Logarithmic compression of digitally telemetered data.
Logarithmic compression of digitally telemetered data for constant maximum percentage error throughout encoded range
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Results for “LOGARITHM”
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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A logarithmic encoder for binary word compression
Logarithmic encoding procedure and error analysis for binary word compression
Sciulli, J. A.↗
Logarithmic variation criteria for the stability of systems with time-varying gains.
Logarithmic variation criteria for stability of feedback systems with time varying gains
Freedman, M.↗
Use of both linear and logarithmic transfer functions to increase dynamic range of visual channel
Using both linear and logarithmic transfer functions in the visual channels of a dual channel radiometer increases the dynamic range to better than 1 to 10,000 foot-lamberts.
Peretko, H. T.↗
Accurate nine-decade temperature-compensated logarithmic amplifier
Transistor-driven temperature-stable amplifier with logarithmic operating characteristics permits presentation of the entire range of the reactor without range switching. This circuit is capable of monitoring ion chamber currents over spans of 8 or 9 decades and is used in nuclear reactor instrumentation. Application is found in materials under ultrahigh vacuum.
Bobis, J. P.↗
Logarithmic variation criteria for the stability of systems with time-varying gains.
Logarithmic variation criteria for stability of feedback systems with time varying gains
Freedman, M.↗
A new solid-state logarithmic radiometer
Combination of temperature-compensated logarithmic amplifiers and p-i-n photodiodes operating in zero-bias mode provides lightweight radiometer for detecting spectral intensities encompassing more than three decades over a range of at least 300 to 800 nanometers at low power levels.
Burrous, C. N.↗
Logarithmic converter Patent
Logarithmic converter for compressing 19-digit binary input number to 8-digit output
Schaefer, D. H.↗
A new solid-state logarithmic radiometer
Solid state logarithmic radiometer, measuring radiation within narrow portions of optical spectrum
Burrous, C. N.↗
A logarithmic converter
Logarithmic signal converter with parallel circuits arrangement for large dynamic range operation
Caron, P.↗
Corrections for small values of the logarithm terms in the electrical conductivity of a fully ionized plasma
Correction factors for small values of logarithm of Debye length ratio to mean impact parameter in electrical conductivity of fully ionized plasma
Viegas, J. R.↗
An analog-to-digital conversion system with a logarithmic characteristic
Detailed analysis of an analog-to-digital conversion system consisting of a linear converter and a logarithmic amplifier containing nonlinear elements. It is shown that the small-signal resolution of such a system is much greater than that of linear systems used under the same conditions. A design for a low-power analog-to-digital converter operating at medium speed with a large input signal variation field is outlined.
Bellomo, A.↗
Logarithmic-function generator
Solid-state logarithmic-function generator is compact and provides improved accuracy. Generator includes a stable multivibrator feeding into RC circuit. Resulting exponentially decaying voltage is compared with input signal. Generator output is proportional to time required for exponential voltage to decay from preset reference level to level of input signal.
Caron, P. R.↗
A new algorithm for the integration of exponential and logarithmic functions
An algorithm for symbolic integration of functions built up from the rational functions by repeatedly applying either the exponential or logarithm functions is discussed. This algorithm does not require polynomial factorization nor partial fraction decomposition and requires solutions of linear systems with only a small number of unknowns. It is proven that if this algorithm is applied to rational functions over the integers, a computing time bound for the algorithm can be obtained which is a polynomial in a bound on the integer length of the coefficients, and in the degrees of the numerator and denominator of the rational function involved.
Rothstein, M.↗
On the logarithmic-singularity correction in the kernel function method of subsonic lifting-surface theory
A logarithmic-singularity correction factor is derived for use in kernel function methods associated with Multhopp's subsonic lifting-surface theory. Because of the form of the factor, a relation was formulated between the numbers of chordwise and spanwise control points needed for good accuracy. This formulation is developed and discussed. Numerical results are given to show the improvement of the computation with the new correction factor.
Lan, C. E.↗
A quick response four decade logarithmic high-voltage stepping supply
An improved high-voltage stepping supply, for space instrumentation is described where low power consumption and fast settling time between steps are required. The high-voltage stepping supply, utilizing an average power of 750 milliwatts, delivers a pair of mirror images with 64 level logarithmic outputs. It covers a four decade range of + or - 2500 to + or - 0.29 volts having an output stability of + or - 0.5 percent or + or - 20 millivolts for all line load and temperature variations. The supply provides a typical step setting time of 1 millisecond with 100 microseconds for the lower two decades. The versatile design features of the high-voltage stepping supply provides a quick response staircase generator as described or a fixed voltage with the option to change levels as required over large dynamic ranges without circuit modifications. The concept can be implemented up to + or - 5000 volts. With these design features, the high-voltage stepping supply should find numerous applications where charged particle detection, electro-optical systems, and high voltage scientific instruments are used.
Doong, H.↗
Logarithmic circuit with wide dynamic range
A circuit deriving an output voltage that is proportional to the logarithm of a dc input voltage susceptible to wide variations in amplitude includes a constant current source which forward biases a diode so that the diode operates in the exponential portion of its voltage versus current characteristic, above its saturation current. The constant current source includes first and second, cascaded feedback, dc operational amplifiers connected in negative feedback circuit. An input terminal of the first amplifier is responsive to the input voltage. A circuit shunting the first amplifier output terminal includes a resistor in series with the diode. The voltage across the resistor is sensed at the input of the second dc operational feedback amplifier. The current flowing through the resistor is proportional to the input voltage over the wide range of variations in amplitude of the input voltage.
Wiley, P. H.↗
Optically isolated logarithmic nanoammeter capable of floating to 5 kilovolts
A logarithmic current-measuring instrument was developed to measure plasma coupling currents at a common mode voltage of 5 kilovolts. Positive or negative currents can be measured from 10 to the -9th power to .001 ampere direct current. Optical isolation is used to control input switching and to provide data referenced to ground potential. Analog meter readouts as well as zero to five volt outputs are provided for peripheral data collection. Six independent channels are provided. Three measure positive currents, and three measure negative currents. Although designed for vacuum operation, it can be used equally well in air to measure low currents at high common mode voltages.
Sturman, J. C.↗