140 results about "Sawtooth wave" patented technology

The invention belongs to the technical field of flow field optical measurement, and particularly relates to a high-enthalpy plasma gas temperature measurement method, system and device based on an absorption spectrum. Generating a composite modulation signal through a high-frequency sine wave and a low-frequency sawtooth wave, and enabling incident light to pass through a flow field measurement area in parallel through laser modulation and beam shaping; the detector receives the transmission light and converts the transmission light into an electric signal containing harmonic information, the signal acquisition device is used for performing signal acquisition, the phase-locked demodulation algorithm is used for extracting second harmonic, and the temperature is inversely deduced by combining the double-spectral-line temperature measurement method and the Fourier coefficient amplitude ratio of the second harmonic with the HITRAN database. The system comprises a signal driving module, a laser emission module, a detection acquisition module and a temperature measurement module. The device is composed of a signal generator, an in-phase adder and the like, and a laser is matched with a driving power supply to guarantee stable work. According to the scheme, aiming at the problems of weak signal absorption and insufficient signal-to-noise ratio under complex working conditions, the measurement accuracy and reliability are improved by composite modulation, harmonic extraction and a bispectral line algorithm, and an effective means is provided for research on thermal characteristics of the high-enthalpy plasma.

The embodiment of the invention provides a converter mode switching control circuit and method, and the circuit comprises a voltage regulation unit circuit, a Buck bridge arm unit control circuit, a Boost bridge arm unit control circuit, and a mode selection circuit. The voltage regulation unit circuit is used for converting an output voltage Vo into an error signal Verror and sending the error signal Verror to the Buck bridge arm unit control circuit and the Boost bridge arm unit control circuit respectively; the sawtooth wave generator outputs a signal vsaw, sends the signal vsaw to the Buck bridge arm unit control circuit, and outputs a Buck bridge arm duty ratio Dy1; the sawtooth wave generator outputs a signal vsaw, sends the signal vsaw to the Boost bridge arm unit control circuit, and outputs a Boost bridge arm duty ratio Dy2; and the mode selection circuit is used for indicating a Boost mode, a Buck mode and a Buck-Boost mode. The invention provides digital and analog control of converter three-mode smooth switching.

The invention discloses a five-degree-of-freedom piezoelectric robot driven based on the inertia stepping principle, and relates to the technical field of robots, the five-degree-of-freedom piezoelectric robot comprises an upper driving system, a lower driving system, a spherical hinge system, an upper output end, a connecting rod and a driving foot; the spherical hinge system comprises a spherical hinge lower end cover, a joint ball, a joint seat, a spherical hinge friction pair, a pre-tightening bolt and a spherical hinge upper end cover; the upper driving system comprises a plurality of piezoelectric driving units, an upper connecting ring and an upper inertia ring; the lower driving system comprises a plurality of piezoelectric driving units, a lower inertia ring, a lower connecting ring and a lower output end; different sawtooth wave voltage excitation signals are applied to the piezoelectric driving unit, the piezoelectric driving unit can output bending deformation in different directions, the driving foot and the upper output end are made to move under the action of inertia force, and finally linear motion displacement output of the upper output end in the x-axis direction and the y-axis direction and rotary motion displacement output around the x-axis, the y-axis and the z-axis are achieved. The method has wide application potential in the fields of aerospace, optical equipment and the like.

The invention discloses a photon-assisted measurement system based on sawtooth wave frequency shift, which is characterized in that antenna modules which are arranged at an interval of 1 / 4 microwave signal wavelength receive echo signals of a space, and meanwhile, a laser generates continuous light which enters an electro-optical modulation module; the modulator simultaneously receives an echo signal, a transmitting signal and a low-frequency sawtooth wave frequency shift signal. An optical signal output by the modulator selects a positive first-order sideband through the optical band-pass filter, and two paths of optical signals with mutually orthogonal polarization states are separated through the polarization beam splitter. The optical signals with orthogonal polarization states respectively pass through a low-frequency photoelectric detector and then two paths of low-frequency signals are output, and Doppler frequency shift and arrival angle information of echo signals are obtained by performing digital signal processing on frequencies and phase differences of the two paths of low-frequency signals. The invention can simultaneously measure the angle of arrival and Doppler frequency shift without direction ambiguity, has low structural complexity and is not influenced by microwave signal power.

