Normalized frequency (unit) resulting units are "radians/sample". The normalized Nyquist frequency is π "radians/sample", and the normalized sample-rate is 2π "radians/sample". The following table shows examples of normalized frequencies for a 1 kHz signal, a sample rate formula_18 = 44.1 kHz, and 3 different choices of normalized units. Also shown is the frequency region containing one cycle of the discrete-time Fourier transform, which is always a periodic function. Normalized frequency (unit) Normalized frequency is a unit of measurement of frequency equivalent to "cycles/sample". In digital signal processing (DSP), the continuous time variable, t, with units of "seconds", is replaced by the discrete integer
Second second per second for acceleration, and per second for frequency. Although the historical definition of the unit was based on this division of the Earth's rotation cycle, the formal definition in the International System of Units (SI) is a much steadier timekeeper: 1 second is defined to be exactly "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom" (at a temperature of 0 K). Because the Earth's rotation varies and is also slowing ever so slightly, a leap second is periodically added to clock