Radio Wave Receiver Filtering for Noisy Time Code Decoding
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Solution Overview
Problem
Conventional radio wave receivers struggle to accurately decode time codes in poor radio wave conditions due to signal attenuation and noise contamination, leading to inaccurate time code decoding.
Innovation Solution
A radio wave receiver system with a low-pass filter having a cutoff frequency twice the transmit frequency of data pulses or less, combined with a data distinction unit that resets charges in the filter, allowing for accurate decoding of time codes even in poor signal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional low-pass filter with a higher cutoff frequency (e.g., 5 Hz or higher) is used to preserve the waveform of data pulses, then the waveform distortion is minimized, but the signal-to-noise ratio deteriorates under poor radio wave conditions
Solution Approach 1:
The patent changes the cutoff frequency parameter of the low-pass filter to 5 Hz or lower, which is a significant deviation from conventional values. This parameter change allows the filter to remove high-frequency noise components while still preserving the essential waveform characteristics of the data pulses, thereby improving the signal-to-noise ratio without excessive waveform distortion
Solution Approach 2:
The patent applies preliminary filtering by the low-pass filter before the signal is further processed by the detection circuit and subsequent stages. This preliminary action of noise removal at the filtering stage prepares a cleaner signal for subsequent detection and processing, preventing noise from propagating through the system and degrading the final decoding accuracy
2Object-affected harmful factors
If signal processing is enhanced to improve noise rejection, then the signal-to-noise ratio is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a threshold value as an intermediary parameter that mediates between the filtered signal and the detection process. By comparing the filtered signal against this threshold, the system can effectively distinguish valid signal components from residual noise without requiring complex processing algorithms. The threshold acts as a simple yet effective mediator that enables robust noise rejection while maintaining system simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enhances the signal-to-noise ratio, enabling accurate data pulse distinction and time code decoding, even in areas with significant radio wave attenuation and noise, by optimizing the low-pass filter's cutoff frequency and using a reset mechanism to maintain signal quality.
Implementation Method 1
a low-pass filter to pass low-frequency components in the detected signal detected by the detection circuit
Data Source
AI summary
Disclosed is a radio wave receiver including: a receiving unit to receive a radio wave including a time code in which a plurality of types of data pulse different in pulse width from one another are arranged with a predetermined period of time; a detection circuit to detect the time code in the radio wave received by the receiving unit to obtain a detected signal; a low-pass filter to pass low-frequency components in the detected signal detected by the detection circuit, a cutoff frequency of the low-pass filter being twice a transmit frequency of the data pulse or less; and a data distinction unit to distinguish the types of data pulse based on an output of the low-pass filter for at least one specific point of time during a transmit period of data pulse.