A superconducting software defined radio frontend with application to the Square Kilometre Array

[摘要] ENGLISH ABSTRACT: Superconducting electronics can make the Square Kilometre Array (SKA) abetter instrument. The largest radio telescope in the world will consist ofseveral arrays, the largest of which, consisting of more than 3000 dishes, willbe situated primarily in South Africa. The ambitions of the SKA are grandand their realisation requires technology that does not exist today.Current plans see signals in the band of interest ampli ed, channelised,mixed down and then digitised. An all-digital frontend could simplify receiverstructure and improve its performance. Semiconductor (analog-to-digital converters)ADCs continue to make great progress and will likelynd applicationsin the SKA, but superconductor ADCs bene t from higher clock speedsand quantum accurate quantisation. We propose a superconducting softwarede ned radio frontend.The key component of such a frontend is a superconducting ash ADC.We show that employing such an ADC, even a small- to moderately-sized one,will signi cantly improve the instantaneous bandwidth observable by the SKA,yet retain adequate signal-to-noise ratio so as to achieve a net improvementin sensitivity. This improvement could approach factor 2 when compared toconventional technologies (at least for continuum observations). We analysekey components of such an ADC analytically, numerically and experimentallyand conclude that fabrication of such an ADC for SKA purposes is certainlypossible and useful.Simultaneously, we address the power requirements of high-performancecomputing (HPC). HPC on a hitherto unprecedented scale is a necessity forprocessing the vast raw data output of the SKA. Utilising the ultra-low-energyswitching events of superconducting switches (certain Josephson junctions),we developrst demonstrators of the promising eSFQ logic family, achievingexperimentally veri ed shift-registers and deserialisers with sub-aJ/bit energy requirements. We also propose and show by simulation how to expand theapplicability of the eSFQ design concept to arbitrary (unclocked) gates.

[发布机构] Stellenbosch University