S2(O)=[M(-0)+M(+0)H(o) HO=Sgn(o+o)-Sgn(o-o) s(0)=[M(+)+M(-0) 41 ( m(t)cosa t [M(+O.)Sgn(+0)-M(-0)Sg(-0) 4 (>m(t)sino t 214 [ ( ) ( )] ( ) 2 1 SSSB () = M  − c + M  + c H  [ ( ) ( )] 2 1 ( ) H  = Sgn  + c − Sgn  − c [ ( ) ( )] 4 1 ( ) SSB M c M c S  =  + +  − [ ( ) ( ) ( ) ( )] 4 1 + M  + c Sgn  + c − M  − c Sgn  − c ( )cos ) 2 1 ( m t t   c ˆ( )sin ) 2 1 ( m t t   c