52 research outputs found

    Standard classification of software documentation

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    General conceptual requirements for standard levels of documentation and for application of these requirements to intended usages. These standards encourage the policy to produce only those forms of documentation that are needed and adequate for the purpose. Documentation standards are defined with respect to detail and format quality. Classes A through D range, in order, from the most definitive down to the least definitive, and categories 1 through 4 range, in order, from high-quality typeset down to handwritten material. Criteria for each of the classes and categories, as well as suggested selection guidelines for each are given

    Tau ranging revisited

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    It is shown that a ranging receiver with a sufficient and reasonable number of correlators is competitive with the current sequential component ranging system by some 1.5 to 2.5 dB. The optimum transmitter code, the optimum receiver, and a near-maximum-lilelihood range-estimation algorithm are presented

    Phase conjugation method and apparatus for an active retrodirective antenna array

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    An active retrodirective antenna array wherein a reference array element is used to generate a phase reference which is replicated at succeeding elements of the array. Each element of the array is associated with a phase regeneration circuit and the phase conjugation circuitry of an adjacent element. In one implementation, the phase reference circuit operates on the input signal at the reference element, a voltage controlled oscillator (VCO) output signal and the input pilot signal at the next array element received from a transmission line. By proper filtering and mixing, a phase component may be produced to which the VCO may be locked to produce the phase conjugate of the pilot signal at the next array element plus a transmission line delay. In another implementation, particularly suited for large arrays in space, two different input pilot frequencies are employed

    Deep space network software cost estimation model

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    A parametric software cost estimation model prepared for Jet PRopulsion Laboratory (JPL) Deep Space Network (DSN) Data System implementation tasks is described. The resource estimation mdel modifies and combines a number of existing models. The model calibrates the task magnitude and difficulty, development environment, and software technology effects through prompted responses to a set of approximately 50 questions. Parameters in the model are adjusted to fit JPL software life-cycle statistics

    Filter for third order phase locked loops

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    Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided

    Third-order phase-locked loop receiver

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    Third-order extension to present second-order systems extends their Doppler tracking capabilities. It widens receiver pull-in range, decreases pull-in time, lowers voltage-controlled oscillator (VCO) noise (determining when no signal is present), and lessens susceptibility to VCO drift

    A simplified, general-purpose deep-space ranging correlator design

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    A much-simplified, yet more general-purpose multi-channel deep-space ranging system correlator design that was used in past JPL spacecraft ranging systems is described. The method applies to detection of both single-component and multiple-component ranging codes, in either sequential (mu) or composite (pi) transmitted forms, and using either pseudonoise or square-wave components. Using this design, the Phobos Probe ranging system correlator computational complexity was reduced by over three orders of magnitude in multiply-and-add circuits and 45,000 bits of accumulator storage

    Theory and Practical Design of Phase-locked Receivers, Volume I

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    Phase locked tracking antenna loop receiver theory and desig

    Standardized development of computer software. Part 2: Standards

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    This monograph contains standards for software development and engineering. The book sets forth rules for design, specification, coding, testing, documentation, and quality assurance audits of software; it also contains detailed outlines for the documentation to be produced

    Standardized development of computer software. Part 1: Methods

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    This work is a two-volume set on standards for modern software engineering methodology. This volume presents a tutorial and practical guide to the efficient development of reliable computer software, a unified and coordinated discipline for design, coding, testing, documentation, and project organization and management. The aim of the monograph is to provide formal disciplines for increasing the probability of securing software that is characterized by high degrees of initial correctness, readability, and maintainability, and to promote practices which aid in the consistent and orderly development of a total software system within schedule and budgetary constraints. These disciplines are set forth as a set of rules to be applied during software development to drastically reduce the time traditionally spent in debugging, to increase documentation quality, to foster understandability among those who must come in contact with it, and to facilitate operations and alterations of the program as requirements on the program environment change
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