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US 2026/0221014 A1Published application
Method for detecting vibroacoustic signals and a device for performing the method
AssigneeAjax Systems Cyprus Holdings Ltd
InventorsVolodymyr HOLODIUK, Ihor DITSKYI
Life of this patent
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Abstract
A method for detecting vibroacoustic signals, and an easy-to-manufacture and easy-to-mount device for performing the method, while providing a high level of operational reliability of the security system and significantly reducing the probability of generation of false alarm signals by providing successive processing and analysis of a vibroacoustic signal, further classifying a nature of a reason of occurrence of the vibroacoustic signal, thereby allowing to timely detect and evaluate characteristic signals as signs of a possible unauthorized access, while distracting those signals that are not intrusion signs.
Claims9
A method for detecting vibroacoustic signals, the method comprising:
- receiving an input vibroacoustic signal from a piezoelectric sensor and transmitting it to a preamplifier;
- filtering a pre-amplified signal by its successive passing through a low-frequency filter and a high-frequency filter between 5.0 kHz and 30.0 kHz;
- amplifying a filtered signal and feeding it to a comparator to which a reference voltage source is connected;
- comparing a level of the amplified signal to a time-constant value in the comparator and generating a command for transmitting the amplified signal through an analog switch to a rectifier, or if the level of the amplified signal exceeds the time-constant value, then generating the command for transmitting the amplified signal through the analog switch to the rectifier and, at the same time, generating a command to an integrator about introducing an amplitude increase coefficient of an integrator input signal;
- rectifying the signal in the rectifier, while converting it into a unipolar signal;
- integrating the unipolar signal by means of the integrator;
- after the integrated signal reaches a power supply voltage level greater than 80.0%, subjecting it to frequency modulation by feeding the signal from the integrator to an impulse generation unit, generating a stable duration impulse and feeding it to the microcontroller, while at the same time generating a command for resetting the integrator;
- measuring repetition periods of the stable duration impulses by means of the microcontroller and accumulating them in a data buffer, and determining a minimum interval between the stable duration impulses in the microcontroller;
- after the data buffer is filled with at least 30 values of the repetition periods of the stable duration impulses, transmitting the data from the data buffer to a monotonicity coefficient calculation unit;
- determining a monotonicity coefficient as a ratio between an average value of the repetition periods of the stable duration impulses and a minimum value of the measured period;
- transmitting the monotonicity coefficient and the minimum interval between the stable duration impulses to a decision-making unit;
- and
- generating an alarm signal in the decision-making unit, when the monotonicity coefficient becomes greater than 3.0 and the minimum interval between the stable duration impulses is within 30.0-2000.0 μs.
10 more elements
A device for detecting vibroacoustic signals, the device comprising:
- a housing with a piezoelectric sensor arranged therein, an output of the piezoelectric sensor is connected to a printed circuit board with a preamplifier arranged thereon, an input of the preamplifier is connected to an input of a low-frequency filter, an output of the low-frequency filter is connected to a high-frequency filter, an output of the high-frequency filter is connected to an amplifier and to a first input of an analog switch, an output of the amplifier is connected to a first input of a comparator and to a second input of the analog switch, a reference voltage source is connected to a second input of the comparator, the reference voltage source is configured to set a comparator switching limit, an output of the comparator is connected to the analog switch, an output of the analog switch is connected to a rectifier, an output of the rectifier is connected to an input of an integrator, an output of the integrator is connected to an impulse generation unit that is configured to generate a command for resetting the integrator, the impulse generation unit has first and second outputs, the first output is connected to the integrator, and the second output is connected to an input of the microcontroller, while a data buffer, a monotonicity coefficient calculation unit, and a decision-making unit are configured within the microcontroller.
Dependencies are inferred from the claim text.