JPH10190817A - Voice input signal correction device for automobile portable telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voice input signal correction device in which a speech sensitivity during driving is improved and the quality of a speakerphone is improved by placing a microphone to both front and rear sides of a driver's seat in the inside of a vehicle respectively and amplifying each output signal from the microphones by using a differential amplifier while eliminating only noise. SOLUTION: This voice input signal correction device provides an automobile portable telephone set with a signal correction means 400, consisting of a 1st microphone 410 placed to a front side and an upper part of a driver's seat, a 2nd microphone 420 placed to a rear side of the driver's seat and a differential amplifier 430 comparing voice signals inputted through the microphones to amplify only a necessary component to a prescribed level, to cancel noise in the vehicle and to output a correction signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellular phone for automobiles, and more particularly, to a microphone for two speakerphones and a differential amplifier to electrically cancel noise in the vehicle. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice input signal correction device for a mobile phone for a vehicle, which can improve call sensitivity during a call.

[0002]

2. Description of the Related Art FIG.
As shown in FIG. 1, a mobile phone body 10 that receives a signal received via an antenna (ANT) and sends out a signal to be transmitted by a speaker, a microphone 20 that is arranged in a vehicle compartment and receives a driver's voice, Mobile phone body 10
And a speaker 30 for outputting the sound received by the speaker 30 and transmitting the sound to be transmitted to the mobile phone main body 10 via the microphone 20 and transmitting the other party's voice transmitted from the mobile phone main body 10 to the speaker 30. Speakerphone module 40 for performing a control operation of outputting through a speakerphone
And it was composed of

The speakerphone module 40 receives a driver's voice input through the microphone 20 and performs a switching operation so as to transmit the voice to the portable telephone body 10. The analog switch for reception 42, which performs a switching operation so that sound is output from the speaker 30, and the audio signals from the analog switches for transmission and reception 41, 42 are input and compared, and the maximum audio signal in the audio signal for transmission and reception is obtained. 43 that outputs the analog signal to analog switches 41 and 42 for transmission and reception
And it was composed of

The microphone 20 normally receives the driver's voice as much as possible, as shown in FIG.
The speaker 30 is mounted inside a speakerphone module 40 by being attached to a glance blocking film or the like above the driver's seat. The operation of the conventional automobile mobile phone configured as described above will be described below. That is, when the driver makes a call and talks with the other party, when the driver speaks, the voice is transmitted via the microphone 20 to the speakerphone module 4.
0 input terminal of the analog switch 41 for transmission and the comparator 43
When the other party speaks, the voice is input to the input terminal of the analog receiving switch 42 and the input terminal S4 of the comparator 43 via the antenna (ANT) and the mobile phone body 10, respectively. Is done.

Next, the comparator 43 outputs the audio signal of the input / output terminal of the transmission analog switch 41 to the input terminal S, respectively.
1 and S2, and receives the audio signals at the input and output terminals of the analog switch for reception 42 from the input terminals S3 and S4, respectively, and outputs one of the most predominant audio signals as compared with each other. At this time, when the driver speaks, the signal input to the input terminal of the transmission analog switch 41 via the microphone 20 is the most dominant, so the comparator 43 controls the transmission analog switch 41. The audio signal input through the microphone 20 is transmitted to the other party through the transmission analog switch 41 and the mobile phone body 10.

Similarly, when the other party responds to the driver's talk, the voice signal input to the input terminal of the analog switch for reception 42 is the most dominant. The switch is turned on by control, and the audio signal transmitted from the other party is output through the analog switch for reception 42 and the speaker 30 so that the driver can listen to the signal.

[0007]

However, in such a conventional automobile portable telephone, one of the transmission and reception signals having a high signal level is selected to conduct the audio path due to the characteristics of the speakerphone. Therefore, when the noise generated from the engine of the vehicle during driving is excessive, there is an inconvenience that the communication sensitivity in the vehicle during driving becomes extremely poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and a signal correction means having two microphones and a differential amplifier is arranged in a speakerphone arranged in a vehicle to reduce noise. It is an object of the present invention to provide a voice input signal correction device for an automobile mobile phone that can improve the call sensitivity of a speakerphone.

[0009]

In order to achieve the above-mentioned object, a voice input signal correcting apparatus for an automobile portable telephone according to the present invention is provided as a microphone for receiving a driver's voice above a driver's seat. The first microphone provided, the second microphone provided behind the driver's seat, and the audio signals input from the first and second microphones are compared to amplify only the necessary components to a predetermined level, so that noise in the vehicle is increased. A signal amplifier comprising a differential amplifier serving as a comparison amplifier for outputting a correction signal by canceling each other, and a plurality of resistors connected between the differential amplifier and the first and second microphones. Mobile phones.

According to such a configuration, the two first and second
Since the microphone and the differential amplifier electrically cancel the noise in the vehicle and output a voice signal, the communication sensitivity during driving can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the voice input signal correction device for a mobile phone according to the present invention includes a first microphone 410 as a front microphone installed above the front of a driver's seat inside the vehicle, and a first microphone 410 inside the vehicle. A second microphone 420 as a rear microphone installed on the rear surface of the driver's seat, and the first and second microphones 4
A differential amplifier 430 serving as a comparison / amplifying means for canceling noise in the vehicle and outputting a correction signal in order to amplify only necessary components to a predetermined level by comparing audio signals respectively input from the signal generators 10 and 420; There is provided a signal correcting means 400 comprising a differential amplifier 430 and a plurality of resistors R1, R2, R3, R4 connected between the first and second microphones 410, 420, respectively. It is provided in a conventional automobile mobile phone.

The configuration of the mobile cellular phone comprises a mobile phone main body 100, a speaker 200 for outputting the voice received by the mobile phone main body 100, and first and second signals of the signal correcting means 400 for transmitting the voice to be transmitted. Transmitted to the mobile phone body 100 via the second microphones 410 and 420,
A speakerphone module 300 that performs a control operation of outputting the other party's voice transmitted from the mobile phone main body 100 via the speaker 200.

The speakerphone module 300
The transmission analog switch 310 performs a switching operation of receiving a driver's voice input through the first and second microphones 410 and 420 and transmitting the voice to the mobile phone main body 100.
And the analog switch 320 for performing a switching operation to output the voice of the other party from the speaker 200 and the audio signals of the analog switches for transmission and reception 310 and 320 are received and compared, and the maximum audio signal in the audio signal for transmission and reception is determined. And a comparator 330 for outputting to the analog switches 310 and 320 for transmission and reception.

The operation of the thus-configured voice input signal correcting apparatus for an automobile portable telephone according to the present invention will be described below. First, when a driver talks to a speakerphone of an automobile mobile phone, the driver's voice is input to each of the microphones 410 and 420 and is converted into an electric signal. (R3, R4)
And input to the inverting terminal (+) and the non-inverting terminal (-) of the differential amplifier 430 respectively. The differential amplifier 430 obtains a difference between the input signals, amplifies the difference by a preset gain, and outputs the amplified signal. . As is known, the operating principle of the differential amplifier 430 used here is characterized in that the signal of the motion state (in-vehicle noise) in the input signal is not amplified but only the difference between the two signals is amplified.

Accordingly, if R1 = R3 and R2 = R4, the output of the differential amplifier =-(R2 / R1) (the output signal of the first microphone at the front-the output signal of the second microphone at the rear). . That is, the first microphone 41 having the same characteristics
When the 0 and second microphones 420 are respectively installed on the front and rear sides of the driver, the difference between the signals of these microphones is amplified by R2 / R1 times and output, and the phase of the signal is 18
It has a state of being inverted by 0 °.

In other words, as shown in FIG. 3A, a sound signal having a waveform including the noise inside the vehicle, the actual sound of the driver, and the noise inside the vehicle is transmitted to the first microphone 410 in the front.
Is input to the inverting terminal (-) of the differential amplifier 430, and an audio signal having a waveform as shown in FIG. 3B is transmitted from the second microphone 420 on the rear surface to the non-inverting terminal (+) of the differential amplifier 430. Is input to the differential amplifier 430
Outputs a voice signal as shown in FIG. 3 (C), since it amplifies and outputs only R2 / R1 times the voice difference of the driver without amplifying the motion state of the noise in the vehicle. .

In this case, as shown in (A) and (B), the noise in the vehicle has almost the same magnitude and the same phase irrespective of the position, so that the first microphone 410 and the second microphone 420 have no noise. Although the same level of noise is input, the first microphone 410 at the front is located at a distance very close to the driver's mouth, so the driver's voice signal is input at a high level and the first microphone 410 at the rear is input. A relatively low level audio signal is input to the two microphones 420.

Therefore, since the differential amplifier 430 outputs only a voice signal from which noise has been removed, it is possible to prevent the switching characteristics of the speakerphone from deteriorating due to noise and to transmit a very clear driver's voice to the other party during a call. can do. Thus, the differential amplifier 43 of the signal correction means 400
When the noise-free sound is output to the speakerphone module 300 according to 0, the comparator 330 of the speakerphone module 300 controls the transmission / reception analog switches 310 and 320, respectively, and the driver operates via the mobile phone. Start talking to the other party.

The above-described apparatus for correcting an audio input signal of an automobile portable telephone according to the present invention can provide very good results when applied not only to a speakerphone but also to an office environment.

[0020]

As described above, the voice input signal correcting apparatus for a mobile phone according to the present invention has microphones installed at both front and rear of a driver's seat inside a vehicle, and outputs signals from the microphones. Since only the noise is removed and amplified using the dynamic amplifier, there is an effect that the communication sensitivity during driving can be improved and the quality of the speakerphone can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a voice input signal correction device for a mobile phone according to the present invention.

FIG. 2 is an explanatory view showing a state where two microphones used in the present invention are arranged inside a vehicle.

FIGS. 3A, 3B, and 3C are waveform diagrams comparing in-vehicle noise detected by two microphones and a driver's actual voice;

FIG. 4 is a block diagram showing a configuration of a conventional automobile mobile phone.

FIG. 5 is an explanatory view showing a state in which a conventional automobile mobile phone is arranged inside a vehicle.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 mobile phone body 200 speaker 300 speakerphone module 310 analog switch for transmission 320 analog switch for reception 330 comparator 400 signal correcting means 410 first microphone 420 second microphone 430 differential amplifier R1 , R2, R3, R4 ... resistance

Claims (2)

[Claims] 1. A mobile phone, a microphone for receiving a driver's voice, a speaker for outputting a voice received by the mobile phone, an analog switch for transmission, an analog switch for reception, and a comparator. And a speakerphone module comprising: a first microphone disposed above and in front of a driver's seat as a microphone for receiving the driver's voice; and a second microphone disposed at the rear of the driver's seat. A comparison and amplification unit that compares the audio signals input from the first and second microphones and amplifies only necessary components to a predetermined level to cancel out noise in the vehicle and output a correction signal; And a plurality of resistors connected between the first microphone and the second microphone; Audio input signal correcting apparatus for an automobile mobile telephone, characterized in that the concatenation of the speakerphone module for automobile phone. 2. The apparatus according to claim 1, wherein the signal correction means is applied to a speakerphone of a mobile phone and an office.