Digital filtering of random digits
Digital simulation of linear filter, investigating noise and rounding errors effects on decoding signals from lunar and interplanetary probes
Jennings, G.↗
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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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Coding - A tool for the digital telemetry link
Digital PCM telemetry link coding techniques, discussing encoding-decoding complexity, and concatenated block scheme for channel
Muller, R. M.↗
An improved telemetry system
Transmission of parity bits together with data bits by a rate one half convolutional code of 25-bit constraint length, with sequential decoding of received signal increases quantity and accuracy of data transmitted by pulse code modulated system operating at given power level.
Lumb, D. R.↗
Convolutional Coding Techniques for Data Protection
Convolutional coding techniques including constructing inverses, algorithms, and code comparing for sequential decoding
Source record↗
Error correcting method and apparatus Patent
Description of error correcting methods for use with digital data computers and apparatus for encoding and decoding digital data
Anderson, T. O.↗
Concatenation of short constraint length convolutional codes
Viterbi algorithm for decoding convolutional codes for space channel application
Erickson, D.↗
Coding systems study for high data rate telemetry links
Performance tests of convolutional decoder systems for high data rate telemetry links
Gilhausen, K. S.↗
Concatenation of convolutional and block codes Final report
Comparison of concatenated and sequential decoding systems and convolutional code structural properties
Odenwalder, J. P.↗
A test set for integration of data compression/ error correction encoding techniques. II - Error correction encoding considerations
Error correction coding/decoding techniques integration, discussing convolutional and block coding and Viterbi, Sequential and Threshold decoding algorithms
Cain, J. B.↗
Improved feedback shift register
Design of feedback shift register with three tap feedback decoding scheme is described. Application for obtaining sequence synchronization patterns is examined. Operation of the circuitry is described and drawings of the systems are included.
Perlman, M.↗
Hybrid circuit modules for motor commutation and control
Thick film hybrid techniques are used to develop circuitry for a brushless dc motor commutator. The power commutator contains the driving circuit and an amplifier that controls the armature current. A position decoder contains digital integrated circuits which receive the signals from the armature position sensors and generate the driving signals for the power commutator in the proper sequence. These units drive motors with stall currents up to about 400 mA.
Dekramer, C.↗
Communications terminal breadboard
A baseline design is presented of a digital communications link between an advanced manned spacecraft (AMS) and an earth terminal via an Intelsat 4 type communications satellite used as a geosynchronous orbiting relay station. The fabrication, integration, and testing of terminal elements at each end of the link are discussed. In the baseline link design, the information carrying capacity of the link was estimated for both the forward direction (earth terminal to AMS) and the return direction, based upon orbital geometry, relay satellite characteristics, terminal characteristics, and the improvement that can be achieved by the use of convolutional coding/Viterbi decoding techniques.
Source record↗
Hybrid coding systems study
The state of efficiency improvement available with high speed decoders presently in operation or under development is summarized. The required ratio of bit-energy-to-noise-density is given in each case for bit error probabilities.
Odenwalder, J. P.↗
A real time programmable data compression system for video data.
Description of the implementation of a data compression system for the real-time operational transmission (through microwave links) of ATS satellite pictures between the command and data acquisition station and a central location for computer processing. The system features the use of general-purpose minicomputers for encoding and decoding; this makes it possible to vary the employed data compression technique and to make simultaneous statistical calculations on the data. Data compression and expansion is accomplished in a manner that does not lower data quality.
Kutz, R. L.↗
Finite group homomorphic sequential systems.
A class of finite-state sequential systems evolving in groups is considered. It represents a broader class of input-output relations than those found in linear system theory. The concepts of controllability, observability, minimality, realizability, and the isomorphism of minimal realizations are developed. Results that are analogous to, but differ in essential details from, those of linear system theory are derived. Algorithmic design and algebraic decoding may benefit from these results.
Brockett, R. W.↗
Digital data command bus
Command bus constructed from coaxial cable has short segments of its outer jacket and shield removed and replaced with small ferrite cores carrying multiturn windings connected to decoder. Device reduces number of wire pairs required to communicate command data to systems and subsystems.
Milligan, G. C.↗
Phase shift keyed, pulse code modulated signal synchronizer
Signal is demodulated and synchronized by three loop circuits: ''Q'' loop uses quadrature signal to stabilize frequency; ''B'' loop acts on baseboard signal to stabilize phase; and decoding ''I'' loop acts on in-phase signal. Synchronizer may be used to eliminate false-lock.
Kobayashi, H. S.↗