Method for synchronising an analog display of a timepiece with its electronic time base
The method of synchronizing the analogue display ( 41 ) of a timepiece ( 40 ), including an electronic time base ( 64 ), is achieved using proximity sensors ( 60, 62 ) respectively associated with wheels ( 46, 48 ) each having an aperture ( 54, 56 ) for defining the angular position of the latter. Determination of the angular position of a wheel requires an angular distance of around 60° to 90° to be travelled with this type of proximity sensor. Dependency of the measurement results upon the temperature generates a problem of precision in determining the angular position of the wheels, in particular a wheel secured to the hour indicator, given that an angle of 60° to 90° corresponds to a time interval of 2 to 3 hours. In order to ensure a measurement in a relatively short time interval where the ambient temperature is substantially constant and thus has no influence on the measurement, the invention provides that, in a analogue display synchronization mode at least one indicator is driven in an accelerated advance mode so that the aperture provided in the corresponding wheel quickly passes opposite the proximity sensor associated with that wheel.
1. A method of synchronising the analogue display of the current time of a timepiece, fitted with a movement having an electronic time base, with said time base, said analogue display including at least one analogue indicator, which is coupled in rotation to a wheel having at least one aperture, said wheel being associated with a proximity sensor arranged for detecting said aperture and for determining the position of a reference semi-axis defined by said aperture, said synchronisation method comprising the following steps:
driving said analogue indicator in an accelerated advance mode until said aperture of said wheel passes opposite said proximity sensor;
determining the real angular position of said reference semi-axis by electronic means receiving a measurement signal provided by said proximity sensor;
calculating, for said analogue display of said timepiece, the theoretical angular position of said reference semi-axis as a function of a reference current time given by said electronic time base; and
driving said analogue indicator until the real angular position of said reference semi-axis corresponds to said theoretical angular position.
2. The synchronisation method according to claim 1 , wherein said analogue indicator is an hour indicator.
3. The synchronisation method according to claim 2 , wherein said timepiece is set into synchronisation mode automatically and periodically in the second half of the nocturnal period.
4. The synchronisation method according to claim 3 , wherein said timepiece is set into the synchronisation mode daily or weekly.
5. The synchronisation method according to claim 1 , wherein said timepiece is set into synchronisation mode automatically and periodically in the second half of the nocturnal period.
6. The synchronisation method according to claim 5 , wherein said timepiece is set into the synchronisation mode daily or weekly.