Asymmetric Triangle Waveform Generator for Direction Detection
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Solution Overview
Problem
Existing electronic animal containment systems lack effective methods for determining the direction of approach relative to a transmitting source, particularly in generating transmit waveforms that allow a companion receiver to accurately determine this direction.
Innovation Solution
The system employs a containment signal generator that converts an uneven duty cycle square wave into an asymmetric triangle wave, or uses a discrete triangle wave generator with adjustable slopes, to produce desired current asymmetry in the wire loop, enabling the companion receiver to determine direction of approach by responding to the rate of change of magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional symmetric waveform is used in the transmit circuit, then the system operation is simple, but the companion receiver cannot determine the direction of approach
Solution Approach 1:
The patent applies asymmetry by generating an asymmetric triangle wave with different positive and negative slopes. The positive slope duration differs from the negative slope duration, creating an asymmetric waveform that enables the companion receiver to detect direction of approach. This asymmetric waveform is produced by controlling the transmit circuit to generate voltage waveforms with unequal rise and fall times, allowing the receiver to distinguish between approaching and receding directions based on the waveform asymmetry.
2Strength
If the wire loop inductance is large, then the magnetic field generation is effective, but the waveform distortion increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing compensation values in lookup tables that account for the wire loop's inductive characteristics. Before generating the actual waveform, the system uses these pre-computed compensation values to adjust the voltage waveform parameters, ensuring that the final waveform maintains accuracy despite the large inductance. This preliminary compensation prevents waveform distortion while maintaining effective magnetic field generation.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the voltage waveform parameters (amplitude, duration, slope) based on the wire loop inductance characteristics. The system modifies the waveform parameters in real-time to compensate for the effects of large inductance, ensuring that the current waveform remains accurate and undistorted while still generating sufficient magnetic field strength for effective operation.
3Loss of energy
If the wire loop resistance is large, then the system can operate with simpler components, but the magnetic field generation efficiency decreases
Solution Approach 1:
The patent applies parameter changes by adjusting the voltage waveform amplitude and duration parameters to optimize power delivery to the wire loop. The system dynamically modifies these parameters based on the measured or known resistance characteristics, ensuring that sufficient power is delivered to generate the required magnetic field strength while accounting for resistive losses. This allows the system to maintain effective magnetic field generation despite higher resistance by compensating through parameter optimization.
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
This approach allows the companion receiver to accurately determine the direction of approach by exploiting the asymmetry in the transmit current, ensuring reliable direction-sensitive capabilities in electronic animal containment systems.
Implementation Method 1
a companion receiver responsive to a rate of change of a magnetic flux density generated by a current in the wire loop
Data Source
AI summary
A method described herein includes describing a load current with a discrete time function. The method includes using a first frequency and a second frequency to provide an approximation of the described load current, wherein a transform applied to the discrete time function identifies the first frequency and the second frequency. The method includes estimating a loop inductance and a loop resistance of a wire loop by exciting a transmit circuit with a voltage reference step waveform, wherein the transmit circuit includes the wire loop. The method includes scaling the approximated load current to a level sufficient to generate a minimum receive voltage signal in a receiver at a first distance between the wire loop and the receiver. The method includes generating a first voltage signal using the scaled load current, estimated loop inductance, and estimated loop resistance. The method includes exciting the transmit circuit with the first voltage signal.