The Next-Generation 21CMA Telescope: Design, Commissioning, and Instrumental Effects in an SKA-LFAA-Like System

TL;DR

This paper details the design, commissioning, and analysis of the Next-Generation 21CMA telescope, highlighting its capabilities and instrumental effects relevant to SKA-LFAA-like systems.

Contribution

It introduces a new digital backend with real-time beamforming, validates system performance with observations, and investigates spectral effects like SLOSS caused by channelization strategies.

Findings

Demonstrated real-time beamforming and high-time-resolution pulsar measurements.

Validated system sensitivity and stability through interferometric observations.

Identified and characterized the SLOSS spectral feature caused by two-stage channelization.

Abstract

As the Square Kilometre Array (SKA) approaches operational status, its complex digital architecture introduces new instrumental challenges. To explore relevant observational and data processing strategies, we have upgraded the 21CMA telescope to the Next-Generation 21CMA (Ng21CMA). This paper presents the design and commissioning of the Ng21CMA system, featuring a digital backend capable of real-time beamforming. We demonstrate its performance through interferometric observations and high-time-resolution pulsar measurements, validating the system's sensitivity and operational stability. As a representative example of instrumental effects accessible with this platform, we investigate the impact of the two-stage channelization strategy used in SKA-LFAA-like systems. We show that it introduces a sawtooth-like spectral structure (SLOSS), characterized using both simulations and observational data. These results provide useful references for understanding instrument-induced spectral features and for guiding system design and calibration in future large-scale aperture arrays.