JP7453901B2 - Level crossing warning sound monitoring device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a level crossing alarm sound monitoring device that monitors alarm sounds emitted from a level crossing alarm.

Level crossings where railroads and roads intersect at level are usually equipped with level crossing warning devices that alert pedestrians of approaching trains using lights and sounds. Level crossing alarms are equipped with warning lights that emit light when a train approaches, and speakers that emit a warning sound.

Conventionally, in order to check whether or not a level crossing alarm is malfunctioning, a worker has to periodically go to the location where the level crossing alarm is installed and check manually. However, since level crossing alarms are installed over a wide range of locations, manual checking is time-consuming, and it is difficult to frequently check all level crossing alarms for malfunctions.

Patent Document 1 describes an alarm device in which a display circuit section performs an alarm operation such as a warning or an alert when an alarm sound of a railroad crossing alarm is detected by an alarm sound detection circuit.

Japanese Patent Application Publication No. 8-310401

The purpose of the invention described in Patent Document 1 is to detect alarm sounds and warn intruders at railroad crossings, etc., and to carry out measurements, etc. to confirm whether the alarm sound of a railroad crossing alarm is sounding normally. It is not intended as a purpose. Therefore, no consideration is given to processing for detecting alarm sounds with high accuracy.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a level crossing alarm sound monitoring device that can accurately detect a level crossing alarm sound.

The invention made to solve the above problems includes a measurement start determination section that determines whether the sound pressure of a sound detected by a sound pressure detection means provided near a level crossing alarm exceeds a measurement start threshold, and a measurement start determination section. the level crossing alarm, in which the sound pressure changes periodically based on a maximum value and a minimum value of the sound pressure detected by the sound pressure detection means within a predetermined time after the part determines that the measurement start threshold has been exceeded; The apparatus is characterized by comprising a period threshold calculation unit that calculates a threshold for determining the period of the sound.

Further, the threshold value includes a first threshold value offset in the direction of increasing and a second threshold value offset in the direction of decreasing with respect to the median value of the maximum value and the minimum value. is preferred.

Further, it is preferable that the apparatus further includes a measuring section that measures the peak value of the sound pressure and the period of the sound pressure based on the threshold calculated by the period threshold calculating section.

Furthermore, after measuring the peak value and the period, the period threshold calculation unit waits for a predetermined period of time until the alarm sound is reduced, and then calculates the period determination threshold again. It is preferable to do so.

Further, the measurement unit measures the peak value and the period of the sound pressure after the sound reduction based on the period determination threshold calculated by the period threshold calculation unit after the sound reduction. is preferred.

Further, a ringing end determination unit determines whether the sound pressure of the sound detected by the sound pressure detection means is below a ringing end threshold; It is preferable that the method is characterized by comprising an output unit that outputs a result.

According to the present invention, the period threshold calculation section calculates the threshold for determining the period of the warning sound of the level crossing alarm within a predetermined time after the measurement start determination section determines that the measurement start threshold has been exceeded. Through the measurement, a threshold value for the main measurement can be calculated. Therefore, in this measurement, accurate peak values and cycles can be measured, and furthermore, the number of rings per unit time can be accurately measured. Furthermore, by determining whether the measurement start threshold has been exceeded, measurement of the peak and period of the sound pressure can be automatically started. Therefore, it is not necessary to input a signal indicating a level crossing operation from the level crossing alarm, and the installation of the device becomes easier.

1 is a schematic configuration diagram of a level crossing warning sound monitoring device according to an embodiment of the present invention. 2 is a graph showing the relationship between the dynamic range of the output signal of the integral amplifier circuit shown in FIG. 1 and the number of bits during AD conversion. 2 is a waveform diagram of the signal processing section shown in FIG. 1. FIG. 2 is a flowchart of the measurement operation of the level crossing warning sound monitoring device shown in FIG. 1. FIG. FIG. 3 is an explanatory diagram of a measurement start threshold. FIG. 3 is an explanatory diagram of sound pressure peak detection processing. FIG. 3 is a diagram showing a sound pressure waveform from the start of sound pressure measurement to the end of sound pressure measurement. It is an explanatory view of a ringing end threshold.

