Nyquist frequency signal, whereas "Nyquist frequency" is a property of a discrete-time system. When the function domain is time, sample rates are usually expressed in samples per second, and the unit of Nyquist frequency is cycles per second (hertz). When the function domain is distance, as in an image sampling system, the sample rate might be dots per inch and the corresponding Nyquist frequency would be in cycles/inch. Referring again to Figure 1, undersampling of the sinusoid at 0.6 f is what allows there to be a lower-frequency "alias", which is a different function that produces the same set of samples. That
Noise and vibration on maritime vessels throughout the ship. In most compartments, this type of vibration normally manifests itself as audible noise. The problem with diesels is that, for a given size, there is a fixed amount of power generated per cylinder. To increase power it is necessary to add cylinders but, when cylinders are added, the crankshaft has to be lengthened and after a very limited number of additions, the lengthened crankshaft begins to flex and vibrate all on its own. This results in an increase of vibrations spread all over the ships structure. Crankshaft vibration can be reduced by a harmonic balancer. Large vessels