Armstrong was born in Scotland and later immigrated to Australia. She received a B.Sc. in electrical engineering from the University of Edinburgh, Scotland in 1974, an M.Sc. in digital techniques from the Heriot-Watt University in Edinburgh, Scotland in 1980, and a Ph.D. in digital communications from Monash University in Melbourne, Australia in 1993. She has published many papers on wireless and optical communications, focusing specifically on Orthogonal frequency-division multiplexing. Her work has led to a number of commercialized patents.
