The ALMA correlator
The ALMA correlator
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ALMA 相关器
DOI：
10.1051/0004-6361:20054519
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发表时间：
2007
影响因子：
6.5
通讯作者：
A. Gunst
中科院分区：
文献类型：
--
作者：
R. Escoffier;G. Comoretto;J. Webber;A. Baudry;C. Broadwell;Joe Greenberg;R. Treacy;P. Cais;B. Quertier;P. Camino;A. Bos;A. Gunst
目标。阿塔卡马大型毫米波阵列 (ALMA) 是一个国际天文设施，用于在智利阿塔卡马沙漠海拔 5000 米的地点对毫米和亚毫米波长的所有类型的天文源进行探测和成像。我们的主要目标是： 描述相关器子系统，它是 ALMA 系统的一部分，它将来自多达 64 个远程单独无线电天线的信号组合在一起，并将它们形成一个仪器；强调 ALMA 相关器的高光谱分辨率和配置灵活性。方法。介绍了为 ALMA 射电天文台构建的相关器的主要数字信号处理功能和框图。给出了相关器系统提供的观测模式和光谱分辨率表以及多分辨率光谱模式的一些示例。结果。相关器按象限交付，第一象限正在测试，而系统所需的大多数其他印刷电路卡已经生产。在其最终版本中，ALMA 相关器将在每个天线的两个极化中使用 8 GHz 的瞬时带宽来处理多达 64 个天线的输出。在分频模式下，可实现无与伦比的频谱灵活性以及极高的分辨率 (3.8 kHz) 和多达 8192 个频谱点。在时分模式下，所有叉积的最小数据转储率为 16 ms，可提供高时间分辨率。
Aims. The Atacama Large Millimeter Array (ALMA) is an international astronomy facility to be used for detecting and imaging all types of astronomical sources at millimeter and submillimeter wavelengths at a 5000-m elevation site in the Atacama Desert of Chile. Our main aims are: describe the correlator sub-system which is that part of the ALMA system that combines the signal from up to 64 remote individual radio antennas and forms them into a single instrument; emphasize the high spectral resolution and the configuration flexibility available with the ALMA correlator. Methods. The main digital signal processing features and a block diagram of the correlator being constructed for the ALMA radio astronomy observatory are presented. Tables of observing modes and spectral resolutions offered by the correlator system are given together with some examples of multi-resolution spectral modes. Results. The correlator is delivered by quadrants and the first quadrant is being tested while most of the other printed circuit cards required by the system have been produced. In its final version the ALMA correlator will process the outputs of up to 64 antennas using an instantaneous bandwidth of 8 GHz in each of two polarizations per antenna. In the frequency division mode, unrivalled spectral flexibility together with very high resolution (3.8 kHz) and up to 8192 spectral points are achieved. In the time division mode high time resolution is available with minimum data dump rates of 16 ms for all cross-products.