A magnetic bubble decoder employs forward magnetic bubble paths each forming a magnetic bubble shift loop, backward magnetic bubble paths, series switches disposed in the forward bubble paths, for straight advancing the magnetic bubbles and parallel switches, disposed in said forward bubble paths, for branching the magnetic bubbles from said forward paths to the backward paths. Control lines are provided for alternatively energizing the series and parallel switches to be operated in cooperation with each other with response to coded electrical signals applied to the control lines. A magnetic bubble output corresponding to the applied coded electrical signal is generated from the shift loop of a specific address.
A multi-turn absolute encoder comprising a shaft angle encoder for measuring the turning angle of a rotating shaft, and a turn detector for detecting the number of turns of the rotating shaft, wherein the turn detector uses a magnetic bubble element for sequentially transferring magnetic bubbles in a pattern in accordance with a magnetic field generated by a permanent magnet turned by the shaft, and a detector to detect the number of turns of the shaft from the positions of the magnetic bubbles which are transferred in the pattern.
