A possible coat of arms for emperor Sigismund.
For use with the imperial coa at File:Arms of the Holy Roman Emperor (c.1433-c.1450).svg
(same shield shape).
Sigismund used many different combinations of coats of arms in the course of his life, not to mention the permutations used in attribution to him after his death, and there isn't a single correct one. 
The inescutcheon version here appears to be slightly anachronistic.
He used the Hungarian coats of arms per pale in one seal, and the Hungarian (Arpad) stripes with the Bohemian lion  per pale in a later seal (used here). 
Equestrian seals also show quartering of the Bohemian lion with the imperial eagle.

Still other seals show  arrangements of up to six separate shields without division of the field, or quartering of the Hungarian (Arpad) stripes with the Bohemian lion.