A level crossing warning sound monitoring device according to an embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of a level crossing warning sound monitoring device 1 according to the present embodiment. As shown in FIG. 1, the level crossing alarm sound monitoring device 1 includes a signal processing section 2, an MPU 3, an RS232C transmission section 4, a power supply section 5, an oscillator 6, a reset IC 7, a SW input 8, It is equipped with

The level crossing alarm sound monitoring device 1 shown in FIG. 1 is installed near a level crossing alarm, detects the alarm sound emitted by the level crossing alarm via a sound pressure sensor 60, and detects the sound pressure, the number of sounds per unit time, etc. Measure.

The signal processing unit 2 is connected to the sound pressure sensor 60 and performs signal processing of the sound pressure value (sound pressure waveform) detected by the sound pressure sensor 60.

The signal processing unit 2 includes an HPF 21, a differential half-wave AMP 22, an LPF 23, an HPF 24, a first integral amplifier circuit 25, a second integral amplifier circuit 26, and a third integral amplifier circuit 27. .

The HPF 21 is a high-pass filter that passes a predetermined frequency (for example, 7.96 Hz) or higher in order to mainly remove DC components from the sound pressure waveform detected by the sound pressure sensor 60. The differential half-wave AMP 22 performs half-wave rectification and amplification on the differential signal input from the sound pressure sensor 60 and passed through the HPF 21 . The LPF 23 is a low-pass filter, and the HPF 24 is a high-pass filter. The LPF 23 and the HPF 24 constitute a filter that passes a frequency range including 700 Hz and 750 Hz that constitute the railroad crossing warning sound.

The first integral amplification circuit 25 is a circuit that integrates the sound pressure signal that has passed through the HPF 24 and amplifies it by a predetermined time (for example, 5.6 times). The second integral amplifier circuit 26 is a circuit that integrates the output signal of the first integral amplifier circuit 25 and amplifies it by a predetermined time (for example, five times). The third integral amplifier circuit 27 is a circuit that integrates the output signal of the second integral amplifier circuit 26 and amplifies it by a predetermined time (for example, five times).

That is, the differential half-wave AMP 22 functions as a half-wave amplification circuit into which a sound pressure signal is input from the sound pressure detection means provided near the level crossing alarm, and the first integral amplification circuits 25 to 27 function as a half-wave amplification circuit. It functions as an integral amplifier circuit into which the output signal of the amplifier circuit is input.

The second integral amplifier circuit 26 and the third integral amplifier circuit 27 enable even if the amplitude of the sound pressure waveform is small, it can be converted into a digital signal with sufficient accuracy in the subsequent AD converter. FIG. 2 is a graph showing the relationship between the dynamic range [dB] and the number of bits [bit] during AD conversion for the output signals of three integrating amplifier circuits. [dB] increases as the horizontal axis moves to the right, and [bit] increases as the vertical axis moves upward.

As shown in FIG. 2, when the dynamic range is large (large range), the number of bits per sound pressure is small and the sensitivity is low. When the dynamic range is medium (medium range), the number of bits per sound pressure is greater than in the large range, so the sensitivity is medium. When the dynamic range is small (small range), the number of bits per sound pressure is even greater than in the medium range, so the sensitivity is high.

That is, whether a large amplitude and a wide dynamic range are required or a small amplitude and a narrow dynamic range are sufficient, a sufficient number of bits can be secured during AD conversion. Here, in FIG. 2, the large range corresponds to the output of the first integral amplifier circuit 25, the medium range corresponds to the output of the second integral amplifier circuit 26, and the small range corresponds to the output of the third integral amplifier circuit 27.

Further, as is clear from the above description, the first integral amplifier circuit 25, the second integral amplifier circuit 26, and the third integral amplifier circuit 27 are connected in series. In the configuration shown in FIG. 1, three stages of integral amplifier circuits are connected in series, but there may be two stages or four or more stages. The number of series connections may be appropriately determined depending on the above-mentioned range classification, circuit scale, cost, etc. Note that depending on the amplitude of the input signal, the integral amplifier circuit may have one stage.

