Showing papers on "Harmonic published in 1970"
TL;DR: In this paper, the authors considered the free harmonic motion of infinite beams on identical, equi-spaced supports and derived the flexural propagation constants for beams on rigid supports which exert elastic rotational restraint.
409 citations
TL;DR: In this paper, general harmonic and hybrid orbital force fields have been calculated for methyl chloride, bromide and iodide using the best available frequency, Coriolis coefficient, and centrifugal distortion data, including the recent 13C frequencies for the chloride and ionide.
Abstract: General harmonic and hybrid orbital force fields have been calculated for methyl chloride, bromide and iodide using the best available frequency, Coriolis coefficient, and centrifugal distortion data, including the recent 13C frequencies for the chloride and iodide. Anharmonicity corrections were made to the fundamental frequencies using Dennison's rule and x values of 0·04 for CH stretching, 0·02 for CH bending, and 0·01 for CX stretching modes. These were the most reasonable values which did not seriously over-compensate for the product rule deficiencies in the 12C and 13C frequencies. The 13C and CD3X frequency information was input in the form of frequency shifts from the 12CH3X frequencies. All 12 parameters in the most general harmonic force fields are determined with significance for the first time, although the previously uncertain parameters F12 and F13 are only determined with good precision when the 13C frequency data are utilized in addition to the other information. The signs of F12, F45 and ...
110 citations
TL;DR: In this paper, new assignments of bands at middle and low frequency regions of Fe(CO) 5 were presented through use of appropriate techniques such as: laser source and low temperature (−190°) for Raman spectra, use of harmonic and combination bands, and spectral analysis of the substituted complexes.
87 citations
TL;DR: In this paper, the properties of small amplitude quasi-longitudinal (QL) and quasi-transverse (QT) body waves in anisotropic heat-conducting elastic materials were investigated.
Abstract: A transversely isotropic elastic material can transmit three body waves in each direction, a quasi-longitudinal (QL) wave, a quasi-transverse (QT) wave, and a purely transverse wave. When the material is able to conduct heat the properties of small amplitude QL and QT waves are modified and we consider here the analysis of such thermo-elastic interactions in plane harmonic disturbances. The modified QL and QT waves are both found to exhibit frequency-dependent dispersion and damping of the kind known to affect dilatational waves in isotropic heat-conducting elastic materials, and in addition we show that the particle paths in the associated motions are ellipses with their axes inclined to the wave normal. This latter effect is peculiar to body waves travelling in anisotropic heat-conducting elastic materials and seems not to have been studied in detail hitherto. Numerical results referring to the propagation of plane harmonic body waves in a single crystal of zinc are presented and discussed.
84 citations
01 Dec 1970
TL;DR: In this article, the theoretical Q-switching behavior derived from the rate equations governing an ideal four-level laser is presented in graphical form, and is found to describe the observed behavior well when the laser is restricted to oscillation in the TEM 00 transverse mode.
Abstract: An acoustooptic loss modulator made by bonding an X-cut quartz transducer to a fused silica scattering medium offers a practical means for repetitively Q-switching continuously pumped Nd : YAlG lasers at repetition rates up to 50 kHz. The peak power output of a multitransverse mode laser is typically enhanced by a factor of about 500 relative to CW operation at low (≪5 kHz) repetition rates and by larger factors when the transverse mode structure is suitably restricted. At high repetition rates, the peak power becomes smaller and the average power output approaches the CW level. The theoretical Q-switching behavior derived from the rate equations governing an ideal four-level laser is presented in graphical form, and is found to describe the observed behavior well when the laser is restricted to oscillation in the TEM 00 transverse mode. Similar calculations for Q-switched intracavity second harmonic generation indicate that the peak output power available at the second harmonic slightly exceeds that available at the fundamental, and that the harmonic coupling necessary to optimally couple the Q-switched laser is several orders of magnitude smaller than that required for CW intracavity conversion. Experiments using Ba 2 NaNb 5 O 15 For intracavity Q-switched harmonic generation roughly verified these predictions. A peak power output of 220 watts at 0.532 µ in the TEM 00 mode was achieved. Surface pitting of the nonlinear crystal after a few hours of operation prevented a thorough comparison with the calculated results. Preliminary experiments using the doubled Q-switched Nd : YAlG laser and an ammonia dihydrogen phosphate crystal to generate ultraviolet (the 0.266-µ harmonic) yielded a peak output power of 40 watts.
83 citations
TL;DR: In this article, the authors considered the reflection and transmission of plane harmonic waves in a flowing medium, by an infinite set of flat plates of arbitrary spacing and stagger, and the problem of solving this equation subject to the pertinent boundary conditions is converted into two consecutive Wiener-Hopf problems.
