US 12,107,709 B1
Timing synchronization in pulse position modulation (PPM) modems
Todd Matthew Drullinger, Redwood City, CA (US)
Assigned to SA PHOTONICS, INC., Los Gatos, CA (US)
Filed by SA Photonics, Inc., Los Gatos, CA (US)
Filed on Jan. 21, 2022, as Appl. No. 17/581,510.
Claims priority of provisional application 63/166,184, filed on Mar. 25, 2021.
Int. Cl. H04B 10/11 (2013.01); H04L 25/49 (2006.01)
CPC H04L 25/4902 (2013.01) [H04B 10/11 (2013.01)] 20 Claims
OG exemplary drawing
 
20. A method for controlling timing in a PPM receiver, the method comprising:
accumulating slot detection signals derived from a PPM-modulated signal for (a) a receiver data slot 1 and (b) a receiver data slot N, wherein each slot detection signal indicates a presence of a pulse in a corresponding one of N receiver data slots; and
generating a phase error signal based on a difference between (a) the accumulated slot detection signals for receiver data slot 1, and (b) the accumulated slot detection signal for receiver data slot N, wherein (a) and (b) are accumulated over a plurality of symbol periods.