In addition, the first integral amplifier circuit 25, the second integral amplifier circuit 26, and the third integral amplifier circuit 27 have amplitude frequency characteristics in a band including two frequencies (700 to 750 Hz) included in the alarm sound emitted by the level crossing alarm, The amplification factor increases in the order of the amplitude frequency characteristic at the frequency of the difference (50 Hz) between the two frequencies, and the amplitude frequency characteristic at the frequency based on the number of rings per unit time. Note that since the warning sound of a level crossing alarm normally sounds about 120 to 130 times per minute, the frequency based on the number of sounds per unit time is about 2 Hz.

Further, in the configuration shown in FIG. 1, the first integral amplifier circuit 25, the second integral amplifier circuit 26, and the third integral amplifier circuit 27 are all configured as integral amplifier circuits, but only the first integral amplifier circuit 25 is an integral amplifier circuit. The second integral amplifier circuit 26 and the third integral amplifier circuit 27 may be amplifier circuits other than integral amplifier circuits.

FIG. 3 shows waveforms of the signal processing section 2 described above. FIG. 3(a) shows the waveform of the alarm sounding three times (strictly speaking, from the second half of the first to the first half of the third). Since the level crossing warning sound generally pulsates, the amplitude of the waveform gradually decreases. FIG. 3(b) is an enlarged view of portion A in FIG. 3(a). In FIG. 3, S1 is a waveform after half-wave rectification, that is, an output waveform of the differential half-wave AMP 22. S2 is a waveform after integral amplification. S2 in FIG. 3 is the output waveform of the first integral amplifier circuit 25.

The MPU 3 is a microprocessor that includes a CPU (Central Processing Unit) and the like. The MPU 3 executes various measurement operations, etc., which will be described later, according to programs stored in a built-in memory. Furthermore, the MPU 3 includes AD converters (ADCs) 31, 32, 33, and 34, UARTs 35 and 36, and an I/O 37.

The AD converter 31 receives the sound pressure waveform output from the first integral amplifier circuit 25 and converts the analog signal into a digital signal. The AD converter 32 receives the sound pressure waveform output from the second integral amplifier circuit 26 and converts the analog signal into a digital signal. The AD converter 33 receives the sound pressure waveform output from the third integral amplifier circuit 27 and converts the analog signal into a digital signal. The AD converter 34 converts the signal input from the voltage monitoring section 51 of the power supply section 5 into a digital signal.

The UART 35 is an interface circuit that converts parallel data sent to the wireless communication unit 70 into serial data, and converts serial data received from the wireless communication unit 70 into parallel data. The UART 35 outputs information such as various measurement results measured by the MPU 3 as serial data. The UART 36 is an interface circuit that converts parallel data sent to the RS232C transmission section 4 into serial data, and converts serial data received from the RS232C transmission section 4 into parallel data.

The I/O 37 outputs a control signal to a regulator of the power supply section 5, which will be described later. Since the level crossing warning sound monitoring device 1 according to the present embodiment is battery-powered, the MPU 3 can control the power supply unit 5 to stop each part inside the level crossing warning sound monitoring device 1 in order to save power.

The RS232C transmission unit 4 outputs information input from the UART 36 to the PC 80 for various settings. Further, the RS232C transmission section 4 outputs signals input from the PC 80 to the UART 36. In this embodiment, communication is performed between the level crossing warning sound monitoring device 1 and the PC 80 according to the RS232C standard, but the communication standard is not limited to the RS232C standard, and other communication standards, whether wired or wireless, may be used.

The power supply unit 5 converts the power supplied from the battery 100 into voltages and the like required by each block of the level crossing warning sound monitoring device 1 and supplies the voltage. The power supply unit 5 includes a voltage monitoring unit 51, a voltage detection unit 52, and regulators 53, 54, and 55.

Voltage monitoring section 51 monitors the voltage output by battery 100. Voltage monitoring section 51 outputs the output voltage value of battery 100 to AD converter 34. Voltage detection section 52 detects the voltage output by battery 100 and outputs the detection result to regulator 53. The regulator 53 converts the voltage (for example, DC 3V) supplied from the battery 100 to, for example, 2.2V and supplies it to the MPU 3, SW input 8, and the like. The regulator 54 converts the voltage supplied from the battery 100 to, for example, 2.2V and supplies it to the signal processing section 2, the sound pressure sensor 60, the wireless communication section 70, and the like. The regulator 55 converts the voltage supplied from the battery 100 to, for example, 2.2V and supplies it to the RS232C transmission unit 4 and the like.

