Ultra-wideband Digital Technologies for the Green Bank Telescope
Abstract
The Green Bank Observatory is a leader in the development of digital instruments for radio astronomy, enabling cutting-edge science in the fields of pulsars, fast radio transients, astrochemistry, star formation, the Local Group, and cosmology. The total bandwidth that can be processed with these systems has increased with the availability of fast analog-to-digital converters and digital signal processing systems, but most instruments have still relied on substantial analog conditioning prior to digitization. New digital technologies are now making it feasible to directly sample ultra-wide bandwidths at radio frequencies with high dynamic range and active detection and removal of radio frequency interference. GBO is developing a proto-type ultra-wideband digital sampling system that will complement a new 0.7-4 GHz radio receiver being built for the Green Bank Telescope. The primary science driver for these systems is the direct detection of nanohertz frequency gravitational waves via pulsar timing, and it will also have applications in the wideband detection and study of radio transients and in molecular spectroscopy. We provide a status report on this prototype system with a focus on a custom interface for 10 Gsamp/s, 12-bit analog-to-digital converters and 100-gigabit Ethernet protocols. We will also summarize results from a variety of approaches to interference identification and removal, including machine learning. This project is the first in a series of advanced upgrades being planned for the GBT that could expand its instantaneous bandwidth by factors of up to 20, drastically improving observations of transients and spectroscopic survey speeds. This work is supported by the National Science Foundation grant number 1910302. The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23517518L