Moving Body Detection Device Dynamic High Pass Filter Cutoff
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Solution Overview
Problem
Conventional moving body detection devices face challenges in reducing the time required for stabilization while maintaining accuracy in detecting slow-moving bodies, particularly when operated intermittently, and in minimizing power consumption.
Innovation Solution
The device incorporates a control portion that adjusts the cutoff frequency of high pass filters dynamically, setting it higher initially for rapid stabilization and lower subsequently to enhance detection accuracy and reduce power consumption, utilizing a variable resistance circuit configuration to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the device operates intermittently to reduce power consumption, then power consumption is reduced, but the time required for stabilization increases and detection accuracy deteriorates
Solution Approach 1:
The patent applies dynamics by making the cutoff frequency of the high pass filter variable rather than fixed. The control portion dynamically adjusts the cutoff frequency based on the operating state: using a first (higher) cutoff frequency during intermittent operation to reduce stabilization time, and a second (lower) cutoff frequency during continuous operation to maintain detection accuracy for slow-moving bodies. This dynamic adaptation resolves the contradiction between power consumption reduction and detection accuracy maintenance.
Solution Approach 2:
The patent changes the parameter of cutoff frequency based on operating conditions. By switching between different cutoff frequency values (first cutoff frequency for intermittent operation, second cutoff frequency for continuous operation), the system optimizes both power consumption and detection accuracy for each operating mode, resolving the technical contradiction.
2Measurement precision
If a fixed low cutoff frequency is used to maintain detection accuracy for slow-moving bodies, then detection accuracy is maintained, but the stabilization time increases
Solution Approach 1:
The system dynamically adjusts the cutoff frequency based on the operational phase. During the initial stabilization phase, a higher first cutoff frequency is used to reduce stabilization time. Once stabilized, the system switches to a lower second cutoff frequency to maintain detection accuracy for slow-moving bodies. This temporal dynamic adjustment resolves the contradiction between stabilization time and detection accuracy.
Solution Approach 2:
The patent applies preliminary action by first establishing rapid stabilization using a higher cutoff frequency before switching to the lower cutoff frequency optimized for detection accuracy. This preliminary stabilization phase ensures the system is ready for accurate detection without prolonged stabilization time, resolving the contradiction.
3Measurement precision
If the high pass filter cutoff frequency is lowered to detect slow-moving bodies, then detection accuracy for slow-moving bodies is improved, but the time required for the filter to stabilize increases
Solution Approach 1:
The control portion dynamically changes the cutoff frequency of the high pass filter based on operational requirements. A higher first cutoff frequency is used initially to reduce stabilization duration, and a lower second cutoff frequency is used subsequently to improve detection accuracy for slow-moving bodies. This dynamic frequency adjustment resolves the contradiction between stabilization duration and detection accuracy.
Solution Approach 2:
The patent changes the cutoff frequency parameter of the high pass filter according to the operational stage. By switching between different frequency values, the system achieves both rapid initial stabilization and accurate subsequent detection of slow-moving bodies, resolving the technical contradiction.
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 reduces the stabilization time and maintains detection accuracy for slow-moving bodies while minimizing power consumption by dynamically adjusting the high pass filter cutoff frequencies.
Implementation Method 1
emitting a continuous energy wave such as an ultrasonic wave or a radio wave into the monitoring space
Implementation Method 2
emitting a continuous energy wave such as an ultrasonic wave or a radio wave into the monitoring space
Implementation Method 3
detecting a frequency shift, of a reflected wave, that is generated by a movement of an object inside the monitoring space
Data Source
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AI summary
A moving body detection device includes an oscillation circuit, a transmitter, a receiver, a phase detection portion, a moving body determination portion, and a control portion. The phase detection portion includes a mixer, a low pass filter that passes only a frequency component that is less than or equal to a first cutoff frequency, a high pass filter that changes a second cutoff frequency and passes only a frequency component that is greater than or equal to the second cutoff frequency, and an amplifier. The control portion controls the high pass filter such that the second cutoff frequency that is applied during a period from when the transmitter starts transmitting a continuous energy wave until a predetermined waiting time elapses is higher than the second cutoff frequency that is applied in a period after the waiting time elapses.