kilohertz

Kilohertz (symbol kHz) is a unit of frequency in the International System of Units (SI). It denotes 1,000 cycles per second, since kilo- is the prefix for 10^3 and hertz is the unit of frequency. Therefore, 1 kHz equals 1000 s^-1, and the period of a 1 kHz signal is 1 millisecond.

Kilohertz is used across a range of disciplines to describe frequencies in the thousands-per-second range. In audio, frequencies from about 20 Hz to 20 kHz span human hearing, so kilohertz terms often describe the upper end of audible tones and related processing or filtering. In digital audio and broadcasting, carrier and signal frequencies frequently fall in the kilohertz region, as well as in radio applications that extend into higher bands. Medium- and short-wave AM radio, for example, uses carrier frequencies in the kilohertz range (roughly hundreds to a few thousand kHz).

In electronics and metrology, kilohertz is a common unit for oscillator frequencies, clock rates in older digital devices, and measurement equipment such as frequency counters and spectrum analyzers. When expressing quantities in kilohertz, the value can be converted to hertz by multiplying by 1,000 (e.g., 2.5 kHz = 2,500 Hz). Kilohertz is one step in the hierarchy of SI prefixes that relate larger or smaller frequencies to the base unit hertz.