The invention relates to a four-tube buck-boost switching power supply control circuit, which is characterized in that a switching tube control circuit is designed to collect inductive current and sampling output voltage in a four-tube buck-boost switching power supply circuit, a VCAboost signal and a VCAbuck signal are generated through signal compensation, a duty ratio signal is generated according to a preset sawtooth wave signal VRAMP, and the VCAboost signal and the VCAbuck signal are output. And finally, converting the control signals into control signals corresponding to the four switching tubes respectively, thereby realizing switching of each mode of the four-switching-tube buck-boost power supply circuit. A direct connection stage is added in a buck-boost mode, inductor energy release in mode switching is effectively realized, a large amount of surge current is prevented from passing through the inductor current to cause inductor damage, voltage conversion efficiency and circuit stability are improved, transition between the buck mode and the Boost mode is optimally controlled through the duty ratio, stable change of the duty ratio when a switching tube works is ensured, and the stability of the switching tube is improved. And current fluctuation and loss are avoided.

The invention relates to the technical field of semiconductor laser control, and discloses an automatic frequency stabilization control system of a semiconductor laser, which comprises a lock-in amplifier used for demodulating a frequency discrimination signal; the modulation signal generator is used for outputting a sinusoidal signal or a cosine signal with the frequency of 100kHz and the peak-to-peak value of 40mV, and taking the sinusoidal signal or the cosine signal as a reference signal; the basic current and frequency sweep signal generator is used for adjusting the direct current offset, aligning a wave crest in a frequency discrimination error curve to a scanning midpoint, and outputting a sawtooth wave frequency sweep signal of which the peak value and the frequency can be adjusted; the PID controller is used for stabilizing the frequency discrimination signal to a saturation absorption peak corresponding value; and the automatic frequency stabilization state judgment and controller identifies a target saturated absorption peak through a two-stage peak searching algorithm, and locks the working frequency of the semiconductor laser on the frequency corresponding to the target saturated absorption peak. According to the invention, the operation process of the frequency stabilization system is simplified, and long-term stable operation of the semiconductor laser is ensured.

The invention discloses a device and a method for testing frequency domain characteristics of a high-speed optoelectronic device. The device comprises a laser, a sawtooth wave generator, a signal source, an acousto-optic modulator, an electro-optic intensity modulator, a low-frequency photoelectric detector, a frequency spectrograph and a computer. An electro-optic intensity modulator is driven through a sawtooth wave modulation technology, and frequency-shifted and non-frequency-shifted optical carriers and frequency-shifted and non-frequency-shifted radio frequency optical sidebands are synchronously generated in an optical path in combination with radio frequency signal modulation. And after the signal is subjected to beat frequency processing by the photoelectric detector, the power of the frequency shift signal in different working states is measured by the frequency spectrograph, so that the frequency domain characteristic parameters of the photoelectric device to be measured are obtained. The method is based on sawtooth wave modulation and an amplitude comparison method, frequency domain response characteristics of a single / dual-drive electro-optic intensity modulator, dual-parallel electro-optic intensity modulation and a photoelectric detector can be accurately represented, the test method is simple, and dependence on a high-frequency test instrument is effectively reduced.

The invention discloses a penetration detection method of a multi-band modulated wave radar in a non-metal medium. The detection method comprises the following steps: constructing a multi-band hybrid modulated wave radar architecture; the sawtooth wave modulation mode and the triangular wave modulation mode are subjected to alternating or mixed waveform modulation; processing the hybrid modulated wave by adopting a near-field strong clutter suppression algorithm; estimating the distance of the target by adopting a wide-range target rough measurement algorithm; calculating the distance of the target by adopting a short-distance high-precision distance measurement algorithm; performing dynamic compensation on the measurement data by adopting a Kalman filtering state estimation algorithm to obtain a distance estimation result; complementary information of long-wave and short-wave radars is utilized to form a complete detection view. And intelligent collaboration of long and short wave data is realized through hierarchical fusion. Therefore, the system can simultaneously complete large-range transmission type detection and close-range millimeter-level high-precision measurement on one platform.

