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Showing papers on "Harmonic published in 1977"



Journal ArticleDOI
TL;DR: The authors give information on harmonic output and explicit design criteria for harmonic-suppression networks to be used with class-E power amplifiers.
Abstract: Class-E RF power amplifiers have advantages of explicit a priori designability, reproducibility, high efficiency, and low-stress operation of the power output devices. The authors give information on harmonic output and explicit design criteria for harmonic-suppression networks to be used with class-E power amplifiers.

137 citations


Book ChapterDOI
TL;DR: In this paper, the motion of an ion in the presence of a constant magnetic field and a perpendicularly propagating electrostatic wave with frequency several times the ion cyclotron frequency is shown to become stochastic for fields satisfying E/Bo > 1/4(Ω/ω)1/3 (ω/k).
Abstract: The motion of an ion in the presence of a constant magnetic field and a perpendicularly propagating electrostatic wave with frequency several times the ion cyclotron frequency is shown to become stochastic for fields satisfying E/Bo > 1/4(Ω/ω)1/3 (ω/k). This stochasticity condition is independent of how close ω is to a cyclotron harmonic. Applications of current interest in supplementary heating of plasmas with rf power near the lower-hybrid frequency are suggested.

133 citations


Journal ArticleDOI
TL;DR: In this article, an extended series of integral harmonic lines in the spectrum of direct backscatter was observed and spectrally resolved up to the eleventh harmonic (0.95 μm) at intensities well above the plasma continuum background.
Abstract: We report the observation of an extended series of integral harmonic lines in the spectrum of direct backscatter of 10.6‐μm radiation incident at intensities ≳1014 W/cm2 onto planar solid targets. We have observed and spectrally resolved up to the eleventh harmonic (0.95 μm) at intensities well above the plasma continuum background.

126 citations


Journal ArticleDOI
TL;DR: In this paper, second-harmonic light generation (SHLG) is analyzed from the viewpoint of photon statistics of the fundamental and generated beams versus the path traversed by the two waves in the medium.

92 citations



Journal ArticleDOI
TL;DR: In this paper, the effects of cold-plasma resonances upon propagation of the radiation from emission layer to observation point are evident: (i) the extraordinary mode first harmonic is always suppressed by the upper hybrid resonance layer; (ii) the ordinary-mode first harmonic was suppressed when the plasma frequency exceeds the cyclotron frequency; (iii) for sufficiently high density the second harmonic is also affected by the hybrid cut-off.
Abstract: Radial observations of emission in the vicinity of the electron cyclotron frequency and its harmonics show the radiation to be polarized; ratio of extraordinary to ordinary mode intensity of about 2:1. In the thermal spectra the effects of cold-plasma resonances upon propagation of the radiation from emission layer to observation point are evident: (i) The extraordinary mode first harmonic is always suppressed by the upper hybrid resonance layer; (ii) The ordinary-mode first harmonic is suppressed when the plasma frequency exceeds the cyclotron frequency; (iii) For sufficiently high density the second harmonic is also affected by the hybrid cut-off. In the non-thermal spectrum the broad-band emission is polarized at high frequency but not at lower. The feature in the vicinity of the plasma frequency at intermediate density is broader than previously observed and almost entirely above ωpe. Internal sawtooth relaxations have been observed in the central temperature even up to peak densities of 7 × 1020 m−3. Temperature profiles deduced from second harmonic cyclotron emission and Thompson scattering data are compared.

75 citations


Journal ArticleDOI
TL;DR: In this article, the phase transitions of the charge density wave (CDW) state in 1T-TaS 2 were studied both theoretically and experimentally, and the positions and intensities of the fundamental and third-order harmonic frequencies were analyzed.
Abstract: The phase transitions of the charge density wave (CDW) state in 1T-TaS 2 are studied both theoretically and experimentally. The positions and intensities of the fundamental and third-order harmonic...

68 citations


Patent
31 May 1977
TL;DR: In this paper, a zero-crossing detector was used to produce a square wave at the frenquency of the input signal to generate the harmonics of a given input frequency, which was then filtered to generate a signal of a predetermined harmonic.
Abstract: A frequency multiplier circuit utilizing a zero-crossing detector for producing a square wave at the frenquency of the input signal to generate harmonics of the input frequency. The square wave is filtered to generate a signal of a predetermined harmonic.

66 citations


Journal ArticleDOI
TL;DR: The first observation of reflected optical second harmonic generation of light due to excitation of fundamental and harmonic surface plasmon modes at the interface between a metallic film and a piezoelectric crystal was reported in this article.

