8 results about "Fourth harmonic" patented technology

The invention belongs to the technical field of laser, and discloses a room-temperature high-energy deep ultraviolet laser generating device based on second-order and third-order nonlinear effects, which comprises a Raman crystal, a frequency doubling crystal, a frequency quadruplicating crystal, a sum frequency crystal and a color separation mirror, the fundamental frequency light is subjected to stimulated Raman scattering in the Raman crystal to generate Stokes light, and the frequency doubling crystal performs frequency doubling on the residual fundamental frequency light to generate second harmonics; frequency doubling is carried out on the second harmonic in the quadruplicated frequency crystal to generate a fourth harmonic; and the sum frequency crystal carries out sum frequency on the Stokes light and the fourth harmonic wave to finally obtain the deep ultraviolet laser with the 216.3 nm wave band. According to the invention, non-linear optical second-order harmonic conversion and third-order stimulated Raman scattering effects are combined, laser with the wavelength slightly longer than the wavelength of fundamental frequency light is obtained through stimulated Raman scattering, and the laser and fourth harmonic of fundamental frequency light are subjected to frequency summation in a large-aperture non-linear crystal under the room temperature condition, so that high-energy deep ultraviolet laser with the waveband of 210 nm is obtained.

The invention provides a method for improving the discrimination threshold of laser methane telemetering equipment, which comprises the following steps: in a dark environment, turning off a laser of the laser methane telemetering equipment, and measuring a first harmonic light intensity value I1c, a second harmonic light intensity value I2c and a fourth harmonic light intensity value I4c; selecting a central wavelength of a laser, and selecting a standard methane gas chamber with a remote measurement value of Wt; calculating a proportionality coefficient k21 considering the influence of the white noise, and calculating a telemetry measurement value W21 after the compensation of the electrical noise; calculating a proportionality coefficient k41 considering optical noise influence and an estimated value W41 of a telemetering value, and calculating a credibility criterion F '; selecting a confidence interval [b-1, b]; the standard methane gas chamber is slowly deflated, Wreal is calculated in real time, when the methane concentration is reduced to enable all the calculated Wreal to be zero, the methane concentration value Cmin at the moment is measured, and the identification threshold Wmin of the laser methane telemetering equipment is obtained through calculation. According to the method for improving the discrimination threshold of the laser methane telemetering equipment, electrical noise can be compensated, and part of optical noise can be filtered out.

The present invention belongs to the field of micro-shell vibrating gyroscope resonant structure processing, and specifically relates to a micro-shell vibrating gyroscope resonant structure processing method, comprising the following steps: S1, placing a substrate on a molding cavity, and matching n matching holes arranged in a circular array on the substrate with n positioning pins arranged in an annular array on the molding cavity one by one, wherein n is equal to a multiple of 8; S2, heating the substrate for a set time, and simultaneously evacuating the molding cavity; S3, taking out the incompletely molded substrate, rotating the substrate 360 ​​degrees / n, and placing the substrate on the molding cavity again, and matching n matching holes with n positioning pins one by one; S4, repeating S2 and S3 for a total of n times to obtain a micro-shell curved surface structure. The micro-shell curved surface structure obtained by the method provided by the present invention is blown in steps to achieve frequency doubling conversion of low-order harmonic errors, and can convert the fourth harmonic error into a higher-order harmonic component with a smaller amplitude, thereby effectively reducing the frequency cracking of the gyroscope.

A method for identifying resonant gyroscope errors based on variable DC bias voltage, involving resonant gyroscope detection technology, including setting... n DC bias voltage U D The frequency split Δ was measured. f and spindle azimuth angle; based on DC bias voltage 𝑈 𝐷 The frequency splitting function and principal axis azimuth function are established using the fourth harmonic coefficient of mass, the fourth harmonic azimuth angle of mass, the fourth harmonic coefficient of gap, and the fourth harmonic azimuth angle of gap. A set of error parameters is randomly selected and substituted into the simulation function to obtain the simulation arrays for frequency splitting and principal axis azimuth. The evaluation and optimization function values ​​are then calculated. MF ; Determine and evaluate the optimization function value MF If the error exceeds a preset threshold, the random error parameter set is updated according to a swarm intelligence optimization algorithm; otherwise, the error parameter is output. This method can identify the fourth harmonic error of the harmonic oscillator mass inhomogeneity and the fourth harmonic error of the lip gap inhomogeneity.