A golf ball is disclosed herein that includes at least one radar detectable mark such that a projected pattern is formed when the at least one radar detectable mark is radially projected onto an outer surface of the golf ball. The projected pattern can have a first wave profile mapped along a path defined by a first spherical arc on the outer surface of the golf ball. The projected pattern can comprise at least one first crest and at least one first trough. The projected pattern can have a periodic function selected from: a sine wave, a sawtooth wave, a triangle wave, or a square wave.

Various examples of a closed-loop optical gyroscope are disclosed. The closed-loop optical gyroscope includes a broadband light source configured to generate broadband optical signal(s). The broadband optical signal(s) propagate in an optical resonator and are coupled in and out of the optical resonator by optical couplers. A phase modulator applies phase modulation to the optical signal(s) based on a sawtooth modulation signal. The optical signal(s) repropagate in the optical resonator in a different direction. The optical signal(s) are then received and analyzed to determine parameter(s) of the phase modulator. One or more processors configure the phase modulator based on the determined parameter(s).

The application discloses a modulation method for eliminating sideband harmonics at the integer multiple carrier frequency of common-mode voltage, which reselects effective voltage vectors in the process of synthesizing reference voltage vectors, so that the common-mode voltage waveform between carrier periods is completely the same, and according to the characteristics of the common-mode voltage waveform, the modulation method can completely eliminate sideband harmonics near the integer multiple carrier frequency of common-mode voltage while reducing the amplitude of common-mode voltage, effectively reducing the adverse effects caused by the amplitude of common-mode voltage and its sideband harmonics. In view of the increase of switching frequency caused by the modulation method, the switching times of each carrier period are reduced by means of sawtooth wave carrier, further reducing the harm of common-mode voltage to the system.

The present application relates to the field of integrated circuits, in particular to a constant root mean square voltage output circuit, the main purpose is to make the output power constant under different power supply voltage, and has the advantages of high efficiency, small area. The main scheme includes root mean square voltage generating circuit (1), first sawtooth wave generating circuit (2), first comparator (3), first inverter (4), second inverter (5), low pass filter circuit (6), second sawtooth wave generating circuit (7), second comparator circuit (8), power drive circuit (9), output stage circuit (10). The circuit of the present application is simple without complex peripheral circuit, which greatly reduces the circuit cost. The power loss is mainly derived from the conduction loss and switching loss of the first PMOS tube, which is very small compared with the output power, so the output efficiency is high.

The application discloses a carrier Doppler frequency shift and code Doppler frequency shift simulation method and device. First, original optical carriers output by a light source module are received, and non-spur frequency shift of the original optical carriers is realized. A carrier Doppler frequency shift amount and a code Doppler frequency shift amount output by a synchronous control module are received. A periodic sawtooth wave signal frequency and a slope are updated based on the carrier Doppler frequency shift amount, and a frequency-shifted optical carrier signal is obtained. A sampling clock frequency is adjusted based on the code Doppler frequency shift amount, and a code Doppler simulation baseband code element signal is obtained. Finally, the code Doppler simulation baseband code element signal is loaded on the frequency-shifted optical carrier signal, an adjusted optical signal loaded with the optical carrier and the code Doppler frequency shift at the same time is obtained, and is output to a laser communication terminal to be measured. The problem of poor sufficiency of Doppler frequency shift simulation is solved.

The present invention discloses a circuit structure and an electronic device. The circuit structure includes: a charging circuit, which is used to transmit the power supply current of a power supply circuit to a sawtooth wave generating circuit under a first pulse signal; a discharging circuit, which is used to adjust the voltage of the sawtooth wave generating circuit under a second pulse signal, and disconnect the power supply circuit from the sawtooth wave generating circuit during the second pulse signal; a comparison circuit, which is used to compare the voltage of the sawtooth wave generating circuit with a reference voltage and output a first level to an operational amplifier circuit; and an operational amplifier circuit, which is used to adjust the power supply current of the power supply circuit based on the first level.

