[GreenKeys] [External] HF radio relating to DSP TU Update

[Jones, Douglas W]

From: Jim Haynes [jhhaynes at earthlink.net] -- Wednesday, July 6, 2022 8:46 PM

> I think the most successful attack on the multipath problem was a system developed at MIT called RAKE, which put the signal through a delay line and then tried to take signals from several taps on the line and combine them constructively. 

See:  Clarence W. Hansell, "Method and Means for Reducing Multiple Signals," U.S. Patent 2,310,692, granted Feb. 9, 1943, applied for in 1939.  Yep, patent does exactly what you describe, using short hunks of coax as delay lines.  The problem they were working on at RCA at the time was multipath interference in TV signals, a common source of ghost images.

I found that patent when I was working on the analog delay line Wikipedia page:
-- https://en.wikipedia.org/wiki/Analog_delay_line

That page is still over 50% my work, despite the passage of time.

         Doug Jones
         jones at cs.uiowa.edu