This invention discloses a dual-frequency deep ultraviolet laser generator, comprising a fundamental frequency seed source, a first harmonic conversion optical path, a second harmonic conversion optical path, and an output optical path. The first harmonic conversion optical path has a first beam combiner, a first second harmonic module, a third harmonic module, and a first delay line arranged sequentially along the propagation direction of the light. The second harmonic conversion optical path has a second beam combiner, a harmonic conversion optical path branch, and a second delay line. The harmonic conversion optical path branch and the second delay line are connected in parallel between the second beam combiner and the output optical path. The harmonic conversion optical path branch has a second second harmonic module and a fourth harmonic module arranged sequentially after the second beam combiner along the propagation direction of the light. The output optical path has a seventh harmonic module and an eighth harmonic module. This invention avoids the single-path power bottleneck by using distributed amplification, breaking through the power limitation of the fundamental frequency in traditional sum-frequency generation methods.

This invention belongs to the field of microelectronics technology and discloses a high-precision eight-phase voltage-controlled oscillator based on a transformer superharmonic coupling network. The oscillator includes four voltage-controlled oscillator units and a superharmonic coupling network, with each unit outputting a pair of differential oscillation signals. The superharmonic coupling network consists of two stage I coupling transformers and one stage II coupling transformer. The stage I coupling transformers are connected to the second harmonic output terminals of the first and second groups of voltage-controlled oscillator units, respectively, creating a 90° phase difference between the corresponding fundamental signals. The stage II coupling transformer is connected to the fourth harmonic coupling terminal of the stage I coupling transformer, creating a 90° phase difference between the second harmonic signals of the four units, thus ensuring that the eight fundamental output signals are sequentially 45° out of phase. This invention achieves high-precision eight-phase output by precisely controlling the fourth harmonic phase to regulate the second harmonic phase of each unit, while not interfering with the fundamental oscillation. It has advantages such as symmetrical structure, small phase error, and consistent output amplitude.

The application discloses a source degeneration type harmonic suppression frequency doubler, which comprises an input transformer, a transistor pair and a source degeneration network and an output transformer connected with the transistor pair in sequence, wherein the gate of the transistor pair is connected with the output end of the input transformer, the drain is connected with the output transformer, and the source is connected with the input end of the source degeneration network respectively. The application can realize high fundamental wave suppression ratio in the output frequency of more than 30GHz and a wide output frequency range by suppressing the output harmonic of the frequency doubler through the internally integrated source degeneration structure, and can simultaneously improve the fourth harmonic suppression ability through the harmonic impedance shaping technology while maintaining the wideband input matching characteristics.

The invention discloses a harmonic shaping oscillator circuit, which comprises a PMOS (P-channel Metal Oxide Semiconductor) cross coupling pair, an NMOS (N-channel Metal Oxide Semiconductor) cross coupling pair, a first source electrode inductance unit, a second source electrode inductance unit, a drain electrode inductance unit, a first adjustable capacitor pair, a second adjustable capacitor pair, a first differential fixed capacitor unit and a second differential fixed capacitor unit. The transformer formed by the first source electrode inductance unit, the second source electrode inductance unit and the drain electrode inductance unit can simultaneously realize differential mode third harmonic impedance expansion and double common mode resonance of second and fourth harmonics, and can avoid introduction of additional inductance while reducing flicker noise and phase noise, so that the stability of the filter is improved. No extra chip area is occupied, and the Q value of the resonant cavity is improved.