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
Roentgen (unit) Roentgen (unit) The roentgen or röntgen () (symbol R) is a legacy unit of measurement for the exposure of X-rays and gamma rays. It is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air. In 1928 it was the first international measurement quantity for ionising radiation to be defined for radiation protection, and was an easily replicated method of measuring air ionization directly by using an ion chamber. It is named after the German physicist Wilhelm Röntgen, who discovered X-rays. Although relatively easy to measure, it had