Matches in SemOpenAlex for { <https://semopenalex.org/work/W853136999> ?p ?o ?g. }
Showing items 1 to 81 of
81
with 100 items per page.
- W853136999 abstract "A method of estimating phase drifts of microwave signals distributed to, and transmitted by, antennas in an array involves the use of the signals themselves as phase references. The method was conceived as part of the solution of the problem of maintaining precise phase calibration required for proper operation of an array of Deep Space Network (DSN) antennas on Earth used for communicating with distant spacecraft at frequencies between 7 and 8 GHz. The method could also be applied to purely terrestrial phased-array radar and other radio antenna array systems. In the DSN application, the electrical lengths (effective signal-propagation path lengths) of the various branches of the system for distributing the transmitted signals to the antennas are not precisely known, and they vary with time. The variations are attributable mostly to thermal expansion and contraction of fiber-optic and electrical signal cables and to a variety of causes associated with aging of signal-handling components. The variations are large enough to introduce large phase drifts at the signal frequency. It is necessary to measure and correct for these phase drifts in order to maintain phase calibration of the antennas. A prior method of measuring phase drifts involves the use of reference-frequency signals separate from the transmitted signals. A major impediment to accurate measurement of phase drifts over time by the prior method is the fact that although DSN reference-frequency sources separate from the transmitting signal sources are stable and accurate enough for most DSN purposes, they are not stable enough for use in maintaining phase calibrations, as required, to within a few degrees over times as long as days or possibly even weeks. By eliminating reliance on the reference-frequency subsystem, the present method overcomes this impediment. In a DSN array to which the present method applies (see figure), the microwave signals to be transmitted are generated by exciters in a signal-processing center, then distributed to the antennas via optical fibers. At each antenna, the signals are used to drive a microwave power-amplifier train, the output of which is coupled to the antenna for transmission. A small fraction of the power-amplifier-train output is sent back to the signal-processing center along another optical fiber that is part of the same fiber-optic cable used to distribute the transmitted signal to the antenna. In the signal-processing center, the signal thus returned from each antenna is detected and its phase is compared with the phase of the signal sampled directly from the corresponding exciter. It is known, from other measurements, that the signal-propagation path length from the power-amplifier-train output port to the phase center of each antenna is sufficiently stable and, hence, that sampling the signal at the power-amplifier-train output port suffices for the purpose of characterizing the phase drift of the transmitted signal at the phase center of the antenna" @default.
- W853136999 created "2016-06-24" @default.
- W853136999 creator A5025000426 @default.
- W853136999 creator A5036112572 @default.
- W853136999 creator A5046533632 @default.
- W853136999 creator A5072563536 @default.
- W853136999 creator A5089033980 @default.
- W853136999 date "2009-09-01" @default.
- W853136999 modified "2023-09-27" @default.
- W853136999 title "Estimating Transmitted-Signal Phase Variations for Uplink Array Antennas" @default.
- W853136999 hasPublicationYear "2009" @default.
- W853136999 type Work @default.
- W853136999 sameAs 853136999 @default.
- W853136999 citedByCount "0" @default.
- W853136999 crossrefType "journal-article" @default.
- W853136999 hasAuthorship W853136999A5025000426 @default.
- W853136999 hasAuthorship W853136999A5036112572 @default.
- W853136999 hasAuthorship W853136999A5046533632 @default.
- W853136999 hasAuthorship W853136999A5072563536 @default.
- W853136999 hasAuthorship W853136999A5089033980 @default.
- W853136999 hasConcept C121332964 @default.
- W853136999 hasConcept C127413603 @default.
- W853136999 hasConcept C146978453 @default.
- W853136999 hasConcept C165838908 @default.
- W853136999 hasConcept C187107819 @default.
- W853136999 hasConcept C199360897 @default.
- W853136999 hasConcept C21822782 @default.
- W853136999 hasConcept C24326235 @default.
- W853136999 hasConcept C24890656 @default.
- W853136999 hasConcept C2779843651 @default.
- W853136999 hasConcept C29829512 @default.
- W853136999 hasConcept C41008148 @default.
- W853136999 hasConcept C44280652 @default.
- W853136999 hasConcept C55494473 @default.
- W853136999 hasConcept C62191587 @default.
- W853136999 hasConcept C62520636 @default.
- W853136999 hasConcept C76155785 @default.
- W853136999 hasConceptScore W853136999C121332964 @default.
- W853136999 hasConceptScore W853136999C127413603 @default.
- W853136999 hasConceptScore W853136999C146978453 @default.
- W853136999 hasConceptScore W853136999C165838908 @default.
- W853136999 hasConceptScore W853136999C187107819 @default.
- W853136999 hasConceptScore W853136999C199360897 @default.
- W853136999 hasConceptScore W853136999C21822782 @default.
- W853136999 hasConceptScore W853136999C24326235 @default.
- W853136999 hasConceptScore W853136999C24890656 @default.
- W853136999 hasConceptScore W853136999C2779843651 @default.
- W853136999 hasConceptScore W853136999C29829512 @default.
- W853136999 hasConceptScore W853136999C41008148 @default.
- W853136999 hasConceptScore W853136999C44280652 @default.
- W853136999 hasConceptScore W853136999C55494473 @default.
- W853136999 hasConceptScore W853136999C62191587 @default.
- W853136999 hasConceptScore W853136999C62520636 @default.
- W853136999 hasConceptScore W853136999C76155785 @default.
- W853136999 hasLocation W8531369991 @default.
- W853136999 hasOpenAccess W853136999 @default.
- W853136999 hasPrimaryLocation W8531369991 @default.
- W853136999 hasRelatedWork W2047619683 @default.
- W853136999 hasRelatedWork W1540738148 @default.
- W853136999 hasRelatedWork W1665821755 @default.
- W853136999 hasRelatedWork W2283012080 @default.
- W853136999 hasRelatedWork W2752790657 @default.
- W853136999 hasRelatedWork W2769101320 @default.
- W853136999 hasRelatedWork W2773463964 @default.
- W853136999 hasRelatedWork W2777317159 @default.
- W853136999 hasRelatedWork W2811869273 @default.
- W853136999 hasRelatedWork W2812559624 @default.
- W853136999 hasRelatedWork W2822220923 @default.
- W853136999 hasRelatedWork W2837190229 @default.
- W853136999 hasRelatedWork W2840154696 @default.
- W853136999 hasRelatedWork W2840726257 @default.
- W853136999 hasRelatedWork W2855014390 @default.
- W853136999 hasRelatedWork W2960359744 @default.
- W853136999 hasRelatedWork W3145532901 @default.
- W853136999 hasRelatedWork W3146404990 @default.
- W853136999 hasRelatedWork W3147258067 @default.
- W853136999 hasRelatedWork W3181991027 @default.
- W853136999 isParatext "false" @default.
- W853136999 isRetracted "false" @default.
- W853136999 magId "853136999" @default.
- W853136999 workType "article" @default.