Dual-Frequency Signal Generator for Buried Cable Location
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Solution Overview
Problem
Current signal generators for locating buried cables and pipes require operator expertise to select suitable frequencies, and existing single-frequency locators are not effective for short lengths or general applications due to high impedance issues, leading to suboptimal locate signal quality.
Innovation Solution
A signal generator that induces alternating currents at two frequencies, such as 33kHz and 66kHz, allowing simultaneous detection and eliminating the need for user-adjustments, using a controller to suppress harmonics and optimize signal quality through amplifiers and filters, and a power supply to regulate current for efficient battery use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single frequency (33kHz) is used for signal generation, then the device complexity is reduced and ease of operation is improved, but the measurement precision and reliability of cable location deteriorate for short cables due to high impedance
Solution Approach 1:
The patent combines multiple frequency signal generators (33kHz and 66kHz) into a single device that operates simultaneously. The signal generator produces both frequencies at the same time, and the locator detects both frequencies contemporaneously, merging the capabilities of multiple single-frequency devices into one unified system.
Solution Approach 2:
The dual-frequency signal generator and locator system provides universal functionality for locating cables under various conditions. By incorporating both 33kHz (for general purposes) and 66kHz (for short cables with high impedance), the system becomes adaptable to different cable lengths and installation scenarios without requiring separate specialized devices.
2Measurement precision
If multiple frequencies are used simultaneously, then the measurement precision and adaptability for different cable conditions are improved, but the device complexity increases requiring user adjustment
Solution Approach 1:
The system performs self-service by automatically detecting and utilizing both 33kHz and 66kHz signals without requiring user intervention for frequency selection. The locator automatically processes both frequencies contemporaneously, eliminating the need for operators to manually adjust settings or choose appropriate frequencies based on cable characteristics.
Solution Approach 2:
The signal generator pre-configures both 33kHz and 66kHz signal paths in advance, with both frequencies ready for simultaneous transmission. The locator is pre-configured to detect both frequencies contemporaneously, so no runtime adjustments or selections are needed during operation.
3Measurement precision
If higher frequency (66kHz) is used for short cables, then the measurement precision is improved, but the loss of energy increases due to rapid signal dissipation
Solution Approach 1:
The system applies partial action by using 66kHz specifically for short cable locations where high impedance prevents adequate 33kHz signal, while using 33kHz for general purposes and longer cables. This selective application of higher frequency only when necessary minimizes energy dissipation while maintaining measurement precision for short cables.
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
Facilitates robust and accurate location of cables and pipes without requiring operator expertise, providing better signal quality and longer range detection by minimizing harmonic interference and optimizing power efficiency.
Implementation Method 1
a signal transmitter may be placed near to the buried conductor and an alternating current signal may be induced in the conductor by an alternating magnetic field produced by the signal generator
Implementation Method 2
Current carrying conductors emit electromagnetic radiation which can be detected by an electromagnetic antenna
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4C
AI summary
A signal generator (100) for coupling to a concealed conductor is described. The signal generator comprises a first oscillator (102) configured to generate a first waveform having a first frequency, a first terminal (106) coupled to the first oscillator through a first band pass filter (104) configured to pass signals of the first frequency, a second oscillator (108) configured to generate a second waveform having a second frequency, and a second terminal (112) coupled to the second oscillator through a second band pass filter (110) configured to pass signals of the second frequency.