100results about How to "Eliminate low frequency noise" patented technology

A method of producing a diode drive current in an oximeter includes sensing at least a part of a current passing through the diode and converting the sensed current to a sensed voltage, inputting the sensed voltage to a feedback amplifier for stabilizing the current passing through the diode, and eliminating an offset voltage across inputs of the feedback amplifier. A pulse oximeter includes a diode for emitting light flashes, a feedback amplifier having inputs, a feedback capacitor, and an output, the feedback amplifier stabilizing a current passing through the diode, a nulling amplifier having inputs, a nulling capacitor, and an output, the nulling amplifier charging and discharging the feedback capacitor until the inputs of the feedback amplifier are at a same voltage. The operation may include synchronizing an elimination of input offset voltages of the feedback and nulling amplifiers with on or off state of diode current.

An object distance deriving device comprises a compound-eye imaging unit for capturing n unit images and a microprocessor for calculating an object distance of an object from the imaging unit based on the unit images. The microprocessor sets a first temporary distance D1 from discrete temporary distances D1-Dn prepared in advance, and rearranges pixels of each unit image at D1 to create one reconstructed image. The microprocessor reversely projects the pixels of each unit image at D1 to create n reverse projection images. The microprocessor calculates and sums n deviations each between a pixel of the reconstructed image and that of each reverse projection image at each xy coordinate position to calculate an evaluation value for D1. The microprocessor repeats this process for the temporary distances D2-Dn to obtain n evaluation values. The microprocessor determines one of the temporary distances D1-Dn giving a minimum evaluation value as the object distance.

A touch analog front-end (AFE) for a touch sensitive screen may include a transmitter configured to charge a touch panel and a receiver configured to sense the touch panel. The receiver may include a charge-to-voltage (C2V) converter configured to convert a change of capacitance received from the touch panel into a voltage signal, a correlated double sampling (CDS) block configured to convert the voltage signal into a differential signal and to sample each of the positive and the negative signals of the differential signal, and an integrator configured to accumulate a difference between the sampled positive and negative signals.

In the hold phase, two negative feedback circuits constituted by the negative feedback capacitors 6p and 6m and two positive feedback circuits constituted by positive feedback capacitors are provided between an input terminal and an output terminal of an operational amplifier. Here, in a sampling phase before a hold phase, charges according an input signal V1p is stored in each of the capacitors, and charges according to an input signal V1p are stored in each of the capacitors. As a result, a gain of the switched capacitor amplifier circuit is derived from (Ca+C) / (Ca−Cx) wherein Ca indicates an electrostatic capacitance of the negative feedback capacitors, and Cx indicates an electrostatic capacitance of the positive feedback capacitors, and thus the gain can be increased without significantly increasing an electrostatic capacitance ratio.

The present invention provides an infrared focal plane array nonuniform self-adapting correcting method pertaining to the field of infrared focal plane detector and the aim of the invention resides in controlling the degenerating of the object, improving the calculating speed and simplifying the hardware realization. The present invention includes an initialization step, a pre-processing step, a coarse correcting step and an exact correcting step. The method adopts an arithmetic combining one point correcting and a self-adapting correcting of neuronic network and containing an edge extracting module and a combined correcting arithmetic is obtained by combining the excellence of each arithmetic, thus, the space low-frequency noise is eliminated effectively and the object degenerating is controlled and the calculating speed is improved comparing to the neuronic network arithmetic directed by the edge.

The invention relates to a reverse time migration imaging method and a device. The reverse time migration imaging method comprises the steps of obtaining focus wave field information and detection point wave field information, detaching a focus wave field into a focus upper wave field and a focus lower wave field and detaching a detection point wave field into a detection point upper wave field and a detection point lower wave field according to the obtained focus wave field information and the obtained detection point wave field information, carrying out reverse time migration imaging process on the focus wave field and the detection point wave field which are detached, and then a reverse time migration imaging section is obtained. According to the reverse time migration imaging method and the device, low frequency noise produced in a reverse time migration process is eliminated, amplitude preservation performance is high, and good parallel characteristics of interior wave field calculation are maintained. The reverse time migration imaging method and the device are especially suitable for being used on a central processing unit (CPU) of a graphics processor or on a CPU heterogeneous platform. Calculating efficiency of reverse time migration is greatly improved.

