Definition of gigahertz unit: = 109 Hz. Billion Hertz. How many cycles happen in one billionth of a second. Cycle per 10 -9 sup> sec. Example: Computer processor cycles (clock rate) are measured in GHz.
Definition of revolutions per day unit: = Hz/86400. The number of events or cycles that occurred in one day. The sign rpd (revolutions per day) the value if Hertz / 86400. It is used to express slow frequencies. The Earth's rotational frequency is 1 rpd (revolution per day)