the engineering processing and manufacturing are facilitated.

The invention relates to a micro-impulse measuring method, in particular to a micro-impulse measuring method based on a multi-beam laser heterodyne second harmonic method and a torsion pendulum method. The micro-impulse measuring method solves the problem of low measurement accuracy caused by poor laser difference frequency signal acquisition effect and low signal processing speed when the existing method of using multi-beam laser heterodyne to measure micro-impulses is adopted. By using the multi-beam laser heterodyne second harmonic method in the micro-impulse measuring method, the measurement of the micro-impulses is converted into the measurement of the swinging angle of a torsion pendulum, the information of the swinging angle to be measured can be obtained indirectly through the measurement of the thickness of a standard plane mirror, the measurement accuracy is effectively improved, the measured impulses are in a linear relation with the incident angles when a rotating angle issmaller than 5 degrees, the measurement error is smaller than 0.5 percent, the requirement on the measurement of the impulse of a laser micro-thruster can be satisfied, and a very good measurement means for evaluating the performance of the laser micro-thruster is provided.

The invention, which belongs to the optical technological field, relates to a method and an apparatus for generating coherent extreme ultraviolet radiation. According to the invention, extreme ultraviolet radiation is generated by utilizing a higher harmonic method and a femtosecond laser amplifier that has a complicated structure with high cost is employ for realizing the generation of the extreme ultraviolet radiation. The method depends on the femtosecond laser amplifier. According to the method and the apparatus provided in the invention, a femtosecond laser oscillator is employed; a focusing laser beam is utilized to irradiate a gold nanoarray structure in a vacuum chamber and a composite target composed of inert gas; and resonance of surface plasmons enable field density of an incident light to be improved substantially, so that a field density threshold for generating higher harmonic of an extreme ultraviolet wave band; therefore, the femtosecond laser amplifier can obtain coherent extreme ultraviolet radiation, so that equipment generated by the higher harmonic becomes simple and compact. The apparatus provided in the invention has a simple structure; the working frequency of the obtained higher harmonic of the extreme ultraviolet wave band can reach 70-80 MHz; such a new light source is in favor of improvement of a photon flow of the light source.

The invention discloses a method which adopts the harmonic method for preparing micro-even particles, and the method comprises the following steps: (1) metal material to be melted is added in a crucible; (2) cooling liquid is added in collection devices, and a vacuum cavity is sealed; (3) the vacuum extraction of the crucible and the vacuum cavity is carried out, and protective gas is filled; (4) the metal material in the crucible is melted; (5) a piezoelectric oscillator is opened; (6) the diameter of liquid drops is calculated; (7) charged main liquid drops and micro-liquid drops are separated when passing a deflecting electric field; (8) the main liquid drops and the micro-liquid drops are fallen into the respective collection devices after the separation of a deflecting polar plate. The device and the method for preparing the micro-even particles have strong process controllability, which can directly obtain the even particles with more micro-size, the process flow is short, the product quality is good, and the equipment investment is greatly reduced.

The invention discloses a method for measuring micro-impulse based on a multi-beam laser heterodyne second harmonic method and a torsion pendulum method, relates to a micro-impulse measurement method, and solves the problem of low measurement accuracy caused by poor effect of acquiring a laser difference frequency signal and low operation speed of signal processing in the conventional method for measuring the micro-impulse by using the multi-beam laser heterodyne second harmonic method. The multi-beam laser heterodyne second harmonic method is applicable to the micro-impulse measurement method; the measurement of the micro-impulse is converted into the measurement of a pendulum angle of torsion pendulum, and the size of the micro-impulse is obtained by directly measuring the pendulum angle of the torsion pendulum by using the multi-beam laser heterodyne second harmonic method, so measurement accuracy is effectively improved; when a rotating angle is smaller than 5 DEG, the measured micro-impulse has a linear relation with an incident angle, and a measurement error is smaller than 0.5 percent; requirements for measurement of the impulse of a laser micro-thruster can be met; and good measurement means can be provided for evaluation of the performance of the laser micro-thruster.

The invention discloses a method for measuring an electrostrictive coefficient by using a multi-beam laser heterodyne quadratic harmonic method, relates to a method for measuring the electrostrictive coefficient and solves the problem of lower measuring precision caused by poor acquisition effect of a laser difference frequency signal and low operation speed of signal processing in a traditional method for measuring the electrostrictive coefficient by using multi-beam laser heterodyne. A galvanometer scanner is introduced in a light path, so that an optical frequency is additionally arranged on optical signals which are incident at different moments, reflecting light passing through the front surface of a thin glass plate and light which is reflected by a plane reflecting mirror for multiple times to transmit through the thin glass plate generate a multibeam laser heterodyne quadratic harmonic signal under the condition of meeting the interference and further information to be measured is modulated in a frequency difference of an intermediate-frequency quadratic harmonic signal. The method disclosed by the invention can be widely applied to the field of engineering design, such ascoherent laser wind-finding radars and the like.

