The paper describes a method of determining overlap lengths for interdigital electrodes of an s.a.w. filter by use of constrained damped least squares. In this method, some constraints which must be met exactly by a designed filter, as well as the effects of electrical terminations, can be simultaneously taken into account. The method was applied to the design of a practical filter for a Japanese television receiver. The filter designed was compared with that designed by a conventional Fourier analysis.