Then the frequency can be read from the calibrated readout on the stroboscope. A stroboscope synchronized with the propeller speed "freezes" the cavitation bubble. Unfocused and undeflected CRTs were used as grid-controlled stroboscope lamps since 1958. Another application of the stroboscope can be seen on many gramophone turntables. Unfocused and undeflected cathode ray tubes were used as stroboscope lamps since 1958. Advancing the idea of the stroboscope, researchers began using lasers to stop high-speed motion. It is one of a number of devices that can be used as a stroboscope. Usually the rate of the stroboscope is adjustable to different frequencies. The LP version contained a cut-out stroboscope. Consider the stroboscope as used in mechanical analysis. A stroboscope can typically have its frequency set to any value. The stroboscope photograph demonstrated the dent in the ball at the point of contact. Several months later, Simon Stampfer patented a very similar "Stroboscope Disc" in Austria. A similar but more controllable effect can be obtained using a stroboscope.