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Pocket sized transmitter, frequency modulated by crystal derived tones, with integral loop antenna provides police with easy operating alert signal communicator which uses patrol car radio to relay signal. Communication channels are time shared by several patrol units.
Computer program computes maximum possible strength of interference pattern sent from high altitude tracking and data relay satellite to low altitude user satellite.
Systems engineering and economic analysis of tracking and data relay satellite system with 16 GHz ground antenna
Optimum preemphasis-deemphasis filter pair for FM transmission of Lunar Communications Relay Unit color television
Traffic control system for supersonic transports using synchronous satellite for data relay between vehicles and ground station
Alarm system design for monitoring one or more relay cicuits
Earth satellite relay station for frequency multiplexed voice transmission
Evaluation of signal processing and modulation techniques for transmission and reception of image type data via millimeter wave relay satellites
Navigational accuracy resulting from sidetone signals relayed by two synchronous ATS-1 and ATS-3 satellites and application to aircraft navigation
Lunar far side communication, discussing libration point and lunar orbit relay system for high bit rate telemetry, TV and astronaut backpack communication
Synchronous meteorological satellite programs, noting earth imaging, data transmission, collection and relay and space environment monitoring
Improved technique was developed for transferring and storing data at faster than real time speeds on hybrid computer. Predominant advantage is combined use of electronic relays, track and store units, and analog-to-digital and digital-to-analog conversion units of hybrid computer.
The system described performs the tracking and communications functions of a tracking and data relay satellite system (TDRS). The spread-spectrum signal format is achieved through wide deviation FM by a sinusoidal subcarrier unique to each multiple-access user. A compound phase-locked loop tracks carrier and subcarrier and demodulates data and ranging signals. Design parameters of user and ground terminals for TDRS are given. Acquisition procedures are described. Performance analyses are presented including the effects of noise, RFI, multipath and other users.
Previously developed models are used to predict communication system performance for two cases: and aircraft/TDRS and a weather satellite/TDRS relay. The magnitude of multipath, differential time delay, Doppler shift, time and Doppler spread, and interference expected to be encountered are reviewed and applied to the two cases of interest.
The effects are studied of nonlinearities in a baseline communications system on the system noise amplitude statistics. So that a meaningful identification of system nonlinearities can be made, the baseline system is assumed to transmit a single biphase-modulated signal through a relay satellite to the receiving equipment. The significant nonlinearities thus identified include square-law or product devices (e.g., in the carrier reference recovery loops in the receivers), bandpass limiters, and traveling wave tube amplifiers.
The radio frequency communications subsystem for a space station is considered, with respect to onboard checkout requirements. The subsystem comprises all equipment necessary for transmitting and receiving, tracking and ranging, command, multiple voice and television information, and broadband experiment data. The communications subsystem provides a radio frequency interface between the space station and ground stations, either directly or indirectly, through a data relay satellite system, independent free-flying experiment modules, and logistics vehicles. Reliability, maintenance, and failure analyses are discussed, and computer programming techniques are presented.
The organization, operations, functions, and objectives of NASA are outlined. Data include manned space flights, satellite weather observations, orbiting radio relays, and new views of the earth and beyond the earth as observed by satellites. Details of NASA's work in international programs, educational training programs, and adopting space technology to earth uses are also given.
The field of view required of the space base antenna is defined for both the tracking and data relay satellite link and detached module links. The gain requirements are established and the feasibility of alternative antenna configurations using phased arrays and reflectors are considered. One recommended and one alternative configuration are presented for each of the required links.