The High Resolution Chirp Transform Spectrometer for the Sofia-Great Instrument

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• 作者：G. Villanueva and P. Hartogh
• 关键词：Radio Astronomy ; High Resolution Spectroscopy ; Chirp Transform Spectrometer ; Radiometers ; Heterodyne Instrumentation
• 刊名：Experimental Astronomy
• 出版年：2004
• 出版时间：April 2004
• 年：2004
• 卷：18
• 期：1-3
• 页码：77-91
• 全文大小：450 KB

文摘

In this paper, we present the design of a high resolution Chirp Transform Spectrometer (CTS) which is part of the GREAT (German REceiver for Astronomy at Terahertz frequencies) instrument onboard SOFIA, the Stratospheric Observatory For Infrared Astronomy. The new spectrometer will provide unique spectral resolving power and linearity response, since the analog Fourier transform performed by the CTS spectrometer was improved through a new design, that we call “Adaptive Digital Chirp Processor (ADCP)”. The principle behind the ADCP consists on digitally generating the dispersive signal which adapts to the compressor dispersive properties, achieving maximum spectral resolution and higher dynamic range. Excellent test results have been obtained such as a white noise dynamic range of 30 dB, and a spectral resolution (FWHM) of 41.68 kHz which would mean if analyzing signals with the high frequency band receiver on the GREAT instrument (4.7 THz) a spectral resolving power (λ/Δ λ) higher than 108.