70 citations
TL;DR: In this article, it was shown analytically that for kth harmonic distortion, the zero-to-peak amplitude of the distortion tail relative to the autocorrelation peak when the seismogram is crosscorrelated with, the undistorted outgoing signal is given approximately by √ 1/(k−1)TW times the amplitude ratio of harmonic to fundamental.
Abstract: Harmonic distortion apparently arising from nonlinear processes, especially coupling of the vibrator to the ground, has often been observed in land seismic operations utilizing a frequency‐modulated mechanical vibrator as a surface source. The effect of harmonic distortion is to add a long oscillatory tail to the correlogram of a single sweep for the case in which the sweep frequency decreases with time. For up‐sweeps the distortion effect appears as a forerunner. It is shown analytically that for kth harmonic distortion, the zero‐to‐peak amplitude of the distortion tail (or forerunner) relative to the autocorrelation peak when the seismogram is crosscorrelated with, the undistorted outgoing signal is given approximately by √1/(k−1)TW times the amplitude ratio of harmonic to fundamental. W is the frequency range of the fundamental sweep and T is its length. Some examples computed by crosscorrelating a fundamental sweep (generated artificially) with its harmonic components are shown to demonstrate the effe...
67 citations
TL;DR: In this paper, the authors investigated the harmonic generation in traveling-wave tubes (TWT's) via large-signal analysis and digital computer techniques, and showed that the second harmonic interference in the beam bunching process leads to substantial efficiency reduction in TWT's employing relatively nondispersive structures.
Abstract: This paper describes the investigation of harmonic generation in traveling-wave tubes (TWT's) via large-signal analysis and digital computer techniques. Efficiency degradation and harmonic power content are shown to be importantly related to such TWT design considerations as circuit dispersion, harmonic coupling impedance ratio, and gain level. Also described is the phenomenon of second harmonic interference in the beam bunching process and how it leads to substantial efficiency reduction in TWT's employing relatively nondispersive structures.
45 citations
38 citations
Patent•
05 May 1970TL;DR: A microstrip impedance matching circuit has fixed harmonic terminations in the form of a pair of open-circuited stubs, each having a length equal to a quarter wavelength of a different harmonic frequency, connected to the main transmission line to cause the impedance at the harmonic frequencies to be made constant irrespective of the nature of the load impedance as mentioned in this paper.
Abstract: A microstrip impedance matching circuit has fixed harmonic terminations in the form of a pair of open-circuited stubs, each having a length equal to a quarter wavelength of a different harmonic frequency, connected to the main transmission line to cause the impedance at the harmonic frequencies to be made constant irrespective of the nature of the load impedance at the harmonic frequencies.
35 citations
TL;DR: In this article, a theory describing the conversion of fast-to-slow waves and vice versa, propagating perpendicular to a static magnetic field in a planar geometry for frequencies near and below the second electron cyclotron harmonic was given.
Abstract: A theory is given describing the conversion of fast‐to‐slow waves and vice versa, propagating perpendicular to a static magnetic field in a planar geometry for frequencies near and below the second electron cyclotron harmonic. The half‐space and slab are treated with collisional effects included. It is shown that the power conversion between the two wave types is directly proportional to the scale length of the density gradient at the point in the plasma where the hybrid resonance condition is satisfied provided this scale length is small compared to a free‐space wavelength. In spite of the small coupling, appreciable interaction is shown to take place between a transverse wave incident on a plasma slab and the longitudinal wave when a resonance condition exists for the longitudinal wave. The linewidth of the resonances is found to depend on both the density gradient near the hybrid resonance points and collisional effects.
Patent•
07 Apr 1970TL;DR: In this article, a stable oscillator is employed to excite the desired plurality of signals in a harmonic comb generator and an injection oscillator, controlled by a selected unidirectional voltage level, is used as a filter to select a desired one of the array of harmonically related signals.
Abstract: A signal source and harmonic signal selector for application in frequency-coherent signal generators or synthesizers and in precision radio communication systems features a novel frequency conversion process to obtain pluralities of selectable stable frequency signals from one source. A stable oscillator is employed to excite the desired plurality of signals in a harmonic comb generator. An injection oscillator, controlled by a selected unidirectional voltage level, is used as a filter to select a desired one of the array of harmonically related signals. Means are provided for purifying the spectrum of the selected output signal.
TL;DR: In this article, the effects of harmonic and sub-harmonic signals on the operation of an avalanche-diode oscillator were investigated and the generation of harmonic signals was also considered.
Abstract: The purpose of this correspondence is to show the effects of harmonic and subharmonic signals on the operation of an avalanche-diode oscillator. Generation of harmonic and subharmonic signals is also considered.
TL;DR: In this paper, the lower bound of a 2 χ (the mean square deviation of the trial function from the exact wave function) is removed, making it exact: an upper bound can be given, and the requirement of knowing the exact eigenvalue is removed.
Patent•
21 Dec 1970TL;DR: In this paper, a system using a resonant cavity sensor for determining density of a fluid within a conduit is described, where the cavity of the sensor is resonated by a source of microwave power.
Abstract: A system using a resonant cavity sensor for determining density of a fluid within a conduit. The system includes a resonant cavity encircling a low loss portion of the conduit through which the fluid may flow. The cavity of the sensor is resonated by a source of microwave power. As the resonant frequency of the sensor is changed due to changing densities of the fluid, the frequency of the source is also changed to maintain a resonant condition. A reference generator output of a predetermined frequency is mixed with a signal of the same frequency as the resonant frequency of the cavity. The output of the mixer is a difference harmonic between the resonant frequency and the predetermined reference frequency with the difference frequency being related to changes in the density of the fluid contained within the low loss portion of the conduit and encircled by the cavity.
TL;DR: Theoretical predictions for the second harmonic a.c. polarographic response of systems involving rate control by diffusion, a first-order preceding chemical reaction and/or heterogeneous charge transfer kinetics are presented and discussed in this article.
TL;DR: In this paper, the authors discuss the theory of generating harmonics and combination frequencies in the current density in plasma, emphasizing the kinetic approach to these problems rather than the elementary phenomenological approach considered by earlier reviewers.
Abstract: Publisher Summary This chapter discusses the theory of generation of harmonics and combination frequencies in the current density in plasma, emphasizing the kinetic approach to these problems rather than the elementary phenomenological approach considered by earlier reviewers. Vilenskii and Wetzel have investigated in detail the effect of the interaction of an electron density gradient with a microwave field on the time dependence of the first two components of the distribution function. The homogeneous and inhomogeneous plasmas are treated separately. Further, among homogeneous plasmas, a distinction is made between the neutral plasmas and plasmas with induced excessive ionization. Sodha and Kaw had investigated the simpler problem of the generation of the second harmonic in the current density in an inhomogeneous magnetoplasma. The problem of the generation and propagation of harmonic and combination frequency waves in an inhomogeneous plasma, when two plane-polarized electromagnetic waves of frequencies are propagating with their electrical vectors along the direction of the density and temperature gradients, has been investigated in detail by Sodha and Kaw. High-mobility semiconductors at low temperatures also hold great promise.
TL;DR: An equivalent circuit is introduced which incorporates the large-signal, “single-frequency” oscillator admittances at the fundamental and second-harmonic frequencies, and the criteria for stable oscillation of the tuned- Harmonic mode is investigated.
Abstract: We discuss characterization of the tuned-harmonic mode of operation in IMPATT oscillators, and introduce an equivalent circuit which incorporates the large-signal, “single-frequency” oscillator admittances at the fundamental and second-harmonic frequencies. Complete characterization of this mode is equivalent to specifying the behavior of each of the four elements of the equivalent circuit as functions of the oscillation state variables: fundamental voltage and frequency, second-harmonic voltage and relative phase. Using the approximate large-signal analysis of Blue,1 the values of the equivalent circuit elements are presented, as an example, for a 6-GHz IMPATT diode under a variety of oscillation conditions. This equivalent circuit is used to clarify the role played by the fundamental and second-harmonic, single-frequency oscillator admittances in the tuned-harmonic mode. Using an approximation to the equivalent circuit, we investigate the criteria for stable oscillation of the tuned-harmonic mode. It is found that the stability criteria are in general quite restrictive. For the same 6-GHz germanium diode, the range of stable phase is investigated, as a function of the RF parameters, for certain special cases. It is found to be possible to satisfy the stability criteria for the phase which gives an optimum enhancement of the fundamental power output if certain conditions on the external RF circuit are satisfied.
TL;DR: LiIO3 placed inside the cavity of an acousto-optically Q-switched, tungsten-pumped Nd:YAlG laser has been employed to generate kilohertz repetition rate pulses at 0532 μ as mentioned in this paper.