60 citations


Journal ArticleDOI
TL;DR: In this article, the propagation of the fundamental and harmonically generated longitudinal elastic waves is treated by means of an asymptotic iterative procedure directly in the governing nonlinear differential equation.
Abstract: The propagation of the fundamental and harmonically generated longitudinal elastic waves is treated by means of an asymptotic iterative procedure directly in the governing nonlinear differential equation. Explicit results are obtained for the steady‐state, spatial growth of the second and third harmonic and the depletion of the input wave. As expected, the analysis indicates that the amplitude of the Nth harmonic depends on all the elastic constants up to order N+1. However, the forms for the amplitudes obtained in the asymptotic solution reveal that, for the known range of ratios of elastic constants of successively increasing order and propagation distances commonly encountered in harmonic generation experiments, only the quadratic nonlinearity, which depends on the second‐ and third‐order elastic constants, is required to accurately account for the experimental results. In addition, the amplitude dependence of the phase velocity of the fundamental longitudinal wave is determined.

Journal ArticleDOI
TL;DR: In this article, the variation of both the fifth and seventh harmonic signals with helium pressure is described, and the fifth harmonic signal is used to produce coherent light at 38 mm from laser pulses at 266.1 nm.
Abstract: Seventh harmonic generation in helium is used to produce coherent light at 38 mm from laser pulses at 266.1 nm. The variation of both the fifth and seventh harmonic signals with helium pressure is described.

Journal ArticleDOI
TL;DR: In this paper, the fundamental and second through the fifth harmonic spectral lines have been observed from the plasma produced when a 75psec Nd':'glass laser (∼1016 W/cm2) is focused onto a planar polystyrene target.
Abstract: The fundamental and second through the fifth harmonic spectral lines have been observed from the plasma produced when a 75‐psec Nd : glass laser (∼1016 W/cm2) is focused onto a thick planar polystyrene target. Both line profiles and relative intensities of these harmonic are given.

Journal ArticleDOI
TL;DR: Output voltage, output current and line current waveforms in a symmetrically pulse width modulated (SPWM) ac chopper are analyzed for harmonic content, displacement factor, distortion factor, power factor and efficiency.
Abstract: Output voltage, output current and line current waveforms in a symmetrically pulse width modulated (SPWM) ac chopper are analyzed for harmonic content, displacement factor, distortion factor, power factor and efficiency. The results are compared with those of phase controlled ac chopper circuit to assess the superiority of SPWM ac chopper. A novel SPWM ac chopper with minimum number of active components is presented. The circuit operation and the design considerations are discussed.

Journal ArticleDOI
01 May 1977
TL;DR: Based on the volt-ampere characteristic of the nonlinear load, an equivalent circuit, containing linear elements, can be determined and load-flow and harmonic compensation studies can be simplified.
Abstract: The classical definitions for the energetical determining factors in power systems are reviewed and a new model for the apparent power is suggested. — Based on the volt-ampere characteristic of the nonlinear load, an equivalent circuit, containing linear elements, can be determined. In this way, load-flow and harmonic compensation studies can be simplified.

Journal ArticleDOI
TL;DR: In this paper, five gravitational constraints were derived for the GEOS 2 orbit (order 13, to 30th degree) whose principal resonant period is 6 days, and the condition equations derived from elementary perturbation theory were shown to account for almost all of the resonant information in the tracking data.
Abstract: Five gravitational constraints were derived for the GEOS 2 orbit (order 13, to 30th degree) whose principal resonant period is 6 days The constraints explain the sinusoidal variation with argument of perigee of a lumped harmonic found from 41 6-day arcs of optical and laser data The condition equations, derived from elementary perturbation theory are shown to account for almost all of the resonant information in the tracking data

Journal ArticleDOI
TL;DR: The results of an investigation of the generation of the second harmonic of a neodymium laser in 33 new organic crystalline powders are given in this article, where ways of a possible search for and synthesis of nonlinear organic materials, and their potential applications are considered.
Abstract: The results are given of an investigation of the generation of the second harmonic of a neodymium laser in 33 new organic crystalline powders. Ways of a possible search for and synthesis of nonlinear organic materials, and their potential applications are considered.

