Design of a multi-function high-speed digital baseband data acquisition system

摘要

A multi-function digital baseband data acquisition system is designed for the sampling,distribution and recording of wide-band multi-channel astronomical signals.The system hires a SNAP2board as a digital baseband converter to digitize,channelize and packetize the received signal.It can be configured dynamically from a single channel to eight channels with a maximum bandwidth of 4096 MHz.Eight parallel HASHPIPE instances run on four servers,each carrying two NVMe SSD cards,achieving a total continuous write rate of 8 GB s^(-1).Data are recorded in the standard VDIF file format.The system is deployed on a 25-meter radio telescope to verify its functionality based on pulsar observations.Our results indicate that during the 30-minute observation period,the system achieved zero data loss at a data recording rate of 1 GB s^(-1) on a single server.The system will serve as a verification platform for testing the functions of the QTT(Qi Tai radio Telescope)digital backend system.In addition,it can be used as a baseband/VLBI(Very Long Baseline Interferometry)recorder or D-F-engine of correlator/beamformer as well.