Square-to-sine wave filter
Square-to-sine wave filter network tested for regulation and stability under fixed loads
STABILITY↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Summary of sine-wave tracking studies
Sine-wave tracking studies indicate predictability of input and control device dynamics in manual control by human operator
MANUAL CONTROL↗
Relative Conservatism Between Transient and Sine Sweep Test Methods
The conservatism and overtest indices measured for multiple transient and SRS tests and a least favorable response test are compared to those of a swept-sine test for a typical spacecraft component.
characterizations used in shock testing shock inte↗
Transient Synthesis Using a Fourier Transform Envelope, An Alternative to Swept-Sine Vibration Testing
Transient vibration tests offer an alternative to the conventional swept-sine vibration test, with controllable conservatism. A method of deriving a single vibration test transient from several spacecraft flight transients is described. These transients were from different physical locations on the spacecraft.
transient↗
Seven place cosines, sines and tangents for every tenth microturn.
Seven place sine cosine tangent tables with decimal fraction of period as argument
TRIGONOMETRIC FUNCTION↗
Circuit operates as sine function generator
Electronic circuit drives sine function generator using square wave and sawtooth sweep generators. The circuit replaces electromechanical driver and increases accuracy.
Bogart, T., Jr.↗
Effect of two-dimensional multiple sine-wave protrusions of the pressure and heat-transfer distributions for a flat plate at Mach 6
Effect of two dimensional multiple sine wave protrusions on pressure and heat transfer distributions for flat plate in hypersonic flow
Cary, A. M., Jr.↗
Wide-band doubler and sine wave quadrature generator
Phase-locked loop with photoresistive control, which provides both sine and cosine outputs for subcarrier demodulation, serves as a telemetry demodulator signal conditioner with a second harmonic signal for synchronization with the locally generated code.
Crow, R. B.↗
Curve resolver for mixtures of damped sine waves.
Waveforms analyzer for mixtures of exponentially damped sine waves, noting application to interferometer curves in plasma wave propagation
Malmberg, J. H.↗
Long-life electromechanical sine-cosine generator
Sine-cosine generator with no sliding parts is capable of withstanding a 20 Hz oscillation for more than 14 hours. Tests show that generator is electrically equal to potentiometer and that it has excellent dynamic characteristics. Generator shows promise of higher-speed applications than was previously possible.
Flagge, B.↗
Half-sine wave pulse firing of electroexplosive devices
Half-sine wave pulse firing of electroexplosive devices
Menichelli, V. J.↗
Effects of vibration and shock on the performance of gas-bearing space power Brayton cycle turbomachinery. 1 - Half- sine shock and sinusoidal vibration
Half-sine shock and sinusoidal vibration tests of gas bearing supported rotor assembly and effects on mechanical performance of Brayton cycle space-power turbomachinery
Curwen, P. W.↗
Low cost, multichannel peak acceleration selector and averager for sine vibration testing
Low cost multichannel peak/average sine vibration control system with acceleration selector and averager
Woodbury, R. C.↗
Statistical properties of two sine waves in Gaussian noise.
A detailed study is presented of some statistical properties of a stochastic process that consists of the sum of two sine waves of unknown relative phase and a normal process. Since none of the statistics investigated seem to yield a closed-form expression, all the derivations are cast in a form that is particularly suitable for machine computation. Specifically, results are presented for the probability density function (pdf) of the envelope and the instantaneous value, the moments of these distributions, and the relative cumulative density function (cdf).
Esposito, R.↗
Comparison of modal test results - Multipoint sine versus single-point random
The Mariner Jupiter/Saturn (MJS) spacecraft was subjected to the traditional multipoint sine dwell (MPSD) modal test using 111 accelerometer channels, and also to single-point random (SPR) testing using 26 accelerometer channels, and the two methods are compared according to cost, schedule, and technical criteria. A measure of comparison between the systems was devised in terms of the cumulative difference in the kinetic energy distribution of the common accelerometers. The SPR and MPSD method show acceptable agreement with respect to frequencies and mode damping. The merit of the SPR method is that the excitation points are minimized and the test article can be committed to other uses while data analysis is performed. The MPSD approach allows validity of the data to be determined as the test progresses. Costs are about the same for the two methods.
Leppert, E. L.↗
Criteria for representing circular arc and sine wave spar webs by non-curved elements
The basic problem of how to simply represent a curved web of a spar in a finite element structural model was addressed. The ratio of flat web to curved web axial deformations and longitudinal rotations were calculated using NASTRAN models. Multiplying factors were developed from these calculations for various web thicknesses. These multiplying factors can be applied directly to the area and moment of inertia inputs of the finite element model. This allows the thermal stress relieving configurations of sine wave and circular arc webs to be simply accounted for in finite element structural models.
Jenkins, J. M.↗
On the solution of the generalized wave and generalized sine-Gordon equations
The generalized wave equation and generalized sine-Gordon equations are known to be natural multidimensional differential geometric generalizations of the classical two-dimensional versions. In this paper, a system of linear differential equations is associated with these equations, and it is shown how the direct and inverse problems can be solved for appropriately decaying data on suitable lines. An initial-boundary value problem is solved for these equations.
Ablowitz, M. J.↗
On sine dwell or broadband methods for modal testing
For large, complex spacecraft structural systems, the objectives of the modal test are outlined. Based on these objectives, the comparison criteria for the modal test methods, namely, the broadband excitation and the sine dwell methods are established. Using the Galileo spacecraft modal test and the Centaur G Prime upper stage vehicle modal test as examples, the relative advantages or disadvantages of each method are examined. The usefulness or shortcoming of the methods are given from a practicing engineer's view point.
Chen, Jay-Chung↗