Signal conditioning to improve high resolution processing for PFM telemetry
Signal conditioning for improved high resolution processing of PFM telemetry data
PULSE FREQUENCY MODULATION /PFM/↗
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Results for “pulsing frequency”
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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Remotely-actuated biomedical switch
Remotely-actuated biomedical switching circuit using transistors consumes no power in the off position and can be actuated by a single-frequency telemetry pulse to control implanted instrumentation. Silicon controlled rectifiers permit the circuit design which imposes zero drain on supply batteries when not in use.
Lee, R. D.↗
Boost regulator design and development
Design criteria for pulse and frequency modulated boost regulator
Mc Lyman, W. T.↗
Electro-optical time marker for high-speed cameras
Electro-optical device converts high-frequency electrical pulses into permanent optical records on film. Accurate, well defined images are formed of electronic pulses having repetition rates greater than 10,000 pulses/sec and pulse widths of 20 microseconds or less. Small electronic switch drives a silicon carbide electroluminescent diode.
Copeland, J. T., Jr.↗
Analog to Digital Converter-Patent
Analog to digital converter for converting pulses to frequencies
Doong, H.↗
Event-sequence detector
Detector consists of matrix of storage elements which are activated by coincidence of failure-voltage pulses and clock pulses. Clock frequency used for event sequence detector can be selected to provide time resolution demanded by test at hand.
Hanna, M. F.↗
The 1969 solar occultation of the Crab Nebula pulsar.
Results of an occultation experiment carried out on June 14-15, 1969, when the Crab Nebula pulsar passed within 80 min of arc from the center of the sun. For a time interval of two months around this event comparisons are made of the reception times of pulses at frequencies of 111.5, 196.5, and 430 MHz for the purpose of determining the contribution of the solar corona to the integrated electron density along the total path length to the pulsar. For impact parameters between 5 and 12 solar radii the measured integrated densities are not incompatible with those that can be derived from a spherically symmetric Baumbach-Allen model. The systematic differences in density obtained at each observation frequency can be explained in terms of refraction effects.
Rankin, J. M.↗
Heart-rate pulse-shift detector
Detector circuit accurately separates and counts phase-shift pulses over wide range of basic pulse-rate frequency, and also provides reasonable representation of full repetitive EKG waveform. Single telemeter implanted in small animal monitors not only body temperature but also animal movement and heart rate.
Anderson, M.↗
The use of a digital computer for calculation of acoustic fields of complex vibrating structures by the reciprocity principle
A program was compiled for calculating acoustical pressure levels, which might be created by vibrations of complex structures (an assembly of shells and rods), under the influence of a given force, for cases when these fields cannot be measured directly. The acoustical field is determined according to transition frequency and pulse characteristics of the structure in the projection mode. Projection characteristics are equal to the reception characteristics, for vibrating systems in which the reciprocity principle holds true. Characteristics in the receiving mode are calculated on the basis of experimental data on a point pulse space velocity source (input signal) and vibration response of the structure (output signal). The space velocity of a pulse source, set at a point in space r, where it is necessary to calculate the sound field of the structure p(r,t), is determined by measurements of acoustic pressure, created by a point source at a distance R. The vibration response is measured at the point where the forces F and f exciting the system should act.
Rimskiy-Korsakov, A. V.↗
Time-domain design of frequency-sampling digital filters for pulse shaping using linear programming techniques
Explore the source record for details and available documents.
Burlage, D. W.↗
Tachometer
A tachometer in which sine and cosine signals responsive to the angular position of a shaft as it rotates are each multiplied by like, sine or cosine, functions of a carrier signal, the products summed, and the resulting frequency signal converted to fixed height, fixed width pulses of a like frequency. These pulses are then integrated, and the resulting dc output is an indication of shaft speed.
Nola, F. J.↗
The evolution of the SEASAT imaging radar
The paper describes the design parameters and development of a synthetic aperture radar for use on the SEASAT spacecraft. This imaging radar is designed to operate at altitudes of 800 km with an orbital inclination of 108 deg, a nominal resolution of 25 m, and a swath width of 100 km. The design evolved from planetary imaging radar studies conducted over many years where an L-band imaging radar was developed and tested on aircraft flights as a prototype system to map the surface of Venus. A solid-state transmitter is used where the pulse repetition frequency is a function of altitude and will be about 2kHz for a 12-m long antenna. The receiver consists of the receiver protector, input filters, the gain control, and the RF amplifier. The ground station uses the standard NASA receiver with a 10-m antenna. The correlator, either optical or digital, must be able to compensate for the pitch and yaw variations of the spacecraft as well as the inherent effective yaw caused by the rotation of the earth, and extract the range curvature and range walk effects.
