103 results about "Amplitude reduction" patented technology

A high-precision splitting sub-mirror relative inclining error photoelectric detection system comprises the following components: a HE-NE laser, a spatial filter, a collimator objective, a cubic beam splitting prism, a detected splitting sub-mirror set, a reference mirror, a light path beam-contracting system, a CCD planar array photoelectric detector and a data processing system. The HE-NE laser, the spatial filter and the collimator objective form a light source arm part of the detection system together. The detected splitting sub-mirror set forms a measuring arm part of the detection system. The reference reflecting mirror forms a reference arm part of the detection system. The relative inclining error information which is detected by the detecting arm and is between the splitting sub-mirrors is detected by the CCD planar array photoelectric detector. The detected interference image information is processed by a data processing system for real-time detecting the inclining error between the splitting sub-mirrors. The invention can execute a real-time high-precision detection. The effect of the relative inclining error between the sub-mirrors to the imagining quality of the telescope can be reduced with a large scale and the invention has the advantage of simple structure.

Systems (200) and methods (100) for noise error amplitude reduction. The methods involve configuring a first microphone system (202) and a second microphone system (302) so that far field sound originating in a far field environment relative to the first and second microphone systems produces a difference in sound signal amplitude at the first and second microphone systems. The difference has a known range of values. The methods involve (128) dynamically identifying the far field sound based on the difference. The methods also involve (130, 132, 134) automatically reducing substantially to zero a gain applied to the far field sound responsive to the identifying step.

The invention relates to a lithium ion supplementing technology of lithium ion batteries. The technology includes firstly, preparing a silicon carbon negative pole piece; then preparing a Li-naphthalene solution; soaking the prepared silicon carbon negative pole piece in the Li-naphthalene solution for 2 hours; and performing leaching. The silicon carbon negative pole piece is embedded with a certain amount of lithium ion before a battery is prepared, and irreversible capacity losses due to an SEI film which is formed by embedding lithium ions into a negative pole for the first time can be eliminated. Under the same charging and discharging depth, volume deformation amplitude reduction of silicon based negative materials during a lithium ion embedding and extracting process after the lithium ion supplementing can help improve the cyclic stability of silicon carbon negative pole based lithium ion batteries. Through experimental confirmation, charging and discharging efficiency of the silicon carbon negative pole for the first time can be significantly enhanced, and the cyclic stability can be improved as well.

The invention provides an SLM (selective mapping) method for reducing a PAPR (peak to average power ratio) of an MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing) system. During a processing procedure of a transmitting end, only one IFFT (inverse fast fourier transform) algorithm and one operation of cyclic shifting and adding and subtracting of a time domain signal are needed, and thus the computation complexity is largely lowered; during a processing procedure of a receiving end, cyclic shifting of a time domain of a transmitting signal corresponds to reverse phase rotation of a frequency domain of a receiving signal, and a modulating signal is recovered by comparing distances between a reverse rotation sequence and a nearest signal constellation point; meanwhile, according to the SLM method, only a selection situation of a selected transmission signal in a certain set is sent as sideband information, and as the sideband information is constant, half-blindness detection is realized. Only a little of sideband information is transmitted, and an original signal can be recovered at the receiving end, so that the utilization efficiency of a frequency spectrum is improved.

The invention provides a channel evaluation method based on TD-SCDMA coupled check technique, comprising that weighting and combining the channel impact response of all windows of the user at initial evaluation, according to the weighting and combining result, confirming the modified channel impact response of each window or code channel, wherein the result can be used as the modified impact response of each window or code channel. According to the weighting and combining result, the invention can confirm the modified channel impact response, comprising that averaging the result, reducing the amplitude of the averaged result, and using the result after amplitude reduction as the modified channel impact response.

The invention discloses a control method of a motor. The control method comprises the following steps that: the rotation speed of the motor is detected; the change rate of the rotation speed of the motor is calculated according to the detected rotation speed of the motor and the given rotation speed of the motor; and when the change rate of the rotation speed of the motor is greater than a preset value, the proportional-integral parameter of a speed ring in a control system of the motor is adjusted, and amplitude reduction adjustment is performed on the q-axis current upper limit of the motor. With the control method of the motor adopted, over-current or stall faults of the motor which are caused by abnormal current can be avoided, and safe and reliable operation of the motor in a low-frequency and heavy-load state and in an entire operation process can be ensured. The invention also discloses a control system of the motor.

The invention discloses a geosynchronous orbit determination and parameter determination method based on differential algebra. A kinetic model described based on geosynchronous satellite orbit elements is selected and used, use of a relatively greater integration step in a numerical integration process is avoided and appearance of singular points is avoided for the kinetic model, moreover, a perturbative force item is added in the kinetic model, polynomial form integration is executed, thus, obit statuses and spacecraft parameters are obtained, high-order prediction is executed for the obtained parameters, and meanwhile, high-order prediction of observed quantity is executed; by means of nonlinear information of the kinetic model and an observation model, estimation accuracy is improved; in combination with actual observed values of a spacecraft, high-order prediction values of the obit status and the spacecraft parameters are updated and high-order estimated values as initial values are obtained; and by repeating the implementation process above, geosynchronous orbit determination and parameter determination can be completed. The method provided by the invention not only can improve accuracy of obit estimation and realize high-precision estimation of the parameters, but also can greatly reduce calculation cost.

