Pulsar huge array with Nyquist-rate digital lens and prism
Pulsar huge array with Nyquist-rate digital lens and prism
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配备奈奎斯特级数字镜头和棱镜的 Pulsar 巨型阵列
DOI：
10.1117/12.390458
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
K. Asuma
中科院分区：
文献类型：
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作者：
T. Daishido;N. Tanaka;H. Takeuchi;Yukinori Akamine;F. Fujii;M. Kuniyoshi;T. Suemitsu;Kentaro Gotoh;Saori Mizuki;Keiju Mizuno;Tomoya Suzuki;K. Asuma
早稻田大学于1989 - 1995年研制了一台8 × 8等于64单元的数字干涉仪.它是一个等间距的二维阵列的2.4米的碟在10.6 GHz，和一个2D FFT处理器用于奈奎斯特率成像。近年来，为脉冲星巡天（1996 - 2000）研制了一个时空（2 + 1）维FFT处理器，其中第一个二维空间FFT将坐标电场转换为动量电场。通过二维空间傅里叶变换，我们得到了奈奎斯特频率下每个64个方向上的电场。下面的时间1D FFT也以奈奎斯特速率分别给出64 ch或256 ch到64个方向的频谱。每个方向的总带宽为20 MHz，所得到的频率分辨率为20/64 MHz或20/256 MHz。对于敏感的脉冲星调查，我们还开发了一个干涉阵列的20米的球形盘在那须平原，东京以北160公里。目前已完成5道菜。用高电子迁移率晶体管（HEMT）的常温接收机进行1.4GHz观测，接收机噪声温度低于40 K。在20 MHz带宽和1 s积分时间条件下，期望均方根检测限（Delta）T约为10-2K。在（Delta）等于40 °时使用单碟进行天顶测量的初步结果表明，（Delta）T等于0.03 K，没有切换。副反射器和馈源喇叭被设计成观察离天顶5度的方向，并且它们围绕Az轴旋转。它使我们能够测量32个
An 8 X 8 equals 64 element digital interferometer was developed at Waseda University (1989 - 1995). It was an equally spaced two dimensional array of 2.4 m dishes at 10.6 GHz, and a 2D FFT processor was used for Nyquist rate imaging. Recently a spatial-temporal (2 + 1)D FFT processor has been developed for pulsar survey (1996 - 2000), in which a first 2D spatial FFT transforms the electric fields of coordinate represented to those of momentum represented. We obtain the electric fields in each 64 direction at Nyquist rate by the 2D spatial Fourier transform. The following temporal 1D FFT gives the spectrum of 64ch or 256ch to 64 directions respectively also at Nyquist rate. The total bandwidths of each direction are 20 MHz and the resulting frequency resolutions are 20/64 MHz or 20/256 MHz. For sensitive pulsar survey, we also have developed an interferometric array of 20 m spherical dishes in Nasu flat, 160 km north of Tokyo. Five dishes are completed at present. Normal temperature receivers of high electron mobility transistors (HEMT) are used at 1.4 GHz observation and the receiver noise temperatures are below 40 K. Expected rms detection limit (Delta) T is about 10-2K under the condition of 20 MHz band widths and 1s integration time. Preliminary results of zenith survey at (delta) equals 40 deg using a single dish show (Delta) T equals 0.03 K without switching. Sub-reflectors and feed horns were designed so as to observe 5 deg off directions from zenith and they rotate around Az axis. It enable us to survey the declination zone of 32