FR2970389A1 - Kit for connecting telephony function with car radio, has radio frequency modulation stage receiving audio output of Bluetooth module, and switch with output connected to antenna input terminal of car radio module - Google Patents

Abstract

The kit has a radio frequency (RF) modulation stage (12) for receiving an audio output of a Bluetoothmodule (11). The modulation stage operates in a frequency modulation mode by a station search code that designates carrier frequency of the modulation stage. A switch (14) includes an input connected to an on-board antenna (31) of a car, and another input connected to an output of the modulation stage. An output of the switch is connected to an antenna input terminal of a car radio module. An on-board microphone (22) sends audio signals to a mobile phone e.g. smartphone (401).

Description

ADMEA2.frd Kit for vehicle on-board equipment

The invention relates to the on-board equipment of vehicles, in terms of audio-frequency reproduction and / or communication.

It has become commonplace to equip a vehicle not only with a car stereo installation, with cassette player, then optical disk drive (CD, then DVD), but also a telephone function. In some cases, the so-called "Bluetooth" wireless communication function of a cellular telephone is used to co-operate with the on-board vehicle facility. The advantage is to benefit from all the functions available in the mobile phone; this advantage is much more pronounced with mobile phones called "smart", which can store a wide variety of content, including music files. Their functionalities are numerous, and their user interface particularly worked. It remains possible to connect them, for example by Bluetooth communication, with the on-board installation of the vehicle.

For a feature such as hands-free calling, a properly installed microphone in the vehicle should be used instead of the microphone built into the mobile phone; it is also advisable to use the on-board power amplifiers, instead of the amplification and sound reproduction functions integrated into the mobile phone, of clearly insufficient power. All this implies a connection that will depend on the brand and model of vehicle considered, which greatly complicates the marketing of this kind of products. In addition, it increases the total cost of ownership, because the choice of elements to install, and their installation itself, are rarely within reach of the end user.

The present invention improves the situation.

The invention is placed in the context of a vehicle on-board equipment, comprising a car radio system, for mounting in a dashboard housing, in cooperation with a power supply, a radio antenna, at least one electroacoustic transducer on board , and a wireless interconnection module,

2 including Bluetooth, suitable for interacting with a mobile phone.

There is provided an add-in kit, including the wireless interconnect module, with its audio output, which goes to a radio frequency modulation stage, and a two-input switch, and an output. One of the inputs of the switch is provided for one socket to an on-board antenna of the vehicle, the other input of the switch is connected to the output of the radio frequency modulation stage, while the output of the switch is intended to be connected to the antenna input jack of a car radio module.

By this means, the audio output of the wireless interconnection module joins the input of the car radio as a radiofrequency electrical signal. This signal is demodulated to be applied to the on-board audio system and then to the speaker (s). The basic audio signal is therefore reproduced on board, without requiring a modification of the interconnection wiring between the on-board audio system, and the speaker (s). The modification of the on-board wiring relates only to the antenna sockets, which are standard. Two antenna cables are provided, one between the on-board antenna and the second switch input, the other between the output socket of the switch and the antenna input of the car radio module.

According to another aspect of the invention, the state of the switch is controlled by a signal detector, depending on the presence of a signal on its first input.

The kit defined above allows for example to play on the vehicle music contained in a mobile phone, after it has been put in connection with the wireless connection module.

In a more advanced version, there is further provided an on-board microphone, also connected to the interconnect module, but this time to send the audio signals to the telephone. This gives a two-way hands-free telephony function.

Other characteristics are interesting, separately or in combination: the radio frequency modulation stage operates in frequency modulation, the radio frequency modulation stage operates in a modulation mode with auxiliary signals, such as the mode of the so-called "TA" signals ( "Traffic Announcement").

There is provided a selection of the modulation mode of the radio frequency modulation stage, among different modes of auxiliary signal modulation.

Moreover, the kit defined above can be marketed alone. It can of course also be marketed with an on-board audio system and / or speakers. On the other hand, the antenna, its wiring, as well as the wiring between the on-board audio system and the speakers are generally pre-installed in the vehicle.

Finally, the kit can also be marketed with a mobile phone, classic, or the so-called "smart" type.

Other features and advantages of the invention will appear on examining the detailed description below, and the accompanying drawings, in which: - Figure 1 illustrates the schematic diagram of the installation of a car radio on board of a vehicle, - Figure 2 illustrates the block diagram of an on-board installation provided with a kit according to the present invention, and Figure 3 illustrates the semi-detailed partial electrical diagram of an embodiment of the invention. edge installation of Figure 2.

The drawings and the description below contain, for the most part, certain elements. The drawings are an integral part of the description and can therefore not only serve to better understand the present invention, but also contribute to its definition, if any.

