229 results about "Impulse frequency" patented technology

The invention relates to an experimental device and method for pulse hydrofracture transforming of a shale gas storing layer. The experimental device comprises a high pressure water pump, a fracturing fluid pond, a filtering device, a waterpower pulse generating device, a triaxial stress loading device, a pressure sensor, a sound emission device, a throttle valve, an overflow valve, a data collection recording system and a core test specimen. The device provided by the invention can simulate the operating environment of a shale sample under main operating parameter such as different pulse pressures and impulse frequencies on a certain confining pressure condition; moreover, the device can monitor a space-time developing rule of cracks and can test permeability change before and after fracture in real time; therefore, an experimental platform is provided for researching pulse hydrofracture of a shale gas storing layer. The experimental device provided by the invention has strong practicality, is easy to assemble, convenient to operate, is compact in structure, and can better imitate fracture damage and permeability change mechanism of a shale sample of the shale gas storing layer under the actions of static pressure and pulse hydrofracture.

A single-axis receiver processing, for example, complex vestigial sideband modulated signals with an equalizer with forward and feedback filters. Forward and feedback filters have parameters that are initialized and adapted to steady state operation. Adaptive equalization employs linear predictive filtering and error term generation based on various cost criteria. Adaptive equalization includes recursive update of parameters for forward and feedback filtering as operation changes between linear and decision-feedback equalization of either single or multi-channel signals. An adaptive, linear predictive filter generates real-valued parameters that are employed to set the parameters of the feedback filter. In an initialization mode, filter parameters are set via a linear prediction filter to approximate the inverse of the channel's impulse / frequency response and a constant modulus error term for adaptation of the filter parameters. In an acquisition mode, equalization is as linear equalization with a constant modulus error term, and possibly other error terms in combination, for adaptation of the filter parameters. In a tracking mode, equalization is as decision feedback equalization with decision-directed error terms for adaptation of the filter parameters. For some equalizer configurations, feedback filtering is applied to real-valued decisions corresponding to complex-valued received data, and includes real-part extraction of the error term employed for recursive update of filtering parameters. Where a training sequence is available to the receiver, initial parameters for forward filtering are estimated by correlation of the received signal with the training sequence.

A programmable laser pulse combines electrical modulation of the pulse frequency and optical modulation of the pulse shape to form laser pulses of prescribed pulse shapes. A prescribed pulse shape features high peak power and low average power. The laser system disclosed also allows for power-scaling and nonlinear conversions to other (shorter or longer) wavelengths. The system provides an economical reliable alternative to using a laser source with high repetition rates to achieve shaped pulses at a variety of wavelengths. The combinatorial scheme disclosed is inherently more efficient than existing subtractive methods.

Provided is a method for enhancing chemical etching through femtosecond laser to manufacture a large-scale micro-lens array. The method includes: choosing hard materials serving as femtosecond laser action targets, and generating a light destroying area at the center of the target with the femtosecond laser acting focus as the center due to the special machining characteristics of the femtosecond laser according to the shape of a micro-lens array needing machining by controlling the target moving speed of a precise machining platform and enabling the femtosecond laser to act for 100-1000 pulse counts on the surface of the target, wherein the impulse frequency is 1KHz; performing chemical corrosion on the target processed by the femtosecond laser through hydrofluoric acid solution with the volume concentration of 1% to 10%, wherein the chemical corrosion is assisted by ultrasonic wave water bath heating, the heating temperature is 30-80 DEG C, and the heating time is 40-80 minutes; and thoroughly cleaning the corroded target in deionized water, therefore a template finished product of the large-scale micro-lens array is obtained. The method for enhancing chemical etching through femtosecond laser to manufacture the large-scale micro-lens array combines the chemical etching technology and finally achieves low-cost and high-efficiency volume production of the large-scale micro-lens array.

The invention discloses a digitized photoelectric detector sensing circuit provided with a plurality of signal paths. The digitized photoelectric detector sensing circuit comprises a front end sensingunit consisting of a plurality of unit circuits, a column-shared integrating circuit connected with the front end sensing unit, a high-speed and high-precision comparator connected with the column-shared integrating circuit, a delay control unit connected with the high-speed and high-precision comparator, a counter connected with the delay control unit and an output buffering stage connected withthe counter, the output buffer stage is further connected with a column selection register, the output buffering stage forms an output end, and the plurality of unit circuits are further respectivelyconnected with a row selection register, wherein each signal path comprises one unit circuit. The digitized photoelectric detector sensing circuit utilizes an analogue-digital signal conversion technology of pulse frequency coding to advance the position from the analogue-to-digital conversion so as to efficiently reduce the analogue signal processing circuit, eliminate the column fixing mode noise and the column sensing noise in the analogue signal sensing circuit and improve the sensing signal-to-noise ratio.

