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
Rayleigh (unit) Rayleigh (unit) The rayleigh is a unit of photon flux, used to measure airglow (auroras, for example). It was first proposed in 1956 by Donald M. Hunten, Franklin E. Roach, and Joseph W. Chamberlain. It is named for John William Strutt, 3rd Baron Rayleigh (1842–1919). Its symbol is R (also used for the röntgen, an unrelated unit). SI prefixes are used with the rayleigh. One rayleigh (1 R) is defined as a column emission rate of 10 photons per square metre per column per second. Note that rayleigh is an apparent emission rate, as no allowances have been made for