A 10.24-GHz-wide digital spectrometer array system for LMT-FINER: system design and laboratory performance verification

Masato Hagimoto; Akio Taniguchi; Yoichi Tamura; Norika Okauchi; Hiroaki Kawamoto; Taku Nakajima; Takumi Hikosaka; Kenichi Harada; Toru Taniguchi; Takeshi Kamazaki; Takeshi Sakai; Kunihiko Tanaka; Ryohei Kawabe

arXiv · 2406.07978

A 10.24-GHz-wide digital spectrometer array system for LMT-FINER: system design and laboratory performance verification

Masato Hagimoto·Akio Taniguchi·Yoichi Tamura·Norika Okauchi·Hiroaki Kawamoto·Taku Nakajima·Takumi Hikosaka·Kenichi Harada·Toru Taniguchi·Takeshi Kamazaki·Takeshi Sakai·Kunihiko Tanaka·Ryohei Kawabe

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Abstract

For efficient spectroscopic redshift identification of early galaxies in the northern hemisphere, we aim to combine the Large Millimeter Telescope (LMT) with a wide-band heterodyne receiver, FINER, which will cover radio frequencies of 120--360 GHz and offer a 3--21 GHz intermediate frequency (IF) per sideband and polarization. To take full advantage of such wide IFs, we present a novel 10.24-GHz-wide digital spectrometer, DRS4 (Elecs Industry Co., Ltd.). It incorporates 20.48 Gsps samplers with an FPGA-based digital signal processing module. To mitigate the noise contamination from the image sideband, it is equipped with a digital sideband separation function to improve the sideband rejection up to 25 dB. Laboratory performance evaluations show that it exhibits an Allan time of at least ~100 s and a total power dynamic range of at least 7 dB. These results demonstrate its capability of instantaneously wide-band spectroscopy toward high-redshift galaxies with position-switching observations.

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Masato Hagimoto, Akio Taniguchi, Yoichi Tamura, Norika Okauchi, Hiroaki Kawamoto, Taku Nakajima, Takumi Hikosaka, Kenichi Harada, Toru Taniguchi, Takeshi Kamazaki, Takeshi Sakai, Kunihiko Tanaka, Ryohei Kawabe. 2024-06-12. A 10.24-GHz-wide digital spectrometer array system for LMT-FINER: system design and laboratory performance verification. https://arxiv.org/abs/2406.07978

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