Digital Spectro-Correlator System for the Atacama Compact Array of the Atacama Large Millimeter/submillimeter Array

TL;DR

This paper presents a digital spectro-correlator system designed for the Atacama Compact Array, capable of processing multiple signals with high spectral dynamic range and low sensitivity loss, enhancing observational capabilities.

Contribution

The paper introduces a novel FX-architecture digital spectro-correlator with flexible spectral configurations for the ACA, including detailed hardware design and verification results.

Findings

Spectral dynamic range exceeds 10^4 relative to Tsys.

Sensitivity loss is confirmed to be 0.9%.

Supports simultaneous processing of four dual polarization pairs across 16 antennas.

Abstract

We have developed an FX-architecture digital spectro-correlator for the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array. The correlator is able to simultaneously process four pairs of dual polarization signals with the bandwidth of 2 GHz, which are received by up to sixteen antennas. It can calculate auto- and cross-correlation spectra including cross-polarization in all combinations of all the antennas, and output correlation spectra with flexible spectral configuration such as multiple frequency ranges and multiple frequency resolutions. Its spectral dynamic range is estimated to be higher than 10^4 relative to Tsys from processing results of thermal noise for eight hours with a typical correlator configuration. The sensitivity loss is also confirmed to be 0.9 % with the same configuration. In this paper, we report the detailed design of the correlator and the verification results of the developed hardware.