Digital spectrometers for the Nobeyama 45-m telescope
Digital spectrometers for the Nobeyama 45-m telescope
复制标题
Nobeyama 45 米望远镜的数字光谱仪
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
Hirofumi Onuki
中科院分区：
文献类型：
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作者：
K. Sorai;K. Sunada;S. Okumura;Iwasa Tetsuro;A. Tanaka;K. Natori;Hirofumi Onuki
本文介绍了Nobeyama 45米望远镜25光束阵列接收系统（BEARS）的新型数字光谱仪。商用数字示波器用作数字化仪。数字转换器以2位（4级）采样模拟数据。512 MHz带宽的数据被同时处理用于四个波束。数据格式化单元将2位8数据并行解复用为32并行，并将输出发送到LSI。用于自相关的通用LSI以32 MHz的时钟速率读取数字数据。级联连接的32个具有32个滞后的32个LSI计算1024滞后自相关，并输出512 MHz带宽的1024通道功率谱。在自相关器模块的前端以1/16的速率拾取数据，获得了32 MHz的带宽。通过对接收机噪声信号的长期积分和对银河系恒星形成区W51的CO谱线观测，验证了系统的总体性能。
New digital spectrometers for the 25-BEam Array Receiver System (BEARS) of the Nobeyama 45-m telescope are described. A commercial digital oscilloscope is used as a digitizer. The digitizer samples analogue data with 2 bits (4 levels). Data of 512 MHz bandwidth are processed for four beams at the same time. The data-formatting unit demultiplexes 2 bits 8 data in parallel to 32 parallels and sends outputs to LSIs. General purpose LSIs for autocorrelation read the digital data with a clock rate of 32 MHz. Thirty-two LSIs of 32 lags connected in cascades calculate 1024-lag autocorrelation, and output a 1024-channel power spectrum of 512 MHz bandwidth. The bandwidth of 32 MHz is achieved by picking up the data in a rate of 1/16 in the front part of the autocorrelator module. The total performances have been demonstrated by long-term integration of noise signals from receivers and observations of the Galactic star-forming region W51 in CO line.