A method for computing the nonlinear interactions between the spectral lines of progressive finite‐amplitude waves in fluid media is developed via Burger's equation. By taking the Fourier transform of the particle velocity, this equation is reduced to a coupled set of ordinary nonlinear differential equations, which are then solved by means of Airy's algorithm. The solution thus obtained consists of a spectral vector, which initially contains the signal spectrum at the source, and is subsequently enriched by nonlinearly generated spectral lines as the signal propagates through the medium. The utility of the method consists in the ease with which it can be implemented on a digital computer and its applicability to different types of source waveform. As an example, the conversion efficiency of parametric interaction between the spectral lines of a finite amplitude source driven simultaneously at two different frequencies and subject to spherical spreading loss is considered. It is shown that the sound press...