The receiver system of a radio telescope uses a cascade of building blocks like amplifiers, attenuators, mixers and filters, to process the very weak astronomical signal. This processing makes the signal compatible for further processing in the digital back-end. The typical gain required in such a scheme is around 80dB. The conceptual design of the system involves distributing the gain among various blocks while ensuring that overall system specifications like noise figure, the ratio of the desired signal component to unavoidable spurious products and radio frequent interference handling capability, are satisfactorily met. A spreadsheet-based approach, developed for the conceptual design of the receiver for the Square Kilometre Array (SKA), is presented. The results for a possible configuration from the antenna elements to the baseband processor is discussed. The scheme is planned to be implemented by means of the so called THousand Element Array, which is the next phase in the series of experimental projects at ASTRON leading towards SKA.
Perspectives on Radio Astronomy: Technologies for Large Antenna Arrays
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