78 results about "Sawtooth wave" patented technology

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 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 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 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.

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 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.

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.

The application provides a temperature coefficient adjustable current source generation circuit and a clock generation circuit, the temperature coefficient adjustable current source generation circuit comprises a first operational amplifier, a second transistor, a third transistor, a first resistor, a second resistor, a third resistor, a first triode and a second triode, and the clock generation circuit further comprises a sawtooth wave generation module, a voltage comparison and enable control module, a threshold voltage generation module and a logic shaping and flip-flop module; the temperature coefficient adjustable current source generation circuit and the clock generation circuit jointly generate a current source with zero temperature coefficient, achieve the temperature compensation effect, and the application has the advantages of low cost, small size, short starting time, no mechanical device and good shockproof effect.

This invention provides a drive control circuit and its operating method, a drive control chip, and a step-down system. The drive control circuit includes: a feedback compensation module for generating a compensation voltage based on a received feedback voltage; a voltage regulation module connected to the feedback compensation module for generating a sawtooth wave voltage through capacitor charging and discharging, and setting a constant discharge current when the compensation voltage is greater than or equal to a preset voltage, and reducing the discharge current based on the compensation voltage when the compensation voltage is less than the preset voltage; and a switch drive module connected to the feedback compensation module and the voltage regulation module for generating a first drive signal based on a comparison between the sawtooth wave voltage and the compensation voltage when the compensation voltage is greater than or equal to the preset voltage, and generating the first drive signal based on a comparison between the sawtooth wave voltage and the preset voltage when the compensation voltage is less than the preset voltage. This invention solves the problem of excessively large output ripple in existing technologies.

The present invention provides an electromagnetic pump malfunction detection device that can accurately determine whether or not there is a malfunction in the pump without being affected by external vibrations. [Solution] The electromagnetic drive pump abnormality detection device 200 according to the present invention is an electromagnetic drive pump abnormality detection device 200 that pumps fluid by causing a plunger 140 to reciprocate using an electromagnetic coil 120, and comprises a drive circuit 202 that drives the electromagnetic drive pump by applying a sawtooth wave voltage to the electromagnetic coil, an ammeter 210 arranged on the drive circuit, and a determination unit 220 that determines an abnormality from the current value acquired by the ammeter, wherein the determination unit measures the current while voltage is applied to the electromagnetic coil, differentiates the measured current value to calculate a derivative value, and determines that the plunger is in a normal state and is not locked if the peak Imax that appears in the calculated derivative value exceeds a predetermined threshold I0.

The invention discloses a charging and discharging control method and a charging and discharging control system, and belongs to the technical field of switching power supplies. The charging and discharging control method comprises the following steps: acquiring a sawtooth wave signal generated by a target capacitor in a working state; the sawtooth wave signal is used for representing the condition that the voltage of the target capacitor changes along with the time length; in a target charging and discharging period, based on the sawtooth wave signal and a maximum electric signal threshold value, a charging and discharging stage of a target capacitor is determined, and the charging and discharging stage comprises a normal charging stage, a first stage or a normal discharging stage; the first stage comprises a time-delay charging stage and an early-stage discharging stage; and under the condition that the target capacitor discharges, based on the charging and discharging stage, controlling the discharging current of the target capacitor. According to the charge-discharge control method, the discharge current of the target capacitor in the discharge stage can be controlled based on the charge-discharge state of the target capacitor, so that the frequency drift is reduced, and the stability of the system is enhanced.

The application relates to the field of spark ignition technology, and proposes a spark control system, which comprises a spark control circuit, the spark control circuit comprises an operational amplifier U2, a resistor R5, a switching tube Q4, a transformer T1, a resistor R4, a spark generator J1 and an optical coupler U3, the inverting input end of the operational amplifier U2 is used for receiving a sawtooth wave signal, the output end of the operational amplifier U2 is connected with the control end of the switching tube Q4 through the resistor R5, the first end of the switching tube Q4 is connected with the first input end of the transformer T1, the second input end of the transformer T1 is connected with a 12V power supply, the first output end of the transformer T1 is connected with the spark generator J1, the first end of the resistor R4 is connected with the first output end of the transformer T1, the second end of the resistor R4 is connected with the first input end of the optical coupler U3, the second input end of the optical coupler U3 is grounded, the first output end of the optical coupler U3 is connected with the 12V power supply, and the second output end of the optical coupler U3 is connected with the non-inverting input end of the operational amplifier U2. Through the technical scheme, the problem of poor reliability and stability of the spark control system in the related art is solved.

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.

The invention discloses a circuit for converting analog signals into PWM signals, and belongs to the technical field of signal transmission application. Comprising a precise sawtooth wave generating circuit and a signal comparison circuit, the precise sawtooth wave generating circuit provides sawtooth wave signals with accurately determined waveform amplitude, and the signal comparison circuit compares the sawtooth wave signals with analog input voltage signals and generates PWM signals with duty ratios linearly related to the amplitude of the analog voltage signals. The method has the advantages that the generated sawtooth wave is high in linearity, the amplitude variation range of the sawtooth wave can be accurately controlled between 0 and the reference voltage VREF, and a stable reference is provided for high-precision comparison; in the measuring range, the duty ratio of the output PWM signal and the amplitude of the input analog voltage are in a strict linear relationship, so that the accuracy of signal conversion is ensured; the duty ratio of the generated PWM signal can be continuously adjusted within the full range of 0-100%, no adjustment blind area exists in a traditional circuit, and the dynamic range and applicability of the signal are improved.

