The RF (radio frequency) search coil-transmitted and received frequency that the metal detector is designed to operate at.
The nominal frequency of the AC component in a transformer or inductor. If the operation requires the frequency to vary, then a range between minimum and maximum is needed to properly design the component.
The actual frequency output with respect to the actual operating conditions of temperature, voltage and load.
The frequency at which a circuit or device is operated. Operating frequency is also used to note a general location on the radio frequency spectrum, such as 800 MHz, 900 MHz, or 1900 MHz.
The radio frequency range which wireless devices use to communicate with one another. Most devices use the 2.4 GHz range. (i.e. the operating frequency for 802.11g and Bluetooth is 2.4 GHz).