Radio-controlled wristwatch power consumption reduction

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Solution Overview

Problem

Radio-controlled wristwatches face challenges in reducing power consumption and preventing erroneous time adjustments when receiving time information from satellite systems, particularly due to the infrequent transmission of week number information, which requires activating high-frequency circuits with high power consumption.

Innovation Solution

The solution involves a radio-controlled wristwatch that selectively receives only the time-of-week information, omitting the less frequent week number information, and uses a reception control unit to limit week information reception based on specific conditions to prevent date inaccuracies, thereby reducing power consumption and ensuring accurate time adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the radio-controlled wristwatch receives week number information (WN) every time GPS time information is received, then the date and time accuracy is maintained, but the activation time of the high frequency circuit becomes longer and power consumption increases

Engineering Contradiction:
Improvedate and time accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The wristwatch performs preliminary reception of week number information only when necessary (at power-on or when date/time adjustment is needed), and then performs time-of-week information reception at regular intervals. This preliminary action ensures that the week number is cached in advance, avoiding the need for frequent high-power receptions while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system switches from continuous periodic reception of week number information to irregular periodic reception - receiving week number information only when power is turned on or when date/time adjustment is required, and receiving time-of-week information at regular intervals. This reduces the frequency of high-power circuit activations while maintaining time accuracy.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If the radio-controlled wristwatch receives week number information frequently, then the current time and date accuracy is maintained, but the reception time becomes longer resulting in shorter continuous operation time

Engineering Contradiction:
Improvecurrent time and date accuracyVSAvoidcontinuous operation time
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The wristwatch performs preliminary reception of week number information only when necessary (at power-on or when date/time adjustment is needed), and then performs time-of-week information reception at regular intervals. This preliminary action ensures that the week number is cached in advance, avoiding the need for frequent high-power receptions while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system switches from continuous periodic reception of week number information to irregular periodic reception - receiving week number information only when power is turned on or when date/time adjustment is required, and receiving time-of-week information at regular intervals. This reduces the frequency of high-power circuit activations while maintaining time accuracy.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If the radio-controlled wristwatch receives only time-of-week information without week number information, then power consumption is reduced, but erroneous time adjustments may occur

Engineering Contradiction:
Improvepower consumptionVSAvoidtime adjustment reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The wristwatch performs preliminary reception of week number information only when necessary (at power-on or when date/time adjustment is needed), and then performs time-of-week information reception at regular intervals. This preliminary action ensures that the week number is cached in advance, avoiding the need for frequent high-power receptions while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback mechanisms to determine when week number reception is necessary - checking whether power has been turned on or whether date/time adjustment is needed before initiating week number reception. This feedback-controlled approach ensures reliable time adjustment while minimizing power consumption.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2743784B1Radio-controlled wristwatch
Publication Date: 2021.05.12 CITIZEN WATCH CO LTD
  • EP2743784B1 patent drawingFigure 1
  • EP2743784B1 patent drawingFigure 2
  • EP2743784B1 patent drawingFigure 3~4

AI summary

Provided is a radio-controlled wristwatch, including: reception means (11) for receiving a radio wave from a satellite to extract time-of-week specifying information and week specifying information; clock means for counting a current date and time; date and time adjustment means for adjusting the current date and time counted by the clock means; week information holding means for holding the week specifying information; week information updating means for updating the week specifying information held in the week information holding means based on the current date and time counted by the clock means; and week information reception limiting means for limiting the reception of the week specifying information performed by the reception means, and controlling the reception means to receive the week specifying information in a predetermined case. Therefore, power consumption required for reception in the radio-controlled wristwatch configured to receive a radio wave containing time information from a satellite in a global positioning system is reduced.