JPS63217757A - Automobile telephone system - Google Patents

Abstract

PURPOSE:To obtain excellent talking by adjusting the intensity of transmission or reception depending on the degree of howling by the transmission/reception of a duplicated signal so as to prevent the generation of unpleasant high frequency noise. CONSTITUTION:When a telephone system 1 of an automobile A and a telephone system 21 of an automobile B are connected, a prescribed level of pilot signal (f) is sent form a pilot signal output section 15 in the controller 4 of the system 1 and inputted to a microphone 2 from a speaker 3 via an amplifier 14 and sent from a transmission section 11. The transmission signal is inputted to a microphone 25 from a speaker 24 of the system 21 via a relay station X and inputted to a reception section 12 of the system 1 via a relay station X and the output is inputted again to the microphone 2 from the speaker 3. In this case, the output of the microphone 2 is inputted to a decision section 16 at the same time and the degree of howling is decided by the comparison with the signal (f) and when the degree is a prescribed value or over, the gain of an attenuator 13 and the amplifier 14 is lowered by the control section 17 to suppress the generation of howling.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention eliminates howling in a car telephone device that is installed in a car and is capable of communicating with other telephone devices outside the car, particularly in this type of phone device. Regarding the configuration.

(Prior Art) For example, as shown in Japanese Unexamined Patent Publication No. 59-186749, it is installed in a car and connected to a telephone device in another car or a fixed type telephone device installed in a home or office. Car telephone devices that are capable of making calls between people have been put into practical use.

This car telephone device wirelessly transmits an audio signal input to a microphone to a relay station via a control device and an antenna, and further transmits it from the relay station to another selected telephone device. The antenna is configured to receive an audio signal from the relay station as a radio signal from the relay station, and output it from the speaker via the control device. In addition to the above-mentioned car phone device that incorporates the microphone and speaker into the handset like a normal telephone device, there are other types of car phone devices that include a microphone and speaker so as not to interfere with the driving operation of the car. There is a so-called hands-free type that is attached to a predetermined position inside the car.

(Problems to be Solved by the Invention) By the way, since this car telephone device transmits and receives wirelessly as described above, the transmission and reception strength may vary depending on the communication state of radio waves or the distance between it and the other party's telephone device. There is a problem in that so-called howling occurs when the transmission and reception strength is larger than necessary. This howling occurs when the sound is input to the microphone of the transmitting telephone device and output from the speaker of the receiving telephone device, which is then input to the microphone of the receiving telephone device and output from the speaker of the transmitting telephone device. This is due to the redundant transmission and reception of signals that are input again to the microphone of this telephone device, producing unpleasant high-frequency sounds. In particular, this howling often occurs in hands-free telephone devices in which the voice output from the speaker is likely to be input to the microphone of the same telephone device.

The present invention addresses the above-mentioned problems in car telephone devices, and aims to prevent howling caused by duplicated transmission and reception of signals, thereby providing a good communication condition.

(Means for Solving the Problems) That is, a car telephone device according to the present invention includes a transmitting means and a receiving means, and is capable of communicating with other telephone devices outside the vehicle. a howling degree determining means for determining the magnitude of howling due to the transmission and reception of duplicate signals with the other telephone device; and according to the howling degree determined by the determining means, the higher the howling degree, the more the transmission The apparatus is characterized by comprising a howling adjustment means for lowering the transmission strength of the means or the reception strength of the reception means. Note that when determining the howling degree by the howling degree determining means, a pilot signal for howling degree determination may be output before the start of the call, or the determination may be made using the ring tone of the other party's telephone device, the voice of the call, etc. You may also do so. Further, the transmission strength or reception strength is adjusted by adjusting the sensitivity of the microphone, the gain of the transmitting circuit between the microphone and the antenna, or the gain of the receiving circuit or amplifier between the antenna and the speaker.

(Function) According to the above configuration, the transmission and reception strength may be higher than necessary depending on the radio wave communication state or the distance to the other party's telephone device.
Therefore, when howling occurs, the howling degree determining means determines its magnitude, and in response to the determination result, the howling adjusting means operates to lower the transmitting strength of the transmitting means or the receiving strength of the receiving means. Therefore, the signals transmitted and received redundantly to and from the other party's telephone device are gradually attenuated, and the howling is quickly eliminated.

(Example) Examples of the present invention will be described below.

FIG. 1 shows a schematic configuration of a car phone device, especially a hands-free type phone device.The phone device 1 basically consists of a microphone 2 and a speaker 3 installed at a predetermined position inside the car A. , an antenna 5 that transmits and receives signals between the control device 4 to which these are connected and the outside (relay station).
It is made up of.

As shown in FIG. 2, the control device 4 includes a transmitter 11 that inputs the voice input to the mailbox 2 as an input signal a, and transmits this as a transmission signal to the outside from a transmitting antenna 51; a receiving section 12 into which the received signal C received by the receiving antenna 52 is input; an attenuator 13 that adjusts the gain (voltage level) of the signal d corresponding to the received signal C output from the receiving section 12; It has an amplifier 14 that amplifies the output signal e of the attenuator 13 and sends it to the speaker 3. Here, the transmitting and receiving antennas 51 and 52 are usually integrated as shown in FIG.

