Performance highlights of the ALMA correlators
Performance highlights of the ALMA correlators
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ALMA 相关器的性能亮点
DOI：
10.1117/12.925700
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S. Iguchi
中科院分区：
文献类型：
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作者：
A. Baudry;R. Lacasse;R. Escoffier;J. Webber;Joe Greenberg;Laurence E. Platt;R. Treacy;A. Saez;P. Cais;G. Comoretto;B. Quertier;S. Okumura;T. Kamazaki;Y. Chikada;Manabu Watanabe;T. Okuda;Yasutake Kurono;S. Iguchi
已经建造了两个大型的发射机，用于将部署在智利阿塔卡马沙漠海拔5050米处的阿尔马天线捕获的信号进行联合收割机组合。基线相关器由NRAO/欧洲团队制造，可在两个极化中处理多达64个天线，用于16 GHz带宽，另一个相关器Atacama紧凑阵列（ACA）相关器由日本团队制造，可处理多达16个天线。除了处理的天线数量外，两种放大器都符合相同的规格。这两台大型机器之间的主要结构差异将被强调。将简要讨论基线和ACA制冷机的选定功能以及设计人员遇到的主要技术挑战。基线相关器是有史以来为射电天文学建造的最大的相关器。其数字混合架构提供了各种各样的观测模式，包括将每个输入基带分为32个频率移动子带的能力，以实现高频谱分辨率，并作为传统的“滞后”相关器进行操作，以实现高时间分辨率。介绍了阿尔马天文台为“早期科学”提供的各种观测模式，以及未来的观测模式。对阵列进行相干定相以提供极致密源的VLBI图是阿尔马放大器的另一个特点。最后，将介绍这些大型机器的状态和可用性。
Two large correlators have been constructed to combine the signals captured by the ALMA antennas deployed on the Atacama Desert in Chile at an elevation of 5050 meters. The Baseline correlator was fabricated by a NRAO/European team to process up to 64 antennas for 16 GHz bandwidth in two polarizations and another correlator, the Atacama Compact Array (ACA) correlator, was fabricated by a Japanese team to process up to 16 antennas. Both correlators meet the same specifications except for the number of processed antennas. The main architectural differences between these two large machines will be underlined. Selected features of the Baseline and ACA correlators as well as the main technical challenges met by the designers will be briefly discussed. The Baseline correlator is the largest correlator ever built for radio astronomy. Its digital hybrid architecture provides a wide variety of observing modes including the ability to divide each input baseband into 32 frequency-mobile sub-bands for high spectral resolution and to be operated as a conventional 'lag' correlator for high time resolution. The various observing modes offered by the ALMA correlators to the science community for 'Early Science' are presented, as well as future observing modes. Coherently phasing the array to provide VLBI maps of extremely compact sources is another feature of the ALMA correlators. Finally, the status and availability of these large machines will be presented.