A method for processing the digital signals of a light-frequency conversion type pulse oxyhemograph includes such steps as using a light-frequency converter to directly convert the light signals received by human tissue to the electric pulse signals, using microprocessor to count the electric pulse signals and time, and calculation to digital signals to obtain the blood oxygen saturation degree and cardiac rhythm value.

The invention discloses a dissimilar intermetallic welding method for high nickel alloy and stainless steel, which adopts pulsed tungsten argon arc welding, and welding technological parameters comprise that: the background current is between 20 and 50A, the impulse current is between 28 and 60A, the impulse duration is between 5 and 10s, the impulse frequency is between 35 and 75Hz, the welding voltage is between 8 and 12V, the welding speed is between 1.0 and 2.6mm / s, the inert gas flow rate is between 5 and 12L / min, the distance between a nozzle of a welding torch and a workpiece is between 5 and 10mm, and the included angle between a tungsten electrode of the welding torch and a weldment is between 70 and 85DEG. The method adopted has the advantages of high welding efficiency, low cost and convenient and flexible operation, can obtain welding joints without defects of cracks, pores and the like, and can meet the use requirement of a heterogenous composite structure of high nickel casting alloy and austenitic stainless steel.

The invention relates to a counter based on a phase-lock loop pulse interpolation technology and a realization method. A door control signal is inputted to an input / output (I / O) pin of a FPGA (field programmable gate array) circuit after being processed by a processing circuit, and a pulse signal of a detected flow meter is inputted to another I / O pin of the FPGA circuit after being processed by the processing circuit. After the phase-lock loop pulse interpolation through the FPGA circuit, the pulse signal of the flow meter is outputted to a liquid crystal display; and meanwhile, the pulse signal is outputted through an RS-232 serial communication interface. Within dozens of seconds or a shorter calibration time, and when the pulse frequency of the flow meter is dozens or smaller, the 0.01 percent pulse counting precision of the detected flow meter still can be satisfied, and the flow meter with large flow rate can be calibrated on a calibration device with a small flow rate range. By adopting the phase-lock loop pulse interpolation technology, the limit of the dual-timing method and the quadrate-timing method requiring the pulse frequency and the uniform duty ratio can be broken through.

The invention discloses a method for measuring technological parameter for prebaked cell for aluminum-reduction, comprising following steps: inserting measuring probe driven by stepper motor into electrolyser, the impulse frequency of rotation rate for stepper motor continuously input into monolithic machine for counting and storing; checking electrolyte liquid surface, anode liquid surface and cathode liquid surface by relative checking circuit according to voltage change feature of different layer in aluminum cell solution, inputting relative measuring signal into monolithic machine; monolithic machine counting out polar distance, aluminum concentration and electrolyte concentration according to set mathematical model; the measured voltage is cathode voltage when the down vertical distance of measuring probe in aluminium liquid is 60- 100 mm; the polar distance, aluminum concentration, electrolyte concentration and electrolytic temperature are input into display screen by monolithic machine for real time display; the over travel-limit switch resetting measuring probe. The measuring device mainly comprises sampling machine and controlling tank; controlling tank is equipped with polarization layer measuring circuit and spacing measuring cathode pressure differential circuit; and sampling machine comprises data collecting device and operation power device.

The invention discloses a switched reluctance motor system based on bus current sampling. The switched reluctance motor system comprises a switched reluctance motor, a power converter, a rotating speed detecting device, current sensors and a controller. The phase current of the SRM system is analyzed, the influence on the phase current waveform by different open sections is discussed, and the phase current overlapping and non-overlapping conditions in a current chopping section are analyzed. According to the phase current overlapping condition, high-frequency impulses are injected into all under-phase tubes in an overlapping section, A / D sampling is triggered at the pulse low level to discompose the direct-current bus current, the injection high-frequency impulse frequency and the A / D sampling frequency are highly synchronous, information of all the open sections is combined, phase currents in all the phase conducting sections can be effectively rebuilt, the use quantity of the sensors is reduced, the system cost and size are greatly reduced, the switched reluctance motor system is more compact, and the problem that as gains of the single current sensors of all the phases are unequal, voltage drop is unbalanced is solved.