The invention discloses a shearlet transform and fast bilateral filter image denoising method, which comprises the steps of: 1) acquiring an envelope signal of a noise image by using a noise imaging system, and establishing a medical ultrasonic image model; 2) carrying out multiscale and multidirectional decomposition on the medical ultrasonic image model after logarithmic transformation obtained in the step 1) by utilizing a pyramid filter bank; 3) performing threshold method contraction processing on a two-dimensional discrete shearlet transform coefficient of a high-frequency part in each subband image obtained in the step 2); 4) using a fast bilateral filter for filtering shearlet coefficients of low-frequency parts in the step 2); 5) and conducting shearlet inverse transform processing on all the coefficients processed in the step 3) and the step 4), so as to obtain a denoised medical ultrasound images. The introduction of the fast bilateral filter in the shearlet transform and fast bilateral filter image denoising method can effectively improve the denoising performance, and greatly increase the processing efficiency.

A wireless radio frequency transceiver system for Internet of Things includes: a wireless radio frequency transmission module and a wireless radio frequency receiving module. The wireless radio frequency transmission module is used to shape signal waveform of digital signals from the Internet of Things to modulate the digital signals to form modulated output signals, and adopt a self-mixing technique to increase voltage / current amplitude of the modulated output signals and reduce phase noise. The wireless radio frequency transmission module is further used to adopt a current reuse technique to amplify the voltage / current amplitude of the modulated output signals, and transmit the amplified modulated output signals through a first antenna to a wireless channel. The wireless radio frequency receiving module is used to detect carrier input signals received from a second antenna to obtain baseband signals and demodulate the baseband signals to form differential signals. The wireless radio frequency receiving module is further used to amplify voltage / current amplitude of the demodulated differential signals several times in an open loop state to produce digital output signals, and transmit the digital output signals to a back-end signal processor.

The invention discloses an automobile noise reduction system with one-fourth wavelength pipes combined with a Helmholtz silencer, and belongs to the technical field of environment control and improvement in order to solve the problems that an existing automobile noise reduction system is high in manufacturing cost, poor in noise elimination effect, high in air inlet resistance and consumed power, poor in fuel economy and not suitable for various automobiles. The Helmholtz silencer is communicated with the side wall of a front air inlet guide pipe, the front air inlet guide pipe is communicated with an air filter, an air filtering net is arranged in the air filter, the air filter is communicated with a first rear air inlet guide pipe, the first rear air inlet guide pipe is communicated with a second rear air inlet guide pipe through a flexible connecting pipe, an air throttling valve is arranged on the second rear air inlet guide pipe, the second rear air inlet guide pipe is communicated with an air inlet header pipe, the air inlet header pipe is communicated with an air inlet manifold, and one ends of the two one fourth wavelength pipes are both connected and communicated with the side wall of the first rear air inlet guide pipe. According to the system, while power property and economy of an automobile are maintained, the noise of the whole automobile can be lowered particularly, the environment quality can be improved, and the system is suitable for various automobiles.

This invention provides an image processing apparatus, image processing method, and computer program, which can visually remove low-frequency noise contained in image data. Image data containing low-frequency noise is input from an input terminal (201). A window unit (202) designates a window made up of a pixel of interest, and its surrounding pixels. A pixel selector (204) selects a selected pixel to be compared with the pixel of interest from the window, and a pixel value determination unit (206) determines a new pixel value of the pixel of interest on the basis of the pixel values of the selected pixel and pixel of interest. New image data is generated by substituting the pixel value of the pixel of interest by the new pixel value.

The invention relates to an intercooling system and a constructing method thereof. The volume, the size of the outlet diameter, the length of an outlet pipe of a resonant cavity are calculated and determined by analyzing the noise of a specific frequency band generated by a supercharger in the operation process of the whole vehicle. The resonant cavity is designed in an intercooling gas outlet hosepipe according to the position of the whole vehicle and the space arrangement condition so as to eliminate the noise of the low-frequency part of the mechanical supercharger and improve the NVH performance of the whole vehicle. The intercooling system pipeline guarantees the hosepipe joint has excellent sealing property and also guarantees the requirements of the pipeline for flexibility and pressure resistance by adopting a thermoplasticity elastic material and a unique structure.

A touch apparatus and a touch sensing method thereof are provided. The touch sensing method includes the following steps. A first touch unit and a second touch unit are detected at different scan periods to obtain a first original signal and a second original signal. A reference signal is obtained according to the second original signal. A subtraction is performed on the first original signal and the reference signal, so as to eliminate low frequency noise of the first original signal.

In the hold phase, two negative feedback circuits constituted by the negative feedback capacitors 6p and 6m and two positive feedback circuits constituted by positive feedback capacitors are provided between an input terminal and an output terminal of an operational amplifier. Here, in a sampling phase before a hold phase, charges according an input signal V1p is stored in each of the capacitors, and charges according to an input signal V1p are stored in each of the capacitors. As a result, a gain of the switched capacitor amplifier circuit is derived from (Ca+C) / (Ca−Cx) wherein Ca indicates an electrostatic capacitance of the negative feedback capacitors, and Cx indicates an electrostatic capacitance of the positive feedback capacitors, and thus the gain can be increased without significantly increasing an electrostatic capacitance ratio.

The invention discloses a remote displacement measurement device, system and method having a clutter inhibition function. The system comprises a central controller, at least one main measurement device and at least one secondary measurement device, wherein the main measurement device is used for sending an emission signal to the secondary measurement device, receiving a forwarding signal emitted by the secondary measurement device and calculating relative displacement according to the received forwarding signal, the secondary measurement device is used for receiving the emission signal of the main measurement device and emitting the forwarding signal, and the main measurement device and the secondary measurement device both have two sets of polarized orthogonal antennas. When the main measurement device emits the signal, natural landform scattered strong clutter signals and a polarized direction of an emission antenna are consistent, polarized characteristics of a reception antenna and the emission antenna are in polarized orthogonal, so the reception antenna has the quite strong inhibition effect on background clutter, so system precision is improved; during cofrequency transmit-receiving, an acquired transmit-receiving isolation degree can be greater compared with a single antenna and the double polarized antennas, a large measurement distance is acquired through enhancing emission power.

The invention discloses an impedance compound muffler. The impedance compound muffler comprises a cavity structure, the cavity structure is formed by a shell, a front end cover and a rear end cover and is separated into a first cavity body, a second cavity body, a third cavity body and a fourth cavity body by a first partition plate I, a second partition plate II and a third partition plate III, the first cavity body is provided with an inlet tube, the fourth cavity body is provided with an outlet tube, a plurality of insert tubes are arranged on the first partition plate I and communicate the first cavity body with the second cavity body, a perforation pipe is fixed on the first partition plate I and the second partition plate II, an inlet of the perforation pipe is positioned in the second cavity body, an outlet of the perforation pipe is positioned in the fourth cavity body, and small holes are uniformly distributed in the middle area of the part in the third cavity body. The impedance compound muffler has the advantages that by means of reasonably combining expansion and resonance, an effect of lowering noise of an air flow in low and intermediate frequencies and an effect of eliminating noise in high frequency are achieved, and a large noise elimination quantity and a wide noise elimination frequency band are acquired; the impedance compound muffler is low in pressure loss and power consumption, simple and easy to implement, convenient to machine and high in economic performance.

