3 links
JPS Communications, Inc.
jps.com
JPS Communications is a manufacturer of DSP equipment for military, shortwave and ham radio applications.
Quantics W9GR Digital Signal Processors
9gr.com
Information about the DSP-3 which removes noise and other unwanted interference from voice and data communications signals.
WD8DAS Sync Page
qsl.net
Offers information about synchronous detection and retrofit synchronous detectors in kit and finished form.