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
First Draft of a Report on the EDVAC to denote a unit time delay, as time delays must be accounted for in a synchronous design. He points out that in one microsecond an electric pulse moves 300 meters so that until much higher clock speeds, e.g. 10 cycles per second (100 MHz), wire length would not be an issue. The need for error detection and correction is mentioned but not elaborated. A key design concept enunciated, and later named the Von Neumann architecture, is a uniform memory containing both numbers (data) and orders (instructions). "The device requires a considerable memory. While it appeared that various parts of this