Figure 1 illustrates a conventional installation of car radio on board a vehicle. The car radio module 5 is provided with a power connection and a ground connection, not shown. It receives on an input terminal 31 a cable 30 from the antenna 3 installed on board the vehicle. Another cable 50 feeds a system of speakers, which are generally four in number, HP1, HP2, HP3 and HP4.

It is proposed here to modify the installation of FIG. 1, as illustrated in FIG.

The cable 30 arrives at the aerial socket 31 which is now housed in a unit 1 (or casing), receiving a + 12 volts supply, and further connected to the vehicle ground. The housing 1 is connected to a second cable 33 of antenna type, which joins the socket 32 arranged in the car radio 5 (it was the socket 31 in Figure 1). As will be seen below, this housing 1 is provided with a Bluetooth function, which allows it to communicate by short-range waves 402 with a smart mobile phone 401, or other device able to communicate in Bluetooth mode.

Preferably, the housing 1 is also provided with a connection to a microphone 22, installed in the vehicle to allow the voices of passengers to be perceived by this microphone, while minimizing pollution by ambient noise.

Reference is now made to FIG. 3, where the antenna, the car radio and the speakers are not shown.

The mobile phone is found in 401. It can communicate with a Bluetooth exchange module 11, incorporated in the housing 1 (also called main unit). The receiving module 11 is also connected to the microphone 22.

The purpose of the Bluetooth exchange module 11 is to establish and maintain the exchange of digital data specific to the Bluetooth protocol, to receive user information from the remote module 401, and to send it user information, if necessary.

The exchange module 11 can support the Bluet000th A2DP mode. In this case, the user information from the remote module 401 is converted to an analog signal. Conversely, the user information to be transmitted is accepted in analog form.

The output of the Bluetooth receiver module, transformed into an analog signal, is applied to a radiofrequency modulator 12. This modulator 12 may be a modulator with a frequency modulation, operating in said mode "RDS-TA" (for "Radio Data System" with "traffic announcement").

In the embodiment described, the radiofrequency modulator 12 comprises three switchable crystals, making it possible to choose between three values of carrier frequency distributed in the FM band, such as 88, 98 or 108 MHz, for example. A four-wire frequency selector 21 makes it possible to choose the one of the three FM carrier frequencies, which is in use in the modulator 12.

It is known that the so-called "TA" function is part of the various "Radio Data System" ("RDS") auxiliary functions of a modulator and / or an FM / RDS receiver. These auxiliary functions are provided by coded signals, transmitted on a 57 kHz subcarrier of the FM signal carrier, beyond the stereo sub-band (23-53 kHz), centered on its subcarrier at 38 kHz. A pure RDS encoded signal indicates to the receiver that it needs to change the FM carrier to continue to receive the same station in good conditions. An RDS-TA encoded signal instructs the receiver to change its FM carrier to receive a priority announcement. The car radio can detect the RDS-TA signal by scanning all RDS-TA subcarriers in the FM band.

The modulator 12 converts the analog sound signal from the Bluetooth receiver module, when it comes from the mobile phone 401, to make a frequency modulation, accompanied by the auxiliary signal specific to the so-called "TA" mode. The carrier frequency is that selected by the selector 21, for example 98 MHz. There is added a coded signal of the RDS-TA type, which designates as priority frequency the selected carrier frequency itself, ie 98 MHz in the example, according to the control of the selector 21. Such self-designation is unusual.

As long as the telephone communication lasts, the Bluetooth exchange module 11 provides a "presence" signal, indicating that the Bluetooth exchange (telephone or other communication) is still in progress, in one or the other direction. This presence signal can be defined as a boolean representing the fact that the analog output of the module 11 is not zero. The presence signal is used by a signal detection module 13. When there is presence of Bluetooth signal, this module 13 switches the selector switch 14 in the high position (the one shown). The output of the modulator 12 is then connected to an antenna cable, which joins the antenna input jack 32 on the car radio module. In some regions, where the FM transmitters are strong, it may be necessary to strongly shield this cable between the modulator 12 and the jack 32. It may also be necessary to ground the input of the selector 14 which comes from the socket. antenna 31, when not connected.

Conversely, when there is no Bluetooth signal, the output of the source selector switch 14 is connected to the socket 31, from the antenna.

Thus, the antenna input 32 of the car radio receives either the signals from the antenna, through the socket 31 and the source selector switch 14, for a conventional car radio operation, or the output of the modulator FM, which will transfer the sound from the Bluetooth receiver module 11, in the manner of a signal "TA".

In the latter case, the car radio detects the auxiliary signal RDS-TA, and switches to search stations to get on the carrier indicated by the signal TA. Thus, the content of the exchanges by the module 11 is very quickly relayed by the car radio to the loudspeaker system (shown in Figure 1). This assumes that the radio's "RDS-TA" mode is turned on, on devices where it can be turned off.