The utility model relates to a goaf site fan foundation horizontal force loading model test device, which comprises a goaf foundation model frame, a fixing device, a loading device, a goaf foundation model and a wind turbine generator model, the front end of an electric cylinder is connected with a loading rod through a spring, and the loading rod is connected with the top of a tower drum in a bolt manner. An adjustable loading system is adopted in the aspect of a wind load loading system, stable output of waveforms such as sine waves, square waves and sawtooth waves can be achieved, and control software can track and correct peak and valley values of controlled variables (such as loads) in the test loading process. The typical value of the dynamic error of each peak value in the whole test process is + / -1% FS, and the adjusting capability is strong; wind loads can be applied to different positions of a goaf site under different engineering geological conditions according to test requirements, and the utilization rate of the test fixing device is improved.

This invention discloses a multi-target hybrid accumulation detection method based on a decoherent clean algorithm, comprising: acquiring the beat signal of a sawtooth frequency-modulated continuous wave signal; performing a one-dimensional Fourier transform on the beat signal to obtain the range dimension information of the target echo, and displaying the target echo's range dimension information as a moving target to obtain a preprocessed signal; searching different coherent segments based on the preprocessed signal, performing coherent accumulation within each segment using GRFT transform, and performing non-coherent accumulation between segments using GRT transform to obtain a hybrid accumulation result; acquiring the peak value in the hybrid accumulation result and comparing the peak value with a hybrid accumulation threshold; extracting the target motion parameters corresponding to the peak value and constructing a decoherent clean signal; removing the clean signal from the beat signal to obtain an updated beat signal, until the updated accumulation peak value is less than the hybrid accumulation threshold. This invention can improve the accumulation gain.

The invention discloses a methane telemetering imaging system and method based on an active infrared absorption spectrum and a fast reflector, and the system comprises a main control module, a laser driver, a laser, a detector, an off-axis parabolic reflector, a voice coil fast reflector, and a distance measurement module. The laser driver controls the laser device to emit modulated laser, the voice coil fast reflecting mirror controls the angle of emergent laser, the semiconductor photoelectric detector receives an echo optical signal, converts the echo optical signal into an electric signal and sends the electric signal to the main control module, and the main control module further completes signal analog-to-digital conversion through an analog-to-digital converter. And a digital lock-in amplifier is used to demodulate the signal to respectively obtain a first harmonic and a second harmonic. The method has the advantages of high imaging speed, high spatial resolution, high detection sensitivity and the like.

The utility model relates to the technical field of low-frequency application occasions for voltage and current measurement and acquisition, in particular to a high-resolution analog-to-digital conversion equivalent circuit device, which comprises a sawtooth wave generating circuit, a voltage / current acquisition and conversion circuit, a signal shaping circuit and an MCU (Microprogrammed Control Unit) analog-to-digital conversion circuit, the voltage / current acquisition and conversion circuit obtains a sampling voltage Vsample, the sawtooth wave voltage V-carrier and the sampling voltage Vsample are compared and shaped through the signal shaping circuit to output a rectangular wave Vduty x, and the rectangular wave Vduty x is processed and transmitted to the MCU analog-to-digital conversion circuit for duty ratio sampling to complete analog-to-digital conversion. The utility model provides a novel voltage and current acquisition circuit which is built by utilizing the comparator and replaces an ADC (Analog to Digital Converter), and has the advantages of low cost, low power consumption, easiness in integration, high stability and the like.

This invention relates to a method and apparatus for resolving velocity ambiguity based on constant frequency assistance. The method includes the following steps: a radar sequentially transmits a constant frequency band signal and a linear continuously modulated pulse train, and acquires the radar echo signal; both the constant frequency band echo signal and the sawtooth band echo signal are mixed to obtain a constant frequency band intermediate frequency signal and a sawtooth band intermediate frequency signal; the constant frequency band intermediate frequency signal is processed by a fast Fourier transform to obtain a target true velocity estimate; the sawtooth band intermediate frequency signal is sequentially processed by a two-dimensional fast Fourier transform, a two-dimensional constant false alarm rate (CFAR) processing, and a centroid condensation processing to obtain a target range velocity estimate; based on a velocity matching method using a Fourier rotation factor, the target true velocity estimate is matched with the target range velocity estimate to obtain the true velocity of all targets. This method not only resolves velocity ambiguity but also improves velocity accuracy, offering advantages such as high velocity measurement accuracy, high real-time performance, and simplicity.

