The present invention realizes a decoder and an error position polynomial calculation method which realize erasure corrections by making less changes to a conventional Berlekamp algorithm calculation circuit. The circuit includes a structure of interconnection layers having a bottom layer of conductor material and a top layer of conductor material where the layers are separated by at least one layer of dielectric material. The tie down assembly is removably attached to the inner surface of the frame, and includes a strap, hook type fasteners on the strap ends, and a tensioning mechanism for imparting a tension to the strap. The weight members have inner end portions releasably attached to opposite surfaces of the flange.