The invention relates to the field of MEMS (Micro Electro Mechanical System) inertial devices, in particular to a high-accuracy fully differential capacitance-voltage conversion circuit system. The high-accuracy fully differential capacitance-voltage conversion circuit system comprises a driving signal generation part, a fully differential charge amplifier and capacitance compensation arrays. A whole conversion circuit and a sensor sensitive structure still adopt an output mode in single-ended connection, and a fully differential circuit structure is realized through time division multiplexing; a circuit adopts a switch capacitance structure for removing the influence of parasitic capacitance, main signal channels adopt a correlated double sampling technology for removing low-frequency noise and detuning, the capacitance compensation array is capable of correcting the detuning and non-linearity of the sensor sensitive structure. According to the high-accuracy fully differential capacitance-voltage conversion circuit system disclosed by the invention, the influence of the parasitic capacitance can be effectively inhibited, common-mode interference generated by switch charge injection and substrate noise can be reduced, harmonic distortion of the circuit is reduced, the linearity of an accelerometer system is increased, and zero drift is inhibited.

The invention discloses a silencing box body for a box-type transformer with a modular structure. The silencing box body comprises a double-layer top cover module, a resonant sound absorbing wall body and a door connected below the double-layer top cover module, a silencing fence, a bottom beam, and a box body foundation provided with an inflow air silencer, wherein the bottom beam, the silencing fence and the box body foundation are fixed together through a positioning connecting rod; and the entire transformer box body is modularized, and comprises four parts. Due to the adoption of the silencing box body, large-scale production can be realized, and convenience is brought to transportation and field installation; meanwhile, convenience is brought to subsequent maintenance; and in particular, when the transformer is required to be overhauled, only a top cover is required to be detached, and the transformer is hoisted out of the box body, so that the cost is lowered.

The invention provides a processing method for eliminating random noises of two dimensional seismic data, and belongs to the field of oil and gas seismic exploration. The method comprises a step a of seismic data input, by inputting seismic acquired single shot data or gather data and common receiver data which are in need of processing; a step b of frequency analysis, by selecting representative single shot or gather or common receiver data and conducting frequency analysis to obtain a frequency range of noise distribution; a step c of three dimension fitting from a two dimension, by fitting the inputted two-dimensional seismic data into a three-dimensional data volume; a step d of frequency domain conversion from a time domain, by converting the three-dimensional data volume acquired in the step c from the time domain into the frequency domain via Fourier transform; a step e of frequency Wiener filter, by conducting Wiener filter processing of the three-dimensional data volume obtained in the step d in the obtained frequency range of noise distribution in the step b; and a step f of time domain conversion from frequency domain, by converting the data after the Wiener filter processing into the time domain by using the Fourier transform formula.

The invention relates to a sensor array readout circuit based on a chopper technology. The sensor array readout circuit based on the chopper technology comprises a fully differential input stage. An input terminal of the fully differential input stage is connected with a signal modulation switch. An output terminal of the fully differential input stage is connected with a difference to single terminal signal switching stage through a signal demodulation switch. The difference to single terminal signal switching stage is connected with the output terminal of an output buffer stage through a first compensation capacitor. And the output terminal of the difference to single terminal signal switching stage is connected with a same-phase terminal of the output buffer stage. The same-phase terminal of the difference to single terminal signal switching stage is connected with the output terminal of the output buffer stage through a second compensation capacitor. An anti-phase terminal of the difference to single terminal signal switching stage is grounded through a third compensation capacitor and the anti-phase terminal of the output buffer stage is grounded. The circuit of the inventionhas a simple structure. An offset voltage and low frequency noises can be eliminated. An integration level of a system and a signal to noise ratio can be increased. A range of application is wide, safety and reliability can be achieved.

