Аннотация:This article is devoted to the problem of high-speed compression of large data streams in ultrasonic diagnostics. Research of the ability to use a well-known method of wavelet-transform for this purpose is being conducted. Besides that, a method of sine approximation is proposed, the idea of which is the approximation of the recorded signal with a sequence of half-periods of sine. Comparison of these methods is performed using real data recorded during diagnostics of welds in pipelines at Russian nuclear power plants.