Horology: time measuring systems or devices – Plural timepiece system or system device – With wireless synchronization
Reexamination Certificate
2000-02-24
2001-09-11
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Plural timepiece system or system device
With wireless synchronization
C368S187000
Reexamination Certificate
active
06288977
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a time signal repeater which relays a radio signal including a time code for a radio correction clock receiving a radio signal to correct its time and to a time correction system using the same.
2. Description of the Related Art
A radio correction clock receives, for example, a standard time radio signal of a long wave (for example, 40 kHz in Japan) transmitting a standard time and corrects the time based on the received radio signal to display the precise time.
This type of radio correction clock has built into it a receiving circuit receiving a standard time radio signal and a control circuit for driving a hand driving system based on the received signal to correct the time. In the radio correction clock, the positions of the hands are corrected to positions according to the time code of the received radio signal.
A radio correction clock exclusively receives the standard time radio signal. There are many cases where it is placed in a location which the radio signal can hardly reach, for example, is in an apartment building or basement, and cannot receive the signal.
In order to eliminate this restriction on the location where the radio correction clock is placed, it has been proposed to provide a time signal repeater for receiving the standard time radio signal and modulating the received time signal by a predetermined carrier and transmitting the modulated signal, and to have the radio correction clock receive the signal transmitted from the repeater to correct the time (see for example Japanese Unexamined Patent Publication (Kokai) No. 5-333170).
Summarizing the problem to be solved by the invention, the modulation frequency of the standard time radio signal differs by country.
For example, the modulation frequency is 40 kHz in Japan, 60 kHz in the U.S., and 77.5 kHz in Germany.
As opposed to this, in the time signal repeaters currently proposed, the resonance frequency of the receiving antenna portion is fixed, so it is possible to use the repeaters in only one country.
Further, it may be considered to change the reception frequency of the radio correction clock to the frequency of the time signal repeater. This change, however, would be complicated and would involve both hardware and software, therefore this is not practical in terms of cost etc.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a time signal repeater capable of selectively relaying standard time radio signals having different modulation frequencies and thereby enabling correction of time based on a plurality of standard time radio signals without changes at the radio correction clock side and a time correction system using the same.
According to a first aspect of the present invention, there is provided a time signal repeater which relays a radio signal including a time code for a radio correction clock receiving a standard time radio signal to correct the time, comprising an antenna portion capable of setting a plurality of resonance frequencies and receiving the standard time radio signal by a set resonance frequency, an oscillating circuit for outputting a signal having a frequency of the received standard time radio signal and synchronized with the standard time radio signal received by the antenna portion, at least one frequency conversion circuit for converting the frequency of the output signal of the oscillating circuit, a receiving circuit for receiving as input the standard time radio signal received by the antenna portion and correcting the time of an internal clock according to the time code included in the received radio signal, a transmission circuit for generating a time radio signal including a time code based on the internal clock based on the output signal of the oscillating circuit or the signal converted in frequency by the frequency conversion circuit at the time of transmission, and a selecting circuit for receiving as input the output signal of the oscillating circuit or the signal converted in frequency by the frequency conversion circuit to the transmission circuit.
According to a second aspect of the present invention, there is provided a time correction system comprising a radio correction clock fixed in reception frequency, receiving a standard time radio signal or radio signal obtained by relaying the standard time signal, and correcting the time to a time according to a time code included in the received signal, and a time signal repeater which has an antenna portion capable of setting a plurality of resonance frequencies and receiving the standard time radio signal with a set resonance frequency, an oscillating circuit for outputting a signal having a frequency of the received standard time radio signal and synchronized with the standard time radio signal received by the antenna portion, at least one frequency conversion circuit for converting the frequency of the output signal of the oscillating circuit, a receiving circuit for receiving as input the standard time radio signal received by the antenna portion and correcting the time of an internal clock according to the time code included in the received radio signal, a transmission circuit for generating a time radio signal including a time code based on the internal clock based on the output signal of the oscillating circuit or the signal converted in frequency by the frequency conversion circuit at the time of transmission, and a selecting circuit for receiving as input the output signal of the oscillating circuit or the signal converted in frequency by the frequency conversion circuit to the transmission circuit.
Further, in the present invention, the transmission circuit modulates an input signal with a different modulation system from an amplitude modulation system of the standard time radio signal.
Summing up, according to the present invention, in the time signal repeater, the resonance frequency is set to a frequency corresponding to the modulation frequency of the standard radio signal transmitted from a radio transmission base station.
When a standard time radio signal having a predetermined format is transmitted from the radio transmission base station in this state, it is received by the receiving antenna portion of the time signal repeater and input to the oscillating circuit and the receiving circuit.
In the oscillating circuit, a signal having the frequency of the received standard time radio signal in synchronization with the standard time radio signal received at the antenna portion is output.
Further, in the receiving circuit, the internal clock is corrected the time according to the time code included in the standard time radio signal received by the antenna portion.
Then, at the time of transmission, when the frequency of the output signal of the oscillating signal is the same as the reception frequency of the radio correction clock, the output signal of the oscillating circuit is selected by the selecting circuit and input to the transmission circuit.
When the frequency of the output signal of the oscillating signal is different from the reception frequency of the radio correction clock, the output signal of the frequency conversion circuit, which converts the frequency of the output signal of the oscillating circuit to a frequency the same as the reception frequency of the radio correction clock, is selected by the selecting circuit and input to the transmission circuit.
In the transmission circuit, at the time of the transmission, a time radio signal including a time code based on the internal clock is generated based on the output signal of the oscillating circuit or the signal converted in frequency by the frequency conversion circuit and the generated signal is transmitted to the radio correction clock.
In the radio correction clock, the time correction is performed according to the time code included in the standard time radio signal or the radio signal transmitted from the time signal repeater.
REFERENCES:
patent: 4083004 (1978-04-01), Cohn
patent: 4210901 (1980-07-01), Whyte et al
Fujita Kenji
Nemoto Kenichi
Sase Masahiro
Takada Akinari
Tanoguchi Masahiro
Birch Stewart Kolasch & Birch, LLP.
Goodwin Jeanne-Marguerite
Miska Vit
Rhythm Watch Co. Ltd.
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