The oscillator 6 is composed of, for example, a crystal oscillator, and generates a clock signal for operating the MPU 3.

The reset IC 7 is a well-known circuit that monitors whether the output voltage of the power supply 5 has become equal to or higher than the operating voltage of the MPU 3 and activates the MPU 3 by canceling the reset signal to the MPU 3.

The SW input 8 is a switch that is operated, for example, when performing wireless communication with the outside via the wireless communication section 70. When the SW input 8 is operated, the MPU 3 etc. are activated even if they are inactive.

The sound pressure sensor 60 is provided near a speaker that emits a warning sound of a level crossing alarm. The sound pressure sensor 60 is composed of, for example, a microphone IC.

The wireless communication unit 70 outputs information such as various measurement results output from the MPU 3 (UART 35) to an external device or the like. The wireless communication unit 70 can be a device that performs wireless communication according to the ZigBee (registered trademark) standard, for example. Of course, other wireless communication standards may be used.

The PC 80 is a computer that serves as a terminal for various settings of the level crossing warning sound monitoring device 1. The PC 80 is connected when necessary for settings and the like.

The battery 100 supplies electric power (for example, DC 3V) to the level crossing warning sound monitoring device 1 . In this embodiment, by using a battery drive, an external power supply is not required and the degree of freedom in installation location is increased. Note that the battery 100 may be a primary battery or a secondary battery.

Next, the measurement operation of the level crossing warning sound monitoring device 1 having the above-described configuration will be explained with reference to FIGS. 4 to 8. FIG. 4 is a flowchart of the measurement operation of the level crossing warning sound monitoring device 1. The flowchart shown in FIG. 4 is executed by the MPU 3. First, the MPU 3 determines whether the sound pressure detected by the sound pressure sensor 60 exceeds a preset threshold (measurement start threshold) for detecting the start of measurement (step S101). If the measurement start threshold is not exceeded (step S101; NO), step S101 is repeated. That is, the MPU 3 functions as a measurement start determination unit that determines whether the sound pressure of the sound detected by the sound pressure detection means provided near the level crossing alarm exceeds the measurement start threshold.

The measurement start threshold will be explained with reference to FIG. FIG. 5 is a waveform diagram illustrating a period from the start of measurement to a period during which a sound pressure cycle threshold value calculation, which will be described later, is performed. As shown in FIG. 5, the measurement start threshold is a threshold for determining whether to start measurement, and is therefore set to a value lower than the peak of the alarm sound or the like. The measurement operation is started using the exceeding of this measurement start threshold as a trigger.

If the measurement start threshold is exceeded (step S101; YES), the MPU 3 performs sound pressure cycle threshold calculation processing (step S102). The sound pressure cycle threshold calculation process is a process that calculates (determines) a sound pressure cycle threshold (threshold for cycle determination) for calculating the sound pressure peak and cycle, which will be described later, during a predetermined period of time after the measurement start determination. . A method for calculating the sound pressure cycle threshold will be described with reference to FIG. 5. In FIG. 5, when the measurement start threshold is exceeded, the sound pressure cycle threshold is determined from the maximum and minimum values of the sound pressure for a predetermined period of time (threshold calculation time). In the case of FIG. 5, if Pmax1 to Pmaxn are the maximum values of each period and Pmin1 to Pminn are the minimum values of each period, for example, the largest value among Pmax1 to Pmaxn and the smallest value among Pmin1 to Pminn. Let the median value be the sound pressure cycle threshold.

That is, the MPU 3 periodically changes the sound pressure based on the maximum and minimum values of the sound pressure detected by the sound pressure detection means within a predetermined time after the measurement start determination section determines that the measurement start threshold has been exceeded. It functions as a cycle threshold calculation unit that calculates a threshold for determining the cycle of the warning sound of the level crossing alarm.

