JPH0687544B2 - In-vehicle communication device audio playback system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a new type audio reproduction system for improving reproduced sound quality in an in-vehicle communication device.

[Prior Art] Since a vehicle-mounted communication device needs to be small and lightweight, it is called a transceiver and the transmitter and receiver are put in the same case.
By using the transmitter circuit and the receiver circuit as commonly as possible,
We are reducing the size by reducing the number of circuit members and adjustment points.

As a result, current in-vehicle transceivers fit into the storage space under the dashboard of the vehicle, making it easier to install in the vehicle.

The transceiver usually has a built-in speaker and can be used by simply attaching an external hand microphone, but it is usually possible to use an external speaker if necessary.

[Problems to be Solved by the Invention]

As mentioned in the previous section, the in-vehicle communication device is usually installed in the storage compartment under the dashboard of the car, and it is convenient for the driver to operate it. Since it is inevitably downsized and there is no mounting space on the front panel surface, it is generally opened on the side surface or the upper and lower surfaces of the case.

For this reason, when the wall is close to the four sides like the case under the dashboard, the sound is distorted and the clarity is significantly reduced, and it is difficult to hear because it is close to the side especially from the driver's seat. There is. Of course, it is recommended that the equipment side install a larger external speaker than the built-in speaker in a good listening position. It is a tedious task and has the drawback of being expensive and time consuming to install. It goes without saying that the use of headphones is not possible because the operation of the driver involves danger.

[Means for Solving the Problems]

Clarity is the most important factor in communication equipment, even when it comes to sound quality.
The range need not be very wide, but at least 30
It is desirable that the voice range of 0 to 3000 Hz can be reproduced flatly, and that the vehicle-mounted device is required to have a volume sufficient to overcome the running noise of the vehicle and a low distortion that does not impair the intelligibility.

In order to satisfy this condition, the present invention oscillates a weak radio wave modulated with an audio output signal of an in-vehicle communication device and receives this by an in-vehicle radio receiver, so that the voice of the communication device is a speaker of the radio receiver. Listen through the device.

As a weak radio wave oscillator, as is known in wireless microphones, it is a radio transmitter out of radio wave regulation that can be used for radio communication at a close range, and in this case, it modulates with the voice output of the communication device instead of the microphone output. Of. As the modulation format, the wireless microphone uses FM modulation, but in this proposal, FM is used according to the format of the radio receiver.
You can use it with AM, but in practice FM is better sound quality and S / N
It is expected that excellent results will be obtained in.

The in-vehicle radio receiver is usually installed in the center of the dashboard, which is convenient for operation from the driver's seat or the passenger seat, and the communication device is often installed close to it in a line with it. It may be possible to connect the audio output of the communication device directly to the radio receiver, but most current radio receivers are integrated with the tape deck, so no audio input terminal is provided. There are many things, and even if you can connect, the connection cord is an obstacle,
There is a problem that it is not easy to work through the dashboard partition.

The antenna of the on-vehicle radio receiver is set up on the outside glass of the vehicle body or set on the back glass, and the weak radio transmitter modulated by the voice output of the communication device is installed on the dashboard near the center of the car, so The maximum distance is about 2 m, and if you can obtain an electric field strength of 100 μV / m or more at that position, you can get a sufficient S / N not only for FM but also for AM, so the target range is several tens of meters. It requires less power than a microphone.

Details of the above configuration will be described in the following [Example] section.

Further, when the in-vehicle communication device is for two communication paths, the weak radio wave oscillator is stereo-modulated by each audio output of the two communication paths, and this is received by the in-vehicle stereo radio receiver, and the communication device The two-channel audio output is reproduced and heard from the left and right speakers, respectively.

The details will be described later in [Other Embodiments].

〔Example〕

 An embodiment of the present invention is shown in FIG.

In FIGS. 1A and 1B, reference numeral 1 is an in-vehicle communication device, 11 is a receiving circuit portion thereof, 12 is a built-in speaker, 13 is a phone jack, and other parts unrelated to the description are omitted.

2 of FIG. 1 (A) is a weak AM radio oscillator constituting the present invention, the crystal oscillator is frequency controlled by the crystal oscillator 22 is 21, 23 audio signal output of the communication device 1 of the quartz oscillator 21 24 It is an AM modulator that is modulated by. Audio signal 24 is phone plug 14
If is inserted into the phone jack of the communication device 1 , it is connected to the audio output of the receiving circuit unit 11, and at the same time, the connection to the speaker 12 is disconnected. The output of the weak radio wave oscillator 2 radiates a weak radio wave using the short electric wire 25 drawn out of the case as a lead antenna.

In FIG. 1 (B), 3 is a weak FM radio wave oscillator.
Is a crystal oscillator whose frequency is controlled by the crystal oscillator 32, and 33 is an output buffer stage. The FM modulation can be simply constructed as a direct FM modulation oscillator by adding the voice output signal 34 of the communication device to the voltage controlled capacitance diode 36 inserted in series or in parallel with the crystal oscillator 22. Weak radio wave oscillator
The output of 3 is radiated by the lead antenna 35.

