Experiments with calibrated digital sideband separating downconversion

TL;DR

This paper presents a digital sideband separating downconverter for radio astronomy that combines simple analog design with digital processing to achieve high sideband isolation over a wide temperature range.

Contribution

It demonstrates a novel approach to re-optimizing radio receiver architecture using digital technology and simple analog design for improved sideband separation.

Findings

Achieved over 50 dB sideband isolation

Operates effectively over a 12°C temperature range

Simplified analog design with digital processing

Abstract

This article reports on the first step in a focused program to re-optimize radio astronomy receiver architecture to better take advantage of the latest advancements in commercial digital technology. Specifically, an L-Band sideband-separating downconverter has been built using a combination of careful (but ultimately very simple) analog design and digital signal processing to achieve wideband downconversion of an RFI-rich frequency spectrum to baseband in a single mixing step, with a fixed-frequency Local Oscillator and stable sideband isolation exceeding 50 dB over a 12 degree C temperature range.