Abstract
We present a relatively simple time domain method for determining the bandpass response of a system by injecting a nanosecond pulse and capturing the system voltage output. A pulse of sub-nanosecond duration contains all frequency components with nearly constant amplitude up to 1 GHz. Hence, this method can accurately determine the system bandpass response to a broadband signal. In a novel variation on this impulse response method, a train of pulses is coherently accumulated providing precision calibration with a simple system. The basic concept is demonstrated using a pulse generator-accumulator setup realised in a Bedlam board which is a high speed digital signal processing unit. The same system was used at the Parkes radio telescope between 2–13 October 2013 and we demonstrate its powerful diagnostic capability. We also present some initial test data from this experiment.
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Acknowledgments
We would like to thank Raman Research Institute and Australia Telescope National Facility for providing the funding for this study. Parkes radio telescope is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. JDB acknowledges support from ERC-StG 307215 (LODESTONE). NP acknowledges support from NSF CAREER award 1352519 and U.S. National Science Foundation (NSF) awards AST-1440343 and AST-1410719. The authors also declare that they have no conflict of interests.
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Patra, N., Bray, J.D., Roberts, P. et al. Bandpass calibration of a wideband spectrometer using coherent pulse injection. Exp Astron 43, 119–129 (2017). https://doi.org/10.1007/s10686-017-9523-8
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DOI: https://doi.org/10.1007/s10686-017-9523-8