The invention discloses a signal processing method based on a laser radar waveform of a coherent system. The method comprises the steps of conducting quantization on phases of chirp signals of the laser radar of the coherent system to obtain the laser radar waveform, generating laser phase modulating signals according to the laser radar waveform, on one hand, obtaining delayed laser phase modulation signals, on the other hand, amplifying and transmitting the laser phase modulating signals, conducting phase demodulating processing on received target echo signals and the delayed laser phase modulation signals, generating quadrature demodulation echo signals, utilizing an analog-digital converter for collecting and recording the quadrature demodulation echo signals, conducting phase error estimation and correction on the the quadrature demodulation echo signals to obtain the echo signals after phase error correction, conducting distance direction Fourier transform on the echo signals after the phase error correction, and obtaining a distance direction pulse compression signal of the target. The method is used for achieving laser radar high distance resolution imaging of the coherent system under the condition of greatly reducing the sampling rate of the analog-digital converter.

The invention relates to an iterative decoding method of the message-passing type for decoding an error correcting code susceptible of representation by a bipartite graph including a plurality of variable nodes and a plurality of control nodes, said messages being expressed in terms of a log likelihood ratio. At each iteration of a plurality of decoding iterations, for each pair consisting of a variable node and a control node, a change is detected in the sign of the extrinsic information intended to be transmitted (α_mn^temp) as a message by said variable node to said control node relative to that transmitted (α_mn) at the previous iteration, and in the event of a sign change, said extrinsic information is subjected to an amplitude reduction operation (F_red) before it is transmitted to the control node.

The invention discloses a pulse amplitude position modulation system based on amplitude reduction type probability forming. In a transmitting terminal of a system, a binary data flow signal is processed by a amplitude reduction type probability forming unit and a position mapping unit, and then a PS-4 * 16APPM pulse signal is output. An Mach-Zehnder modulator modulates a generated pulse signal tothe wavelength of 1550 nm, and after power control of the optical attenuator, the optical signal is sent to the single-mode optical fiber to be transmitted to the receiving end of the system. According to the invention, the traditional APPM is combined with the probability forming technology, the introduction of probability forming changes the distribution characteristic of the original pulse amplitude, and the characteristic is transmitted in the mapping process, so that the finally mapped signal is the APPM signal with amplitude compression. The system is suitable for an optical modulation and demodulation system for direct detection, does not need to use a coherent receiver, and can effectively reduce the complexity of the system, thereby improving the processing efficiency.

An embodiment of the invention provides an audio signal processing method and equipment and a storage medium. The method includes: acquiring a frequency distribution range of an audio signal to be played by audio playing equipment; if target frequency matched with resonant frequency of the audio playing equipment exists in the frequency distribution range, determining amplitude reduction amount corresponding to the target frequency according to a corresponding relationship between the resonant frequency and the amplitude reduction amount; adjusting an amplitude value of the audio signal at thetarget frequency according to the amplitude reduction amount corresponding to the target frequency; outputting an audio signal after the amplitude value is adjusted through the audio playing equipment. Abnormal sound generated by the audio playing equipment due to resonance when the audio signal is broadcasted can be reduced by lowering the amplitude value at the target frequency causing resonance in the audio signal and broadcasting the audio signal after amplitude adjusting.

A method for reducing the radiation amplitude of material vibration modes (division vibrations) from a loudspeaker transducer diaphragm mechanically vibrated for the purpose of transforming an electrical signal into an acoustic signal. The diaphragm material may consist of formed paper or plastic sheet materials or molded paper pulp. The amplitude reduction of material vibration modes and pressure waves within the diaphragm material is accomplished by impressing small, shaped structures within the diaphragm material at critical locations determined by measurement with laser vibration analysis or position sensitive transient analysis of a loudspeaker transducer. The method is applied to the diaphragm material after it has been formed into the shape of a loudspeaker transducer diaphragm, either before or after the diaphragm has been assembled into a loudspeaker transducer.

The invention discloses a method for eliminating interference among carriers based on low-complexity frequency domain linear equalization and belongs to the technical field of wireless communication. The method comprises the following steps: a linear time-variant channel is equivalent to product of a time-variant factor without delay and another time-variant channel; a cyclic prefix of a time domain receiving signal is removed to obtain a signal sequence; one-dimensional time domain filtering pre-process is carried out on the signal sequence to obtain a time domain initial recovery signal sequence; fast Fourier transform is carried out on the time domain initial recovery signal sequence to obtain a frequency domain initial recovery signal sequence; low-complexity frequency domain linear equalization is carried out on the frequency domain initial recovery signal sequence to obtain a final frequency domain sending signal recovery sequence. Most interference among carriers are eliminated by the one-dimensional time domain filtering pre-process, a banding approximate structure is used to control complex multiplication times required in the inversion process of a channel frequency domain response matrix, thus reducing system complexity greatly in the condition of obtaining high performance, and the method is more suitable for a high-frequency wireless communication system, the hardware of which has low complexity demand.

