FREQUENCY

The frequency, denoted f, of a wave is the reciprocal of the period. That is, f = 1/T, and T = 1/f. In the olden days (prior to the 1970s), frequency was specified in cycles per second, abbreviated cps. High frequencies were expressed in kilocycles, megacycles, or gigacycles, representing thousands, millions, or billions of cycles per second. Nowadays, the standard unit of frequency is known as the hertz, abbreviated Hz. Thus 1 Hz = 1 cps, 10 Hz = 10 cps, and so on.
Higher frequencies are given in kilohertz (kHz), megahertz (MHz), gigahertz (GHz), and terahertz (THz). The relationships are
1 kHz = 1,000 Hz = 10³ Hz
1 MHz = 1,000 kHz = 10⁶ Hz
1 GHz = 1,000 MHz = 10⁹ Hz
1 THz = 1,000 GHz = 10¹² Hz