JPH0313638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system for transmitting and receiving so-called traffic information, such as the status of traffic congestion on a road, for a moving object passing through a road.

While a moving vehicle is traveling on an expressway or other motorway, traffic information is received in a predetermined area of the road and received by a receiving device such as a car radio installed in the vehicle. The method has already been proposed and is in operation. In such a system, since traffic information is repeatedly transmitted by radio waves in the predetermined area along the road, when traffic information is received, the input of the receiving device is automatically switched to be given to the speaker, For example, if you ensure that the content can be heard when receiving traffic information even if the information is being heard from other sound sources, cars passing through the area will hear the same traffic information repeatedly, and It was very annoying.

The present invention has been made in view of such conventional problems, and allows the content to be automatically heard from start to finish when receiving traffic information, and also allows the user to automatically listen to the content of the traffic information from start to finish. The purpose is to provide traffic information that prevents repeated listening.

The present invention includes a start identification signal indicating the start of broadcasting of traffic information, traffic information, and an end identification signal indicating the end of broadcasting of the traffic information. A receiving device that receives traffic information broadcasting that is repeatedly transmitted in the order of signals, the tuner 10 demodulating the start identification signal, the traffic information, and the end identification signal; an identification circuit 19 that detects an end identification signal and outputs a signal from when the start identification signal is detected to when the end identification signal is detected; a first control means 21, 23, 22, 11 that performs switching control so as to give the output signal of No. 10 to the speaker 17; , the first control means 2 based on the detection of the start identification signal.
Second control means 24, 25, 27, 28, which inhibits the switching control hands of 1, 23, 22, 11 for a predetermined period of time;
30, 29, and 18.

FIG. 1 is a diagram schematically showing an embodiment of the present invention. On a road 1, which may be a motorway such as an expressway, an automobile 2 as a moving object is traveling in a direction indicated by an arrow 3. In the roadside area of the road 1, traffic information is emitted from an antenna 5 in the form of radio waves in a predetermined area 4. This antenna 5 is embedded in the roadside strip of the road 1. Radio waves are given to the antenna 5 from a transmitter 6 .

FIG. 2 is a block diagram of the receiving device mounted on the automobile 2, and FIG. 3 is a waveform diagram for explaining its operation. The transmitting device 6 repeatedly emits a start identification signal, traffic information, and an end identification signal in this order, as shown in FIG. 31. The carrier wave of such a signal is, for example, a medium-wave amplitude modulated wave, and is set at a frequency near the upper or lower limit of the receivable limit of a receiving device such as a so-called car radio that can receive normal radio broadcasts. It is assumed that a car 2 traveling on a road 1 takes time W to pass through a predetermined area 4. A carrier wave modulated by the audio frequency signal shown in FIG. , 10. Chiyuna 9 is primarily used to receive conventional radio broadcasts,
The audio frequency signal thus demodulated is applied from line 10 to one individual contact 12 of changeover switch 11. Another individual contact 13 is supplied with the demodulated audio frequency signal from the tuner 10 via a line 14. The signal from the common contact 15 of the changeover switch 11 is sent to the amplifier circuit 16.
The signal is amplified by the speaker 17 and turned into sound by the speaker 17.

The tuner 10 is provided to listen to traffic information in a predetermined area 4. This Chuyuna 10
The receiving frequency of is determined to be the frequency of the modulated carrier wave containing the traffic information in the area 4. The demodulated signal derived from the tuner 10 onto the line 14 is applied from the switch 18 to the identification circuit 19. The identification circuit 19 detects the start identification signal and continues to derive a high level signal to the line 20, and receives the end identification signal and continues to derive a low level signal to the line 20. When line 20 is high, transistor 21 conducts, thereby causing relay coil 23 of relay 22 to
is excited. By energizing the relay coil 23, the common contact 15 of the changeover switch 11 becomes electrically connected to the individual contact 13. Note that the transistor 21, the relay 22, the relay coil 23, and the changeover switch 11 constitute a first control means. When the relay coil 23 is demagnetized,
The common contact 15 is electrically connected to the individual contacts 12.

