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Main Authors: Li, Jiyun, Zhu, Renjie, Guo, Shaoguang, Rui, Ping, Xu, Zhijun
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.15446
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author Li, Jiyun
Zhu, Renjie
Guo, Shaoguang
Rui, Ping
Xu, Zhijun
author_facet Li, Jiyun
Zhu, Renjie
Guo, Shaoguang
Rui, Ping
Xu, Zhijun
contents Customized digital backends for Very Long Baseline Interferometry (VLBI) are critical components for radio astronomy observatories. There are several serialized products such as the Digital Baseband Converter (DBBC), Reconfigurable Open Architecture Computing Hardware (ROACH) Digital BackEnd (RDBE), and Chinese Data Acquisition System (CDAS). However, the reliance on high-speed analog-to-digital converters (ADC) and Field Programmable Gate Arrays (FPGAs) often necessitates dedicated hardware platforms with long development cycles and prohibitive cost, limiting scalability and adaptability to evolving observational needs. To address these challenges, we propose a design leveraging the versatile and cost-effective ROACH2 hardware platform, developed by CASPER (Collaboration for Astronomy Signal Processing and Electronics Research). ROACH2's mature technology and streamlined firmware development capabilities significantly reduce the hardware platform's development cycle and cost, making it ideal for modern astronomical applications. This VLBI digital backend, based on the ROACH2 platform, incorporates key technologies such as Polyphase Filter Banks (PFB) algorithm implementation, digital complex-to-real baseband signal conversion, Mark5B data formatter design and two-bit optimal threshold quantization. These features ensure compatibility with existing systems while providing enhanced performance. The backend's performance was validated through multi-station VLBI experiments, demonstrating its ability to achieve good correlation fringes compared to the customized CDAS2-D system. Furthermore, this platform offers flexibility for rapid deployment of additional digital backends, such as those for spectral line observations, showcasing its potential for broader astronomical applications.
format Preprint
id arxiv_https___arxiv_org_abs_2502_15446
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Development and Performance Validation of a Versatile VLBI Digital Backend Using the ROACH2 Platform
Li, Jiyun
Zhu, Renjie
Guo, Shaoguang
Rui, Ping
Xu, Zhijun
Instrumentation and Methods for Astrophysics
Customized digital backends for Very Long Baseline Interferometry (VLBI) are critical components for radio astronomy observatories. There are several serialized products such as the Digital Baseband Converter (DBBC), Reconfigurable Open Architecture Computing Hardware (ROACH) Digital BackEnd (RDBE), and Chinese Data Acquisition System (CDAS). However, the reliance on high-speed analog-to-digital converters (ADC) and Field Programmable Gate Arrays (FPGAs) often necessitates dedicated hardware platforms with long development cycles and prohibitive cost, limiting scalability and adaptability to evolving observational needs. To address these challenges, we propose a design leveraging the versatile and cost-effective ROACH2 hardware platform, developed by CASPER (Collaboration for Astronomy Signal Processing and Electronics Research). ROACH2's mature technology and streamlined firmware development capabilities significantly reduce the hardware platform's development cycle and cost, making it ideal for modern astronomical applications. This VLBI digital backend, based on the ROACH2 platform, incorporates key technologies such as Polyphase Filter Banks (PFB) algorithm implementation, digital complex-to-real baseband signal conversion, Mark5B data formatter design and two-bit optimal threshold quantization. These features ensure compatibility with existing systems while providing enhanced performance. The backend's performance was validated through multi-station VLBI experiments, demonstrating its ability to achieve good correlation fringes compared to the customized CDAS2-D system. Furthermore, this platform offers flexibility for rapid deployment of additional digital backends, such as those for spectral line observations, showcasing its potential for broader astronomical applications.
title Development and Performance Validation of a Versatile VLBI Digital Backend Using the ROACH2 Platform
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2502.15446