A switch mode power supply (SMPS) has optimized efficiency over an entire operating range, from no load to full load, by transitioning between pulse frequency modulation (PFM) and pulse width modulation (PWM) for control of the SMPS depending upon load current. Accurate, smooth, and seamless transitions between PFM and PWM modes of operation occur at a preset load current(s), PFM operation improves efficiency during light load conditions, and PWM has better efficiency at higher load currents. This is advantageous in battery powered applications, and thereby results in a longer time before battery replacement or recharge is necessary.

A system for setting and adjusting a frequency of electrical output pulses derived from an oscillator in a network is disclosed. The system comprises an accumulator module configured to receive pulses from an oscillator and to output an accumulated value. An adjustor module is configured to store an adjustor value used to correct local oscillator drift. A digital adder adds values from the accumulator module to values stored in the adjustor module and outputs their sums to the accumulator module, where they are stored. The digital adder also outputs an electrical pulse to a logic module. The logic module is in electrical communication with the adjustor module and the network. The logic module may change the value stored in the adjustor module to compensate for local oscillator drift or change the frequency of output pulses. The logic module may also keep time and calculate drift.

It is a programmable multi-module frequency divider, which is to divide one source impulse frequency to output the aim impulse according to multiple update divisor signals. The divider comprises at least one first frequency divider units crossing with each other and simultaneously repeats each operations of the divider according to a repeat signal to trigger the loaded update divisor signal operation according to the repeat signals.

A method and apparatus is operative for multiple target detection in a radar system which employs a radar waveform of two or more frequency diverse subpulses. The apparatus adds coherent processing of the subpulse echo signals to determine the presence of multiple scattering centers within the radar resolution cell. The subpulses are coherently combined and one can then estimate the number of scattering centers by forming a sample covariance matrix between the subpulse frequency channels and then performing an Eigenvalue decomposition. The resulting Eigenvalues represent the signal strengths of the scattering centers when the associated Eigenvectors correspond to the optimal subpulse weights associated with that signal. A single strong Eigenvalue indicates a single target while two or more strong Eigenvalues or those Eigenvalues larger than the noise related Eigenvalues or a threshold, indicates the presence of multiple targets.

A method detects proper connection of an endoscope to an endoscope processor by measuring pressure pulses applied to the connection point. The method can include measuring for the pressure pulses at a second connection point on the endoscope processor and measuring for a beat frequency produced variations in the frequency of pressure pulses input at each connection point. The method can also include looking for echoes of the pressure pulsations from physical structures within a lumen of the endoscope connected to the connection point.

The invention discloses an energy storage type solar LED lamp. The invention comprises a solar battery panel, a storage battery, a LED load and controller, wherein, the controller comprises a system detecting circuit, a state detecting circuit, a storage battery voltage detecting circuit, a clock controller, and a pulse adjusting circuit; the controller can automatically adjust the output impulse frequency through the pulse adjusting circuit, and adjust the output power through testing the capability of the storage battery and according to the capability of the storage battery,, thus the LED lamp has high efficiency and outstanding energy saving effect when the LED lamp is operated under perfect pulse condition. The energy storage type solar LED lamp of the invention has the advantages of environmental protection, safety, easy installation, good application effect, and small maintaining quantity, thus the invention can be widely applied to the lighting in the street and the courtyard.

A power factor correction circuit for driving a switch of a boost type converter circuit having an AC line frequency input, comprising a sense circuit for sensing and comparing the output voltage of the boost type converter circuit to a reference voltage, a circuit responsive to the output of the sense circuit for providing a drive signal for driving the switch, wherein the drive signal comprises a pulsed signal comprising a pulse grouping during each half cycle of the AC line frequency comprising at least one pulse wherein the number of pulses and frequency of the pulses of the pulse grouping changes with the output of the sense circuit up to a threshold value with the pulse width of the pulses being substantially constant; and when the output of the sense circuit has reached the threshold value, the pulse width of the pulses of the pulse grouping are varied in accordance with the output of the sense circuit.