Journal ArticleDOI
TL;DR: In this article, a planar surface-oriented Pt/GaAs Schottky-barrier diodes have been fabricated and used to detect signals at submillimeter wavelengths.
Abstract: Planar surface-oriented Pt/GaAs Schottky-barrier diodes have been fabricated and used to detect signals at submillimeter wavelengths. Video detection has been observed up to frequencies as high as 890 GHz. Harmonic mixing between the ninth harmonic of a 74.21-GHz signal and the second harmonic of 333.95-GHz radiation has also been obtained.

Journal ArticleDOI
TL;DR: In this article, the authors examined two-ion-species plasmas from the fundamental tritium cyclotron resonance (ω = ωCT) to the first deuteron harmonic (ω = 2ωCD) and found that a sufficiently large parallel wavelength greatly reduces the region of confluence between the fast wave and ion Bernstein wave.
Abstract: Supplementary wave heating is examined for two-ion-species plasmas from the fundamental tritium cyclotron resonance (ω = ωCT) to the first deuteron harmonic (ω = 2ωCD). At the first harmonic, it is found that a sufficiently large parallel wavelength greatly reduces the region of confluence between the fast wave and ion Bernstein wave. Power absorption considerations neglecting mode conversion processes show that first-harmonic heating efficiency is relatively insensitive to the species concentrations and that a dominant ion heating can be expected. For minority heating at the fundamental deuteron resonance, it is shown that inclusion of the two-ion hybrid resonance absorption considerably lowers the Q from the case where only minority species cyclotron damping is considered.

Patent
04 Jan 1977
TL;DR: In this article, the authors proposed a controller that minimizes periodic torque or force perturbations in an inductor-type synchronous motor drive by supplying current waveforms to each motor phase that contain a fundamental frequency component and selected harmonic components.
Abstract: A controller minimizes periodic torque or force perturbations in an inductor-type synchronous motor drive by supplying current waveforms to each motor phase that contain a fundamental frequency component and selected harmonic components. The harmonic components in the phase currents heterodyne with the periodic permanent magnet flux fundamental frequency to create periodic torques or forces which subtract from the unwanted torques or forces perturbing the moving portion of the motor. The controller, which includes an interpolator, a memory, and a converter, provides for smooth incremental movement of a member such as a plot head, at substantially constant velocity, by applying selected continuous periodic waveform signals as phase currents to the windings of inductor-type synchronous motors.

Journal ArticleDOI
TL;DR: In this paper, a simple method that corrects the eddy current component of core loss for the effects of flux harmonics is used to estimate the total loss due to a distorted waveform, provided the waveform does not contain harmonics greater than the 5th.
Abstract: This paper examines the behaviour of the core losses in thin laminations when the flux density waveform is highly distorted at peak flux densities of up to 2.0 T. It is shown that the presence of harmonics can increase the loss significantly over the value that exists when the flux density waveform is purely sinusoidal. A simple method that corrects the eddy current component of core loss for the effects of flux harmonics is used to estimate the total loss due to a distorted waveform. Provided the waveform does not contain harmonics greater than the 5th, it is shown that such a method of estimation yields acceptable results for the distortion levels encountered in practice.

01 Dec 1977
TL;DR: In this article, a detailed theoretical analysis of nonresonant third harmonic generation (THG) is given which includes the intensity dependent refractive indices of the nonlinear medium as an integral part.
Abstract: A detailed theoretical analysis of nonresonant third harmonic generation (THG) is given which includes the intensity dependent refractive indices of the nonlinear medium as an integral part. According to the third-order analytic solution, the maximum attainable conversion efficiency is only limited by a nonlinear parameter β which is essentially the ratio of the Kerr-constants and the third harmonic coefficient. Only for |\beta| intensity (energy) conversion efficiencies in excess of 90 percent (40 percent) are possible. The influence of the intensity distribution of the input beam is discussed. Diagrams are given from which the optimum experimental conditions can be deduced in order to get the optimum harmonic output. Limiting processes, such as fifth-order effects or self-focusing, are analyzed. As an example, the optimum conditions for efficient frequency tripling of powerful Nd:glass laser radiation are evaluated.

Journal ArticleDOI
TL;DR: In this paper, the propagation of free harmonic waves, in a periodically supported infinite pipe, has been studied and the response of the infinite pipe to a convected harmonic pressure field has also been obtained.

