Radio clock

A radio clock is a clock that is synchronized by a time code bit stream transmitted by a radio transmitter associated to a time standard such as an atomic clock. The picture shows a type of radio controlled digital clock. With special mechanism, radio controlled analog clocks are also available.
A radio controlled clock consists of an antenna for intercepting the RF time code signal, a receiving circuit to exchange the time code RF signal into digital time code, and a controller circuit to decode the time code bit streams and to drive an output circuit which can be LCD in case of digital clocks or stepping motors in case of analog clocks.