JPH0522976Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a device for automatically controlling the volume of a conversation in a hands-free telephone for use in a vehicle.

[Conventional technology]

As a car phone, without using a handset,
So-called hands-free telephones, which carry out simultaneous loudspeaker calls using a microphone and a speaker, have been developed and put into practical use in some cases (for example, Japanese Patent Application Laid-Open No. 141838/1983).

These hands-free telephones listen to the audio coming from a speaker located far away from the vehicle occupants, so they can communicate with each other when the vehicle is passing through a place with a lot of environmental noise, such as train tracks or a construction site. Alternatively, when the vehicle stopped, there was a risk that environmental noise would interfere with telephone calls.

Therefore, as disclosed in Utility Model Application No. 61-168747, the ambient noise level input from the transmitter is detected, and the variable amplification audio amplifier of the receiving line is amplified according to the detected ambient noise level. A technique has been proposed (not yet known) to control the volume of the telephone receiver and the volume of the telephone receiver.

[Problem that the invention attempts to solve]

However, such a system that simply adjusts the volume of the handset according to the ambient noise level input from the handset makes it difficult to adjust the volume of the handset depending on the ambient noise level input from the handset, for example, when checking the siren of an emergency vehicle or listening to traffic information on the radio, etc.
There was a problem in that if it became necessary to reduce the received voice for some reason, it could not be done.

Therefore, the purpose of the present invention is to make it easy to always obtain optimal voice reception regardless of the noise inside the vehicle due to environmental noise, etc., and also to be able to cope with the need to reduce voice reception. An object of the present invention is to provide a volume control device for a hands-free telephone.

[Means for solving problems]

The volume adjustment device for a hands-free vehicle telephone according to the present invention is a hand-free telephone volume adjustment device for a vehicle, which has a microphone for transmitting a voice, a speaker for receiving a voice, and a controller for manually adjusting the volume from the speaker during a voice call. A toll-free phone will be installed inside the vehicle. and a detection means for detecting a frequency signal outside the audio band from a frequency signal collected through the microphone, and a first control for controlling the gain of an amplifier that drives the speaker according to the detection signal from the detection means. a determining means for determining whether or not the volume has been adjusted by manual operation of the controller; and a determining means for determining whether or not the volume has been adjusted by manual operation of the controller; and second control means for stopping the gain control of the amplifier and controlling the gain of the amplifier so that the volume corresponds to the manual operation.

[Effect]

As a result, when the noise inside the vehicle increases due to environmental noise, etc., the transmitting microphone of the hands-free telephone collects the sound, and the detection means detects only frequency signals outside the voice band, Since the control means (1) automatically controls the gain of the amplifier that drives the speaker and adjusts the volume from the speaker, it is possible to always easily obtain appropriate reception sound without using any special equipment. .

Further, when the determination means determines that the received voice needs to be reduced due to some circumstances and the volume is adjusted in the direction of decrease by manual operation of the controller, the second control means controls the amplifier by the first control means. The gain control is stopped and the gain of the amplifier is controlled so that the volume corresponds to the manual operation.

〔Example〕

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

FIG. 1 shows a block diagram of an embodiment of the present invention, in which reference numeral 11 indicates a microphone, and 12
20 is a band pass filter (BPF) corresponding to a detection means, and 30 is a volume controller corresponding to a determination means and first and second control means.

Audio from the microphone 11 is amplified by an amplifier (AMP) 13 and input to a radio 14. The radio 14 receives the input audio signal Ti.
The signal is modulated into the 900 MHz band and transmitted to the base station 40.
The base station 40 sends a voice signal Ti to the communication side telephone,
The voice signal from the communication side telephone is modulated into the 800MHz band and transmitted to the radio device 14. The radio device 14 demodulates the transmitted modulation signal and amplifies it with an amplifier (AMP) 15 to obtain a speaker drive output Ri. The speaker 12 is driven by the drive output Ri to generate communication-side audio. like this,
Microphone 11, speaker 12 and radio 1
16, which together with 4 constitutes a hands-free telephone, is
This controller is used to input telephone numbers, turn on/off the telephone switch (phone switch), control the volume, etc.

The bandpass filter 20 receives the output signal from the amplifier 13 and is in the audio band (approximately 300 to 3000Hz).
Only the external frequency signal Tn is detected and output to the volume controller 30.

The volume controller 30 variably controls the gain of the amplifier 15 in accordance with the magnitude of the signal Tn, and is configured around a microcomputer 31 as shown in FIG. The microcomputer 31 is activated by a hook signal, and the signal Tn from the amplifier 13 is sent to the integrator 32.
The driving output Ri from the amplifier 15 is integrated by the integrator 34 and taken in via the analog/digital converter 35. On the other hand, the microcomputer 31 includes a memory (ROM) 36 that stores programs and gain maps, and a memory (RAM) 37 that temporarily stores calculated values. is used to calculate the gain of the amplifier 15, and a control signal is output to the amplifier 15 via the digital/analog converter 38.

Next, the program stored in the memory 36 will be explained with reference to the flowchart shown in FIG.

This program is started by a hook signal from the radio 14, and first, in steps 101 and 102, a signal Tn obtained by removing the audio band signal from the signal Ti collected by the microphone 11 and a speaker drive output Ri are taken in. Proceed to step 103.

In step 103, memory 3 is loaded based on signal Tn.
From the gain map shown in FIG. 4 stored in step 6, a drive output Rn corresponding to a frequency signal outside the audio band, that is, noise is calculated, and the process proceeds to step 104.

In step 104, it is determined whether or not the volume has been adjusted by the controller 16.
If the volume has not been adjusted, a negative determination is made and the processing from step 105 is performed, and if the volume adjustment has been made, an affirmative determination is made and the processing of step 108 is performed.

If step 104 is negative, step 105
, it is determined whether the actual drive output Ri is larger than the calculated drive output Rn depending on the noise. If the actual drive output Ri is larger than the calculated drive output Rn, an affirmative judgment is made and the process proceeds to step 106.
In this step, the gain of the amplifier 15 is controlled so that the set value is as shown in FIG. Actual drive output
If Ri is smaller than the calculation drive output Rn, a negative determination is made and in step 107, the amplifier 15 is set to the calculation drive output Rn so that the voice received from the speaker can be heard without being affected by noise.
A signal for controlling the gain of is outputted via the digital/analog converter 38.

On the other hand, since the volume has been adjusted, if step 104 is affirmative, then in step 108,
The actual drive output Ri is the drive output Ri of the previous routine _-1
If it is determined whether Ri is smaller than Ri or not, and if Ri has been reduced by volume adjustment, it is determined that it is necessary to reduce the received voice due to some reason, and an affirmative determination is made, and step 106 described above is performed. Perform processing. If Ri has been increased by the volume adjustment, step 108 will be a negative judgment.
Gain control is performed after step 105 described above.

By repeating the above process,
By controlling the gain of the amplifier 15 according to the noise inside the vehicle, it is possible to always adjust the received voice from the speaker to an appropriate value, and even if it becomes necessary to reduce the received voice for some reason. can be dealt with.

Although a specific embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and includes various embodiments within the scope of the claims for utility model registration. For example, it memorizes the volume set manually and the vehicle interior sound (frequency signal outside the audio frequency band) at the time the volume is set, and controls the gain so that the relative values of both are equal depending on the noise. Then, the speaker sound may be adjusted to the initial setting state. Further, the gain may be increased in steps according to an increase in noise.

[Effect of idea]

As described above, according to the present invention, the sound inside the vehicle is collected using the microphone of the hands-free telephone, so there is no need to provide a sound collection means such as a dedicated microphone, and the sound collected Since only frequency signals outside the audio band are extracted from the signal, there is no need to add special circuits or the like to complicate the control circuit, and it is easy to obtain appropriate voice reception according to the noise inside the vehicle. This is what you can get. Further, according to the present invention, when it becomes necessary to reduce the received voice due to some circumstances and the volume is adjusted by manual operation of the controller, the determination means determines this and the second control means adjusts the volume. Since the gain of the amplifier is controlled so that the volume corresponds to the manual operation, for example, the siren of an emergency vehicle can be easily confirmed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an internal circuit diagram of the volume controller in the above block diagram, and FIG. 3 is a flowchart showing the program of the microcomputer in the volume controller. FIG. 4 shows a gain characteristic diagram according to a noise signal, and FIG. 5 shows a volume characteristic diagram of a volume controller. 11...Microphone, 12...Speaker, 1
5...Amplifier, 20...Band pass filter, 3
0...Volume controller.

Claims (1)

[Scope of utility model registration request] In a volume adjustment device for a hands-free vehicle telephone, which has a microphone for transmitting a voice, a speaker for receiving a voice, and a controller for manually adjusting the volume from the speaker during a voice call, the volume of the voice is collected through the microphone. a detection means for detecting a frequency signal outside the audio band from a sound signal; a first control means for controlling the gain of an amplifier for driving the speaker according to a detection signal from the detection means; and a manual control means for controlling the controller. determination means for determining whether or not the volume has been adjusted by operation;
If the determination means determines that the volume has been adjusted in a decreasing direction, the gain control of the amplifier by the first control means is stopped, and the gain of the amplifier is controlled so that the volume corresponds to the manual operation. 1. A volume adjustment device for a hands-free telephone for a vehicle, characterized in that the device is provided with a second control means.