Furthermore, this control device 4 includes a pilot signal output section 15 that outputs a pilot signal f for howling degree determination to the speaker 3 via the amplifier 14 at the start of a call, and an input signal a from the microphone 2 and a pilot signal. Output section 15
A howling degree determination unit 16 receives a pilot signal f from the input terminal and compares the levels of both signals a and f to determine the degree of howling, and a control unit 17 receives a signal g from the determination unit 16. It is being The control section 17 controls the howling degree determination section 16.
The attenuator 13 adjusts the gain of the attenuator 13 according to the degree of howling indicated by the signal g from the attenuator 1.
A gain adjustment signal is output for 3. In that case,
The control unit 17 outputs a gain adjustment signal so that the gain of the attenuator 13 is lowered stepwise or steplessly as the degree of howling increases.

Next, the operation of the car telephone device 1 according to this embodiment will be explained according to the communication operation with the telephone device 21 installed in another car B.

First, in the telephone device 1, when a start switch (not shown) such as a hook switch is turned on to start a call, and the telephone number of the other party's telephone device 21 is input, the process is different from that of a normal telephone device. Similarly, when the other party's telephone device 21 emits a ring tone and the receiver performs a predetermined reception operation, both telephone devices 11 and 21 become ready for communication. In this case, in the telephone device 1, a pilot signal f of a predetermined level is output from the pilot signal output section 15 of the control device 4, simultaneously with the output of the ringing tone, or when the call becomes possible. be done. This signal f is outputted as a pilot sound (a) from the speaker 3 via the amplifier 14, inputted to the microphone 2 of the telephone device 1, inputted as the signal a to the transmitter 11, and further transmitted as a transmission signal. The signal is transmitted from the transmitting antenna 51 to the outside of the vehicle. Then, this transmission signal is transmitted to the telephone device 2 of the other vehicle B called via the relay station X.
The received signal i is sent to the receiving unit 23 from the receiving antenna 221 of
and the speaker 24 in the telephone device 21
The pilot sound (b) is outputted from the telephone device 21 and inputted to the microphone 25 of the telephone device 21. Furthermore, the pilot sound (b) input to the microphone 25 is made into a transmission signal j, which is transmitted from the microphone 25 to the outside of the vehicle via the transmitting section 26 and the transmitting antenna 222, and is also transmitted via the relay station X. The signal is received by the receiving antenna 52 of the telephone device 1 of the automobile A, and is input as a received signal C to the receiving section 12 of the control device 4 of the telephone device 1. Then, from the receiving section 12, an attenuator 13 and an amplifier 14 are provided.
The pilot sound (A') is again outputted from the speaker 3 via the telephone device 1, and inputted again to the microphone 2 of the telephone device 1.

In this way, microphone 2 receives the same pilot sound (A).
, (A'), (A''), etc. will be repeatedly input, but if the radio wave communication status between the telephone devices I and 21 in cars A and H is good, or if the communication between both cars A and B is Because the distance is short, each of the above signals is ignored.

When the transmission/reception strength of i, j, c is high, the microphone 2 of the telephone device 1 of the car A is The received signal a output from the receiver is gradually amplified, and as a result, howling occurs.

In this telephone device 1, the amplified received signal a is input to the howling degree determining section 16 of the control device 4, and the determining section 16 outputs the pilot signal output section 15.
The howling degree is determined based on the degree of amplification with respect to the pilot signal f, and the determination result is input to the control section 17 as a signal g. And the control section 17
outputs a gain adjustment signal to the attenuator 13 to reduce the gain when the degree of howling is greater than a predetermined value that would generate unpleasant high-frequency sound. As a result, the pilot sound (A), which was once transmitted from the speaker 3 to the microphone 2 in the telephone device 1 of the vehicle A, is transmitted to the telephone device 21 of the other vehicle B and the receiving section 12 of the telephone device 1.
When the pilot sound (A') is output again from the speaker 3 via the attenuator 13 and amplifier 14, it is attenuated by the attenuator 13 before being output. Similarly, as the pilot sound is gradually attenuated, the occurrence of howling or unpleasant high-frequency sounds can be quickly eliminated.

The above explanation is for the case where the other party's telephone device 21 is also installed in a car, but the same applies even if the other party's telephone device is a normal fixed type telephone device, and both telephone devices are hands-free. It may be of a type other than the above type. Furthermore, in the above embodiment, the reception sensitivity (gain of the attenuator 13) is adjusted according to the degree of howling, but the gain of the amplifier 14 and the microphone 2
The sensitivity of the transmitter 11 or the gain of the transmitter 11 may be adjusted.

(Effects of the Invention) As described above, according to the present invention, howling occurs due to the transmission and reception of duplicate signals in a car telephone device that has a transmitting means and a receiving means and is capable of communicating with a telephone device outside the vehicle. Since the transmitting strength of the transmitting means or the receiving strength of the receiving means is adjusted according to the magnitude of the howling, the generation of unpleasant high-frequency sound accompanying howling can be quickly eliminated, and this kind of Calls using the telephone device can be made successfully.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram of a car telephone device, and FIG. 2 is a block diagram showing the configuration of a control device in the telephone device together with the configuration of the other party's telephone device. 1... Car telephone device, 2,5.11... Transmitting means (microphone, transmitting antenna, transmitting unit), 3.52.12
...Receiving means (speaker, receiving antenna, receiving section)
, 13.17... Howling adjustment means (attenuator, control section), 15.16... Howling degree determination means (pilot signal output section, howling degree determination section)
.

Claims (1)

[Claims] (1) A car telephone device that has a transmitting means and a receiving means and is capable of communicating with other telephone devices outside the vehicle, and is capable of transmitting and receiving duplicate signals with the other telephone device. Howling degree determining means for determining the magnitude of howling; and howling adjusting means for receiving the output of the determining means and lowering the transmission strength of the transmitting means or the receiving strength of the receiving means as the howling degree increases. A car telephone device characterized by: