4

"1" is a single low pulse of length T, followed by a single high pulse of length T

"0" is a single low pulse of length 2T, followed by a single high pulse of length 2T

enter image description here

This is similar to BFSK, except that this scheme only has one full cycle per bit, whether that bit is 0 or 1. For BFSK, the "1" bit would get 2 full cycles, and the "0" bit would get only one full cycle.

I can find a usage of this scheme, in digital model railroads and digital slots cars, where power and data are transmitted through the metal rails in the form of square wave AC.

I've searched high and low, and cannot find any name or other usages of this fairly simple, and quite useful looking keying scheme.

Greg Woods
  • 141
  • 5
  • it is similar to some remote control IR protocols – jsotola Apr 28 '20 at 23:39
  • 1
    Kind of like a weird Manchester encoding with FSK. Or a differential FSK of sorts. – MadHatter Apr 29 '20 at 03:56
  • FSK seems an appropriate description. – Andy aka Apr 29 '20 at 13:26
  • A binary FSK is the closest, but in every example I've seen of FSK, the total width of each 0 or 1 is always the same, just the frequency within that "bit" changes. Whereas in this scheme, it is the number of transitions which stays the same.and the width of the "bit" varies. – Greg Woods Apr 30 '20 at 09:05

0 Answers0