JP2002142009A - Emergency notice system terminal and emergency notice system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a emergency notice system terminal where a hands-free unit uses a signal processing means such as a DSP so as to conduct echo control and howling control that is further provided with a means that adjusts a level of a voice signal through gain control. SOLUTION: In the case of receiving a transmission voice signal having a voice signal level, a frequency characteristic and a signal component similar to those acquired from a received voice signal, a signal processor 171 discriminates that the signal is an echo component of the received voice signal picked up by a microphone 6, applies processing to eliminate the echo component to the voice signal and provides an output to an emergency notice contact means 11 via an operational amplifier 3 (174). Furthermore, a signal level detector 180 receives the received voice signal outputted from a speaker amplifier 176 and when the level of the received voice signal is a prescribed level or over, the detector 180 outputs a control signal to turn on a transistor(TR) 179. The TR 179 receiving the control signal to apply processing of connecting a resistor 2(178) to GND. In this case, the transmission voice signal outputted from the operational amplifier 3(174) is attenuated through resistance division processing by resistors 1(177) and 2(178).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency call system terminal device mounted on a vehicle and transmitting data such as vehicle position information to a center in an emergency, and more particularly to an emergency call system terminal device equipped with a hands-free device. About.

[0002]

2. Description of the Related Art Conventionally, an emergency call, which is mounted on a vehicle such as an automobile and performs a telephone call processing to a center having jurisdiction over an emergency call system such as a police station or an emergency call center via a base station of a communication carrier. 2. Description of the Related Art An emergency call system terminal device provided with a communication unit is known.

[0003] A conventional emergency call system terminal device uses a DSP to suppress howling and echo in a hands-free voice call in a voice call at the time of an emergency call.
(Digital Signal Processor) and the like, and voice communication by two-way communication was realized.

[0004]

However, in the conventional emergency call system terminal device, a two-way voice call can be realized during a voice call, but when a received voice signal of a certain level or more is input, an echo is generated. I was

Further, depending on the performance of speakers and microphones,
When the voice of the other party of the emergency notification system terminal device is input to the microphone via the speaker, a received voice signal which is an echo component that has been eliminated by the signal processing becomes a frequency phase or the like from the speaker to the microphone. A change in the frequency component or a change in the level of the audio signal occurs, and the echo component cannot be completely removed.

[0006]

According to a first aspect of the present invention, there is provided an emergency call system terminal device mounted on a vehicle and automatically making an emergency call to a center in charge of the emergency call system. A hands-free device for realizing a voice call at the time of processing, wherein the hands-free device has a signal processing unit having at least one of echo canceling and howling control functions of a voice signal of the emergency notification system; and An emergency call system terminal device comprising a gain control unit for adjusting a signal level.

[0007] With such a configuration, echo cancellation or howling control of an audio signal is performed.
By lowering the level of the echo generated in the voice signal by lowering the level of the voice signal, by preventing the echo from being input to the other party of the voice call of the emergency call system,
A natural voice call can be made.

According to a second aspect of the present invention, when the transmission audio signal level increases, the gain control section
2. The emergency notification system terminal device according to claim 1, wherein a gain adjustment for lowering an audio signal level of the received audio signal is performed.

With this configuration, when the level of the transmitted voice signal increases, the level of the echo is lowered by lowering the voice signal level of the received voice signal.
By preventing the echo from being input to the other party of the voice call of the emergency call system, a natural voice call can be performed.

According to a third aspect of the present invention, when the level of the received audio signal increases, the gain control section
2. The emergency notification system terminal device according to claim 1, wherein a gain adjustment for lowering an audio signal level of the transmission audio signal is performed.

With this configuration, when the level of the received voice signal increases, the level of the echo is lowered by lowering the level of the transmitted voice signal, and the echo is input to the other party of the voice call of the emergency call system. By doing so, a natural voice call can be made.

According to a fourth aspect of the present invention, the gain control section monitors an audio signal level of a signal path to be output to a speaker, and lowers the audio signal level of a transmission audio signal when the audio signal level exceeds a certain level. The emergency notification system terminal device according to claim 1, wherein adjustment is performed.