The invention discloses a band-pass filtering circuit and a control method of the band-pass filtering circuit. The band-pass filtering circuit receives input signals and provides effective in-band output signals with out-of-band noise being filtered out. The band-pass filtering circuit sequentially executes the following steps in each sampling cycle that the input signals are sampled at the input end of an operational amplifier and stored in a capacitor at the input end in an electric charge mode, sampling causes changes of the quantity of electric charge of the capacitor at the input end, and the part of electric charge, changed due to sampling, of the capacitor at the input end is transmitted to an output capacitor from the input end of the operational amplifier; part of capacitance is reset to a common mode voltage, and the remaining capacitance maintains the quantity of electric charge in the last state. A switched capacitor circuit technology is adopted by the band-pass filtering circuit, the structure is simple, only one operational amplifier is needed, the area is small, the complexity is lowered, in this way, the power consumption of a whole chip is lowered, and the area of the chip is reduced.

An image sensor, and a reading circuit and a reading method of an amorphous silicon TFT pixel unit are provided. The amorphous silicon TFT pixel unit comprises an amorphous silicon TFT and a photoelectric diode. The reading circuit of the amorphous silicon TFT pixel unit comprises an operational amplifier, a first capacitor, a first switch, a second switch, a third switch, and a sampling and holding unit. According to the image sensor, and the reading circuit and the reading method of the amorphous silicon TFT pixel unit provided by the invention, the signal-to-noise ratio of the output signal of the reading circuit of the amorphous silicon TFT pixel unit is improved.

The invention discloses a torsion shock absorber, a transmission shaft and a vehicle. The torsion shock absorber comprises a tubular skeleton and a damping shaft core arranged in the tubular skeletonand further comprises a plurality of elastic parts connected between the tubular skeleton and the damping shaft core. The elastic parts are arranged along the outer surface of the damping shaft core at intervals. The elastic part axial projections located at the end of the torsion shock absorber are distributed and arranged in the circumferential direction at intervals. In this way, normal twisting of the damping shaft core relative to the tubular skeleton can be ensured, friction between the elastic parts and the tubular skeleton and the damping shaft core is reduced, and heat effect on the elastic parts is weakened; and in addition, gaps between the elastic parts provide deformation spaces of the elastic parts, the fact that the elastic parts are forced to be plastic-deformed or damageddue to no deforming spaces is prevented, the durability of the elastic parts is improved, and the service life of the torsion shock absorber is prolonged.

The invention discloses an amplifier with band-pass filtering function, which comprises a variable gain amplifier, wherein the output end of the variable gain amplifier is connected with the input end of the variable gain amplifier through a Gm-C low-pass filter, which forms a feedback loop, so that the band-pass filtering function of the variable gain amplifier is realized. The input signal and the output signal of the variable gain amplifier are both differential signal, and the structure of the variable gain amplifier comprises ten MOS tubes, so that the amplifier has the advantages of simple circuit structure, small domain area and easy realization, and can effectively eliminate the influence of DC maladjustment of the low-frequency noise.

The invention discloses an automobile muffler which comprises a casing, an air inlet pipe, an air outlet pipe and a primary resonance tube and further comprises at least three baffle plates and at least one secondary resonance tube; the outer edges of the baffle plates are hermetically connected with the inner wall of the casing and divide the interior of the casing into a front cavity, middle cavities and a rear cavity; a first through hole is formed in the pipe body of the air inlet pipe positioned in one middle cavity; the primary resonance tube is communicated with the front cavities and the rear cavities; and one end of the secondary resonance tube is positioned in one front cavity, passes through at least one middle cavity and extends to the next middle cavity. According to the invention, the interior of the muffler is divided into the front cavity, the plurality of middle cavities and the rear cavity, which are independent from one another, by the baffle plates; air enters the rear cavity from one port of the air inlet pipe, exchanges continuously at the first through hole in the pipe body of the air inlet pipe, then flows to the front cavity through the primary resonance tube and the secondary resonance tube, and is discharged from the muffler through the air outlet pipe; and meanwhile, air interferes in the cavities, so that noise of all frequencies is eliminated.

