Radio Clock Time Code Extraction Using Waveform Correlation
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Solution Overview
Problem
Conventional time information obtaining devices face challenges in accurately extracting time codes from standard time radio waves due to interference from weak electric signals and noise, leading to prolonged processing times and errors in synchronization and decoding.
Innovation Solution
A radio clock with a signal comparison circuit that generates estimated waveform data to calculate correlation values with input waveform data, allowing for precise detection of code beginnings and synchronization points, even in noisy conditions, by shifting code data and accumulating correlation values for accurate pattern matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional synchronization and decoding processes are used to extract time codes from standard time radio waves, then time information can be obtained, but the processing time becomes extremely long due to repeated processing required to overcome noise interference
Solution Approach 1:
The invention performs preliminary actions by pre-calculating expected waveform patterns for all possible time code values and storing them as reference data. During actual time code extraction, the received signal is directly compared against these pre-prepared reference waveforms, eliminating the need for repeated synchronization and decoding trials. This preliminary preparation of reference patterns allows for rapid identification of the correct time code without iterative processing.
Solution Approach 2:
The invention creates copies of expected time code waveforms in advance and stores them as reference patterns. Instead of generating and analyzing waveforms repeatedly during processing, the system uses these pre-copied reference waveforms for direct comparison with the received signal. This copying approach replaces complex real-time waveform generation and analysis with simple pattern matching, dramatically reducing processing time while maintaining extraction accuracy.
2Measurement precision
If conventional pulse width measurement methods are used to determine binary codes, then time information can be decoded, but errors occur due to noise interference affecting pulse width detection
Solution Approach 1:
The invention creates reference copies of expected binary code waveforms (both '0' and '1' states) and stores them as template patterns. Instead of detecting binary codes by measuring pulse widths in the noisy received signal, the system compares the received waveform directly against these clean reference copies. The binary code is determined by identifying which reference pattern (0 or 1) produces a better match, making the detection immune to noise-induced pulse width variations.
Solution Approach 2:
The invention replaces the mechanical measurement approach (pulse width measurement) with a waveform pattern matching approach. Instead of physically measuring the duration of voltage pulses and interpreting them as binary codes, the system uses correlation-based comparison between the received waveform and reference waveforms. This substitution transforms a noise-sensitive measurement process into a robust pattern recognition process that can tolerate noise interference.
3Measurement precision
If minute synchronization is performed by detecting frame beginnings every 60 seconds, then code incorporation can start, but the process takes several minutes to detect multiple frames and confirm synchronization
Solution Approach 1:
The invention performs preliminary action by pre-calculating and storing reference waveforms that include the characteristic frame structure and synchronization patterns. During synchronization, the received signal is immediately compared against these reference patterns, allowing the system to identify frame beginnings and minute boundaries in a single pass through the data. This eliminates the need to wait for and detect multiple complete frames before confirming synchronization.
Solution Approach 2:
The invention creates copies of the expected frame structure and synchronization patterns as reference templates. Instead of detecting synchronization by monitoring the received signal over multiple minutes and identifying repeated frame patterns, the system uses these pre-copied reference patterns to directly identify the correct frame boundaries and minute synchronization point. This pattern matching approach accelerates synchronization from several minutes to a fraction of the time.
Data Source
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AI summary
Disclosed is a time information obtaining device comprising: a reception section to receive a standard time radio wave; an input waveform data generation section to generate input waveform data, based on data having the unit of time length; an estimated waveform data generation section to generate estimated waveform data, wherein the estimated waveform data comprises the value in which each sample point is described by the plurality of bits, and has the same time length as the input waveform data, and comprises at least one code which configures the time code, and a waveform of the estimated waveform data is sequentially shifted by a predetermined sample; a correlation value calculation section to calculate a correlation value; a correlation value comparison section to compare the correlation value to calculate an optimal value; and a control section to specify a beginning position of a second in the time code.