Upper and lower bounds for numerical radii of block shifts

‎For an n-by-n complex matrix A in a block form with the (possibly) nonzero blocks only on the diagonal above the main one‎, ‎we consider two other matrices whose nonzero entries are along the diagonal above the main one and consist of the norms or minimum moduli of the diagonal blocks of A‎. ‎In this paper‎, ‎we obtain two inequalities relating the numeical radii of these matrices and also determine when either of them becomes an equality.