The invention discloses a pulse width modulation method for simulating a zero-input working mode of a D-type audio power amplifier, which comprises the following steps of: S1, detecting the state of an audio input signal in real time through a zero-input detection module U1, and outputting a real-time zero-input marking signal ZDET; s2, a sawtooth wave generator U3 is controlled by the zero input mark signal ZDET; and S3, inputting the zero input mark signal ZDET into a configuration adjustment module U2, properly adjusting a corresponding loop bandwidth parameter value, and adjusting the pulse width duty ratio values of the final OUTP and OUTN under zero input. According to the pulse width modulation method for simulating the zero-input working mode of the D-type audio power amplifier disclosed by the invention, the system can output OUTP and OUTN pulse waveforms with stable working frequencies under the zero-input condition of lasting for a period of time or when the change of an audio output signal passes 0V, and harmonic distortion under the condition of small-amplitude audio output is reduced.

The invention discloses an anti-aging highlight veneer shaving board and a preparation method thereof, and belongs to the technical field of wood board production. The manufacturing method comprises the steps of eucalyptus wood shaving preparation, primary drying, potassium acetate treatment, secondary drying, acetic anhydride treatment, tertiary drying, gluing, assembly, pre-pressing and hot pressing, and the acetylated eucalyptus wood shaving board is manufactured. And then sanding, melamine paper pasting, hot pressing, colored paint roller painting, varnish and UV paint curing are conducted, and the anti-aging highlight veneer shaving board is obtained. The product has lasting highlight on the surface, solves the problem of reflection imaging sawtooth waves of a common shaving board, and is suitable for high-end furniture and indoor decoration.

The invention provides a ripple signal generation circuit and a switching converter, and the ripple signal generation circuit comprises a first signal unit which comprises a first adjustment module and a first output module; the second signal unit comprises a second adjusting module and a second output module, and an output node of the second output module is connected with a second node of the first output module; in the switching period, the first adjusting module and the second adjusting module work cooperatively to adjust the voltage of the first node and the output node of the first output module, and a ripple signal is obtained according to the voltage difference value of the first node and the output node. The ripple signal generation circuit provided by the invention mixes the triangular wave signal and the sawtooth wave signal to generate the ripple signal. Therefore, the ripple signal not only has the advantages of the triangular wave signal to ensure the stability of the system, but also has the advantages of the sawtooth wave signal to improve the dynamic response performance of the system.

The present application relates to a kind of background guided schlieren temperature field reconstruction method and device combined with laser absorption spectrum, the method includes the following steps: step one, build the measuring device of background guided schlieren tomography, complete laser collimator alignment;Step two, kHz sawtooth wave signal is generated using function signal generator, the output wavelength range of tuning laser is scanned repeatedly the absorption spectral line of each gas component in flame;Step three, using multi-camera acquisition a group of schlieren image when temperature and density are uniformly distributed in the measurement region, and the schlieren image of the measurement region is synchronously collected when the temperature and density to be measured are non-uniformly distributed;Step four, move background pattern board through time-sharing mechanism;Step five, acquisition multi-wavelength laser scanning signal;Step six, according to laser intensity, Voigt line type fitting is carried out;Step seven, inversion operation is carried out, and the three-dimensional temperature field of measurement region is obtained.The method can obtain higher resolution three-dimensional temperature field distribution.

The present invention discloses a voltage release circuit for the CS pin of a switching power supply control chip. This circuit modulates the input waveform at the current sampling pin of the PWM switching power supply control chip, converting an input triangular wave with a non-zero amplitude and a low rising slope into a post-peak sawtooth wave with a zero amplitude and a large rising slope. After this modulation step, the PWM switching power supply has lower design requirements for the RC filter parameters of the current sampling circuit, preventing control loop instability caused by RC filter circuit parameter drift due to long-term use of the power supply. This circuit also improves the control loop stability margin and enhances anti-interference capabilities.

This invention discloses a method and system for detecting internal thread parameters based on laser point cloud analysis. Addressing the shortcomings of incomplete results and slow speed of traditional internal thread measurement methods, this device can quickly acquire point cloud information of the internal thread to be measured. Within the system, outlier removal, cylindrical fitting, and sawtooth wave fitting operations are performed on this point cloud information to determine the major diameter, minor diameter, pitch diameter, pitch, and thread angle parameters of the internal thread.

