On Thu, 10 Jan 2019 at 09:10, David Van Horn < david.vanhorn@backcountryaccess.com> wrote: > I'm looking for info on DFT or similar approaches to detect very weak CW > signals buried in noise. > I'm only interested in a 200Hz window, and I can control where it falls > frequency wise, between 150Hz (center) and several kHz. > I need as much frequency detail as possible, sub 1Hz definitely, but the > "dot" is pretty short. At 20WPM that works out to well below. > https://www.w8ji.com/cw_bandwidth_described.htm > > Is the CW signal > originated from a remote source over which you have no control wrt time o= f > origin, pattern etc > or do you have control of tx and rx ends and want to establish how/if it transits some medium. I assume the former but, in the event of the rather niche latter case, a lock-in-amplifier may well be what you want https://wiki2.org/en/Lock-in_amplifier and *a zillion more * (Garglabet search) Russell > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .