EP0283708B1 - Radio receiver with two traffic radio decoders - Google Patents

Abstract

An autombile radio capable of receiving VHF entertainment programs from a station in which traffic information signals are modulated in a 57 kHz subcarrier is equipped with two decoders for the 57 kHz subcarrier signals, one decoder for traffic information signals modulated in an analog fashion on the subcarrier and another decoder for digital signals modulated on that subcarrier by double-sideband suppressed-carrier modulation. The first decoder is for a system already in use in which traffic information, at least if urgent, is intended to override the entertainment program, and the receivier has the usual circuits for that override. The second decoder is for a system that is planned but not yet in use in which the received digital signals can call out one or more standard messages or message portions from a read-only memory and either the memory addresses or the memory outputs are storable. They are made audible by speech synthesizer and, because they are stored at least until the next message comes in, can be recalled if the user wishes. The receiver switch for turning on the traffic information feature is a selector switch with positions selecting either type of decoder and, in a modification designed for where both systems are available, the corresponding switching system gives priority to the presently existing system, since the output of the other system will not be lost and can be reproduced when the signals of the existing system have ceased.

Description

The invention relates to a radio receiver with an LF amplifier and with at least one traffic radio decoder for received traffic information according to the preamble of claim 1.

To improve the flow of traffic and traffic safety, it is known to send traffic information via certain radio stations (traffic radio stations), which can in principle be received by any radio receiver. In order to make it easier for the driver, in particular, to find the traffic radio station responsible for his local area, a widespread identification system (driver broadcasting information) has been in use for a long time. used, which uses three characteristic frequencies that are modulated in the FM area in addition to the useful modulation of the FM traffic radio station. This system is already used in several European countries.

A 57 kHz carrier is provided for the station identification, which serves to identify all traffic radio stations. For the purpose of range identification, the 57 kHz carrier is modulated with one of six possible range frequencies (letters A-F). In this way, identification is made about which traffic radio area the traffic radio station in question belongs to.

A second modulation of 125 Hz on the 57 kHz carrier is used as the announcement identifier during a traffic announcement to identify the relevant traffic information.

A special decoder is required within the radio receiver for the evaluation and processing of the three identifications or identification frequencies mentioned, and the known system advantageously allows the construction of very inexpensive traffic radio decoders which are able to provide the driver with the traffic information inevitably bring to hearing. An additional receiver in the car radio searches for the responsible traffic radio station using the transmitter and area identification. By evaluating the announcement identifier, the driver is given the traffic information acoustically even if he hears another program or music from a cassette, for example.

Because of its many advantages, the above system has now predominantly established itself as an identification system for traffic information. However, not all possibilities can be fully exploited with the known system. The radio program just heard by the driver via the car radio must inevitably be interrupted for the duration of the traffic announcement, which is sometimes perceived as annoying. In addition, the number of traffic information is limited due to the required announcement time and also due to a decreasing attention of the driver to be observed during longer announcement times. In the case of possible traffic announcements in foreign languages (for transit traffic during the holiday period), the announcement time is multiplied accordingly.

To further improve an optimal traffic radio system a traffic radio decoder for processing digital signals has therefore already been described, the digital signals identifying the traffic information, and the digital signals being obtained by demodulating an auxiliary carrier on which the digital signals are modulated (magazine "Internationales Verkehrswesen"; reprint) from issue 5/85; Peter Brägas "Control and information systems in motor vehicles - a contribution to improving traffic flow and traffic safety", pages 2 - 8).

This is an RDS traffic radio decoder, with the digital signals being transmitted in accordance with the RDS system (Radio Data System) with RDS signals. The RDS system is intended for the transmission of digital signals on a subcarrier of 57 kHz via VHF radio transmitters, with a double-sideband amplitude modulation of the 57 kHz carrier (carrier is suppressed) with the biphase-coded data signal. Due to the biphase coding, no spectral lines appear in the vicinity of the carrier, so that there is compatibility with the other system, which can thereby be further developed in an advantageous manner.

The basic idea behind the alternative of the RDS system is to transmit digital memory addresses or code words, the components of structures of traffic information being stored in the radio receiver or in the traffic radio decoder under the respective addresses and ready for display and for display playback using a speech synthesizer. The focus is therefore not on sending a traffic announcement, but on the transmission of digital signals that represent certain traffic announcements, so that in addition to the RDS system, other digital transmission systems can also be considered in principle.

Of particular importance is the knowledge that the traffic information, despite its possible number, can be standardized and divided into certain standard texts. This leads to significant advantages in connection with digital signal transmission, because it is now possible in a simple manner to assign address signals to certain components of the standardized traffic information and to store them in a memory. The traffic radio transmitter then only needs to send certain digital address signals within an RDS signal, so that as a result, traffic information is only transmitted in the form of a memory address.

From EP-A-0 200 977 a digital demodulator for radio receivers has become known which is capable of receiving and evaluating RDS information. If the radio station interrupts its program and transmits traffic information, a so-called VRF identifier is also transmitted, which identifies whether or not traffic radio information is broadcast by the corresponding transmitter. These signals can also be evaluated by the digital demodulator. This makes it possible to obtain switching information that is transmitted by the so-called VRF transmitters. From the magazine Funkschau, Volume 58, No. 1, January 1986, pages 43 to 47, W. Hinz, "New Developments on Radio Waves", it is known that traffic identification codes can be transmitted by means of RDS, and this results in the advantage for car radios that two different modules are not required for the evaluation of identification signals. Finally, it is proposed to also transmit radio text using RDS. Texts accompanying the program can be output here via LCD displays or also via speech synthesizers - for example artists, pieces of music or program changes.

In practice, however, the RDS system is only at the beginning of a technically practical introduction, while - as already mentioned above - the first system has been in use for a long time. Since the RDS system has not yet been introduced correctly, and since the first system will not be replaced overnight, but rather will still be used during a long transition phase, the problem with the already existing and also with the newly manufactured radio devices is that the Users can either only receive traffic messages from the first system or only RDS traffic messages.

It should also be borne in mind that there will continue to be countries in which only the first system will still be used, or where the transition phase to the RDS system will take an extremely long time.

Here there is now the danger that certain traffic reports will not reach the listener or driver because the radio receiver used is not corresponding is designed for the respective system.

The object of the invention is to create a radio receiver to avoid the disadvantages described, which offers the listener the possibility of receiving all traffic reports, in particular during the transition phase to the RDS system.

This object is achieved by the radio receiver mentioned in the preamble of claim 1 by the features listed in the characterizing part.

The invention is based on the fact that, in addition to the new RDS system, the tried and tested other system will continue to be used during a long transition phase, and that in certain areas only this system will still be used. Nevertheless, the traffic announcements and the traffic information should reach the listener regardless of the type of system, even if the respective traffic information is broadcast in parallel according to the first system and according to the RDS system.

Characterized in that both a traffic radio decoder of the first system and an RDS traffic radio decoder is provided in the radio device according to the invention, and that either either the traffic radio decoder of the first system or the RDS traffic radio decoder by means of a selector switch to the Amplifier of the radio receiver can be switched through, it is ensured that, given the parallelism of both systems, the radio receiver can still be used universally.

The selector switch ensures that traffic information received according to the first system on the one hand and the RDS system on the other hand is not heard in parallel, which would completely confuse the driver. Rather, it is ensured that only the traffic announcement of the first system or the RDS traffic announcement is brought to the listener or the driver. Since the radio receiver can receive both systems, it is ensured during the transition phase that no traffic information is lost.

In an expedient embodiment of the invention, it is possible to receive traffic information at the same time the first traffic radio decoder and the RDS traffic radio decoder to connect the first traffic radio decoder, which will still have priority during the long transition phase, to the amplifier.

This solution is also particularly advantageous because the traffic information can be saved using the RDS system. It is therefore possible to first reproduce the traffic information of the first system acoustically, and then, if necessary, the parallel RDS traffic information can then also be called up from the memory and played back via a speech synthesizer.

Other expedient refinements and advantageous developments of the invention result from the subclaims and the following description and the drawing.

Fig. 1

ein schematisches Blockschaltbild eines Rundfunkempfängers mit einem ersten Verkehrsfunk-Decoder und einem RDS-Verkehrsfunk-Decoder, und

Fig. 2

das Blockschaltbild einer abgewandelten Ausführungsform eines Rundfunkempfängers gemäß Fig. 1.

On the basis of the exemplary embodiments shown in the drawing, the invention is explained in more detail below for better understanding. Show it:

Fig. 1

a schematic block diagram a radio receiver with a first traffic radio decoder and an RDS traffic radio decoder, and

Fig. 2

2 shows the block diagram of a modified embodiment of a radio receiver according to FIG. 1.

The radio receiver, designated as a whole by the reference number 10, has a receiving antenna 12 for receiving the programs broadcast by a traffic radio station or also by another station. In a conventional manner, the radio receiver 10 comprises a mixer stage 14 which is controlled by an oscillator 16 and to which an IF amplifier 18 and a demodulator 20 are connected.

The demodulator 20 is connected via a volume control 34 to an LF output stage 36, via whose loudspeaker 38 the demodulated signals can be reproduced. The radio receiver described so far is known per se.

A first traffic radio decoder 22 is connected to the demodulator 20, the output of which leads to a switching stage 24. When a traffic announcement is transmitted, the switch of the switching stage 24 is closed, while the program just heard via the loudspeaker 38 is interrupted by the transmitter. After the traffic announcement has ended, the system automatically switches back to the current radio program.

The switching stage 24 therefore interacts with a selector switch 26 which has three switch positions and can therefore connect the volume control 34 to three different contacts.

In the position shown above, the demodulated radio signal reaches the LF output stage 36 via the volume control 34. In the middle switch position of the selector switch 26, only a traffic announcement from the first traffic decoder 22 is heard.

In parallel to the traffic radio decoder 22, the output of the demodulator 20 leads to an RDS traffic radio decoder 28, which is followed by a memory 30. A memory synthesizer 32 follows the memory 30, whose output is connected to the lower contact pole of the selector switch 26, so that in the lower switch position of the selector switch 26 the speech synthesizer 32 is connected to the LF output stage 36 via the volume control 34.

Since the new radio receiver 10 is additionally provided with an RDS traffic radio decoder 28 in addition to the first traffic radio decoder 22, it is possible with the aid of the selector switch 26 to send either the first traffic radio decoder 22 or the RDS traffic radio decoder 28 to the To switch on the NF output stage 36, in the latter case the synthetic speech of the RDS traffic radio decoder 28 is reproduced via the speech synthesizer 32.

Thus, the user or the driver can be brought to listen to the traffic announcement that is currently being received with the aid of the automatically controllable selector switch 26, it then being immaterial whether the traffic announcement is transmitted according to the first system or according to the RDS system and Will be received. It is thus ensured that all traffic messages are received during a transition phase in which both systems coexist can be.

It is also conceivable that both traffic information according to the first system and according to the RDS system are available and received at the same time. For this case, in an expedient embodiment of the invention according to FIG. 2, the first traffic radio decoder 22 is primarily connected to the LF output stage 36.

The RDS traffic information received simultaneously from the RDS traffic radio decoder 28 initially remains in the memory 30 and is only switched to the LF output stage 36 after the traffic information has ended, so that the traffic information is only then reproduced via the speech synthesizer 32. The LF output stage 36 is connected here to the volume control 34 via a decoupling resistor 40.

The last-described operating mode with simultaneous presence of both a first traffic notice and an RDS traffic notice is indicated in FIG. 2 by the dashed lines 46. During the playback of the ARI traffic information, the switches 42 and 44 are open, so that the one just received Broadcasting program and the speech synthesizer 32 are switched off by the LF output stage 36.

In the case of a subsequent transmission of a normal radio program, switch 42 according to FIG. 2 is closed, while switches 24 and 44 are open. When an RDS traffic information is transmitted, only switch 44 is closed, while switches 42 and 24 are open. It is possible to route a stored RDS traffic message to the LF output stage 36 via the speech synthesizer 32 and to make it audible via the loudspeaker 38.

Claims (3)

1. Broadcast receiver, particularly a car radio, comprising an AF amplifier, having a first traffic programme decoder (22) for received traffic information, the first traffic programme decoder (22) being used for processing switching signals of a known information and warning system for car drivers, and having a decoder for decoding digital information (RDS decoder) which is received by the broadcast receiver, characterised in that a second traffic programme decoder (28) is provided for decoding the digital information which represents traffic information, and in that optionally either the information released by the first traffic programme decoder (22) or the information decoded by the second traffic programme decoder (28), which is converted into voice by means of a voice synthesizer (32), can be switched through to the amplifier (36) of the broadcast receiver (10) by means of a selection switch (26), in that the selection switch (26) automatically switches the output of the traffic programme decoder (22, 28) which receives a traffic information item through to the amplifier and in that in the case of simultaneous reception of a traffic information item both by the first traffic programme decoder (22) and by the second traffic programme decoder (28), the first traffic programme decoder (22) is connected with priority to the amplifier (36).
2. Broadcast receiver according to Claim 1, characterised in that the traffic information item received by the second traffic programme decoder (28) is stored in a memory (30), and in that the memory (30) is connected to the amplifier (36) via the voice synthesizer (32) for reproduction of the traffic information item after the end of the reproduction of the traffic information item by the first traffic programme decoder (22).
3. Broadcast receiver according to one of Claims 1 or 2, characterised in that the information received by the traffic programme decoder (28) can be stored in the memory (30), and in that the memory (30) can be connected to the amplifier (36) via the voice synthesizer (32) for reproducing the information.

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