113 results about "Harmonic spectrum" patented technology

A signal portion is extracted per frame having a specific duration from an input signal, thus generating a per-frame input signal. The per-frame input signal in the time domain is converted into a per-frame input signal in the frequency domain, thereby generating a spectral pattern of spectra. Peak spectra having peaks are detected in the spectral pattern. A harmonic spectrum is determined, in the peak spectra, having a harmonic structure showing a relationship between a fundamental pitch and a harmonic overtone.

The invention relates to a laser wavelength calibration method and device and a gas concentration analyzer. The wavelength calibration method includes the steps: storing a zero-gas secondary harmonicspectrum and a standard concentration secondary harmonic spectrum acquired in calibration; acquiring the secondary harmonic spectrum of gas to be detected; determining the absorption peak center position of the gas to be detected according to the maximum value of an absorption peak when judging that the concentration of the gas to be detected is within a first range, acquiring deviation between the absorption peak center position of the gas to be detected and the absorption peak center position of the standard concentration spectrum and generating feedback signals according to the deviation exceeding a preset value to calibrate wavelengths; determining the absorption peak center position of the gas to be detected according to the similarity of the spectrum of the gas to be detected and thezero-gas spectrum when judging that the concentration of the gas to be detected is within a second range, acquiring deviation between the absorption peak center position of the gas to be detected andthe absorption peak center position of the zero-gas spectrum and generating feedback signals according to the deviation exceeding the preset value to calibrate the wavelengths. The first range is notoverlapped with the second range, and the value of the first range is larger than that of the second range.

A modulation clock supplied to a drive circuit (7) of a display panel (1) is frequency-modulated so as to spread its harmonics spectrum. The frequency deviation is so restricted that, if at least two pixels corresponding to two adjacent scanning wirings are displayed based on arbitrary same luminance data, a difference in display luminance in a specified period between one pixel and the other pixel is less than or equal to a tolerable value determined by the luminance data. Consequently, reduction in unnecessary radiation can be achieved at a lower cost while suppressing deterioration in image quality

The invention discloses a device and a method for measuring the diffusion velocity of an electronic wave packet and aims at measuring a higher harmonic spectrum, screening the relationship between the elliptic polarization independence for exciting the wavelength of laser generated by the high harmonic spectrum and the wavelength of the laser and calculating the speed of the electronic wave packet and the sizes of the electric wave packets corresponding to different laser wavelengths according to the relationship between the sensitivity to the laser elliptic polarization degree and the electronic wave packet kinetic process. The measuring device and the measuring method have the characteristics of simpleness and effectiveness and important significance on understanding the evolution of the electronic wave packets in the strong-field physics and the electronic micro kinetics.

The invention belongs to the field of digital holography, and discloses a digital holographic harmonic detection and elimination method based on spectrum energy. The method includes six steps to complete the processing of an image with harmonic interference, which are Fourier transform of the image, search of a harmonic spectrum, readout of coordinates and a complex value of the harmonic spectrum, calculation of the frequency and interference intensity coefficient of harmonics in horizontal and vertical directions and the initial phase, construction of harmonic distribution using parameters, and image correction. The method of the invention only utilizes the energy relationship between the zero-order Fourier transform spectrum and the harmonic spectrum without the need to design a filter; the acquisition of the range of harmonics corresponding to the spectrum is not required; no impact will be exerted on the information of the original light; an inverse Fourier transform is not required on the spectrum; and after the harmonic parameters are obtained using the energy relationship, the harmonic intensity distribution is constructed, the harmonic is eliminated by direct subtraction and the calculation is simple.

The invention discloses a loop signal analysis method and a device for a DC control protection board, which relate to the technical field of signal processing and aim at solving the problem that spectrum leakage generated during a loop signal analysis process can not be effectively restrained. The method mainly comprises steps: according to a preset sampling frequency, board loop signals are sampled uniformly, and discrete signals are acquired; the discrete signals are intercepted according to a mixed convolution window, and filter signals are acquired; the result of carrying out FFT (Fast Fourier Transformation) on the filter signals is determined to be a harmonic spectrum; in the harmonic spectrum with the distance with a preset basic frequency point to be smaller than preset frequency offset, a peak frequency point nearest to the preset basic frequency point and with the maximum amplitude is searched; according to the amplitudes corresponding to the preset basic frequency point and the peak frequency point, the amplitude offset is calculated; and according to the offset, every-order harmonic parameters in the harmonic spectrum are calculated, wherein the harmonic parameters comprise the amplitude, the phase and the frequency. The method and the device are mainly applied to loop signal analysis for the DC control protection board.