The invention discloses a jump vibration prevention control system and a jump vibration prevention control method of a vibration road roller. The control system comprises a start switch, a vibration switch, a controller, a pressure sensor and a buzzer. One or multiple thresholds are set; after the road roller is started, the jump vibration prevention control system is used to monitor the pressure of a vibration hydraulic system; according to the threshold range of the pressure, the methods of vibration frequent reduction and amplitude reduction are respectively used to control jump vibration prevention till the pressure of the vibration hydraulic system reaches the maximum threshold, so as to stop the vibration. According to the control system and method, the jump vibration of a vibration wheel can be prevented, so as to avoid over pressing of foundation, road surface or other pressed material to cause resource waste.

The invention provides a sealed ground beam. The sealed ground beam is composed of a protective door, a manual gear rotating table, a rotating table fixed shaft, a cross rod with rotating teeth, horizontal fixed riveting grooves, transverse movable linking bars, reversing connecting bars, vertical movable linking bars, vertical fixed riveting grooves, latching bolts, a linkage cross rod with positioning bolts, an amplitude reduction chute with radian, a movable linking piece and a sealed ground beam body. According to the sealed ground beam, influences of the sealed ground beam body to a channel can be avoided, meanwhile, the ground beam body can be protected from being worn, sealing effects can be improved, and the protective door with the sealed ground beam body can be used for occasions where requirements on protection levels are high, such as headquarters, funk holes and airplane shelters in wars.

A driver circuit that prevents amplitude reduction at a high temperature comprises a differential pre-buffer circuit 22 for performing signal clamping by diodes 16 and 17 each having a nonlinear voltage-current characteristic with respect to an input signal and a differential output circuit 23 for amplifying output signals of the differential pre-buffer circuit 22, for output. The driver circuit further includes a temperature characteristic compensation circuit 44 for controlling direct currents to be passed through the diodes 16 and 17 based on a current to be passed through a diode 43 having a voltage-current characteristic with the same temperature coefficient as those of the diodes 16 and 17. A current related to constant currents I1 and I2 is supplied from the temperature characteristic compensation circuit 44 as a current that cancels the temperature characteristic of a fall in forward voltages of the diodes 16 and 17.

The invention provides a double-beam input laser cooling atom three-dimensional magneto-optical trap device, and aims to overcome the defects that an optical path system of an existing magneto-opticaltrap is easily affected by the external environment, and generated cold atoms have large-amplitude random jitter, and extra errors are introduced although random jittering of cold atom parameters caused by optical fiber factors is reduced. A unique three-dimensional MOT optical path transmission topology is designed, six polarization maintaining optical fibers required originally are reduced to two polarization maintaining optical fibers, and the influence of unstable incident laser polarization degree and light intensity fluctuation on the generated cold atom quality is greatly eliminated; polarization characteristics of laser beams are utilized, multiple times of light beam splitting and reflection are performed, independent adjustment of power and polarization of six beams of laser used for atom cooling is achieved under the condition that only two paths of input light exist, particularly, the power of the six beams of light which are oppositely emitted in pairs at a convergence point can be adjusted to be strictly equal, and the influence caused by inconsistent fluctuation pace of the power of the six beams of light in the working process of the device is greatly reduced.

This invention relates to a phase-amplitude converter of low power loss and non-ROM list including a condition negation unit, a control signal generator, an input data flip-latch, a phase amplitude conversion logic unit composed of K phase amplitude conversion logic modules, a multiple selector and a N-bit adder, in which, the input of the control signal generator is connected with the output of the condition negation unit, the input of the flip-latch is connected with the output of the condition negation unit, a second bit of an input phase and the output of the control signal generator, the input of a phase amplitude conversion logic unit is connected with the output of the flip-latch, the input of the selector is connected with the outputs of the logic unit and the generator and the input of the adder is connected with the output of the selector.

Disclosed is a vector modulation error compensation method based on analog base band correction. The method belongs to the testing technical field and is characterized by comprising following steps: 1, introducing a component for correcting phase included angles via a parameter KCI and a parameter KCQ, calculating the KCI and the KCQ according to a phase included angle theta of an in-phase component and an orthogonal component, obtaining the KCI equal to -ctg theta and the KCQ equal to 1/sin theta; 2, enabling inputted analog base band signals to be zero, enabling kI and kQ to be equal, minimizing the magnitude of a carrier signal by properly adjusting values of VI and VQ; 3, enabling the magnitudes of the inputted analog base band signals to be equal, enabling the magnitudes of components of a vector signal to be equal by properly adjusting values of KI and KQ; 4, repeating the step 2 and the step 3 until error modulation of the vector signal meets design requirements. The method can properly correct the analog base band signals by means of introducing a correction vector relevant to a base band signal Q to a base band signal I according to the basic principle of vector signal combination, thereby substantially reducing vector modulation errors and improving quality of output signals of a vector modulator.