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
Collision frequency Collision frequency Collision frequency is defined in chemical kinetics and collision theory, in the background of "theoretical kinetics". If a system contains "n" type-a molecules per unit volume and "n" type-b molecules in that same unit volume, then the number of a-b collisions per unit time in that volume will be proportional to the product "nn". or, in terms of molar volumes ("[x]=n /N" where N is the Avogadro constant) By kinetic theory it can be shown that: where The collision frequency ("Z") is usually expressed in units of "moles of collisions" per unit time per unit volume: or equivalently: