JP3035505B2 - Emergency signal transmission device and method for determining the number of emergency signal transmission devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention
The present invention relates to an emergency signal transmitting device for transmitting an emergency signal for rescuing a victim and a method for determining the number of emergency signal transmitting devices.

[0002]

[Prior Art] Victims and victims of disasters such as house collapses and landslides caused by earthquakes, etc. are covered with collapsed houses and earth and sand, and the damage situation cannot be confirmed from the outside. It was difficult to determine the rescue, and it took a long time to determine the necessity of rescue and the rescue method.

[0003] However, in these disasters, the earlier the rescue, the higher the probability of surviving the victim, the more urgent the rescue. Therefore, Japanese Patent Publication No. 57-4054
A rescue signal transmitting device as disclosed in Japanese Patent Application Laid-Open No. 6-206 is devised. This device is used for creating victims in snowy mountains and the like, and includes an oscillator that oscillates a frequency signal in the broadcast frequency band and an antenna that radiates the oscillator wave,
When a person carries this device and the person is distressed, the position of the person is searched for while detecting the strength of the transmitted wave by a receiver that receives the transmitted wave.

This rescue signal transmitting apparatus is provided with a temperature sensing element for detecting the body temperature of the carrier, and the transmission interval of the oscillator is changed according to the body temperature of the carrier. Therefore, the life and death of the carrier can be estimated from the reception interval of the transmitted wave received by the receiver.

[0005] In this rescue signal transmitting device, the transmitting frequency of each device is different, and the receiver can identify a carrier based on the frequency.

[0006]

However, at the time of a large-scale disaster such as an earthquake, there is a high possibility that a large number of victims will come out in a wide range, and the location and time of the disaster cannot be predicted. Cannot be used as it is. First, assuming a large-scale disaster, everyone needs to carry this transmitting device. The transmitting frequencies of the transmitting devices owned by each person must be different from each other, and a certain interval must be provided between the transmitting frequencies of the transmitting devices to avoid interference. Such fine frequency setting becomes very troublesome in terms of the circuit configuration of the transmission device. Furthermore,
When the number of transmitting devices is large, the transmitting frequencies of the individual transmitting devices must be set to be different over a wide frequency range beyond the broadcast frequency band.

[0007] Further, when the transmission frequencies are dispersed in such a wide frequency range, the receiver for separating and receiving the transmission frequencies needs to be configured to be able to receive signals in a wide frequency range. In addition, since this transmission device has a random transmission interval, in the event of a disaster, it must simultaneously receive signals in this wide frequency range in order to grasp the victim, which makes the receiver extremely complicated. There is.

[0008] As described above, the transmitting device disclosed in Japanese Patent Publication No. 57-40456 is effective for a specific small number of disasters such as a disaster in a snowy mountain, but not for a large-scale disaster. Difficult to apply. Therefore, when a large-scale disaster such as an earthquake disaster is assumed, it is necessary to develop a signal system that separates and accurately receives a plurality of emergency signals in a new narrow frequency region.

In consideration of such an emergency signal communication that is optimal for such a large-scale disaster, first, in an emergency, it is essential to detect the presence and number of callers at the disaster site as reliably as possible. Subsequently, it is desirable that the information content of each sender can be accurately determined.
As a system for separating and receiving a large number of outgoing signals satisfying such requirements, there are mobile communication technologies such as a mobile phone and a PHS.

[0010] However, these communication systems are:
This system pursues communication efficiency after optimally designing a network and communication environment in advance. The system is large in scale and the capital investment in advance is enormous. Therefore, it is difficult to provide a system for emergency communication. In addition, in these communication systems, the system itself and the devices that make up the system are too complex, and as an emergency communication system that must secure minimum communication under severe conditions that can occur in the event of a disaster, reliability is low. There's a problem. That is, the design concept required in an emergency communication system different from the ordinary public mobile communication system is summarized as follows.

(1) Radio waves or sound waves are used for communication, but the reception level of each transmission signal varies greatly depending on the collapse situation or weather condition.

(2) It is not possible to know in advance the number of persons simultaneously transmitting from the same disaster site, and it must be assumed that the number of persons is extremely large.

(3) Under such conditions, it is required to separate and receive a number of overlapping transmission signals.

