Engineering topics
Publications and source records attributed to Easterling, M. F..
Diversity reception system combines narrow-band signals from several antennas to yield amplified demodulated signal. System was developed for spacecraft command signals, which typically have bandwidths of few hundred hertz.
RF carrier array includes one master and slave receiving system to improve overall signal-to-noise ratio. Greater number of slave systems creates additional improvement. Scheme reduces detection threshold of low-rate telemetry signals transmitted from spacecraft, enhancing communications efficiency.
A method and apparatus for increasing the signal to noise ratio of a receiving facility for coherent frequency reception by arraying receiving systems using separate antennas for each, or one antenna for all systems are presented. One system is operated with a carrier tracking loop to provide a first local oscillator frequency for the first and all other systems arrayed, with individual tracking loops in all other systems operated at IF for tracking out any phase differences due to separate group delays using an adjustable phase shifter for a second reference to compensate for different group delays in the antenna and low noise amplifier of each of the other systems. The second IF output of all systems is summed into the first system. This technique may also be used when two systems are arrayed to an antenna designed for circular or linear polarization diversity reception to effectively provide the same signal to noise ratio for both polarized signal transmission channels that would result from matched polarization. An arrangement adapted to high rate telemetry reception is disclosed. With additional components, the same arrangement is adapted to provide low rate telemetry reception as well.
A pulse code modulated communication system is disclosed for transmitting two subcarrier modulated carriers from a single transmitter comprising two channels for phase modulating the two carriers independently. The modulating subcarriers are independently modulated by data and/or pseudonoise (PN) codes as desired. The modulated carriers are switched alternately to the single transmitter in synchronism with operation of a PN code generator when PN code modulation is present, as for ranging.
Two carriers transmit two high-power signals from single transmitter, each phase-modulated by subcarrier which, in turn, is modulated by data bits; switching between two carriers is alternated at high rate. Resulting composite signal is multiplied up to desired frequency and used to drive power amplifier which feeds transmitting antenna.
Synchronizing clocks at remote locations with master clock by radar reflected from moon for Deep Space Network
Clock synchronization system using lunar radar reflections for Deep Space Network needs, discussing remote clock receiver and antenna
Time synchronization system for synchronizing clocks at remote locations with master clock using moon reflected coded signals
High rate telemetry system for Mariner Mars 1969 mission
Mariner 1969 multimission high rate deep space telemetry system design, hardware and application
Phase locked loop with sideband rejecting properties in continuous wave tracking radar
Signal spectra and digital characteristics in design of binary modulation systems
Operational ranging systems using waves coded by sequences having multiple peaks in their autocorrelation functions