Next, the MPU 3 performs sound pressure peak detection processing (step S103). In the sound pressure peak detection process, the ON value and OFF value shown below are set based on the sound pressure cycle threshold calculated in step S102, and a sound pressure peak is detected. The sound pressure peak detection process will be explained with reference to FIG. In FIG. 6, an ON point is set at a position of +25% and an OFF point is set at a position of -25% with the sound pressure cycle threshold value as a reference. The ON point is a threshold value for detecting that the sound pressure is increasing and heading towards the maximum value (peak), and the OFF point is a threshold value for detecting that the sound pressure is decreasing and heading towards the minimum value. . That is, the sound pressure cycle threshold includes a first threshold offset in the direction of increasing and a second threshold offset in the direction of decreasing with respect to the median value of the maximum value and the minimum value.

In FIG. 6, the circles displayed on the waveform are sampling points. Among these sampling points, for the period P1, ON detection is performed at the sampling point on1 that first exceeds the ON point. On the other hand, OFF is detected at the first sampling point off1 below the OFF point. Then, the maximum value of the sampling points from exceeding the ON point to falling below the OFF point becomes the peak value in the period P1. Similarly, for the period Pn, ON detection is performed at the sampling point onn that first exceeds the ON point. On the other hand, OFF is detected at the first sampling point offn below the OFF point. Then, the maximum value of the sampling points from exceeding the ON point to falling below the OFF point becomes the peak value in the period Pn.

Then, the peak value of each cycle is acquired over a plurality of cycles until the end of the sound pressure measurement, and, for example, the average value is output as the peak value in the sound pressure peak detection process. Note that when calculating the average value, processing may be performed to remove the maximum value and minimum value. By obtaining the peak value for each period as in this embodiment, processing such as averaging and filtering can be performed thereafter, and accurate peak values can be obtained.

Next, the MPU 3 performs sound pressure cycle detection processing (step S104). The sound pressure cycle detection process detects a sound pressure cycle based on the sound pressure cycle threshold calculated in step S102, and calculates the number of rings per unit time based on the cycle. The sound pressure cycle detection process will be explained with reference to FIG. FIG. 7 is a diagram showing a sound pressure waveform from the start of sound pressure measurement to the end of sound pressure measurement. The sound pressure cycle threshold, ON point, and OFF point are as explained in FIG. 6. At this time, in this embodiment, one cycle is detected from one ON point to the next ON point. Of course, one cycle may be detected from one OFF point to the next OFF point. Then, the number of rings per unit time is calculated based on the detected period.

That is, the MPU 3 functions as a measuring section that measures the peak value of the sound pressure and the period of the sound pressure based on the threshold calculated by the period threshold calculating section.

Next, the MPU 3 determines whether it is time to start reducing the sound (step S105). If it is not the sound reduction start time (step S105; NO), step S105 is repeated. Some railroad crossing alarms reduce their sound after a predetermined period of time has passed after they start sounding. The predetermined time until this sound reduction is determined in advance. Therefore, in this embodiment, instead of detecting the sound reduction, by determining the point in time (sound reduction start time) when a predetermined time (sound reduction time) has elapsed, measurements in the sound reduction state described below are performed. are doing. That is, after measuring the peak value and period, the MPU 3 waits for a predetermined period of time until the alarm sound is reduced. In this embodiment, in order to measure the state after the sound has been reduced, the sound reduction start time may be set to a time when it is certain that the sound has been reduced.

If it is the sound reduction start time (step S105; YES), the MPU 3 performs sound reduction sound pressure cycle threshold calculation processing (step S106). The sound pressure cycle threshold calculation process for sound reduction is to perform the sound pressure cycle threshold calculation process (step S102) in the sound reduction state. The processing contents of the sound reduction sound pressure cycle threshold value calculation process are the same as the sound pressure cycle threshold value calculation process, so a description thereof will be omitted. That is, the MPU 3 calculates the threshold value for period determination again.

Next, the MPU 3 performs sound reduction sound pressure peak detection processing (step S107). The reduced sound pressure peak detection process is to perform sound pressure peak detection processing in the reduced sound state (step S103). The processing contents of the reduced sound pressure peak detection process are the same as the sound pressure peak detection process, so a description thereof will be omitted.

In addition, in the sound pressure peak detection process and the sound pressure peak detection process, the value of the AD converter that is not saturated among the outputs of the AD converters 31 to 33 is adopted. By doing so, even in the case of a small amplitude, a peak value can be obtained with appropriate resolution and accuracy.

Next, the MPU 3 performs sound reduction sound pressure cycle detection processing (step S108). The reduced sound pressure cycle detection process is to perform sound pressure cycle detection processing in the reduced sound state (step S104). The processing contents of the reduced sound pressure cycle detection process are the same as the sound pressure cycle detection process, so a description thereof will be omitted.

Next, the MPU 3 determines whether it is less than the ringing end threshold (step S109). If it is not less than the ringing end threshold (step S109; NO), step S109 is repeated. The sounding end threshold is a threshold for detecting that the sounding of the level crossing alarm has ended, and will be explained with reference to FIG. 8. FIG. 8 is a diagram showing the relationship between the sound pressure waveform and the ringing end threshold. As shown in FIG. 8, when the sound pressure value is less than the ringing end threshold, step S110, which will be described later, is executed. Note that the ringing end threshold may be the same value as the measurement start threshold described above. That is, the MPU 3 functions as a ringing end determination section that determines whether the sound pressure of the sound detected by the sound pressure detection means has fallen below the ringing end threshold.

Next, the MPU 3 performs output processing (step S110). The output processing includes the peak value detected by the sound pressure peak detection process, the number of rings per unit time calculated based on the period detected by the sound pressure cycle detection process, the peak value detected by the sound pressure peak detection process, and the peak value detected by the sound pressure peak detection process. The measurement result including the number of rings per unit time calculated based on the period detected by the sound pressure period detection process is transmitted to the outside via the wireless communication unit 70. That is, after the ringing end determination unit determines that the sound has fallen below the ringing end threshold, it functions as an output unit that outputs the result measured by the measuring unit.

The above-described flowchart is executed once from the start of the ringing to the end of the ringing. Here, in this embodiment, the period from the start of sounding to the end of sounding (also simply referred to as sounding) refers to a period during which, for example, a warning sound is sounded intermittently and a warning light is blinking, from the time when a train approaches until it passes.

According to the present embodiment, the level crossing alarm sound monitoring device 1 includes a differential half-wave AMP 22 into which a sound pressure signal is input from a sound pressure sensor 60 provided near the level crossing alarm, and an output of the differential half-wave AMP 22. Based on the output signals of the first integral amplifier circuit 25 to third integral amplifier circuit 27 to which signals are input, and the output signals of the first integral amplifier circuit 25 to third integral amplifier circuit 27, the warning sound of the level crossing alarm per unit time is calculated. It includes an MPU 3 that calculates the number of ringings.

By configuring the level crossing warning sound monitoring device 1 as described above, the warning sound can be detected accurately with a simple circuit configuration without having to detect sounds of two different frequencies.

Furthermore, since a plurality of amplifier circuits from the first integral amplifier circuit 25 to the third integral amplifier circuit 27 are connected in series, it is possible to convert the waveform into a digital signal with sufficient accuracy in the subsequent AD converter according to the amplitude of the waveform. become. Therefore, accurate measurement is possible for alarm sounds with a wide dynamic range.

Further, the amplitude frequency characteristics of the first integral amplifier circuit 25 to the third integral amplifier circuit 27 are the amplitude frequency characteristics of two frequency bands (700 to 750 Hz) included in the warning sound emitted by the level crossing alarm, The amplification factor increases in the order of the amplitude frequency characteristic at the frequency of the frequency difference (50 Hz) and the amplitude frequency characteristic at the frequency based on the number of rings per unit time. By doing this, high frequency components are difficult to amplify, so even if two frequency components are mixed, the amplitude and number of rings per unit time can be measured with high precision using an AD converter with a slow sampling rate. can do. Therefore, an expensive AD converter is not required, and costs can be reduced.

Furthermore, since the MPU 3 calculates the number of alarm sounds per unit time based on the cycle of the output signal of the signal processing unit 2, the number of alarm sounds per unit time can be easily calculated based on the cycle. .

Moreover, since the MPU 3 obtains the period based on the threshold value for period determination set in the output signal of the signal processing section 2, the period can be easily determined by setting the threshold value.

