Pulse repetition frequency Pulse repetition frequency The pulse repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit, normally measured in pulses per second. The term is used within a number of technical disciplines, notably radar. In radar, a radio signal of a particular carrier frequency is turned on and off; the term "frequency" refers to the carrier, while the PRF refers to the number of switches. Both are measured in terms of cycle per second, or hertz. The PRF is normally much lower than the frequency. For instance, a typical World War II radar like
Eotvos (unit) Eotvos (unit) The eotvos is a unit of acceleration divided by distance that was used in conjunction with the older centimeter-gram-second system of units (cgs). The eotvos is defined as 1/1,000,000,000 galileos per centimetre. The symbol of the eotvos unit is E. In SI units or in cgs units, 1 eotvos = 10 second. The gravitational gradient of the Earth, that is, the change in the gravitational acceleration vector from one point on the Earth’s surface to another, is customarily measured in units of eotvos. The Earth's gravity gradient is dominated by the component due to Earth's near-spherical shape, which