Patent
31 Oct 1977
TL;DR: In this paper, a frequency measuring apparatus is disclosed wherein a plurality of sets of harmonic signals are mixed with a received signal to produce a plurality groups of beat frequency signals, each one being fed by a corresponding one of the groups of signals.
Abstract: A frequency measuring apparatus is disclosed wherein a plurality of sets of harmonic signals is mixed with a received signal to produce a plurality of groups of beat frequency signals. A plurality of filters, each one being fed by a corresponding one of the groups of beat frequency signals, is provided to reject the beat frequency signals in such group having frequencies greater than one-half the fundamental frequency of the set of signals producing the group of beat frequency signals fed to such one of the filters. A plurality of counters, each one coupled to the output of a corresponding one of the filters, converts the frequency of the beat frequency signals fed to such counter to corresponding digital words. A logic network is provided to calculate the frequency of the received signal from the digital words provided by the counter.

Patent
02 Nov 1977
TL;DR: In a dynamic drive circuit for light-emitting diodes, at least one of the rise and fall times of the current flowing through the light emitting diode is elongated to reduce the higher harmonic components contained in the current as discussed by the authors.
Abstract: In a dynamic drive circuit for light-emitting diodes, at least one of the rise and fall times of the current flowing through the light-emitting diode is elongated to reduce the higher harmonic components contained in the current.

Journal ArticleDOI
TL;DR: In this paper, the effect of series resistance and junction capacitance on the high-frequency limit of IMPATT diode operation is studied with a Read-type small-signal theory, and confirmed experimentally.
Abstract: The effect of series resistance and junction capacitance on the high-frequency limit of IMPATT diode operation is studied with a Read-type small-signal theory, and is confirmed experimentally. Oscillation frequencies from 30 to 400 GHz have been measured with Si p+-n-n+abrupt junction diodes with a depletion layer width of 0.2 µm. The highest oscillation frequency increases as the junction diameter is decreased, owing to reduced junction capacitance and increased bias-current density. The highest oscillation frequency observed is 423 GHz, which is obtained in the fifth harmonic mode with a diode of 16-µm junction diameter. Fundamental oscillation frequency is found to depend strongly on dc bias-current density, and to be close to the avalanche frequency of the small-signal theory.

Journal ArticleDOI
TL;DR: In this paper, a theoretical exposition of the output signal of a.c. voltammetry was given for the presence of six harmonics, and a simple hyperbolic function was obtained for the fundamental harmonic valid for high values of the superimposed voltage.

Journal ArticleDOI
TL;DR: In this article, the spectral asymmetries of the light diffracted by surface waves are analyzed in order to evaluate the complex coupling coefficient in second harmonic surface wave generation and the experimental conditions are such as to keep the acoustic energy mostly confined to within fundamental and second harmonic waves.
Abstract: The spread of results obtained by different theoretical approaches in studying acoustic surface wave nonlinear interaction and difficulties in treating strongly piezoelectric materials indicate a need for more experimental data. In the present work the spectral asymmetries of the light diffracted by surface waves are analyzed in order to evaluate the complex coupling coefficient in second harmonic surface‐wave generation. The experimental conditions are such as to keep the acoustic energy mostly confined to within fundamental and second harmonic waves. Amplitude and phase of nonlinear coupling coefficients were separately determined for LiNbO3 and crystalline SiO2 substrates through different geometries of the acousto‐optical interaction, crystal cuts, and propagation directions of the waves.

Journal ArticleDOI
TL;DR: In this article, the relative strength of the fifth-order mixing processes in He and Ne is discussed, and a comparison of fifth and third harmonic generation in He shows higher conversion to the fifth harmonic for sufficiently tight focusing.
Abstract: The generation of coherent radiation at four new frequencies (59.1, 62.6, 71.0, and 76.0 nm) in the XUV by fifth‐order frequency mixing of harmonics from a Nd : YAG laser is reported. The relative strength of the fifth‐order mixing processes in He and Ne is discussed. Comparison of fifth and third harmonic generation in He shows higher conversion to the fifth harmonic for sufficiently tight focusing.

Journal ArticleDOI
TL;DR: In this paper, a non-collinearly phase matched second harmonic generation was studied and the effects of phase mismatching and of the interaction volume of two differently directed fundamental laser beams were considered.
Abstract: A formulation of the theory on the noncollinearly phase matched second harmonic generation is given. The theory treats the effects of phase mismatching and of the interaction volume of two differently directed fundamental laser beams. When the crystal is rotated from the matching angle, the second harmonic power decreases more rapidly with the enlargement of the interaction volume. The experimental results suggest the validity of the theory. Comparison with the collinear case indicates that higher power can be obtained in the noncollinear case.