Abstract: LiIO3 placed inside the cavity of an acousto‐optically Q‐switched, tungsten‐pumped Nd:YAlG laser has been employed to generate kilohertz repetition rate pulses at 0532 μ The peak output power of 855 W obtained in the TEM00 mode at a repetition rate of 1 kHz was about 15 times greater than that available from the same laser at the fundamental laser wavelength, 1064 μ Volume damage occurred in the LiIO3 typically after several hours of operation at 1 kHz, an improvement over Ba2NaNb5O15
Patent•
NEC1
TL;DR: In this article, a rectangular waveguide bandpass filter for transmitting fundamental electromagnetic waves f 0 in a fundamental mode TE101 and attenuating second harmonic waves 2f 0 therein, comprising two susceptance elements spaced apart a distance of one-third waveguide wavelength in a lengthwise direction interiorly of the waveguide to form a resonant cavity for passing a frequency band including the fundamental wave f 101, attenuating the second harmonic wave 2f 101, and preventing resonant frequencies of modes higher than the fundamental modes TE101 from decreasing into a frequency region below the second harmonics.
Abstract: A rectangular waveguide bandpass filter for transmitting fundamental electromagnetic waves f 0 in a fundamental mode TE101 and attenuating second harmonic waves 2f 0 therein, comprising two susceptance elements spaced apart a distance of one-third waveguide wavelength in a lengthwise direction interiorly of the waveguide to form a resonant cavity for passing a frequency band including the fundamental wave f 101, attenuating the second harmonic wave 2f 101, and preventing resonant frequencies of modes higher than the fundamental mode TE101 from decreasing into a frequency region below the second harmonic; and one or two adjustable screws disposed between the two susceptance elements in one or both waveguide wide walls to project into the interior of the cavity at a position which is one-twelth of the one-third waveguide wavelength susceptance element spacing and which is from an adjacent narrow waveguide wall one-third of the overall distance between the two narrow waveguide walls whereby the screws are restricted to function as one or two capacitive elements only for the TE101 mode.
Journal Article•
01 Feb 1970
TL;DR: In this paper, a rectified-voltage waveform caused by integral-cycle triggering of thyristors was found to contain most subharmonics and harmonics, odd and even, from zero to infinity.
Abstract: A rectified-voltage waveform caused by integral-cycle triggering of thyristors is found to contain most subharmonics and harmonics, odd and even, from zero to infinity. For a control period (on-plus-off time) of T supply cycles, the lowest subharmonic has a frequency of 1/T of the supply frequency. Subharmonics and higher harmonics can have amplitudes exceeding that of the average load voltage, dependent on T and the number of conducting cycles N. The ripple factor is a function of N/T and exceeds unity for N/T < 1/9. Average load voltage and load power both vary in proportion to N/T. In connection with electromagnetic interference, a method is developed for estimating the amplitude of high-order harmonic components.
Patent•
15 May 1970
TL;DR: A metal detector using an ordinary radio receiver and a signal generator having its fundamental and second harmonic frequencies located equidistantly on either side of the frequency of the local oscillator of the radio is described in this paper.
Abstract: A metal detector using an ordinary radio receiver and a signal generator having its fundamental and second harmonic frequencies located equidistantly on either side of the frequency of the local oscillator of the radio. The fundamental and second harmonic of the generator are beat against the frequency of the local oscillator, producing two difference signals that are amplified and rebeat together to produce and audio signal. Frequency change in the signal of the generator due to inductance of metal is multiplied threefold in audio output, which triples sensitivity as compared with other detectors. The search coil comprises a printed circuit board having concentric coil circles on one side and radial shielding lines on the other.
TL;DR: A quantum-mechanical solution for phase-matched second-harmonic generation exhibits a periodic behaviour in direct contrast to the hyperbolic tangent solution of classical theory.
Patent•
25 Jun 1970
TL;DR: In this article, a thin-film device for second harmonic generation in which the fundamental beam is carried by the film and the second harmonic is generated as a freely propagating well-collimated beam in the substrate is presented.
Abstract: A thin-film device for second harmonic generation in which the fundamental beam is carried by the film and the second harmonic is generated as a freely propagating well-collimated beam in the substrate. The process is basically a Cerenkovlike radiation process, achieved when the optical dispersions of the film and substrate materials provide that the fundamental propagates faster in its guided mode than the second harmonic propagates freely in the substrate. An example is a polycrystalline ZnS film on a ZnO substrate, neither being significantly birefringent.
Patent•
15 Jul 1970
TL;DR: In this article, a sound generating system comprising means for producing signals of fundamental frequency, and means for generating formant frequency signals of frequency higher than the fundamental frequency which starts oscillation synchronizingly with said signal of fundamental frequencies and continues said oscillation only for a desired length of time during the period of said signals of formant frequencies.
