Title :
A highly stable, phase coherent, wideband microwave synthesizer for radio astronomy applications
Author_Institution :
Netherlands Found. for Res. in Astron., Dwingeloo, Netherlands
Abstract :
A description is given of a wideband microwave synthesizer that is used as a local oscillator in a novel front-end design. This front-end design is used in a synthesis radiotelescope operating in the frequency range up to 8.6 GHz. The aperture synthesis principle on which this radiotelescope is based, as well as Very Long Baseline Interferometry (VLBI) techniques require exceptional phase and frequency stability which are fulfilled by the presented oscillator design. A phase stability of better than 5° r.m.s., averaged over 60 seconds, is obtained at 5 GHz over periods of 12 hours. Allan-variance values approaching 10-14 are measured for τ=1000 seconds. The output signals among two synthesizers tuned to the same frequency are always phase coherent with a fixed phase offset
Keywords :
circuit stability; circuit tuning; coherence; frequency stability; frequency synthesizers; microwave oscillators; radiotelescopes; radiowave interferometers; 250 MHz to 8.6 GHz; LO application; SHF; VLBI techniques; aperture synthesis principle; frequency stability; front-end design; highly stable microwave synthesizer; local oscillator; phase coherent synthesizer; phase stability; radioastronomy applications; synthesis radiotelescope; very long baseline interferometry techniques; wideband microwave synthesizer; Frequency synthesizers; Local oscillators; Optical design; Phase measurement; Phased arrays; Radio astronomy; Radio interferometry; Stability; Telescopes; Wideband;
Conference_Titel :
Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European
Conference_Location :
Besancon
Print_ISBN :
0-7803-5400-1
DOI :
10.1109/FREQ.1999.841380