The application relates to the technical field of gas concentration detection, and discloses a digital modulation method and system of a single-laser multi-gas-component TDLAS sensing system, which comprises the following steps: S1, generating a low-frequency sawtooth wave scanning signal, a high-frequency sinusoidal wave modulation signal and a square wave control signal; S2, using the square wave to switch the amplitude of the high-frequency sinusoidal wave, then carrying out hardware superposition on the sawtooth wave and the segmented-amplitude sinusoidal wave to obtain a composite modulation signal; S3, driving a single laser after the composite modulation signal is converted into an analog signal, so that the laser sequentially outputs laser covering the absorption peaks of the first target gas and the second target gas in a single sawtooth wave scanning period; and S4, the laser signal after gas absorption is detected and demodulated to extract the concentration information of the first target gas and the second target gas. The application can realize synchronous optimal detection of multiple gases under the premise of keeping the single-laser structure simple.

The invention discloses a circuit breaker opening and closing coil intelligent detection method and device, relates to the technical field of circuit breaker detection, adopts a composite machine learning model to construct an intelligent detection model, can identify weaker and more complex early fault features, improves the detection accuracy and sensitivity, and improves the detection accuracy. And then training an intelligent detection model by adopting a logarithmic spiral exploration strategy, a vortex path exploration strategy based on information entropy and a fractional order balance exploration strategy based on a damping sawtooth wave oscillation factor, so that the algorithm can be effectively prevented from falling into local optimum, and when facing data of circuit breakers of different models and different working conditions, the algorithm can be accurately detected. The training of the intelligent detection model can be effectively realized, so that the intelligent detection accuracy of the opening and closing coil of the circuit breaker is ensured.

The present application relates to the technical field of cooling tower packing processing, in particular to a micro-channel structure cooling tower packing for efficient evaporation cooling and a processing technology thereof, which comprises the following steps: plasma activation treatment is performed on a base material of a body, the power is 280-320 W, and the time is 50-70 s; mold pressing forming: the base material preheated to 105-115 DEG C is placed into a mold with a temperature of 160+ / -5 DEG C, and the pressure is kept at 7-9 MPa for 25-35 s; laser trimming: the edge of the micro-channel unit is scanned by ultraviolet laser after mold pressing forming; spraying coating: a nano-hydrophilic coating is formed on the surface of the body by spraying and infrared curing process. Through the sawtooth corrugation, gentle slope corrugation and transition zone curvature control, the present application completes the airflow turbulence strengthening and water film residence time extension, and achieves the effect of improving the evaporation efficiency compared with the traditional packing. Through the micro-channel network construction, the present application completes the water film global diffusion driven by capillary force, and achieves the effect of improving the water film coverage compared with the traditional honeycomb hole and prolonging the anti-clogging cycle.

A low scattering turntable for improving quiet zone test performance and a quiet zone test method is provided, and relates to the technical field of quiet zone test. The low scattering turntable includes an L-shaped baffle, a rhombic inclined wedge supporting column, a bottom plate, a turntable base, a fixed block, a longitudinal rotating shaft and a transverse rotating shaft. In the disclosure, the rhombic inclined wedge supporting column is adopted, the sharp wedge diffraction and traveling wave scattering effects are reduced. Multi-layer side wave-absorbing materials layout are used in the rhombic inclined wedge supporting column, which can effectively reduce electromagnetic reflection and scattering in a wide frequency range. By adding sawtooth wave-absorbing material to the edge of L-shaped baffle, the reflection intensity of electromagnetic wave is reduced and the overall wave-absorbing efficiency is improved. The oval bottom plate is adopted to reduce the measurement error.

The invention discloses a double-voltage output circuit and electronic equipment, and belongs to the technical field of power output control. The double-voltage output circuit comprises a sawtooth wave circuit, a first error amplifier, a first comparator, a first output circuit, a first feedback circuit, a second error amplifier, a second comparator, a second output circuit and a second feedback circuit. The double-voltage output circuit shares the sawtooth wave circuit, so that the circuit design cost is saved. Moreover, the first pulse width modulation signal and the second pulse width modulation signal are generated by comparing the same sawtooth wave with respective error signals, so that the switching frequencies of the positive and negative output voltages are ensured to be completely synchronous. Each voltage output circuit is provided with an independent error amplifier, a feedback circuit and a comparator, so that each path of output voltage can be subjected to quick response and independent closed-loop regulation. The feedback circuit can generate feedback voltage according to the current of the output circuit, when the load current suddenly changes, the duty ratio of the pulse width modulation signal can be rapidly changed, and the voltage is kept stable.

The application discloses a kind of Φ-OTDR sensing method and system based on composite modulation pulse coding, comprising: obtaining high coherence continuous laser and being divided into probe light and local light;DDS control word of sequence is generated using FPGA to drive DDS to generate two-phase coding sequence and generate linear sawtooth wave voltage to control voltage-controlled oscillator to form linear frequency modulation signal of specified slope;High coherence continuous laser is modulated into two-phase coding light, modulated into composite modulation pulse string twice and signal power amplification is carried out, and is injected into the optical fiber to be measured;Probe pulse is injected into the optical fiber to be measured, backscattering Rayleigh echo is received, and light beat frequency is carried out with local light, and intermediate frequency optical signal is generated and converted into real-time high-speed sampling intermediate frequency electrical signal, signal demodulation, noise reduction and positioning signal processing are carried out.The application breaks through the restriction problem between sensing distance and spatial resolution in traditional distributed optical fiber sensing system, and greatly improves system performance.