{"title":"The Synthesis Convolver","authors":"J. Bunton","doi":"10.1142/s225117172350006x","DOIUrl":null,"url":null,"abstract":"A system, the synthesis convolver, is described that can process the output of an analysis filter bank and: • Reconstruct the analysis filter bank input signal, • Implement continuous convolution on the reconstructed signal, and • Resample the reconstructed signal to different sample rates. The synthesis convolver combines the capabilities of a synthesis filter bank and a continuous convolver. The synthesis convolver is based on earlier work but improves upon it, adding convolution and resampling. As well as reconstructing filterbank data, convolution allows dechirping of pulsar signals and resampling allows synthesized data to conform to the VLBI VDIF standard. The spectral overlap-add approach described, compared to earlier work, reduces errors and is more robust to channel gain errors. The system uses windows with smoothed or apodized edges, with the classical Tukey window being used previously. Here the Tukey window is generalized leading to a class of apodized windows. This class of windows is explored and one is found that is close to optimal in all conditions and can reduce errors by up to 40[Formula: see text]dB compared to an equivalent Tukey window. Achievable aliasing errors are lower than those of a standard polyphase synthesis filter bank. The synthesis convolver provides a high quality and versatile replacement for polyphase synthesis filter banks.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Astronomical Instrumentation","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1142/s225117172350006x","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
A system, the synthesis convolver, is described that can process the output of an analysis filter bank and: • Reconstruct the analysis filter bank input signal, • Implement continuous convolution on the reconstructed signal, and • Resample the reconstructed signal to different sample rates. The synthesis convolver combines the capabilities of a synthesis filter bank and a continuous convolver. The synthesis convolver is based on earlier work but improves upon it, adding convolution and resampling. As well as reconstructing filterbank data, convolution allows dechirping of pulsar signals and resampling allows synthesized data to conform to the VLBI VDIF standard. The spectral overlap-add approach described, compared to earlier work, reduces errors and is more robust to channel gain errors. The system uses windows with smoothed or apodized edges, with the classical Tukey window being used previously. Here the Tukey window is generalized leading to a class of apodized windows. This class of windows is explored and one is found that is close to optimal in all conditions and can reduce errors by up to 40[Formula: see text]dB compared to an equivalent Tukey window. Achievable aliasing errors are lower than those of a standard polyphase synthesis filter bank. The synthesis convolver provides a high quality and versatile replacement for polyphase synthesis filter banks.
期刊介绍:
The Journal of Astronomical Instrumentation (JAI) publishes papers describing instruments and components being proposed, developed, under construction and in use. JAI also publishes papers that describe facility operations, lessons learned in design, construction, and operation, algorithms and their implementations, and techniques, including calibration, that are fundamental elements of instrumentation. The journal focuses on astronomical instrumentation topics in all wavebands (Radio to Gamma-Ray) and includes the disciplines of Heliophysics, Space Weather, Lunar and Planetary Science, Exoplanet Exploration, and Astroparticle Observation (cosmic rays, cosmic neutrinos, etc.). Concepts, designs, components, algorithms, integrated systems, operations, data archiving techniques and lessons learned applicable but not limited to the following platforms are pertinent to this journal. Example topics are listed below each platform, and it is recognized that many of these topics are relevant to multiple platforms. Relevant platforms include: Ground-based observatories[...] Stratospheric aircraft[...] Balloons and suborbital rockets[...] Space-based observatories and systems[...] Landers and rovers, and other planetary-based instrument concepts[...]