The invention relates to an impulse type drip irrigation system. After passing through an impulse valve which is in front of each capillary pipe, pressurized water enters each capillary pipe in a fast-rising and slowly-reducing pressure impulse flow manner, and is sprinkled to irrigate crops in an impulse way through a micro-sprinkler head mounted on each capillary pipe. The fast-rising pressure can form a strong impact on obstructions while the slowly-reducing pressure cannot enable the water in the capillary pipe behind the impulse valve to generate resilience; and a negative pressure is formed at a water outlet of an irrigator to cause negative pressure suction blockage of the water outlet. The impulse frequency which is adjustable within a large range can be reduced at the same irrigation strength; and an impulse type micro-sprinkler irrigation system without need of a filter is formed by irrigators with larger water outlet apertures. The impulse irrigation mode is used for the micro-sprinkler irrigation to overcome defect of annularly concentrated precipitation amount of other micro-sprinkler irrigation equipment. The impulse type drip irrigation system provided by the invention has the characteristics of blockage prevention, uniform sprinkling and low cost.

Accepts inputs via an input device and displays resulting power consumption for example in a color-coded format that enables a doctor or other programmer to observe how changes in one programming parameter affects power consumption. This enables the apparatus to accept input values and display the resulting power consumption that would occur if the input values were programmed into an implantable device in an intuitive graphical manner. In one or more embodiments programming parameters associated with power consumption may be set for electrical stimulation pulses, namely the voltage amplitude, the frequency of pulses per unit time and the pulse width of the pulses in units of time.

The present invention provides a signal processor including a microprocessor for generating and supplying a control signal pulse train, a gain control circuit having a first switching device opened / closed by the control signal pulse train and resistors for determining an amplification factor with respect to a signal voltage as input and varying the resistances of the resistors in response to a pulse duty of the control signal pulse train, thereby controlling the amplification factor with respect to the signal voltage as input, and a switched capacitor filter circuit having second switching devices opened / closed by the control signal pulse train and a charging / discharging capacitor connected to the second switching devices, thereby adjusting filter characteristics in response to the pulse frequency of the control signal pulse train. The control signal pulse train is supplied commonly to the first and second switching devices.

The invention discloses a stepping frequency radar system based on a chaotic signal source. The system comprises a signal emission module, a signal receiving module, the chaotic signal source and a data rearrangement module. The chaotic signal source generates chaotic signals, on one hand, controls the emission frequency sequence of an emission pulse string, and on the other hand, performs reordering control on echo signals received by the signal receiving module. The invention also discloses a channel construction method of a stepping frequency radar system. The method enables each chaotic signal sampling value to be corresponding to a group of frequency modulation sequences after normalization processing is performed on each chaotic signal sampling value, controls the signal emission module to emit pulse strings corresponding to the group of frequency modulation sequences, and controls the signal receiving module to rearrange signal echo vectors according to pulse frequencies in an increasing order. The method, on one hand, enables emission signals to be provided with higher anti-interference capability and lower interception probability, and at the same time, solves the problem of quite poor clutter inhibition capability of stepping frequency signals in a conventional stepping frequency system.

The invention discloses a fusion welding of magnesium and Al heterogeneous metals, which adopts low magnesium Al alloy weld stick as the filling materials, the indifferent gas to protect, the electromagnetic pulse AC tungsten Ar arc to weld magnesium and Al. there into, the mass percentages of the weld stick are: magnesium is 0.5-3.0% with 2.0-3.0mm diameter; the said indifferent gas is Ar gas with purity more than 99.9%; the parameter of the tungsten Ar arc welding is: the basic current is 50-130A, the impulse current is 200-350A, the impulse time is 5-10s, the impulse frequency is 35-75Hz, the welding voltage is 24-26V, the welding speed is 1.0mm / s-1.8mm / s, the Ar gas flux is 10-18L / min, the extension length of the tungsten polar is 5-6mm, the distance between the welding torch jet and the working piece is 6mm-10mm, the thickness of the working piece is 1.5mm-14mm. the invention has high welding efficiency, low cost, convenient operation, and is suitable for the manufacturing of magnesium-Al heterogeneous compound structure.

The winding testing unit provides systems and methods for determining normal and / or abnormal characteristic signatures of same-voltage windings residing in a device, such as transformer, without the need for a comparison to past historical data. A plurality of characteristic signatures [H(f)'s] are determined for each of a plurality of windings. A plurality of differential characteristic signatures [H(f)'s] are then determined from a plurality of H(f) pairs selected from the plurality of H(f)'s. The differential H(f)'s are compared and at least one significant asymmetry is identified between the differential H(f)'s.

The invention discloses an impulse frequency correction system of a serial bus clock and a method thereof. A first frequency regulation device, a second frequency regulation device and a third frequency regulation device share one oscillator to correct the accuracy of the multi-stage clock impulse frequency of different frequency regulation ranges, and therefore the optimal frequency accuracy can be obtained. In addition, system design is greatly simplified, and element cost is lowered.