Abstract: A sound generating system comprising means for producing signals of fundamental frequency, and means for generating formant frequency signals of frequency higher than the fundamental frequency which starts oscillation synchronizingly with said signal of fundamental frequency and continues said oscillation only for a desired length of time during the period of said signals of fundamental frequency, wherein said signals of formant frequency are generated at the same starting point for each frequency interval as said signals of fundamental frequency. Sounds thus produced consist of a fundamental frequency component and harmonic components, and the frequency spectrum of said sounds presents a peak in a formant frequency, so that the system eliminates the necessity of using an electrical filter having complicated frequency characteristics in electrically producing sounds having a complicated frequency spectrum.
Patent•
16 Mar 1970
TL;DR: In this article, an electrical musical instrument for simulating pipe organs, and having a natural ensemble effect, spatial tone distribution effect, air turbulence effect, wind pressure change effect, tracker-keying effect, piano voice keying effect and exact differently modulated harmonic pitch registers for mutation and compound stops and chiff.
Abstract: An electrical musical instrument for simulating pipe organs, and having a natural ensemble effect, spatial tone-distribution effect, air turbulence effect, wind-pressure-change effect, tracker-keying effect, piano voice keying effect, and exact differently modulated harmonic pitch registers for mutation and compound stops and chiff. These effects are achieved by modulator units coupled between harmonic filtered, tone frequency current sources and a stereophonic amplifier-speaker system which produces outputs having levels of amplitudes which vary differently with respect to each other. The outputs connected to the two speakers have inequalities in amplitudes so that each tone has its own distinctive spatial location. The modulator units comprise insulated gate field-effect transistors which are utilized to modulate the tone frequency currents with different patterns of subsonic frequencies including those producing the simulation of natural air turbulence and wind pressure change. Insulated gate field-effect transistors are also used for switching tone and chiff frequency currents so that the change in amplitude is sigmoid during turn-on and turnoff. RC circuitry in combination with the switching insulated gate field-effect transistors permit tracker keying and piano voice keying.
TL;DR: In this paper, the propagation wave analysis of an ultrasonic resonator is extended to include some effects of nonparallelism, guided wave phenomena, and electrical loading, which contributes an "inhomogeneous" broadening to the continuous wave frequency domain response and an ''inhomogenous'' damping to the time domain decay.
Abstract: The ``propagating wave'' analysis of an ultrasonic resonator is extended to include some effects of nonparallelism, guided wave phenomena, and electrical loading. Each of these effects contributes an ``inhomogeneous'' broadening to the continuous wave frequency domain response and an ``inhomogeneous'' damping to the time domain decay. Experimental verification for ultrasound propagating in both thin and bulk solid specimens is obtained by utilizing the sampled‐continuous wave ultrasonic spectrometer. Quantitative evaluation of interference effects among harmonic and inharmonic responses is achieved using the spectrometer in the time domain mode of observation.
Patent•
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04 Jun 1970
TL;DR: In this paper, an improved LASER RADAR system is used to monitor a VARIABLE PULSE-LASER TRANSMITTER, where a portion of the output is DELAYED, POLARIZED, and limited to a MAXIMUM INTENSITY VALUE.
Abstract: AN IMPROVED LASER RADAR SYSTEM COMPRISES A VARIABLE PULSE LASER TRANSMITTER A PORTION OF THE OUTPUT OF WHICH IS DELAYED, POLARIZED IN A FIRST DIRECTION AND LIMITED TO A MAXIMUM INTENSITY VALUE. THE REMAINDER OF THE TRANSMITTER OUTPUT IS DIRECTED TO A REMOTE TARGET WHEREBY IT IS REFLECTED BACK TO THE RECEIVER. THE RECEIVED REFLECTED ENERGY IS FILTERED AND POLARIZED IN A SECOND DIRECTION NORMAL TO THE SAID FIRST DIRECTION. THE RECEIVED AND DELAYED ENERGY IS COMBINED AND DIRECTED TO A SECOND HARMONIC GENERATING CRYSTAL AT A PREDETERMINED ORIENTATION. ONLY ENERGY HAVING BOTH ORTOGONAL POLARIZATION COMPONENTS OPERATES TO PRODUCE SECOND HARMONIC ENERGY WHICH IS FILTERED AND DETECTED BY A SECOND HARMONIC DETECTOR. THE DETECTOR OUTPUT SIGNAL IS COMPARED WITH THE DELAYED SIGNAL TO ESTABLISH THE DISTANCE TO THE TARGET.