Assume that a car 2 is traveling on a road 1 and enters a region 4 at time t1. Before the time t2 until the identification circuit 19 detects the start identification signal, the signal led out to the line 20 of the identification circuit 19 is at a low level as shown in FIG. Therefore, transistor 21 is cut off. Therefore, the relay coil 23 is demagnetized, and the common contact 15 of the changeover switch 11 is electrically connected to the individual contact 12. The radio broadcast thus received by the tuner 9 is amplified by the amplifier circuit 16 and turned into sound by the speaker 7.

When the identification circuit 19 detects the start identification signal at time t2, the identification circuit 19 outputs the third signal to the line 20.
The high level signal shown in FIG. 2 is derived. As a result, the transistor 21 becomes conductive, the relay coil 23 is energized, and the common contact 15 of the changeover switch 11 is switched to the individual contact 13, thereby becoming conductive. Therefore, the traffic information outputted to line 14 by tuner 10 is amplified by amplifier circuit 16 and can be heard from speaker 17. The output from the identification circuit 19 is inverted by the inverting circuit 24 to obtain the signal shown in FIG. This inversion circuit 2
4 derives the signal shown in FIG. 3 to the differentiating circuit 25.

The identification circuit 19 receives the end identification signal at time t.
3, a low level signal is derived on line 20. As a result, the inversion circuit 24 derives a signal that rises to a high level at time t3. In response to this rising waveform, the differentiating circuit 25 operates as shown in FIG.
A pulse shown in is applied to the monostable circuit 27. The monostable circuit 27 applies a high level signal to the transistor 28 for a predetermined time Ta as shown in FIG.
Energize 0. Note that the inverting circuit 24 and the differentiating circuit 2
5. The monostable circuit 27, the transistor 28, the relay 29, the relay coil 30, and the switch 18 constitute a second control means.

The time Ta is the time W required for the automobile 2 to pass through the area 4 of the road 1, and the time Tb during which a set of start identification signals, traffic information, and end identification signals are generated.
The value that is greater than or equal to the time is selected by subtracting the value.

Ta≧W−Tb (1) Since the monostable circuit 27 is at a high level for the time Ta, the relay coil 30 of the relay 29 is excited, and the switch 18 is cut off for the time Ta. Therefore, the identification circuit 19 continues to output a low level signal to the line 20. In this way, at time Ta, the identification circuit 19 does not receive the start identification signal again. Therefore, even if the traffic information is repeatedly transmitted a plurality of times during the time W during which the automobile 2 is passing through the area 4, the traffic information can only be heard once through the speaker 17. Therefore, traffic information is not listened to multiple times, which is convenient.

As another embodiment of the present invention, the identification circuit 19 may count and detect the end identification signal a predetermined number of times using a counter, and then the monostable circuit 27 may perform a timing operation. In this way, it is also possible to listen to traffic information as many times as desired.

The output from the tuner 10 is passed through a filter 130,
131 and level setting circuit 153. Filters 130 and 131 select and derive identification signals having frequencies 1 and 2, respectively. The outputs from the filters 130 and 131 are sent to the detection circuit 1.
32,133. The detection circuit 132 is
It includes a coupling capacitor 151, a detection diode 152, and an integrating capacitor 136. The detection circuit 133 has the same structure as the detection circuit 132. The output from the detection circuits 132 and 133 is
It is applied to one input of comparison circuits 134 and 135. The other input of the comparison circuits 134 and 135 has
A signal is provided from the level setting circuit 153 via the detection circuit 154 . The detection circuit 154 has the same structure as the detection circuits 132 and 133. The outputs from the comparison circuits 134 and 135 are sent to the time judgment circuit 13.
7,138 respectively.