(4) Since the transmitter operates on a battery, its short life time must be considered.

(5) However, the amount of information to be transmitted is extremely small, and the same data can be repeatedly transmitted for a relatively long time.

[0016]

According to the first aspect of the present invention, there is provided an emergency signal transmitting apparatus, comprising: a signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval which varies randomly within a predetermined time range; Data transmission means for transmitting a data signal modulated at a frequency different from that of the radio signal as a pair with the radio signal is provided. The emergency signal transmitting device according to claim 2, further comprising signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval randomly changing within a predetermined time range, wherein the randomly changing time interval of the signal transmitting means is , A time obtained by adding a random change time to the reference time, and the signal transmission time of the signal transmission means is shorter than the random change time. An emergency signal transmitting device according to claim 3, wherein the signal transmitting means repeatedly transmits a radio signal of a predetermined frequency at a time interval that randomly changes within a predetermined time range, and is modulated at a frequency different from the radio signal of the predetermined frequency. Data transmission means for transmitting the data signal paired with the radio signal, wherein the data signal is transmitted after the radio signal of the predetermined frequency. The emergency signal transmitting device according to claim 4, wherein the signal transmitting means repeatedly transmits a radio signal of a predetermined frequency at a time interval that randomly changes within a predetermined time range, and is modulated at a frequency different from the radio signal of the predetermined frequency. Data signal for transmitting the data signal paired with the radio signal.
Data transmitting means, and the data signal includes ID data unique to the transmitting device. The method for determining the number of emergency signal transmitting devices according to claim 5 includes a plurality of emergency signal transmitting devices provided with signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval that randomly changes within a predetermined time range. An emergency signal receiving device including a counting means for receiving a predetermined frequency signal having a predetermined time width transmitted from the plurality of emergency signal transmitting devices and counting the number of times of reception, and the emergency signal receiving device comprising: A timer that measures and outputs the elapsed time from when the first counting is performed, the predetermined frequency of the plurality of emergency signal transmitting devices is the same, and the time interval at which the signal transmitting means randomly changes is , A time obtained by adding a random change time to the reference cycle T, and when the timer output Tm and the count C by the counting means, the number N of the emergency signal transmitting devices is N = -
The number of the emergency signal transmitting devices is determined as T / Tm.

[0017]

[0018]

[0019]

[0020]

According to the first aspect of the present invention, the data signal modulated at a frequency different from the radio signal of the predetermined frequency is transmitted as a pair with the radio signal, so that not only the presence of the victim but also the victim is transmitted. It is possible to inform the user of the data relating to the situation described above, and since the data signal is modulated at a frequency different from that of the radio signal, it is possible to prevent each signal from interfering.

According to the fifth aspect of the present invention, a predetermined frequency signal having a predetermined time width is received, and the number of emergency signal transmitting devices transmitting the signal can be confirmed by the counting means for counting the number of receptions. it can.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an outline of a system according to an embodiment of the present invention will be described with reference to FIG. The emergency signal transmitting device 1 is held by the user, and is activated when the user encounters any disaster, and transmits the emergency signal ES. The emergency signal ES is received by the emergency signal receiving device 2 installed at a disaster countermeasure center or the like.

As described above, the emergency signal at the time of a disaster is to notify the existence of the victim at the worst, that is, to determine the number of persons on the searcher (receiver) side when there are a plurality of victims. And Subsequently, it is desirable that, if possible, it is possible to transmit detailed data that allows the situation of each victim to be grasped and to receive the detailed data.

Therefore, the emergency signal transmitting device 1 of this embodiment
As shown in FIG. 1, a signal TB indicating only the presence of a victim as surely as possible and a signal DS indicating personal data including safety information of each victim are modulated at different frequencies, and at different timings. Send. Hereinafter, a signal (ton burst TB) notifying the existence of the victim and a data signal (individual data DS) notifying the situation of the victim will be described in this order. After that, the emergency signal transmitting device 1 for transmitting both signals and the emergency signal receiving device 2 for receiving will be described. 1-1. Tone burst transmission method A signal for notifying the presence of a caller is transmitted for a predetermined time (D
Second), a signal (tone burst TB) in which a sine wave of a constant frequency (foHz) continues. Each transmitting device 1 repeatedly and intermittently transmits the tone burst TB. Since all the transmitting devices 1 transmit the tone burst TB of the same frequency, if there are a plurality of transmissions at the same site, the signals may collide with each other. Normally, the timing of the disaster differs slightly depending on the situation of the victim, the region, and the like. Therefore, the transmission timing of the tone burst TB differs slightly for each transmission device 1.

