  Exteded Yangian algebras of orthogonal and symplectic types are defined by
the Yang-Baxter RLL relation involving the fundamental R-matrix with $so(n)$ or
$sp(2m)$ symmetry. We study representations of highest weight characterized by
weight function ratios. We consider the algebra relations for the linear and
the quadratic evaluations and the resulting conditions imposed on the
representation weights. We present expressions of L-operators constructed on
underlying Clifford and Heisenberg algebras and characterize their
representations.