Brown, W. E., Jr.↗
Laser space rendezvous and docking system study continuation
Investigations were made of a configuration for a spaceborne laser radar (ladar) to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. An analysis was completed of laser phase locking techniques, while experimental verification was made of pulse repetition frequency and resonant scanning control loops. Data measurements on a satellite mock-up were also made. The investigation supports the original contention that a rendezvous and docking ladar can be configured to offer a cost effective and reliable solution to envisioned space missions.
Adelman, S.↗
The gravitational wave detection experiment: Description and anticipated requirements
The experiment to detect gravitational waves in ultraprecise two-way Doppler data is described, as are the anticipated requirements for the Deep Space Network, the spacecraft, and the data processing system. The special feature which allows the usage of ultraprecise Doppler data for the possible detection of gravitational waves is a unique three-pulse signature which is a function of the spacecraft, earth, and gravitational wave propagation direction geometry. The pulses (fractional frequency shifts) result from effects which are conveniently described as follows: Clock speed-up (earth only effect) and buffeting (equal earth and spacecraft effect).
Berman, A. L.↗
Electrical discharges in the atmosphere of Venus
Data received from Venera 11 and 12 experiments involving the electrical activity of the atmosphere of Venus show that the electrical discharges occur in the cloud layer. Their energy is roughly the same as in terrestrial lightning, but with a pulse repetition frequency of the discharges which is much greater.
Ksanfomaliti, L. V.↗
Bistatic synthetic aperture radar using two satellites
The paper demonstrates the feasibility of a bistatic synthetic aperture radar (BISAR) utilizing two satellites. The proposed BISAR assumes that the direction of the two narrow antenna beams are programmed to coincide over the desired area to be imaged. Functionally, the transmitter and receiver portions can be interchanged between the two satellites. The two satellites may be in one orbit plane or two different orbits such as geosynchronous and low-earth orbits. The pulse repetition frequency and imaging geometry are constrained by contours of isodops and isodels. With two images of the same area viewed from different angles, it is possible in principle to derive three-dimensional stereo images. Applications of BISAR include topography, water resource management, and soil moisture determination.. Advantages of BISAR over a monostatic SAR are mentioned, including lower transmitter power and greater ranges in incidence angle and coverage.
Tomiyasu, K.↗
Coherent anti-Stokes Raman spectroscopy - Spectra of water vapor in flames
The results of experimental measurements of the coherent anti-Stokes Raman spectra of water vapor in flames are reported. A pulsed, frequency-doubled neodymium laser was used to supply the pump beam and to pump a dye laser to provide a broadband Stokes beam at 6600 A. Spectra were obtained in the postflame region of a premixed methane-air flame in the Raman frequency shift region of the symmetric stretch mode (3651.7 kaysers) at an approximate temperature of 1675 K. A theoretical calculation of the coherent anti-Stokes Raman spectrum of water vapor at this temperature was made, taking into account only isotropic Q-branch transitions, and using the energy level data of Floud et al. (1976). The theoretical prediction is shown essentially to reproduce all qualitative features of the experimental spectrum, and to exhibit a strong temperature dependence.
Hall, R. J.↗
Improving the performance of soft decision Viterbi decoding in a non-Gaussian environment through non-linear quantization
The performance of Viterbi decoding in a non-Gaussian environment is investigated using a nonlinear quantization strategy. The channel model consists of a convolutionally encoded BPSK signal transmitted to a satellite where it is corrupted with additive white Gaussian noise and pulsed radio frequency interference (RFI). The resultant signal is then passed through a satellite nonlinearity and transmitted to a ground station where it is coherently detected. Interleaving is assumed in order to make the channel memoryless. The presence of RFI makes the channel statistics non-Gaussian, leading to a nonlinear log-likelihood function. A near optimum quantization scheme is found by maximizing a channel parameter, or by matching the quantizer to the log-likelihood function in a mean square error sense. Bit error rate performance improvement is achieved by using such nonlinear quantization.
Mcgregor, D. N.↗