9 results about "Frequency periods" patented technology

A method for operating a discharge lamp by modulating a current signal is presented. The discharge lamp is operated with at least two different frequencies. At first a probability distribution function for a first number of first frequency periods and a second number of second frequency periods is defined. Next, the first number of first frequency periods and the second number of second frequency periods are determined depending on the probability distribution function by at least one random number. The current signal is modulated by applying the first number of first frequency periods and the second number of second frequency periods to the current signal for operating the discharge lamp.

The present application relates to the technical field of laser radar, and especially relates to a non-aliasing frequency modulation continuous wave radar detection system and method, the non-aliasing frequency modulation continuous wave radar detection system comprising: a light source, a beam splitter, a circulator, a 90-degree frequency mixer, a signal conversion module and a signal processing unit, the signal processing unit being configured to: construct a complex vector signal S based on a first electrical signal I and a second electrical signal Q, S=I+jQ, wherein j is an imaginary operator, and obtain a double sideband spectrum based on the complex vector signal S, determine the frequency of a signal peak in an up-sweeping frequency period and the frequency of a signal peak in a down-sweeping frequency period in the double sideband spectrum, and obtain the distance and speed of a target to be detected based on the frequency of the signal peak in the up-sweeping frequency period and the frequency of the signal peak in the down-sweeping frequency period.The present application is at least beneficial to solve the signal aliasing problem when detecting the target to be detected.

This invention discloses an ADRC method for attenuating periodic disturbances in time-delay systems, belonging to the field of automatic control technology. The method includes: 1. Obtaining the controlled process model and disturbance frequency, and establishing an extended state model containing the periodic disturbance; 2. Constructing a reduced-order extended state observer and tuning the gain using the bandwidth parameter method; 3. Introducing a pure time-delay module into the observer's output channel to construct an ADRC structure; 4. Revealing the mechanism by which periodic disturbances in time-delay systems cannot be attenuated through two-degree-of-freedom equivalent transformation analysis; 5. Based on the frequency domain characteristic equation, analytically determining the delay of the time-delay module to achieve effective attenuation of periodic disturbances at specific frequencies. This invention solves the problem of attenuating periodic disturbances in time-delay systems without significantly increasing structural complexity. Compared to traditional schemes that require high-gain or complex prediction structures, this invention only requires adjusting the pure time delay of the observer's output channel, and the parameter tuning process is clear and intuitive, significantly lowering the threshold for engineering applications.

Method for monitoring a section (20) of a hydraulic pressure system (10), wherein a pressure of a fluid is built up in the section (20) by an upstream pump and wherein the fluid exits the section (20) via a valve (25) which opens with a valve control frequency and a duty cycle, characterized in that a pressure profile is detected by a pressure sensor (17) arranged downstream of the pump and upstream of the section (20) at least during one period of the valve control frequency, and that frequency components in the frequency spectrum of the pressure profile are determined by means of a Fourier transform.that if the frequency spectrum determined in this way matches the frequency spectrum of an intact subsection (20), it is concluded that the subsection (20) is intact, and that if the frequency spectrum determined in this way deviates from the frequency spectrum of an intact subsection (20), a defect in the subsection (20) is concluded, wherein the duty cycle of the opening valve (25) is changed from a first value to a second value, or that a period is considered in which the duty cycle changes, that local maxima of the frequency components in the frequency spectrum are determined, and that a defect in the subsection (20) is concluded if the amplitude of the local maxima decreases quasi-monotonic with increasing frequency.

The invention discloses a one-dimensional signal analysis method for a sweep-frequency series-parallel DFB array laser sensing system, and the method comprises the following steps: receiving a signal of the sweep-frequency series-parallel DFB array laser sensing system in a complete sweep-frequency period, the signal comprising a trigger signal and a data signal; reading a data signal in a complete frequency sweep period, and dividing the data signal into frequency sweep time periods corresponding to each lasing channel in the DFB array laser in a time domain; identifying and segmenting the frequency repeated overlapping part in the frequency sweeping time period of the adjacent lasing channels; processing the Mach-Zehnder interference signal by using Hilbert transform, and resampling the signal to be processed by taking the obtained phase change as a reference; and carrying out fast Fourier transform calculation, and analyzing one-dimensional distribution information of the measured object in the light reflection direction. According to the method, the problem of analysis signal distortion of the DFB array laser is solved, lossless extraction of returned information is realized, and a high-reduction-degree image is obtained.