With this configuration, the level of the audio signal in the signal path to be output to the speaker is monitored, and when the level rises above a certain level, the level of the transmission audio signal is lowered to lower the level of the echo, thereby making an emergency call. By preventing the echo from being input to the other side of the system voice call, a natural voice call can be performed.

According to a fifth aspect of the present invention, the gain control unit monitors an audio signal level of a signal path to be output to a speaker, and when the signal level rises to a certain level or more, transmission before performing echo cancellation and howling control. The emergency notification system terminal device according to claim 4, wherein gain adjustment for lowering the audio signal level is performed on the audio signal.

With this configuration, the audio signal level of the signal path to be output to the loudspeaker is monitored. If the audio signal level rises to a certain level or higher, the audio signal is transmitted to the transmission audio signal before echo cancellation and howling control. By lowering the level of the signal to lower the level of the echo and preventing the echo from being input to the other party of the voice call of the emergency call system, a natural voice call can be performed.

According to a sixth aspect of the present invention, the gain control section monitors an audio signal level of a signal path to be output to a speaker, and when the signal level rises to a certain level or more, performs echo cancellation and howling control. The emergency notification system terminal device according to claim 4, wherein gain adjustment for lowering the audio signal level is performed on the transmission audio signal.

With this configuration, the audio signal level of the signal path to be output to the speaker is monitored, and when the audio signal level rises to a certain level or higher, the transmission audio signal after echo cancellation and howling control is performed. By lowering the level of the voice signal to lower the level of the echo and preventing the echo from being input to the other party of the voice call of the emergency call system, a natural voice call can be performed.

The invention according to claim 7 is characterized in that the gain control section uses a voltage control circuit by resistance division for gain adjustment for lowering the audio signal level. An emergency call system terminal device described in

With such a configuration, by adjusting the gain by the voltage control circuit based on resistance division, it is possible to lower the audio signal level and lower the echo level.

The invention according to claim 8 is a voltage control circuit for adjusting the audio signal level by changing a resistance value for adjusting the gain of the operational amplifier in the gain adjustment for lowering the audio signal level. The emergency notification system terminal device according to any one of claims 1 to 6, wherein

With this configuration, the level of the audio signal can be reduced and the level of the echo can be reduced by changing the resistance value for adjusting the gain of the operational amplifier and adjusting the gain.

According to a ninth aspect of the present invention, the emergency notification system terminal device according to any one of the first to eighth aspects controls the system and receives an emergency notification transmission signal from the emergency notification system terminal device. And an emergency call center.

With this configuration, it is possible to perform a natural voice call by preventing an echo from being input to the other side of the voice call of the emergency call system.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) An emergency call system terminal device according to a first embodiment of the present invention is a signal for eliminating echoes in a hands-free voice call in transmission processing by voice call at the time of emergency call notification. A gain control process is added along with the process.

FIG. 1 is a block diagram showing the configuration of the emergency notification system terminal equipment according to the first embodiment of the present invention. In FIG. 1, an emergency call system terminal device 1 is mounted on a vehicle such as an automobile, and has a center (hereinafter, referred to as a center) that controls an emergency call system such as a police or an emergency call center in an emergency such as a traffic accident or sudden illness. Then, data such as the current vehicle position information and the registered vehicle is transmitted, and an emergency vehicle dispatch request is made.

The communication antenna 2 transmits the transmission signal from the emergency notification communication means 11 to the base station of the communication carrier and outputs the reception signal from the communication business to the emergency notification communication means 11. The emergency call transmission button 3 is pressed by a user in an emergency such as a traffic accident or sudden illness to generate a signal for starting an emergency call transmission process. The GPS antenna 4 is a GPS
Receive data from satellite.

The main battery 5 supplies power to the electrical equipment of the vehicle and also supplies power to the terminal device 1 of the emergency notification system. The microphone 6 is a microphone module having a built-in amplifier circuit and the like, and outputs a user's voice to the emergency notification system terminal device 1 at the time of voice communication in the emergency notification communication process. The speaker 7 is used for the voice call communication,
Sounds the audio signal received from the center.

Next, the internal configuration of the emergency notification system terminal device 1 will be described. The emergency call notification means 11 includes a control unit 12
In response to the outgoing request signal from, a telephone call process is started to the other party corresponding to the telephone number via the base station of the communication carrier using the telephone number input from the control unit 12.
When receiving a signal that shifts during a call, such as an outgoing response from a call partner or a busy signal, the control unit 12 shifts to a voice call control or a data communication control, and sends a signal to the control unit 12 indicating that the shift has been performed during the call. Output. Further, the information such as the traveling direction and direction of the vehicle and the data such as the position information input from the control unit 12 are transmitted to a center, which is a communication partner corresponding to the telephone number, via a base station of a communication carrier. Perform outgoing call processing.

The control unit 12 performs control to record data such as position information acquired from the position information acquisition processing unit 14 in the storage unit 15. Further, it is recognized from the operation signal from the emergency call transmission button 3 that an emergency call request has been made, and obtained from the position information acquisition processing unit 14 and recorded in the storage unit 15 or the like in order to start the emergency call contact processing. Enter data such as location information. Further, the telephone number of the center is acquired from the storage unit 15. Emergency call notification means 11 using the telephone number
Make a phone call request to.

Further, the control unit 12 sends a response signal from the other party corresponding to the telephone number,
Alternatively, when a signal such as a busy signal that shifts to a busy state is received, it is recognized that the state has shifted to a talking state. The control unit 12 also transmits a signal for transmitting the location information history data obtained from the location information acquisition processing unit 14 to the center, which is the other party corresponding to the telephone number, via the base station of the communication carrier. A process for outputting to the notification communication means 11 is performed.

The gyro sensor 13 generates information such as the traveling direction and direction of the vehicle. The position information acquisition processing unit 14 receives the data from the gyro sensor 13 and the GPS receiver 16
Data such as position information generated by data received from the antenna 4 and the like is output to the control unit 12. Storage unit 15
Records information such as the telephone number of the center, the registration number of the vehicle equipped with the emergency notification system terminal device 1, and the position information generated by the position information acquisition processing unit 14. Further, it performs a process of outputting the recorded data according to the request signal from the control unit 12.

The GPS receiver 16 performs a process of outputting data such as position information to the position information acquisition processing unit 14 based on the data obtained from the GPS antenna 4. The hands-free device 17 uses signal processing and a level adjustment function to transmit a voice signal from a user and a voice signal received from the center during a voice call in order to realize a hands-free voice call during an emergency call contact process. An echo cancellation process and a howling control process are performed on the audio signal. The power control device 18 supplies power to the internal circuit of the emergency notification system terminal device 1.

The operation of the terminal device of the emergency call system according to the first embodiment of the present invention configured as described above will be described.
In FIG. 1, the position information acquisition processing unit 14 is a gyro sensor.
The position information data is generated based on data from the GPS receiver 13, data received by the GPS receiver 16 from the GPS antenna 4, and the like. The control unit 12 performs processing of periodically acquiring data such as position information from the position information acquisition processing unit 14 and recording the data in the storage unit 15.

The user presses the emergency call button 3 in an emergency such as a traffic accident or sudden illness. Emergency call button 3
Outputs to the control unit 12 a signal indicating that the user has pressed the button. The control unit 12 recognizes from the operation signal from the emergency call transmission button 3 that an emergency call transmission request has been made, and starts the emergency call communication process.

The control unit 12 obtains the data such as the positional information accumulated from the storage unit 15 and the telephone number of the center, and makes a call request to the emergency call communication means 11 using the telephone number. Emergency call notification means 11 uses telephone antenna 2 to initiate a telephone call process to the other party corresponding to the telephone number via the base station of the communication carrier.

When receiving a call response from the other party or a signal such as a busy signal that shifts to a busy state, the emergency call notification means 11 recognizes that the state has shifted to the talking state, and performs voice call control or data communication. With the transition to control,
A signal notifying that the call has been transferred is output to the control unit 12. The control unit 12 determines that the call has been successful, and performs processing for transmitting data such as position information to the center, which is the call partner corresponding to the telephone number, via the base station of the carrier or the like. Do.

When the center receives all the position information data from the emergency call system terminal device 1, the center switches to a voice call. Emergency call system terminal equipment 1
When receiving the signal indicating the shift to the voice call, the emergency call notification unit 11 built in the controller outputs a signal indicating the shift to the voice call to the control unit 12. Control unit 12
When receiving a signal indicating that voice communication has been started, performs control to connect the emergency call notification means 11 and the voice path of the hands-free device 17, and shifts to voice communication notification processing.

At the time of voice call contact processing, emergency call contact means 11
Hand-free device 17
Output to The hands-free device 17 obtains an audio signal level, frequency characteristics, and the like from the received audio signal by using a signal processing unit, and further performs processing such as increasing the audio signal level of the received audio signal. Output. The speaker 7 performs a process of sounding a received voice signal input from the hands-free device 17 and transmits the signal to the user.

The microphone 6 obtains a voice signal from the user and a received voice signal sounded from the speaker 7 and outputs them to the hands-free device 17. The hands-free device 17
When a transmission audio signal having the same signal component as the audio signal level and frequency characteristics obtained from the reception audio signal is input, the transmission signal is determined to be an echo component of the reception audio signal input by the microphone 6, and the echo component is removed. Perform the following processing. Further, the hands-free device 17 detects an audio signal level such as a received audio signal to be output to the speaker 7, and when the received signal level reaches a certain level, attenuates the level of the transmitted audio signal.

If the received signal level is lower than a certain level, the level attenuation processing is canceled. The transmission audio signal, by the level adjustment, when the reception signal is above a certain level, the audio signal level is reduced by attenuation processing,
Output to the emergency call communication means 11. Emergency call notification means 11
Receives the transmission audio signal from the hands-free device 17,
Perform processing to transmit to the center.

As described above, the removal of the echo component applied to the transmission audio signal is performed not only by the echo cancellation function of the signal processing means built in the hands-free device 17, but also by the gain adjustment function of the audio signal level of the echo component. By performing the attenuation process, it becomes possible to remove echo from a transmission voice signal acquired by a user of a communication partner who makes a voice call with the emergency notification system terminal device.

(Second Embodiment) An emergency call system terminal device according to a second embodiment of the present invention is configured such that, when a received sound to be output to a speaker is a signal of a certain level or more, the sound signal level of the transmitted sound signal And a hands-free device for removing echo components is provided.

FIG. 2 is a block diagram showing a configuration of a hands-free device that removes an echo component by adjusting the audio signal level of the emergency notification system terminal device 1. 2, the microphone 6 has the same configuration as the microphone 6 shown in FIG. 1, and the speaker 7 has the same configuration as the speaker 7 shown in FIG. The emergency call notification means 11 has the same configuration as the emergency call notification means 11 shown in FIG.
17 has the same configuration as the hands-free device 17 shown in FIG.

In the hands-free device 17 shown in FIG.
The signal processing device 171 is a DSP (Digital Signal Process
r), a device having an echo canceling or howling control function composed of a channel codec or the like,
The operational amplifier 1 (172) adjusts the level of the audio signal received from the emergency call notification unit 11, performs filtering, and the like.
The operational amplifier 2 (173) adjusts the level of the audio signal received from the signal processing device 171 or performs a filtering process. The operational amplifier 4 (175) performs level adjustment or filtering of the transmission audio signal from the microphone 6. Operational amplifier 3 (1
74) performs level adjustment or filtering of the transmission audio signal from the signal processing device 171.

The speaker amplifier 176 amplifies the received audio signal and generates a signal for sounding the speaker 7. Resistance 1 (1
77) is inserted in series with the transmission audio signal line,
Along with (178), the transmission audio signal level is controlled. Resistance 2
(178) is obtained by ON / OFF control of the transistor 179.
Controls the transmission audio signal level. Transistor 179
Performs connection control between the resistor 2 (178) and GND (Ground) according to a control signal from the signal level detection device 180. The signal level detection device 180 detects the level of the audio signal output to the speaker 7, and performs ON control of the transistor 179 when an audio signal of a certain level or more is input.

In the voice call communication process at the time of the emergency call notification process, the signal processing device 171 uses the received voice signal input from the emergency call notification means 11 via the operational amplifier 1 (172) to determine the voice signal level and frequency characteristics. The data is obtained and output to the operational amplifier 2 (173). Operational Amplifier 2 (173)
Outputs the input audio signal to the speaker amplifier 176, which amplifies the signal level and outputs the amplified signal to the speaker 7. The speaker 7 performs a process of sounding the received audio signal input from the speaker amplifier 176 and transmits the signal to the user.

The microphone 6 acquires a voice signal from the user and a received voice signal sounded from the speaker 7, and outputs the signal to the signal processing device 171 via the operational amplifier 4 (175).
The signal processing device 171 determines that the received audio signal is an echo component of the received audio signal input by the microphone 6 when a transmission audio signal having the same signal component as the audio signal level and frequency characteristics obtained from the received audio signal is input. , And performs a process of removing the echo component, and outputs the result to the emergency notification communication means 11 via the operational amplifier 3 (174).

Further, the signal level detecting device 180 receives the received audio signal output from the speaker amplifier 176, and outputs a control signal for turning on the transistor 179 when the received audio signal level is equal to or higher than a predetermined level. The transistor 179 performs a process of connecting the resistor 2 (178) to GND according to the control signal. In this case, the transmission audio signal output from the operational amplifier 3 (174) is attenuated by the resistance dividing process of the resistor 1 (177) and the resistor 2 (178).

The attenuation level can be adjusted by adjusting the resistance values of the resistor 1 (177) and the resistor 2 (178).
If the resistance values of (177) and the resistor 2 (178) are R ₁ and R ₂ , respectively, it is possible to attenuate to the level of R ₂ / (R ₁ + R ₂ ). The transmission audio signal whose level has been adjusted according to the level of the reception audio signal is transmitted to the other party via the emergency notification communication unit 11.

As described above, the hands-free device according to the present embodiment adjusts the level of the transmitted voice signal when the received voice signal is input, so that the voice generated by the other party can be transmitted from the speaker via the microphone. An echo component, which is a voice component to be transmitted and output to the other party, is converted to a signal processing device 17.
1 and the signal level detection device 180 can remove it.

(Third Embodiment) An emergency call system terminal device according to a third embodiment of the present invention adjusts the signal level of a transmission voice signal when a reception voice to be output to a speaker is a signal of a certain level or more. By lowering, a hands-free device for removing an echo component is provided, but the configuration is partially different from the configuration of the hands-free device described in the second embodiment.

FIG. 3 is a block diagram showing a configuration of a hands-free device for removing an echo component by adjusting the voice signal level of the terminal device of the emergency call system.

In FIG. 3, the microphone 6 has the same configuration as the microphone 6 shown in FIG.
It has the same configuration as the speaker 7 described. The emergency call notification means 11 has the same configuration as the emergency call notification means 11 shown in FIG. 2, and the hands-free device 17 has the same function as the hands-free device 17 shown in FIG. Are different.

In the hands-free device 17 shown in FIG.
The operational amplifier 1 (172) has the same configuration as the operational amplifier 1 (172) shown in FIG. 2, and the operational amplifier 2 (173)
The configuration is the same as that of the operational amplifier 2 (173) described. The operational amplifier 3 (174) has the same configuration as the operational amplifier 3 (174) shown in FIG. 2, and the operational amplifier 4 (175) has the same configuration as the operational amplifier 4 (175) shown in FIG.

The speaker amplifier 176 has the same configuration as the speaker amplifier 176 shown in FIG. 2, and the signal level detection device 180 has the same configuration as the signal level detection device shown in FIG.

The resistor 3 (181) is inserted in series with the transmission audio signal line, and controls the transmission audio signal level in the operational amplifier 3 (174). The resistor 4 (182) is connected to the operational amplifier 3
The feedback processing of (174) is performed. Resistance 5 (183) is equivalent to resistance 4 (182)
And the operational amplifier 3 (17) together with the resistor 4 (182).
Performs the feedback processing of 4) and turns ON / O the analog switch 184.
The transmission audio signal level is controlled by the FF control. The analog switch 184 performs connection processing of the resistor 5 (183),
The transmission audio signal level is controlled by controlling the analog switch 184.

The difference from the second embodiment is that the gain control uses an adjustment method based on the feedback resistance of an operational amplifier. The analog switch 184 is turned on / off according to the signal level output to the speaker 7. Adjusts the level of the transmission audio signal.

In the hands-free device 17 shown in FIG.
A signal processing device 171 including a DSP (Digital Signal Processor) or the like receives a reception signal output from the operational amplifier 1 (172). The signal processing device 171 acquires a signal from the operational amplifier 1 (172) and analyzes a frequency component. Since the signal processing device 171 operates by digital signal processing, it is desirable to input an audio level close to the dynamic range. Further, the signal processing device 171 outputs the received audio signal after the analysis to the operational amplifier 2 (173). The received audio signal is an operational amplifier 2 (173),
The sound is processed as sound through the speaker amplifier 176 and the speaker 7.

Further, the microphone 6 acquires the voice of the user (passenger) and the voice sounded from the speaker 7, and inputs the voice to the signal processing device 171 via the operational amplifier 4 (175). The sound signal to the signal processing device 171 is desirably input at a sound level close to the dynamic range in order to operate by digital signal processing. Operational amplifier 2 (173) so that sound close to the dynamic range can be input,
Adjust operational amplifier 4 (175).

The signal processing device 171 includes an operational amplifier 4 (175)
The frequency component of the transmission audio signal acquired from the above is analyzed, and when a signal having the same frequency characteristic as the acquired reception audio signal is acquired, it is determined to be an echo, and a process of removing the echo is performed.

In the above echo canceling process, since a slight echo remains, a process of apparently eliminating the echo is performed by lowering the gain of the signal. The point of gain control is that when voice is input to the received voice signal, and when the volume level is high, the input voice does not return unless it is returned to the transmitting side, so it will not be an echo, so only when such received voice is input Perform gain control. When the sound volume level is low, the sound returned as an echo is also small, and is not conspicuous as an echo. In addition, the sound input to the DSP has a dynamic range as large as possible, and if the volume level is changed in the middle, there is a delay time before the voice responds according to the volume level. Therefore, the configuration shown in FIG. 3 that avoids level adjustment in the audio path input to the DSP is most effective. Note that the detection of the volume level uses the output signal of the speaker amplifier 176 whose level change is most easily detected. Further, the level adjustment uses the output signal of the signal processing device 171 related to the transmission voice.

When the other party has a conversation, the received voice signal is input to the hands-free device 17. The received audio signal is output from the speaker amplifier 176 via the operational amplifier 1 (172), the signal processing device 171, and the operational amplifier 2 (173). The signal level detection device 180 monitors the audio output signal of the speaker amplifier 176, and outputs a control signal for turning on the analog switch 184 when a volume level equal to or higher than a certain value is input due to the conversation of the other party. The received audio signal output from the speaker 7 is input from the microphone 6 as an echo, and is input to the operational amplifier 3 (174) via the operational amplifier 4 (175) and the signal processing device 171. Operational amplifier 3 (1
74) are resistors 3 (181), 4 (182), and 5 (18
Adjust the gain according to 3). When the sound volume from the speaker 7 is equal to or lower than a certain value, the signal level detection device 180 turns off the analog switch 184.

Now, the resistance value of the resistor 3 (181) is R ₃ ,
When the resistance value of (182) is R ₄ and the resistance value of resistor 5 (183) is R ₅ , the gain control in the operational amplifier 3 (174) is R ₄ / R ₃ . When a volume level equal to or higher than a certain value is input due to the conversation of the other party, the signal level detection device 180 outputs a control signal for turning on the analog switch 184, so that the gain control is ｛(R ₄ × R ₅ ) /
(R ₄ + R ₅ )｝ / R ₃ , and the gain amplification amount is reduced. The echo that could not be removed by the signal processing device 171 is reduced by lowering the level of the audio signal and lowering the echo level of both the audio signal, so that the echo is apparently reduced.

As described above, the hands-free device according to the present embodiment adjusts the level of the transmission audio signal when the audio signal is input to the transmission audio signal. , And an echo component which is a voice component to be output to the communication partner can be removed.

[0066]

As is apparent from the above, according to the present invention, the hands-free device in the terminal device of the emergency call system performs echo cancellation and howling control by signal processing means such as a DSP (Digital Signal Processor). Not only that, a function for adjusting the level of the audio signal by gain control is also provided. With this configuration, the hands-free device in the emergency notification system terminal device can be removed by the signal processing means such as a DSP. For a voice call in which no echo occurs, the level of the echo is lowered by lowering the level of the voice signal, and by preventing the echo from being input to the other party of the voice call of the emergency call system, a natural voice call is made. Is performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an emergency call system terminal device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a structure of a hands-free device for removing an echo component by adjusting a voice signal level of an emergency notification system terminal device according to a second embodiment of the present invention;

FIG. 3 is a block diagram showing a structure of a hands-free device for removing an echo component by adjusting a voice signal level of an emergency notification system terminal device according to a third embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Emergency call system terminal device 2 Communication antenna 3 Emergency call transmission button 4 GPS antenna 5 Main battery 6 Microphone 7 Speaker 11 Emergency call communication means 12 Control unit 13 Gyro sensor 14 Location information acquisition processing unit 15 Storage unit 16 GPS receiver 17 Hands Free device 18 Power supply control device 171 Signal processing device 172 Operational amplifier 1 173 Operational amplifier 2 174 Operational amplifier 3 175 Operational amplifier 4 176 Speaker amplifier 177 Resistance 1 178 Resistance 2 179 Transistor 180 Signal level detector 181 Resistance 3 182 Resistance 4 183 Resistance 5 184 Analog switch

Continued on the front page F-term (reference)

Claims (9)

[Claims] 1. An emergency call system terminal device mounted on a vehicle and automatically making an emergency call to a center having jurisdiction over an emergency call system, comprising: a hands-free device for realizing a voice call during an emergency call contact process; The hands-free device includes a signal processing unit having at least one of echo canceling and howling control functions of an audio signal of the emergency notification system, and a gain control unit that adjusts the audio signal level. An emergency call system terminal device. 2. The emergency notification system terminal device according to claim 1, wherein the gain control unit performs a gain adjustment for lowering the audio signal level of the received audio signal when the transmitted audio signal level increases. 3. The emergency notification system terminal device according to claim 1, wherein the gain control unit performs a gain adjustment to lower the audio signal level of the transmission audio signal when the reception audio signal level increases. 4. The gain control section monitors an audio signal level of a signal path to be output to a speaker, and performs a gain adjustment to reduce an audio signal level of a transmission audio signal when the audio signal level rises to a certain level or more. Claim 1
The described emergency call system terminal equipment. 5. The gain control unit monitors an audio signal level of a signal path to be output to a speaker, and when the signal level rises to a certain level or higher, an audio signal level of a transmission audio signal before performing echo cancellation and howling control. The emergency notification system terminal device according to claim 4, wherein gain adjustment for lowering the level is performed. 6. The gain control unit monitors an audio signal level of a signal path to be output to a speaker, and if the audio signal level rises to a certain level or more, the gain control unit performs audio cancellation on a transmission audio signal after performing echo cancellation and howling control. 5. A gain adjustment for lowering a signal level.
The described emergency call system terminal equipment. 7. The emergency notification system according to claim 1, wherein the gain control unit uses a voltage control circuit based on resistance division for gain adjustment for lowering an audio signal level. Terminal equipment. 8. The gain control section uses a voltage control circuit for adjusting an audio signal level by changing a resistance value for adjusting the gain of an operational amplifier for the gain adjustment for lowering the audio signal level. An emergency call system terminal device according to any one of claims 1 to 6. 9. An emergency call system terminal device according to any one of claims 1 to 8, and an emergency call center for controlling the system and receiving an emergency call transmission signal from the emergency call system terminal device. Emergency call system.