However, if the time interval of repetitive transmission is constant and the period is the same for all the transmitting devices 1, if two or more transmitting devices 1 start transmitting simultaneously at the same time, the same transmitting device 1 The collision will last forever. In order to avoid such a collision, in the present invention, the transmission cycle of each transmission device 1 is set to be random.

That is, as shown in FIG. 2, a basic period is T seconds, and a random change time T _K seconds is added to the basic period T + T _k seconds (where the change width L of the random change time T _K , That is, −L <T _k <L is naturally L <TD). The K−1-th and K-th tone burst TB
Start time interval. Since the random number generation calculation for determining T _k is started using a different seed in each transmitting device 1, T _{k of} each transmitting device has a different value.

FIG. 3 shows an example in which four transmitting devices 1a to 1d are transmitting tone burst TB. In this example, the duration (D seconds) and the random variation width (L seconds) of the tone burst TB are set to D = T / 10 and L = T / 2 in order to clearly show the case where a collision occurs. Therefore, in FIG. 3, the times t ₁ , t
Tone bursts TB are colliding with each other at three points of _2, t _3. However, this collision did not occur repeatedly with the torn burst TB of the same transmitting device continuously, and the transmitting timing of the torn burst TB of each of the transmitting devices 1a to 1d was built in. Since the values are independently changed by the random number generator, a timing occurs in which the outputs from all the transmitting devices 1a to 1d are transmitted without collision.

Further, in FIG. 3, the duration (D seconds) and the random change width (L seconds) of the tone burst TB having a high collision probability are selected in order to show the state of collision. D and L are selected to be very small compared to T in order to reduce the probability. The practical example of such a selection, for example, f _o = 100 Mega Hz T = 1 sec D = 1 msec = T / 1000 L = 10 ms = T / 100 is considered. According to the computer simulation, the collision probability in this setting is such that, for example, the probability that a tone burst TB transmitted from 100 transmission devices 1 collides is about 0.5%. That is, in this example, about 100 tone bursts TB per second.
, But these collisions occur only once in about 3 minutes.

Therefore, the tone burst TB
Has a very high probability of arriving at the emergency signal receiving device 2 without collision, and even if there is a torn burst TB that has collided at a certain timing, this
If the number of strike TBs is counted, and the count probability is added to the count result, the number of the transmitters 1 that are transmitting the tone burst TB in the receiver 2, that is, the number of victims is grasped. It becomes possible.

1-2. Personal data transmission method The personal data DS is safety information including the user's safety, heart rate, body temperature, sweating, and the like measured by an ID number set for each transmitter and a biometric sensor. These pieces of information are assembled into a packet in the transmitting device 1 and organized into a data signal. The data signal DS is transmitted from the transmitting device 1 following the tone burst TB as shown in FIG. That is, the emergency signal ES transmitted from the transmission device 1 in an emergency such as a disaster is composed of a tone burst TB and personal data DS following this signal. The emergency signal ES already has 1-1. In from being transmitted repeatedly in a cycle obtained by adding a random variation time T _k to the reference period T, as described, individual de - data DS also repeated in cycle obtained by adding a random variation time T _k to the reference period T in outgoing Is done. Since the transmitting device 1 is small and driven by a battery, the data that can be collected is limited, and the length of these data is at most about 64 bytes (64 * 8 = 512 bits). In order to transmit such a series of data more reliably, a technique of adding data redundancy and transmitting the data as longer data has been widely used. The main ones are firstly error correction (detection) codes, and secondly, spread spectrum codes. The second spread spectrum code is
The larger the spreading factor is, the more reliable it is to improve the reliability of reception even when there is collision between data or when background noise is larger than the signal. I have.

If the second method is adopted, a different random spreading code must be distributed to all callers in advance. In general, for reception in the spread spectrum system, it is necessary that the spread code of each sender is known. A normal mobile communication system is a two-way communication, and a spread code is assigned to each terminal from a base station at the start of communication.

However, in the emergency signal transmitting apparatus, since communication is one-way and the victim is unknown, all spread codes must be prepared inside the receiver in order to perform this reception. And correlation detection must be performed using all of them. This is not really possible. Further, an increase in the transmission speed of personal data due to diffusion also poses a problem in circuit realization. Therefore, in this embodiment, the first error detection coding method is adopted. The reason that the error correction code is not adopted is that the biometric information is measured and updated at intervals of several minutes.Therefore, between the update and the next update, it is necessary to repeatedly transmit data of the same individual many times. it can. Under such conditions, discarding suspicious data by detection without correction can achieve more reliable reception.

In this embodiment, the actually transmitted packet data is composed of a control bit sequence (512 bits) necessary for various control circuits of the receiving device 2 and a sequence (512 bits) obtained by error detection encoding of personal data. Bit) and serial data of 1024 bits (128 bytes) in total.

Therefore, assuming that this is transmitted in 1 millisecond, the transmission speed is about 1 Mbit / sec, and this is converted to binary DSBAM (Double Side Band Amplitude Mod).
, modulation by double-sided band amplitude modulation). The carrier used for this modulation has a frequency different from the frequency of the tone burst TB in order to avoid collision with the tone burst TB output from another transmitting device. As a result, even when the personal data DS is transmitted from 100 transmitting devices 1 as in the case of the tone burst TB, the collision probability of each data signal is about 0.5%.

1-3. Tone burst receiving method When the collision probability is about 0.5% as in the above example, even if a plurality of transmitting devices 1 operate simultaneously, each tone burst TB is almost certainly separated. Sent. However, tone burst T transmitted from each transmitting device
Since all B have the same frequency, the transmitting device 1 that is transmitting on the receiving device 2 side cannot be distinguished and specified. It should be noted that the personal data signal DS includes an I that can distinguish the transmitting device 1.
D data is included, but personal data which is a data signal
The probability that the receiver signal DS is correctly received by the receiver 2 is considerably lower than that of the tone burst TB.

[0036] 1-2. As described briefly in the above, the receiving device 1 can determine the number of transmitting devices 1 that are transmitting, that is, the number of victims, by measuring the tone burst for a long time. If 1-2. In the case where the transmitting device 1 having the reference period T = 1 second described in (1) is used, assuming that the total number of tone burst TBs received by the receiving device 2 in one minute is N, one transmitting device 1 operates for one minute. Since the number of times the tone burst TB is transmitted is 60 times, N / 60 indicates the number of transmitting devices 1 transmitting the tone burst TB.

However, this calculation is accurate when the collision probability is small, but the collision probability increases as the number of transmissions from the same disaster site increases.
Is not shown, that is, the number of victims. However, also in this case, if the system parameters T, D, L, and the like are determined, there is a certain relationship between N and the number of transmissions depending on the collision probability. Therefore, the number of transmissions can be determined from this relationship. is there.

The calculation method for determining the number of victims from the reception result of the tone burst TB has been described above.
However, actually, the reception level of each tone burst TB greatly varies depending on the distance from the receiving device 2 to the transmitting device 1 and a disaster situation. It is necessary to reliably determine the tone burst TB based on this large level difference.

In the receiving process, first, the tone burst TB is received as shown in FIG. 4 by a narrow band filter having a resonance frequency of f _o Hz in order to suppress the background noise, and the output thereof is half-wave rectified. Then, through a low-pass filter, the envelope of the tone burst as shown in FIG. 5 is extracted. This process is a common practice in communication technology using radio waves. The problem here is how to accurately separate and determine the tone burst TB from this envelope signal. Even if the duration of the 100-MHz tone burst output from the narrow-band filter is as short as 1 millisecond, a 100,000-period sine wave is included in the burst. Therefore, the trapezoidal envelope clearly appears in the background noise as shown in FIG. The width A of each trapezoidal envelope is 1 millisecond, but the size (height in FIG. 5) is different. The method of determining the presence of this trapezoidal envelope is as follows.

First, when the output of the low-pass filter is input to a filter having an ideal trapezoidal signal having the same width as an impulse response, a triangular pulse as shown in FIG. 6 is obtained. The number of tone bursts TB for a predetermined time can be counted by detecting the apex of the triangular pulse and integrating the number of the apex. In this counting, the output of the narrow band filter can be accurately realized by using a digital filter having a trapezoidal pulse as an impulse response. The A / D converter included in the digital filter desirably has an accuracy of about 16 bits in consideration of large variations in tone burst amplitude.

When the tone burst TB collides, the shape of the envelope is distorted, the trapezoid is no longer displayed, and the width is different from A. Therefore, the envelope is ignored and is not counted.

1-4. Individual reception system ID number and safety information and heart rate from the biosensor measured data, body temperature, personal de a safety information consisting of perspiration - outgoing data DS to be assembled on outbound flight from motor, a _1, a ₂ , A ₃ , a ₄ , ... =-1, + 1, -1, -1, ...
...

[0043] With due connexion modulates the binary sequence to DSBAM, the modulated wave is _{R (t) = {Σa k} p (t-K · Td)} cos (2πf
Represented by ₁ t). Here, Td is a pulse transmission interval,
f ₁ is the frequency of the carrier. FIG. 7 shows the waveform of R (t). FIG. 7A shows transmission data, FIG. 7B shows a carrier wave cos (2πf ₁ t), and p (t) has a pulse waveform as shown in FIG.

The receiver 2 synchronously detects R (t) after passing the data signal through automatic gain control. That is,
A voltage-controlled oscillator (local oscillator) for outputting a carrier wave cos (2πf ₁ t + θ) having the same frequency as the carrier wave output from the transmitting device is provided inside the receiver in advance, and the carrier wave and the received signal R (t) are multiplied by a multiplier. obtains the product of two by inputting to, which give the signal wave through a low pass filter, X a _{(t) = {Σa k p} (t-K · Td)} cos (θ). Here, θ is an indeterminate phase.

Subsequently, the uncertain phase θ is made zero by carrier phase control. This principle utilizes the fact that θ becomes zero when the power of X (t) is maximized. That is,
X (t) is passed through a squaring circuit, and the result is passed through an integrating circuit to control a voltage control generator inside the receiver by a signal obtained. The result X (t) is as _{X (t) = Σa k p} (t-K · Td).

Next, X (t) is sampled every Td seconds, and _ak is determined based on the polarity of the sampled value.
Since the pulse p (t) has the waveform shown in FIG. 8, the sampling is just p (t) to avoid intersymbol interference.
(At the point Pn in FIG. 7C). The following operation is performed to control the sampling phase to the peak position. First, assuming that the sampling phase is τ, the power of the discrete signal X (n · Td + τ) = Σak (n · Td + τ−Kt) _obtained by sampling X (t) at t = n · Td + τ, that is, the time average of the square is It is maximum when τ is zero. Therefore, the sampling phase can be moved to an optimum position by controlling the power of the discrete signal to be maximum. The result X (n · Td) = Σa k p (n · Td-K · Td) = a
_k p (o), and this polarity coincides with the polarity of the data a _k . Therefore, data strings a ₁ , a ₂ , a ₃ , a ₄ ,
... = -1, + 1, -1, -1,..., The personal data transmitted from the oscillator can be grasped by the receiver.

Summarizing the above, the sequence from the reception of the data signal DS to the determination of _ak is automatic gain control, synchronous detection with carrier phase control, sampler with phase control, and polarity determination. The phase of the carrier wave and the phase of the sampling complete convergence while receiving the 512-bit control data sequence sent before the personal data.

5 determined from the latter half signal after the convergence is completed
The 12-bit personal data sequence is input to an error detection circuit, which is rejected if there is an error, and correct data if there is no error.
Removed from the receiver.

2-1. Emergency signal transmitting device 1-1 An embodiment of the emergency signal transmitting device 1 for transmitting the tone burst TB and the personal data DS whose principle has been described in the embodiments 1-2, with reference to FIG. explain.

A control circuit 14 composed of a microcomputer and its peripheral circuits is supplied with a shock sensor, a manual start switch, and the like as a start switch 15 for starting a transmission operation. Further, the control circuit 14 is further input with an ID data storage circuit 3 used for composing personal data, and a biological sensor 4 for measuring heart rate, body temperature, perspiration, and the like. The ID data storage circuit 3 is assigned a number unique to the transmitter 1, and when the personal data DS is received, the ID data is stored in advance by the ID data and the owner of the transmitter 1. It can be used to identify the victims by having one-to-one correspondence. It is desirable that such data be incorporated in an EEPROM or the like at the manufacturing stage in advance.

When the start sensor 15 detects the damage, the control circuit 14 starts the operation of the oscillator 5, the timing generator 6, and the data assembly circuit 7. When the operation starts, the oscillator 7 always outputs a sine wave (ton burst) of f _o Hz. The timing generator 6 is connected to the random number generator 8. The random number generator 8 outputs a random time T _k (−L <
An output corresponding to T _k <L) is performed. This time T _k is added to the reference cycle T generated in the timing generator 6. Then, the timing generator 6 calculates T + T _k after the addition.
Switch 9 at the start of timing
Turn on. Further, the switch 9 is turned off after the elapse of the time D from the start of the timing, and at the same time, the data assembling circuit 7 is instructed to start data output. The data assembling circuit 7 performs error detection encoding of personal data including various sensor data and ID data input from the control circuit 14, and adds a control bit sequence to the first half of the signal.

The timing generator 6 inputs a new random time T _k again from the random number generator 8 at the end of measuring the time of T + T _k , and thereafter repeats the above operation.

[0053] When the switch 9 is turned on by the timing generator 6, f _o Hz bets output from the oscillator 5 - down BAS - after strike TB is appropriately amplified by the amplifier 10, as a radio wave from the antenna 11 Be sent. Then, after the elapse of the D time, the switch 9 is turned off, and the transmission of the tone burst TB ends. At the same time as this, the data signal DS is output from the data assembling circuit 7. The output personal data is subjected to error detection encoding in the data assembling circuit 1-7, and a control bit sequence is added thereto.

The bit sequence assembled here is output in accordance with a command from the timing generator 6, and the modulation circuit 1
1 is amplitude-modulated in both sidebands at a frequency f ₁ Hz, amplified by an amplifier 12 and transmitted from an antenna 1-4 as a radio wave. The de - data signaling completion after the timing generator 6, until the count end time T + T _k,
No signal is transmitted.

As described above, a pair of signals of the tone burst and the subsequent personal data is intermittently launched at random intervals.

2-2. Emergency signal receiving device FIG. 10 is a block diagram of the emergency signal receiving device for receiving the signal transmitted by the emergency signal transmitting device 1 described above. A signal received from the antenna 21 is split into two, one of which is a narrow band filter 22 having a resonance frequency of f _o Hz, and the other is a band pass filter (BPF) 23 having a center frequency of f ₁ Hz. Is entered.

The narrow band filter 22 allows only signals in the frequency band of the tone burst TB to pass from the received signal. The output of the narrow band filter 22 is an automatic gain controller 2
4, the gain is adjusted to a predetermined value.
The signal is half-wave rectified and passes through a low-pass filter (LPF) 26 to be output as an envelope. This envelope output is a digital filter-3 having a triangular pulse as an impulse response as shown in FIG. 6 when a trapezoidal waveform is input.
Input to 0. The digital filter 30 includes an A / D converter 31 for performing A / D conversion for digitizing an input waveform in accordance with the size thereof in a predetermined cycle and a filter 33 having a predetermined response characteristic. Is done. Therefore,
When a tone burst TB having a trapezoidal waveform exists at the input, the digital filter 30 outputs a triangular wave as shown in FIG.

Subsequently, the output of the digital filter 30 is input to the transmission number counting circuit 40. First, in the peak detection circuit 41, when a triangular wave is present in the output of the digital filter 30, its peak is detected to determine the presence or absence of a tone burst. If a triangular wave exists, a signal is output from the peak detection circuit 41 to the counter 43. The counter 43 increases the count by one each time the peak detection circuit 41 detects a triangular wave. Therefore, the count number C of the counter 43 indicates the number of received tone bursts from the start of reception. The counter 43 is connected to a timer 42 which starts counting from the time when the first tone burst arrives at the counter 43 and outputs the counted time. Finally, both the clock output Tm (seconds) of the timer 42 and the count C of the counter 43 are output as the reception result. In the setting of the transmitting device 1 already described, the reference period T of the tone burst TB is set to 1 second. Assuming that there is no collision in the tone burst TB, the number of transmitting transmitters is as follows. C
/ Tm, the number of transmitting devices that are transmitting can be calculated from the time output Tm (seconds) of the timer 42 and the count C of the counter 43.

The number N of transmitting devices that are transmitting when there is no collision is generally represented by N = C · T / Tm. However, the actual transmission period of the tone burst TB is represented by T + _Tk , and the random time _Tk (-L <
Since _Tk <L) is added, it is desirable that Tm is considerably larger than T. In addition, 1-2. As described in, when the number of transmissions from the same disaster site increases, the collision probability increases, and N in the formula does not match the number of transmitting devices transmitting, but the system parameters T, D, L, etc. Is determined, there is a fixed relationship between N and the number of transmitting devices that are transmitting according to the collision probability, and it is possible to determine the number of callers from this relationship.

Further, the number of tone bursts per reference period T is sequentially determined using the time output Tm (second) of the timer 42 and the count number C of the counter 43, and this is observed for a certain long time. After eliminating extremely large values (erroneous reading data due to the influence of noise, etc.), selecting the maximum count number allows the transmitting device that is transmitting the tone burst to some extent accurately. It is also possible to know the number, that is, the number of victims.

On the other hand, on the receiving side of the personal data DS, f ₁
The signal that has passed through the band-pass filter 23 that passes the signal with a center frequency of Hz is first sent to the automatic gain controller 2-1.
At 1, the gain is controlled to a predetermined value. This output is input to the synchronous detection circuit 50. In the synchronous detection circuit 50, first, the input signal is input to the multiplier 51. The other carrier of the multiplier 51 receives the reproduced carrier of f ₁ Hz output from the voltage controlled oscillator (VCO) 55. These signals are multiplied by a multiplier 51 and input to a low-pass filter (LPF) 52. Low-pass filter 5
2 is branched into two, one of which is supplied to an A / D converter 61 in a sampling circuit 60 at the next stage, and the other is a square circuit 53.
Is input to

The output of the squaring circuit 53 is input to an integrator 54. The output of the integrator 54 represents the power of the signal output from the low pass filter 52. This output is input to the voltage controlled oscillator 55, which controls the phase of the reproduced carrier in the direction in which the output of the integrator 54, that is, the power of the signal increases. As a result, the phase of the received carrier wave of the personal data matches the phase of the reproduced carrier wave, and the personal data signal is output from the low-pass filter 52 in an accurate form.

This personal data signal DS has the envelope waveform shown in FIG. 7C, and is then input to the A / D converter 61 in the sampling circuit 60. The sampling cycle of the A / D converter 61 is set in advance to be the same as the transmission cycle of personal data, but the sampling phase is determined by digital signal processing as follows. First, the output of the A / D converter 61 is branched into two, one of which is squared by a squarer 62, subsequently input to an integrator 63, and then input to a sampling phase adjustment circuit 64. The sampling phase adjusting circuit 64 adjusts the sampling phase of the A / D converter 61 so as to maximize the output of the integrator 63. As a result, the sampling timing of the A / D converter 61 becomes
The phase of the A / D conversion is optimized by matching the peak of the personal data waveform.

The output of the A / D converter 61 is input to a polarity determiner 71, which determines whether the A / D conversion output data is positive or negative. Therefore, the polarity determiner 71 outputs positive or negative polarity data every sampling period. This output is supplied to a decoding circuit 72 and a data judgment circuit 73.
Is input to The data determination circuit 73 determines the presence or absence of a specific bit sequence previously set as a start bit at the end of the 512-bit control bit sequence preceding the 512-bit personal data. That is, it is determined whether the signal sequence output from the polarity determiner 71 is a start bit. If the start bit is confirmed, the decoding circuit 72 is instructed to start decoding.

The adjustment of the sampling phase of the received signal by the sampling phase adjusting circuit 64 must be completed before the last start bit of the control bit sequence is received.