The invention provides a device and method for measuring micro impulse by means of a linear frequency modulation multi-beam laser heterodyne quadratic harmonic method and a torsional pendulum method, and belongs to the field of optics. The device and method are aimed to solve the problems that according to an existing laser interference method for measuring the micro impulse, accidental errors are large and measurement precision is low. Linearly polarized light emitted from a linear frequency modulation laser device is reflected through a first plane reflection mirror and a second plane reflection mirror and then enters a plane standard lens, light beams penetrating through the front surface of the plane standard lens are reflected by the rear surface and the front surface of the plane standard lens in the plane standard mirror for many times, then multiple beams of reflection light are obtained, the beams of reflection light penetrate through the front surface of the plane standard lens, then the beams of the reflection light and the light beams reflected through the front surface of the plane standard lens penetrate through a vacuum window and are converged to a photosensitive face of a photoelectric detector outside a vacuum chamber through a convergence lens, the photoelectric detector outputs electric signals to a signal processing system, and the signal processing system obtains the micro impulse borne by a standard beam according to the electric signals received continuously. The device and method are suitable for measuring the micro impulse.

The invention belongs to the technical field of material thermal conductivity measurement and discloses a harmonic method based hydrogel thermal conductivity testing device. The hydrogen thermal conductivity testing device comprises a detector, a precision resistance box, a signal generator, voltage followers and a phase-locking amplifier; the detector comprises a container, a support plate, an electrode and metal heating wires, the support plate is placed at the top of the container, the electrode is installed on the support plate and includes multiple copper bars, and lower ends of the copper bars are connected through the metal heating wires; the copper bar a is connected with the signal generator, both the copper bar b and the copper bar c are connected with the first voltage follower,the copper bar d is connected with the precision resistance box, the precision resistance box is connected with the second voltage follower and the signal generator, and the first voltage follower and the second voltage follower are connected with the phase-locking amplifier. By the arrangement, thermal conductivity of hydrogel can be measured through the harmonic method accurately and conveniently.

The invention provides a device and method for measuring the micro-impulse based on a linear frequency modulation multi-beam laser heterodyne quadratic harmonic method and a torsional pendulum method, and belongs to the field of optics. The device and the method aim at solving the problems that when the micro-impulse is measured through an existing laser interference method, accidental errors are large and measurement accuracy is low. The device comprises a linear frequency modulation laser device, a first plane mirror, a torsional pendulum system, a pulse laser device, a plane standard mirror, a converging lens, a photoelectric detector and a signal processing system. Laser beams emitted by the pulse laser device and a working medium target act to generate plasma jetting, and a standard beam is made to rotate under the reverse jetting action. Linearly-polarized light passes through the surface of a second plane mirror pasted on the standard beam, the light, transmitted by the front surface of the plane standard mirror, of reflected light is reflected by the rear surface of the plane standard mirror and then converged to the light sensitive face of the photoelectric detector through the converging lens together with the light, reflected by the front surface of the plane standard mirror, of the reflected light, the tilt angle of the standard beam is obtained through the signal processing system, and therefore the micro-impulse generated when lasers and the working medium target act is measured.

The invention discloses a micro water steam concentration detection method with a self-controlled measuring range, and belongs to the field of gas sensor system detection. The system comprises a single chip microcomputer, a laser temperature controlling and driving module, a DFB laser, a gas chamber, a photoelectric detector, a current-voltage conversion module, a lock phase amplifier, a high precision reference voltage generator, a subtractor, a gain control module, and a signal collecting module. The measuring range selecting module of multipath fixed parameter of a conventional secondary harmonic method micro water steam detection system is modified to obtain the provided system; after the lock phase amplifier obtains the harmonic amplitude containing concentration information, the gain control module is used to control the harmonic gain, at the same time, through the information exchange between the gain control module and the signal collecting module, the measuring range self control can be realized; and finally the water steam concentration of a gas to be detected can be calculated according to the harmonic amplitude and the gain value. The provided method breaks the limitation of concentration measuring range on circuit detection, enlarges the detected concentration range, effectively improves the signal/noise ratio, and is beneficial for extracting gas concentration information.

The invention relates to the technical field of transformers, and discloses a transformer fault diagnosis system based on a harmonic method. The transformer fault diagnosis system comprises the following steps of: randomly extracting a plurality of cases from a fault case library of a transformer, sorting and classifying the extracted cases, and establishing a fault diagnosis rule library, whereinthe transformer can generate different higher harmonics under different working states and different degradation degrees, and the working states and degradation conditions of the transformer have direct corresponding relations with the higher harmonics. According to the transformer fault diagnosis system based on the harmonic method, the diagnosis precision is improved by utilizing harmonic diagnosis; harmonic diagnosis equipment not only can detect the operation state of the equipment online, but further can predict the degradation trend of the same electrical equipment through long-term tracking detection of the same electrical equipment and perform effective tracking management, the detection process does not influence normal electrical equipment, problems are found in advance and early warning is performed, and sudden accidents are avoided.

The invention relates to the technical field of motors and generators, and further discloses a motor and generator fault diagnosis system based on a harmonic method. The motor and generator fault diagnosis system comprises a current detection part, wherein the output end of the current detection part is electrically connected with the input end of a switcher, the input end of the switcher is electrically connected with the output end of a magnetic field detection part, the input end of a selective amplification circuit is electrically connected with the output end of the switcher, and the output end of the selective amplification circuit is electrically connected with the input end of an A/D converter. By adopting the motor and generator fault diagnosis system based on the harmonic method,real-time data of a motor and a generator in an operating state are acquired by using non-contact current harmonic waves, the harmonic waves refer to integral multiples of basic frequency and have regularity, the frequency and noise are often mixed together under general conditions, but the harmonic waves generally comprise fractional harmonic waves of fundamental waves and take about 3-3.6 KHz as an object, and the frequency is alternating current of a frequency band of a KHz level from 10 KHz.