  We present a basic model for the calculation of the luminosity distribution
of supernova remnant populations. We construct theoretical Ha and joint [S II]
- Ha luminosity functions for supernova remnants by combining prescriptions
from a basic evolution model that provides the shock velocity and radius for
SNRs of different age and pre-shock density, with shock excitation models that
give the gas emissivity for shocks of different physical parameters. We assume
a flat age distribution, and we explore the effect of different pre-shock
density distributions or different magnetic parameters. We find very good
agreement between the shape of the model Ha and the joint [S II] - Ha
luminosity functions and those measured from SNR surveys in nearby galaxies.
