Radio controlled clock

• US 20030189876A1
• Filed: 03/27/2003
• Published: 10/09/2003
• Est. Priority Date: 04/04/2002
• Status: Active Grant

• Current Assignee: IDT-LCD Holdings (BVI) Limited
• Original Assignee: IDT-LCD Holdings (BVI) Limited
• Inventors: Chan, Raymond
• Granted Patent: US 6,898,152 B2
• Time in Patent Office: Days
• US Class Current: 368/47
• CPC Class Codes: G04G 21/04 using radio waves radio-controlled time-pieces G04R
• CPC Class Codes: G04R 20/10 Tuning or receiving; Circuits therefor

Abstract

A radio controlled clock (100) comprising a main unit (200) and three interchangeable antenna modules (300). The main unit (200) includes an operating circuitry (250) and contacts (240). The circuitry (250) has a CPU (251) and three decoders (251′/252/253) connected thereto for decoding RF time signals of different carrier frequencies received by the modules (300), which decoders are connected to the contacts (240). Each module (300) has a body (310) connectable to main unit body (210), an operating circuitry (350), and contacts (324) connectable to the contacts (240) when the module (300) is connected to the main unit (200). The circuitry (350) has a receiver (330) tuned to receive a RF time signal of a specific carrier frequency broadcast in a particular country and then send the received signal via the contacts (324/240) to the relevant decoder (251′/252/253) for enabling the CPU (251) to display the local time at display (217).

Claims

1. A radio controlled clock comprising a main unit and at least two separate antenna modules selectively connectable to the main unit for co-operation therewith;

which main unit comprises a body, an LCD display and a plurality of keys provided on the body, an operating circuitry housed within the body, and a plurality of electrical contacts supported by the body;

the operating circuitry comprising a CPU control unit connected to the display for displaying time and to the keys for control, and at least two decoders connected to the CPU control unit for decoding radio frequency time signals of different carrier frequencies received by the antenna modules respectively, the decoders being connected to the contacts;

each of the antenna modules comprises a body releasably connectable to the body of the main unit, an operating circuitry housed within the body, and a plurality of electrical contacts supported by the body for connection to the contacts of the main unit respectively when the antenna module is connected to the main unit;

the operating circuitry comprising a receiver tuned to receive a radio frequency time signal of a specific carrier frequency broadcast in a particular country or region and then send the received signal, via the inter-connected contacts, to the respective decoder of the main unit for enabling the CPU control unit to display local time at the display according to the received signal.

2. The radio controlled clock as claimed in claim 1, wherein the receivers of said at least two antenna modules are tuned to receive radio frequency time signals of different carrier frequencies selected from 77.5 kHz, 60 kHz and 40 kHz for subsequent decoding by the respective decoders of the main unit.

3. The radio controlled clock as claimed in claim 2, wherein a third said antenna module is included and the main unit includes a third said decoder for this antenna module, the three receivers being tuned to receive radio frequency time signals of respective carrier frequencies of 77.5 kHz, 60 kHz and 40 kHz for subsequent decoding by the respective decoders.

4. The radio controlled clock as claimed in claim 1, wherein each antenna module includes a respective antenna connected to the corresponding receiver.

5. The radio controlled clock as claimed in claim 1, wherein the CPU control unit includes a circuit connected to at least one of the main unit contacts for automatically identifying the connected antenna module by detecting a high/low level signal provided at said at least one main unit contact by the receiver of the connected antenna module.

6. The radio controlled clock as claimed in claim 3, wherein the CPU control unit includes a circuit connected to two of the main unit contacts for automatically identifying the connected antenna module by detecting a high/low level signal provided at each of the two main unit contacts by the receiver of the connected antenna module.

7. The radio controlled clock as claimed in claim 1, wherein the receiver of one of the antenna modules is tuned to receive radio frequency time signals of the same carrier frequency but different data protocols, and the CPU control unit includes a circuit for prompting manual selection of an appropriate protocol on the display in response to the connection of this antenna module to the main unit.

8. The radio controlled clock as claimed in claim 1, wherein the CPU control unit includes a self-counting clock circuit capable of independent operation in the absence of any one of the antenna modules being connected to the main unit, such that the main unit operates as a stand-alone clock.

9. The radio controlled clock as claimed in claim 1, wherein the CPU control unit includes a thermal sensor for measuring and indicating the indoor temperature at the display.

10. The radio controlled clock as claimed in claim 1, wherein the body of each of the antenna modules includes a plug projecting therefrom for insertion into the body of the main unit, thereby connecting the antenna body to the main unit body.

11. The radio controlled clock as claimed in claim 10, wherein one of the main unit and antenna bodies includes a spring-loaded catch for engaging a part of the other body through a snap action upon insertion of the plug into the main unit body, thereby locking the two bodies connected together.

12. The radio controlled clock as claimed in claim 10, wherein the main unit and antenna bodies have substantially the same outer cross-section such that when the bodies are connected together, their adjacent peripheral surfaces substantially match and lie flush with each other.