This invention relates to the field of data processing technology, specifically to a data analysis-based intelligent operation and maintenance status detection method for generators. The method includes: monitoring and obtaining the horizontal and vertical decomposition curves of both the generator and the helicopter, and acquiring the relative acceleration of the helicopter at each moment; eliminating the influence of the relative acceleration on the horizontal decomposition curves of the helicopter and its generator to obtain the horizontal amplitude modulation curves of the helicopter and its generator; analyzing the frequency period invariance and the consistency of the frequency amplitude reduction ratio when helicopter vibration is transmitted to the generator to obtain the horizontal denoising decomposition curve of the generator; obtaining the vertical denoising decomposition curve of the generator; and fusing the horizontal and vertical denoising decomposition curves to perform operation and maintenance status detection on the generator. This invention aims to eliminate the vibration interference of the helicopter on the generator during operation and maintenance status detection, thereby improving the accuracy of operation and maintenance status detection.

The present application belongs to the technical field of cleaning efficiency optimization, and specifically discloses an efficiency optimization method for cleaning offshore light buoys based on cavitation jet, which collects the ship attitude and the target distance between the nozzle and the light buoy in real time, samples the target distance sliding window to determine whether to trigger distance adjustment, identifies the wave main frequency period based on the attitude data when triggered, divides the wave main frequency period into phase intervals and extracts the phase angular velocity, locks the target distance adjustment phase window, predicts the wave displacement change trend in the window, matches the distance adjustment mode containing the action direction and the response speed mode, and finally generates the target distance adjustment operation instruction and outputs it to the display terminal of the ship operation management system. The present application can accurately lock the target distance adjustment opportunity, adaptively compensate the target distance fluctuation caused by the wave, thereby ensuring the stable collapse of the cavitation bubble, avoiding ineffective cleaning, and greatly improving the offshore light buoy cleaning operation efficiency.

The application belongs to the field of laser ranging, and particularly relates to an absolute distance measurement method and device based on time delay interference, which comprises the following steps: introducing an arbitrary light source, first injecting a frequency modulation signal into the light source to prepare a frequency period jitter modulation note, then splitting the light with period jitter and injecting different frequencies, which are used to form heterodyne interference, one of the lights is used as reference light, the other light is processed twice by time delay, the reference light and the light processed by time delay are combined to realize twice heterodyne interference, and the first time delay processing contains distance information to be measured. The application uses the frequency period jitter modulation note of heterodyne interference light, combines the time delay interference method, calculates the time delay time, and calculates the absolute distance information contained in the time delay time, realizes low-cost and large-scale absolute distance measurement, and realizes the time delay interference algorithm, and the ranging reliability is high.

This invention discloses a servo control method based on low-frequency period similarity. First, through digital sampling, the servo adjustment deviation at each sampling moment within the -1th optical disc rotation cycle is obtained. Then, based on the servo controller, the servo drive quantity at each moment within the -1th cycle is obtained. Based on the servo adjustment deviation and servo drive quantity at adjacent moments within the -1th cycle, the incremental value of the low-frequency jitter of the optical disc at each moment within the 1st cycle is obtained through a low-pass filter. This is then combined with the 1st... n cycle t The servo drive quantity at time t, obtain the t period. t The actual servo drive quantity at each moment, thus obtaining the first... n cycle t The servo drive adjusts the position at time +1, and then repeatedly executes servo control based on low-frequency periodicity similarity within the optical disc rotation cycle, eventually causing the servo drive to adjust the position to reach the target position.