We know that mobile phones such as 401, especially when they are of the so-called "smart" type, can store quite large sound files, including music files.

With the embodiment just described, such a file can be selected in the mobile phone 401, which is put in Bluetooth enabled mode if necessary.

After the initial mutual recognition specific to the Bluetooth protocol, the sound file is received by the Bluetooth receiver module 11, which outputs analog sound signals corresponding to the sound file. The sounds are then used for a frequency modulation, by the modulator 12, in the form of an FM signal comprising a carrier with the auxiliary signal "TA". This FM signal is transmitted by the source selector 14 to be reproduced in priority by the car radio on the acoustic acoustic installation.

The same process occurs when the phone 401 is in telephony mode. The microphone 22 excites the Bluetooth receiver module, for transmission of the rising voice telephone by the mobile phone 401, provided that a Bluetooth communication is in progress. This allows the vehicle passengers to talk to their telephone partner.

The signal detection module 13 can be arranged with two time constants: at the rise, that is to say when the presence Boolean signal from the module 11 becomes "true", the module 13 instantaneously switches the switch Source selector 14 in the position shown in Figure 3. The car radio will then cut the program being listened to (FM, CD, USB or other) to authorically switch to FM mode, and stalled on the announced carrier frequency by the signal TA (and defined by the carrier selector 21). - Conversely, on the descent, that is to say when the Boolean presence signal from the module 11 becomes "false", the signal detection module 13 waits a certain time, typically 5 seconds, more generally a few seconds before returning the source selector switch to the direct link position of the antenna to the car radio. As soon as the unit no longer receives an FM -RDS-TA signal, it will return to its previous mode (CD player, USB player or other). To effectively return to the FM mode, the selector switch 14 must first reconnect the car radio to the onboard antenna.

Although Figure 3 is a detailed diagram, some elements remain simplified. For example, the source selector switch 14 is shown as a physical switch. This will preferably be a semiconductor switch stage.

It is proposed here a complement kit, comprising at least the module 1 of Figure 3, with the module 2 for mobile telephony. Module 1 can be installed in the dashboard of the vehicle, at the rear of the car radio. It is inserted between the antenna and the car radio. Its presence is enough to give the car radio the ability to reproduce sounds of any kind from a portable source capable of Bluetooth wireless dialogue.

In the embodiment described, the microphone 22 and the frequency selector 21 are part of the same module 2, which is mounted on the front face of the dashboard, and offers, next to the sound recording by the microphone, the ability to manually adjust the carrier frequency used by the modulator 12. The microphone could be omitted, if the hands-free telephony function was not desired. However, the selection of the transmission carrier will be retained.

The antenna connectors are "universal" in a vehicle. The proposed device therefore makes it possible to inject an audio signal into any type of automobile edge system, even a very advanced one: multi-amplification, transmission of the output signals of the car radio by optical fiber, in particular. In addition, the example described uses the Bluetooth mode for wireless close communication. This is not limiting. One could, for example, use WiFi signals for the same purpose, at least for the function of playing audio files from the phone. 8 25 30

Claims (8)

REVENDICATIONS1. Kit for on-board equipment, characterized in that it comprises a wireless interconnection module (11), with its audio output, a radio frequency modulation stage (12), which receives the audio output of the module of wireless interconnection, and a switch (14) with two inputs, and an output, in that the radio frequency modulation stage operates in frequency modulation, in a modulation mode by a station search code which designates its own frequency carrier, in that one of the inputs of the switch (14) is provided for one socket to an on-board antenna of the vehicle, and the other input of the switch is connected to the output of the radio frequency modulation stage (12) , while the output of the switch (14) is intended to be connected to the antenna input jack of a car radio module. 2. Kit according to claim 1, characterized in that it comprises a signal detector (13) which controls the state of the switch (14). 3. Kit according to one of claims 1 and 2, characterized in that there is further provided an onboard microphone (22), also connected to the wireless interconnection module (11), for sending audio signals to a phone. 4. Kit according to one of claims 1 to 3, characterized in that there is provided a selection (21) of the carrier frequency of the radio frequency modulation stage (12) among several possibilities. 5. Kit according to one of the preceding claims, characterized in that it further comprises an onboard audio system and / or speakers. 6. Kit according to one of the preceding claims, characterized in that it further comprises a mobile phone, having a wireless local communication function. 7. Kit according to one of claims 1 to 6, characterized in that the wireless communication function is of the so-called Bluetooth type. 8. Kit according to one of claims 1 to 7, characterized in that the wireless communication function is of the so-called WiFi type.