In Figure 1 (C) is vehicle radio receiver, the receiver main body 4 is mounted on the dashboard of the motor vehicle, in addition to the channel selection performed by the tuning knob 41 and the frequency display 42, a channel selection button 43 _a ~ 43 _n It is usually possible to receive a broadcast of a preset frequency with one touch.

Put accordance with the frequency one of the of the weak radio wave oscillator tuning of the radio receiver 4 button with the oscillation frequency of 2 · 3 set to a frequency no radio 43 _a ~ 43 _n is the practice of the present invention By doing so, it is possible to quickly and easily switch from the radio reception state to the communication device reception state.
It is reproduced with sound quality.

Whether (A) AM or (B) FM is used for the weak radio wave oscillator depends on the format of the radio receiver, but the current in-vehicle radio receivers in Japan usually use both AM and FM. There are many advantages to using waves.

[Other Embodiments] FIG. 2 shows another embodiment of the present invention.

There are several different types of two-way communication devices, but the typical one is that the communication circuit of separate frequency bands such as UHF band and VHF band is stored in one communication device. It is used by selecting either of the two communication paths by switching, but for the purpose of saving cost and space as common except the front stage part where the circuit configuration is greatly different such as UHF band and VHF band or SW band It is often found in communication devices.

In FIG. 2 (A), 6 is a configuration in which the weak radio wave oscillator of the present invention is incorporated in an on-vehicle communication device for two communication paths, 61 is a UHF circuit, 6
2 is a VHF circuit (one of which may be another frequency band such as a SW circuit), the output of which is a common IF / demodulation /
It is supplied to the built-in speaker 65 through the AF circuit 63.

The weak FM radio oscillator is the same as 3 in Fig. 1 (B),
The modulated signal of this example distributes the UHF band speech output and the VHF band speech output to the R and L sides of the stereo multiplex signal and modulates them. However, in this case, even if it is called a stereo modulated wave, the R side and the L side do not modulate at the same time. For example, only the R side of stereo is voice-modulated when receiving in the UHF band, and only the L side when receiving in the VHF band. It is voice-modulated.

Switching of the operation of the UHF circuits and VHF circuits is usually a of performing switching power supply circuit by UHF / VHF selection switch 66 _a, which the R side of the stereo signal generator 67 a sound output signal by the switch 66 _b in conjunction This is performed by switching between input and L-side input.

As the stereo signal generator 67, for example, an IC such as NJM2035 type manufactured by Japan Radio Co., Ltd. has been sold by several companies, so that it can be easily obtained and applied.

FIG. 2 (B) shows an FM multiplex stereo receiver, which is currently installed as standard equipment as an onboard radio in Japan. 7 is a receiver body, a tuning knob 71, a frequency display 72,
The channel selection button 73 _a to 73 _n are the same as in FIG. 1 (C).

If the stereo speaker 8 is on the R side and 9 is on the L side, the communication device
When operating in the UHF band, the sound can be heard from the R-side speaker, and when operating in the VHF band, it can be heard from the L-side speaker, so that the operating frequency band can be identified without checking the communication device.

〔The invention's effect〕

Since the in-vehicle communication device is not standard equipment, there are restrictions on the installation location, and it is often difficult to use an external speaker with good sound quality because of the installation location, the labor and cost of the installation work, and the present invention. For example, the in-vehicle radio receiver, which is installed as standard, can listen to the call through the sound reproducing device that is excellent in both volume and sound quality, which has the effect of improving the intelligibility of the communication content.

Furthermore, by distinguishing the voice output of the two-channel communication device according to the second aspect of the present invention from the R-side speaker and the L-side speaker of the vehicle-mounted stereo radio receiver, the distinction between the working channel can be confirmed. Since it can be intuitively determined without requiring
In a communication device operated by a driver, it is extremely effective from the viewpoint of danger prevention.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of another embodiment. 1, 6 ... vehicle communication device, 2, 3 ... weak radio wave oscillator, 4, 7
… On-board radio receiver, 11 ・ 61 ・ 62 ・ 63… Communication circuit, 12
… Built-in speaker, 5/8/9 ... External speaker, 43 _a to 43 _n
· 73 _a ~73 _n ... channel selection buttons, 67 ... stereo modulator.

Claims (1)

[Claims] 1. A structure for oscillating a weak radio wave modulated by an audio output signal of an in-vehicle communication device and a structure for receiving the weak radio wave by an in-vehicle radio receiver, which are for two communication paths. , Oscillates a weak radio wave in which each channel output signal is distributed to the left and right channels and is stereo-modulated, and the weak radio wave is received by the vehicle-mounted stereo radio receiver, and the two channel output signals of the vehicle-mounted communication device are respectively separated. An audio reproduction method for an in-vehicle communication device, which is characterized by being reproduced from a speaker.