After the start bit, the data determination circuit 73
Are output to the personal data decoded by the error detection decoding circuit 72 and output together with the error detection result. As a result, in the receiver, personal data DS output by each transmitting device is collected. Although the preferred embodiment has been described above, a data signal is not necessary for the purpose of grasping only the number of victims, and the emergency signal may be constituted only by the tone burst. In this embodiment, the data signal is transmitted after the tone burst, but the order of the tone burst and the data signal is not limited to this. Instead, the signals may be transmitted in a pair at the same random period, the order of the signals may be reversed, or an interval may be provided between the two signals.

[0067]

As described above, according to the first aspect of the present invention, there is provided data transmitting means for transmitting a pair of a radio signal and a data signal modulated at a frequency different from the radio signal of a predetermined frequency. Therefore, it is possible to notify not only the existence of the victim but also data on the situation of the victim. further,
Since the data signal is modulated at a frequency different from that of the radio signal, it is possible to prevent each signal from interfering.

According to the fifth aspect of the present invention, since a counting means for receiving a predetermined frequency signal of a predetermined time width and counting the number of receptions is provided, the number of emergency signal transmitting devices transmitting the signal is confirmed. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement of an emergency signal transmitting device and an emergency signal receiving device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an emergency signal transmitted by the emergency signal transmission device according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating a state in which a plurality of emergency signal transmitting devices are transmitting an emergency signal;

FIG. 4 is an illustration of a tone signal transmitted by an emergency signal transmitting device.
It is a waveform diagram of a burst.

FIG. 5 is a diagram showing an envelope of a tone burst.

FIG. 6 is a waveform diagram illustrating characteristics of a digital filter used for receiving a tone burst.

FIG. 7 is a diagram showing a personal data signal waveform transmitted from the emergency signal transmitting device based on the personal data.

FIG. 8 is a diagram showing a signal waveform for each bit of personal data.

FIG. 9 is a circuit block diagram of the emergency signal transmitting device.

FIG. 10 is a circuit block diagram of an emergency signal receiving device for receiving an emergency signal transmitted by the emergency signal transmitting device.

[Explanation of symbols]

 ES: emergency signal TB: tone burst signal DS: personal data signal 1: emergency signal transmitter 2: emergency signal receiver

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G08B 19/00-31/00 H04B 1/06 H04B 1/16

Claims (5)

(57) [Claims] A signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval randomly varying within a predetermined time range, and a data signal modulated at a frequency different from the radio signal of the predetermined frequency. An emergency signal transmitting device, comprising: data transmitting means for transmitting a pair with the radio signal. 2. A signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency within a predetermined time range at randomly changing time intervals, wherein the randomly changing time interval of the signal transmitting means is random to a reference time. The emergency signal transmission device according to claim 1, wherein the signal transmission time of the signal transmission means is shorter than the random change time. 3. A signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval randomly varying within a predetermined time range, and a data signal modulated at a frequency different from the radio signal of the predetermined frequency. An emergency signal transmission device, comprising: data transmission means for transmitting a pair with the radio signal, wherein the data signal is transmitted after the radio signal of the predetermined frequency. 4. A signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval randomly changing within a predetermined time range, and a data signal modulated at a frequency different from the radio signal of the predetermined frequency. An emergency signal transmission device, comprising: data transmission means for transmitting a pair with the radio signal, wherein the data signal includes ID data unique to the transmission device. 5. A plurality of emergency signal transmitting devices provided with signal transmitting means for repeatedly transmitting a radio signal of a predetermined frequency at a time interval which varies randomly within a predetermined time range, and a plurality of emergency signal transmitting devices. An emergency signal receiving device provided with a counting means for receiving a predetermined frequency signal having a predetermined time width and counting the number of times of reception, and an emergency signal receiving device comprising: A timer for measuring and outputting time, wherein the predetermined frequencies of the plurality of emergency signal transmitting devices are the same, and a randomly changing time interval of the signal transmitting means is obtained by adding a random changing time to a reference cycle T. Time
When the timed output Tm of the timer and the count number C by the counting means, the number N of the emergency signal transmitting devices is N = C · T / T.
A method for determining the number of emergency signal transmitting devices, wherein the number of the emergency signal transmitting devices is determined as m.