The time determination circuit 137 includes a resistor 139, an integrating capacitor 140, a comparison circuit 141, and a resistor 13.
The comparator circuit 141 includes a diode 142 connected in parallel to the comparator circuit 141, and one input of the comparator circuit 141 receives the output from the integrating capacitor 140. Comparison circuit 1
A signal at a predetermined level is applied from a terminal 143 to the other input of 41. Another time determination circuit 138 has a similar structure to time determination circuit 137.

The output from the time determination circuit 137 is given to one input of an AND gate 145 via a monostable circuit 144, and also directly to the AND gate 146.
is given to one input of Time judgment circuit 138
The output from is ANDed through monostable circuit 147.
It is applied to the other input of gate 146 and directly to the other input of AND gate 145. The output of AND gate 145 sets flip-flop 148 and
The output from 6 resets flip-flop 148. Transistor 21 (see FIG. 2) is rendered conductive by the set output from flip-flop 148.

For example, as shown in FIG. 5, the monostable circuit 144 includes a diode 110 and an integrating capacitor 111.
, a resistor 112 that forms a time constant circuit together with an integrating capacitor 111, and a transistor 113 that forcibly and instantaneously discharges the integrating capacitor 111, and the output of the integrating capacitor 111 is level-discriminated by the threshold of an AND gate 145. be done.

Referring to FIG. 6, when the tuner 23 is receiving the signal, the signal shown in FIG.
Assume that it is derived from 0. Filter 13
0 selects only the identification signal having the audio frequency 1 and supplies it to the detection circuit 132. As a result, the output of the integrating capacitor 136, that is, the detection circuit 1
The output of 32 is as shown in FIG. 62. The identification signal having an audible frequency of 1 is sent to the level setting circuit 153.
is applied to the detection circuit 154 from the comparator circuit 134.
determine the discrimination level. When only the identification circuit having the audible frequency 1 is being received, the output from the detection circuit 154 and therefore the discrimination level of the comparison circuit 134 is low. Therefore, when an identification signal of audio frequency 1 exceeding this discrimination level is given from the detection circuit 132, the comparison circuit 134 derives the waveform shown in FIG. 6. The output from this comparison circuit 134 is integrated by an integrating capacitor 140 via a resistor 139. The output waveform of the integrating capacitor 140 is shown in FIG. Integrating capacitor 1
When the output of the comparator circuit 14 exceeds the discrimination level given to the terminal 143 after the elapse of time T1, the output of the comparator circuit 14
1 derives a signal having the waveform shown in FIG. In this manner, the comparator circuit 141 derives an output only when the identification signal of the audio frequency 1 is continuously received for a time T1 or more. monostable circuit 144
is the predetermined pulse width W7 as shown in FIG.
Derive a pulse with . During the period of this pulse width W7, as described below, the audible frequency 2
An identification signal having the following information will be received and detected.

An identification signal having an audible frequency of 2 is transmitted to the tuner 10.
When the identification signal is output from the filter 13, the identification signal is output from the filter 13.
1 and detected by the detection circuit 133. The output from the detection circuit 133 is shown in FIG. The output from the comparison circuit 135 is the sixth
7, and the output from time determination circuit 138 is shown in FIG. 6. Time judgment circuit 138
The output from is derived when the identification signal having an audible frequency of 2 continues for a time T2 or more. In this way, from the AND gate 145,
A waveform shown at 0 is obtained. Therefore, the flip-flop 148 is set, and the traffic information from the tuner 10 is outputted from the speaker 17 via the changeover switch 11, the amplifier circuit 16, and the like.

When the radio broadcast of traffic information ends, identification signals having audible frequencies 2 and 1 are derived from the tuner 10 in this order. audible frequency 2
When an identification signal having a predetermined pulse width W8 is detected, a signal having a predetermined pulse width W8 is derived from the monostable circuit 147. Pulse width W8 may be equal to pulse width W7. During the period when the output is being derived from this monostable circuit 147, the audio frequency 1
When an identification signal having ? is detected, the output from AND gate 146 causes flip-flop 148 to be reset. Therefore, the changeover switch 11 directs the signal from the tuner 9 to the amplifier circuit 16, and the radio broadcast being received by the tuner 9 can be heard again from the speaker 17.