The application discloses a photon-assisted measurement system based on sawtooth wave frequency shift, which receives echo signals of space by antenna modules arranged at intervals of quarter microwave signal wavelength, and a laser generates continuous light into an electro-optical modulation module, and the modulation module simultaneously receives echo signals, transmission signals and low-frequency sawtooth wave frequency shift signals. The modulation module outputs optical signals through an optical band-pass filter to select positive first-order sidebands, and the optical signals are separated into two optical signals with mutually orthogonal polarization states through a polarization beam splitter. The two optical signals with orthogonal polarization states are output as two low-frequency signals after passing through low-frequency photoelectric detectors, and the Doppler shift and the angle of arrival of the echo signals are obtained by performing digital signal processing on the frequency and phase difference of the two low-frequency signals. The application can simultaneously measure the angle of arrival and the Doppler shift without direction ambiguity, has low structural complexity and is not affected by the power of the microwave signal.

Methods and devices provide physiological movement detection with active sound generation. In some versions, a processor may detect breathing and / or gross body motion. The processor may control producing, via a speaker coupled to the processor, a sound signal in a user's vicinity. The processor may control sensing, via a microphone coupled to the processor, a reflected sound signal. This reflected sound signal is a reflection of the sound signal from the user. The processor may process the reflected sound, such as by a demodulation technique. The processor may detect breathing from the processed reflected sound signal. The sound signal may be produced as a series of tone pairs in a frame of slots or as a phase-continuous repeated waveform having changing frequencies (e.g., triangular or ramp sawtooth). Evaluation of detected movement information may determine sleep states or scoring, fatigue indications, subject recognition, chronic disease monitoring / prediction, and other output parameters.

The invention provides a distributed photovoltaic power station unmanned intelligent security method and system, and the method comprises the steps: collecting a video stream of a key region of a power station through an AI camera, and recognizing an abnormal event; extracting event types, space coordinates and timestamps of the abnormal events; constructing a two-dimensional coordinate system by taking the timestamp as a horizontal axis and the space coordinate as a longitudinal axis; generating a dynamic waveform based on the two-dimensional coordinate system and the event type, generating a constant amplitude waveform based on the green event, generating a rectangular pulse wave based on the yellow event, and generating a sawtooth wave based on the red event; updating a database based on a constant amplitude waveform, pushing an alarm to a coordinate radius preset range based on a rectangular pulse wave, and activating an emergency tracking protocol based on a sawtooth wave; historical data of database updating, alarm pushing and emergency tracking protocol activation are aggregated, a security weak point thermodynamic diagram and an equipment risk prediction report are generated, and the security efficiency is improved.

The present disclosure relates to a method and apparatus for reconstructing a three-phase current of an electric machine, in which the method includes constructing a sawtooth wave as a first carrier with respect to a first phase of the electric machine; phase-shifting the first carrier by the target phase to generate a second carrier with respect to a second phase and a third phase of the electric machine; generating phase voltages respectively corresponding to the three phases according to the size relationship between the three-phase modulation waves of the motor and the carrier waves of the corresponding phases; determining a first sampling window according to the phase voltages corresponding to the three phases respectively; and determining a second phase current and a third phase current at the first sampling window, and reconstructing the first phase current according to the second phase current and the third phase current. According to the scheme, the three-phase current of the motor can be accurately reconstructed.

This application provides a phase-locked loop (PLL), a control method, and a frequency source. It includes a controller, a time-to-digital converter (TD-to-digital converter), an arithmetic logic unit (ALU), a digitally controlled oscillator (DCO), and a frequency divider. The DCO outputs a linearly swept frequency signal based on a frequency control signal from the ALU. The frequency divider generates a divided frequency signal based on the output frequency of the DCO. The TD-to-digital converter outputs the phase difference between the divided frequency signal and a reference signal. The ALU outputs a frequency control signal based on the phase difference and a control code to adjust the output frequency of the DCO. The controller acquires the output signal of the TD-to-digital converter after a step point in the division ratio, and adjusts the control code until the output signal of the TD-to-digital converter after the step point is zero when the output signal is not zero. This method improves the linearity of the sawtooth waveform generated by the PLL at the step point.