A novel single-ring absolute optical shaft encoder is designed by studying the encoding principle of traditional absolute optical shaft encoder in this paper. The description of the orientation algorithm of the encode...A novel single-ring absolute optical shaft encoder is designed by studying the encoding principle of traditional absolute optical shaft encoder in this paper. The description of the orientation algorithm of the encoder is specified, and an example for explaining the orientation arithmetic is given, which indicates that the theory of the encoder works. The visual interface to acquire signals of CCD is shown with VB,which provides reliable foundation to process data. The effective factors of measurement precision of the encoder are analyzed.展开更多
This paper consider Hexagonal-metric codes over certain class of finite fields. The Hexagonal metric as defined by Huber is a non-trivial metric over certain classes of finite fields. Hexagonal-metric codes are applie...This paper consider Hexagonal-metric codes over certain class of finite fields. The Hexagonal metric as defined by Huber is a non-trivial metric over certain classes of finite fields. Hexagonal-metric codes are applied in coded modulation scheme based on hexagonal-like signal constellations. Since the development of tight bounds for error correcting codes using new distance is a research problem, the purpose of this note is to generalize the Plotkin bound for linear codes over finite fields equipped with the Hexagonal metric. By means of a two-step method, the author presents a geometric method to construct finite signal constellations from quotient lattices associated to the rings of Eisenstein-Jacobi （E J） integers and their prime ideals and thus naturally label the constellation points by elements of a finite field. The Plotkin bound is derived from simple computing on the geometric figure of a finite field.展开更多
文摘A novel single-ring absolute optical shaft encoder is designed by studying the encoding principle of traditional absolute optical shaft encoder in this paper. The description of the orientation algorithm of the encoder is specified, and an example for explaining the orientation arithmetic is given, which indicates that the theory of the encoder works. The visual interface to acquire signals of CCD is shown with VB,which provides reliable foundation to process data. The effective factors of measurement precision of the encoder are analyzed.
基金supported by 973 project under Grant No.2007CB807901the Fundamental Research Funds for the Central Universities under Grant Nos.YWFF-10-02-072 and YWF-10-01-A28
文摘This paper consider Hexagonal-metric codes over certain class of finite fields. The Hexagonal metric as defined by Huber is a non-trivial metric over certain classes of finite fields. Hexagonal-metric codes are applied in coded modulation scheme based on hexagonal-like signal constellations. Since the development of tight bounds for error correcting codes using new distance is a research problem, the purpose of this note is to generalize the Plotkin bound for linear codes over finite fields equipped with the Hexagonal metric. By means of a two-step method, the author presents a geometric method to construct finite signal constellations from quotient lattices associated to the rings of Eisenstein-Jacobi （E J） integers and their prime ideals and thus naturally label the constellation points by elements of a finite field. The Plotkin bound is derived from simple computing on the geometric figure of a finite field.
