  Inelastic neutron scattering is used to measure spin excitations in fully
deuterated single crystal samples of the strong-leg antiferromagnetic S=1/2
spin ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_4$. Sharp resolution-limited
magnons are observed across the entire one-dimensional Brillouin zone. The
results validate the previously proposed {\it symmetric} spin ladder model and
provide a reliable estimate of the relevant exchange interactions.