In addition, in the level crossing alarm sound monitoring device 1, the MPU 3 determines whether the sound pressure of the sound detected by the sound pressure sensor 60 installed near the level crossing alarm exceeds a measurement start threshold, and determines that the sound pressure exceeds the measurement start threshold. After that, a threshold value for detecting the period of the alarm sound is calculated based on the maximum value and minimum value of the sound pressure detected by the sound pressure sensor 60 within a predetermined period of time.

By configuring the level crossing warning sound monitoring device 1 as described above, it is possible to calculate the threshold value for main measurement by preliminary measurement. Therefore, in this measurement, accurate peak values and cycles can be measured, and furthermore, the number of rings per unit time can be accurately measured. Furthermore, by determining whether the measurement start threshold has been exceeded, measurement of the peak and period of the sound pressure can be automatically started. Therefore, it is not necessary to input a signal indicating a level crossing operation from the level crossing alarm, and the installation of the device becomes easier.

In addition, after measuring the peak value and period, the MPU 3 waits for a predetermined period of time until the alarm sound is reduced, and then calculates the threshold for period determination again, so the threshold is set to match the reduced sound state. can do. Further, the sound reduction state can be reliably measured without determining whether the sound is reduced based on the sound pressure.

Moreover, since the MPU 3 measures the peak value and the period of the sound pressure signal after the sound reduction based on the threshold value for period determination calculated after the sound reduction, accurate measurement can be performed even when the sound is reduced.

Further, the MPU 3 determines whether the sound pressure of the sound detected by the sound pressure sensor 60 has fallen below the ringing end threshold, and after determining that the sound pressure has fallen below the ringing end threshold, outputs the measured result to the outside via the wireless communication unit 70. . In this way, by detecting the end of the sound, it can be determined that no train has passed, and wireless communication can be performed without a train interfering with wireless communication.

Note that the present invention is not limited to the above embodiments. That is, those skilled in the art can implement various modifications based on conventionally known knowledge without departing from the gist of the present invention. Such modifications are, of course, included within the scope of the present invention as long as they still have the configuration of the level crossing warning sound monitoring device of the present invention.

1 Level crossing alarm sound monitoring device 2 Signal processing section 22 Differential half-wave AMP (half-wave amplifier circuit)
25 First integral amplifier circuit (integral amplifier circuit)
26 Second integral amplifier circuit (integral amplifier circuit)
27 Third integral amplifier circuit (integral amplifier circuit)
3 MPU (calculation unit, measurement start determination unit, cycle threshold calculation unit, measurement unit, ringing end determination unit, output unit)
60 Sound pressure sensor (sound pressure detection means)

Claims (6)

a measurement start determination unit that determines whether the sound pressure of the sound detected by the sound pressure detection means provided near the level crossing alarm exceeds a measurement start threshold;
the level crossing alarm in which the sound pressure changes periodically based on the maximum and minimum values of the sound pressure detected by the sound pressure detection means within a predetermined time after the measurement start determination unit determines that the measurement start threshold has been exceeded; a cycle threshold calculation unit that calculates a threshold for determining the cycle of the alarm sound of the aircraft;
A railroad crossing warning sound monitoring device comprising: 1 . The threshold value includes a first threshold value offset in the direction of increasing the median value of the maximum value and the minimum value, and a second threshold value offset in the direction of decreasing the median value of the maximum value and the minimum value. The railroad crossing warning sound monitoring device described in . The level crossing warning sound monitoring according to claim 1 or 2, further comprising a measuring section that measures the peak value of the sound pressure and the period of the sound pressure based on the threshold calculated by the period threshold calculating section. Device. After measuring the peak value and the period, the period threshold calculation unit waits for a predetermined period of time until the alarm sound is reduced, and then calculates the period determination threshold again. The level crossing warning sound monitoring device according to item 3. 4. The measurement unit measures the peak value and the period of the sound pressure after the sound reduction based on the period determination threshold calculated by the period threshold calculation unit after the sound reduction. The railroad crossing warning sound monitoring device described in . a ringing end determination unit that determines whether the sound pressure of the sound detected by the sound pressure detection means is below a ringing end threshold;
an output unit that outputs the result measured by the measurement unit after the ringing end determination unit determines that the sound has fallen below the ringing end threshold;
The level crossing warning sound monitoring device according to any one of claims 3 to 5, comprising:

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