The invention provides an energy-saving comprehensive noise reduction fan pipeline and a transformation method. The energy-saving comprehensive noise reduction fan pipeline comprises a fan, an air inlet pipeline and an air supply pipeline, wherein an air inlet and an air outlet of the fan are connected with the air inlet pipeline and the air supply pipeline respectively, and the air supply pipeline at least comprises one bent pipe. The energy-saving comprehensive noise reduction fan pipeline is characterized in that an expansion silencer is installed at the inlet of the air inlet pipeline andused for reducing noise of the air inlet pipeline and ventilation resistance of airflow; interference silencing flow deflectors are arranged between the air inlet pipeline and the inlet of the fan, between the air supply pipeline and the outlet of the fan and in the bent pipe respectively and used for eliminating and weakening vortexes. The flow field characteristics can be optimized and improvedthrough the interference silencing flow deflectors, pressure loss is reduced, and vibration and impact effects induced by a pulsating flow field are reduced. Expansion silencing and interference silencing are combined, the design of the pipeline is improved, the pipeline has certain silencing capacity, the expansion silencer is adopted at the inlet, and noise caused by vertical air intake is reduced.

The invention relates to a multilevel vibration-attenuation multilayer sound insulation structure. The structure comprises a vibratory noise source, a multilevel vibration-attenuation buffer structure, a sound insulation device and the like. A vibratory noise source (1) is flexibly connected with a primary vibration-attenuation support plate (3) through a vibration-attenuation rubber (2), rhe primary vibration-attenuation support plate (3) is flexibly connected with a secondary vibration-attenuation support plate (5) through a vibration-attenuation rubber (4), and the secondary vibration-attenuation support plate (5) is flexibly connected with a shell noise enclosure (7) through a vibration-attenuation rubber (6). An installation base (8) is flexibly connected with the secondary vibration-attenuation support plate (5) through the vibration-attenuation rubber (9), or is flexibly connected with a shell coaming (7) through the vibration-attenuation rubber (9), and an inner sound insulation cover (10) is arranged on the vibration-attenuation support plate. A sound insulation material is arranged on the surfaces of the shell coaming (7) and the inner sound insulation cover (10), and certain gaps are formed between the surfaces of the shell coaming (7) and the inner sound insulation cover (10). According to the structure, vibration attenuation and noise reduction can be effectively realized.

There is provided a method of post-correction of a 3D feature point-based direct teaching trajectory, which improves direct teaching performance by extracting shape-based feature points based on curvature and velocity and improving a direct teaching trajectory correction algorithm using the shape-based feature points. Particularly, there is provided a method of post-correction of a 3D feature point-based direct teaching trajectory, which makes it possible to extract and post-correct a 3D (i.e., spatial) trajectory, as well as a 2D (i.e., planar) trajectory, with higher accuracy.

The invention discloses a muffler provided with double exhaust pipes. The muffler comprises a casing, a first end cover, a second end cover, a first partition board, a second partition board, a third partition board, a gas inlet pipe, a left exhaust pipe, a right exhaust pipe and a plurality of guiding pipes, wherein the first end cover and the second end cover are fixed at two ends of the casing respectively; the first partition board, the second partition board and the third partition board are arranged in the casing; the gas inlet pipe is L-shaped and comprises a first pipe body parallel to an axis of the casing, a second pipe body vertical to the first pipe body as well as a first guiding pipe, a second guiding pipe and a third guiding pipe which are welded in the tail end of the first pipe body; the left exhaust pipe penetrates through and is fixed on the first partition board and the first end cover, and two ends of the left exhaust pipe are communicated with a second chamber and outside atmosphere respectively; the right exhaust pipe penetrates through and is fixed on the second partition board, the third partition board and the second end cover, and two ends of the right exhaust pipe are communicated with the second chamber and the outside atmosphere respectively. The muffler is good in noise reducing effect, meanwhile, airflow circulation is smooth, pressure loss is smaller, and exhaust back pressure can meet related requirements.