In the above embodiment, when a signal having a frequency spectrum covering a wide frequency band including audio frequencies 1 and 2 is derived from the tuner 10, the level of the signal from the level setting circuit 132 via the detection circuit 154, that is, the comparison circuit 134 , 135 have a high discrimination level. Therefore, the comparison circuit 134,1
The output of 35 remains at a low level. In this way, only when the identification signal having only the frequency spectrum of audible frequencies 1 and 2 is received by the tuner 10, high level outputs are obtained from the comparison circuits 134 and 135 as described above. This prevents erroneous detection of traffic information. In addition, the time determination circuits 137 and 138 use the audible frequency 1,
2 is greater than or equal to time T1 (see Figure 6, 5) and time T
Outputs are obtained from the time determination circuits 137 and 138 only when they each last for more than 2 (see FIG. 6 and 8). Therefore, it is possible to more reliably prevent erroneous detection of traffic information. Furthermore, by the action of monostable circuits 144 and 147, the audible frequencies 1 and 2 are
Flip-flop 148 operates only when the identification signal having . This also further reliably prevents erroneous detection of traffic information.

Diode 14 included in time determination circuit 137
2 functions to discharge the charge in the capacitor 140 immediately when the output of the comparator circuit 134 becomes low level. Therefore, the comparison circuit 134 that is input next
can be reliably integrated by the capacitor 140 via the resistor 139, and the accurate time T
1 can be obtained.

The audible frequencies 1 and 2 of the identification signal may be selected to have a chord relationship that satisfies the first equation to obtain good hearing.

2=1.5・1…(1) For example, 1 is 900Hz and 2 is 1.350Hz.

In order to detect that there is a pause period W2 between the signals of durations W1 and W3 in the start identification signal and thereby more reliably avoid false detection, the present invention is configured as follows. Detection circuit 154
The output from the comparator circuit 156 is applied to one input of the comparator circuit 156. The other input of this comparison circuit 156 is given a voltage Vr1 that determines a predetermined discrimination level. When the output from the detection circuit 154 exceeds the discrimination level corresponding to the voltage Vr1, the comparison circuit 156 sends a high level signal to the AND gate 157.
give to The output from time determination circuit 137 is given to differentiation circuit 158. The output of the differentiating circuit 158 is given to one input of the comparing circuit 159. The other input of the comparison circuit 159 is given a voltage Vr2 that determines the discrimination level. Comparison circuit 1
59, the output from the differentiating circuit 158 is the voltage Vr2
, a high level signal is output to the AND gate 157. The above-described differentiating circuit 158 derives high-level and low-level differential pulses at the rise and fall of the time determination circuit 137, respectively. In this way, a high level pulse is derived from the comparison circuit 159 at the time of the fall of the time determination circuit 137. The output of the AND gate 157 is applied to a pulse shaping circuit 160, where the pulse width is shaped to a predetermined value and applied to the transistor 113 of the monostable circuit 144 (see FIG. 5). The monostable circuit 144 is reset in response to the output from the pulse shaping circuit 160, and its output is set to a low level.

Assume that a start identification signal having a normal waveform shown in FIG. 7 is derived from the tuner 10 on the line 14. In this case, the detection circuit 154
A signal shown in FIG. 6 is applied to the comparator circuit 156 from the above. The output of the comparator circuit 156 is shown in FIG.
As shown in The time determination circuit 137 derives the signal shown in FIG.
44 and also to the differentiating circuit 158. The output of the differentiator circuit 158 is shown in FIG. By the functions of the differentiating circuit 158 and the comparing circuit 159, the AND gate 1 is output from the comparing circuit 159.
57, a pulse is derived at the falling edge of the pulse shown in FIG. AND gate 157
The output of the pulse shaping circuit 160 remains at a low level, so that the pulse shown in FIG. 7 is derived from the pulse shaping circuit 160. Therefore, monostable circuit 14
The transistor 113 of No. 4 is cut off, and its output is at a high level for a period W7 as shown in FIG. 7 and FIG. The output of time determination circuit 138 is shown in FIG. Therefore, AND gate 1
The pulse shown in FIG. 7 is derived from 45, and flip-flop 148 is set.

Assume that a signal is mixed as shown in FIG. 81 in the pause period W2 included in the start identification signal. The output of the detection circuit 154 is shown in FIG.
The output of the comparison circuit 134 is as shown in FIG. 8, and the output of the time determination circuit 137 is as shown in FIG. 8. The output of the differentiating circuit 158 is the eighth
As shown in FIG. AND gate 15
7 derives a high level pulse in response to the signal from the comparator circuit 156 that remains at high level and the pulse from the comparator circuit 159. The pulse shaping circuit 160 derives the pulse shown in FIG. 8 and makes the transistor 113 of the monostable circuit 144 conductive. Therefore, capacitor 111 is discharged and the output of monostable circuit 144 is forced to a low level after being at a high level for a very short time as shown in FIG. Time judgment circuit 13
The output of 8 is shown in FIG. The output of AND gate 145 remains at a low level as shown in FIG. 8, and flip-flop 148 is not set. In this way, during the pause period W2, when there is a frequency signal, the flip-flop 148
is not set, and erroneous detection of the start identification signal is prevented.

As described above, according to the present invention, the start identification signal and the end identification signal sent before and after the traffic information are respectively detected, and the output of the tuner for receiving traffic information is selectively given to the speaker. , the content of traffic information can be automatically listened to from start to finish. Furthermore, when it is detected that the output signal of the identification circuit is cut off by the detection of the end identification signal, switching to the traffic information receiving tuner by the first control means is inhibited for a predetermined period of time, so that the same content can be detected. It is possible to prevent traffic information from being listened to repeatedly.

[Brief explanation of the drawing]

FIG. 1 is a simplified diagram of one embodiment of the present invention, FIG. 2 is a block diagram showing a specific configuration of a receiving circuit installed in an automobile 2, and FIG. 3 is a waveform for explaining its operation. 4 is a block diagram showing the specific configuration of the identification circuit 19, FIG. 5 is an electric circuit diagram showing the specific configuration of the monostable circuit 144, and FIGS. FIG. 2 is a waveform diagram for explaining the operation of FIG. 1...road, 2...car, 4...area, 5...
...Antenna, 6...Transmitter, 9, 10...Tuner, 16...Amplification circuit, 17...Speaker, 1
9...discrimination circuit, 25...differentiation circuit, 27...monostable circuit.

Claims (1)

[Scope of Claims] 1. Includes a start identification signal indicating the start of broadcasting of traffic information, traffic information, and an end identification signal indicating the end of broadcasting of the traffic information, and when transmitting traffic information, the start identification signal, the traffic information, A receiving device that receives traffic information broadcasts that are repeatedly transmitted in the order of the end identification signal, comprising a tuner 10 that demodulates the start identification signal, traffic information, and end identification signal; an identification circuit 19 that detects a start identification signal and an end identification signal and outputs signals from when the start identification signal is detected until when the end identification signal is detected; and an identification circuit connected to the identification circuit 19; a first control means 21, 23, 22, 11 for switching control so as to give the output signal of the tuner 10 to the speaker 17 according to the output signal; When detecting that, the first control means 2 based on the detection of the start identification signal
2nd control means 24, 25, 27, 28, 3 for suppressing switching control of 1, 23, 22, 11 for a predetermined period of time;
0, 29, 18.