Synchronization via radio consists in the reception, every minute, of the (1.encoded 2.coded) sign emitted by the French broadcasting station (DCF), thereby enabling the set of clocks to have always the exact time and automatically do the summer/winter time change.

Every minute, the France-Inter transmitter emits a encoded hour sign (hour, minute, date) in phase modulation overlapping the amplitude modulation.

The France-Inter receiver takes the hour sign and transmits it to the clock for its synchronization by modulating its power current.


The clock analyses the sign for three minutes and only accepts it when three messages are coherent. This method makes it possible to remove all strays.

The signs are usually received all over Europe and Northern Africa.

The signs correspond to the European time encoded according to the CCIR regulation.

The radio synchronization guarantees a complete precision.




Hour distribution

The hour distribution emerges from the need to perfectly synchronize a set of receiver clocks from a main clock called master clock.

The master clock is the time base which constitutes the reference of an hour distribution installation. It synchronizes the receiver clocks by means of an electric connection transmitting a encoded time message.

The hour distribution in encoded time consists in sending a total time message: “Hour, minutes, seconds, day, month and year”.

The master clock has a operation reserve, so that it enables the automatic time setting of the receiver clocks after a possible brake of current.


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