The invention relates to a method for preparing nanometer powdered carbon for fertilizer. The method comprises the following steps of providing a system comprising an anode, a cathode, a separator plate and an electrolyte aqueous solution, wherein the anode, the cathode and the separator plate are prepared from high-purity graphite, connecting the anode and the cathode to a pulsed power supply with impulse frequency of 40-60Hz and effective voltage of 12-20V so that nanometer carbon sol is obtained, wherein effective current density formed between the anode and the cathode is in a range of 50 to 100A / m<2>, adding 0.3-1wt% of a potassium-containing compound into the nanometer carbon sol to obtain potassium ion-containing nanometer carbon gel, and drying the potassium ion-containing nanometer carbon gel to obtain the nanometer powdered carbon. The method can control nanometer powdered carbon particle size and yield by adjusting voltage and current so that the method is suitable for industrial production of fertilizer.

With self oscillating pulse width modulators, using a hysteretic comparator to change the output duty cycle according to the input signal, as often used for example for Class-D amplifiers or switching regulators, the frequency varies with output power and supply voltage. The disclosed invention presents a method to drastically reduce the frequency variation by introducing the combination of an analog and a digital feedback loop to shift the hysteretic threshold, ideally by providing a single absolute value, which is proportional to the pulse frequency and by alternating the polarity of shifting the hysteretic threshold, based on the actual output pulse phase.

Disclosed are methods and systems and methods for methods for neuromodulation of deep-brain and other neural targets in mammals using optogenetics to treat clinical conditions or achievement of a physiological state. The neuromodulation can produce acute or long-term effects. The latter occur through Long-Term Depression (LTD) and Long-Term Potentiation (LTP) via training. Included is control of optical intensity / amplitude, pulse width, pulse shape, pulse rate, burst frequency, pulse pattern, burst rate, burst width, and optical-fiber configuration including through the stimulation of incorporated opsins in the target neural membranes accomplishing up-regulation and / or down-regulation.

A circuit for a charge amplifier for converting piezoelectric measurement signals continuously sets the output signal of the amplifier to a value close to zero, such that a reset switch becomes unnecessary. The amplifier includes a pulse generator that provides the output signal of the amplifier in the form of pulses, which are easy to transmit with low interference. The pulse frequency is proportional to the rate of change of charge. The pulses, which are added in a counter, represent a value proportional to the change in the charge since the last counter reset, which is proportional to the present measured value at the measurement element.

The utility model provides a semiconductor etching device and a semiconductor etching method. The semiconductor etching device comprises a reaction cavity, an air supplying source, a plasma radio-frequency power source and a polarization radio-frequency power source, wherein a piece-bearing table is arranged in the reaction cavity and used for placing to-be-etched substrates, the air supplying source is used for introducing air into the reaction cavity, the plasma radio-frequency source is used for changing the air in the reaction cavity into plasma, and the polarization radio-frequency power source is used for forming bias voltage on the surface of each to-be-etched base piece. Radio-frequency signals of the plasma radio-frequency power source and / or the polarization radio-frequency power source are impulse signals, and impulse frequency and a duty ratio of the impulse signals are changed along with change of time. The semiconductor etching device can adjust density and the bias voltage of plasma in the reaction cavity in real time according to requirements to control exchange of the plasma in a through hole and a reaction rate in the through hole so that control of appearance of the side wall of the through hole can be benefited.

The invention relates to a pulse parameter encrypted laser ranging system and method. The pulse parameter encrypted laser ranging system includes a laser detector, a pulse transmitting system, a laserpulse receiving system, a micro controller, a time interval measurement unit and a pulse demodulation encoding device, wherein the laser pulse receiving system is used for performing reception and processing before the pulse echo reflected from a detection target enters the laser detector; the micro controller controls the laser detector, the pulse transmitting system and the laser pulse receiving system to perform calculation and processing; the pulse demodulation encoding device performs random demodulation and encoding on the laser transmitting pulse frequency, width or peak power under control of the micro controller, and sends and receives demodulation; the time interval measurement unit is used for timing; and the micro controller demodulates the corresponding reception laser according to the time and laser transmitting pulse frequency, width or peak recorded by the time interval measurement unit during the demodulation process, so as to measure and obtain the demanded data. Thepulse parameter encrypted laser ranging system can effectively eliminate interference, can prevent blinding, and is high in decoying capability.