JPS6210456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is currently practiced primarily in West Germany.
Regarding radio receivers that can receive traffic information broadcasts using the FM band, even when receiving other reception bands, when the traffic information broadcast starts, the FM
The present invention relates to a radio receiver characterized in that it is configured to receive traffic information broadcast by switching to a different band.

First, I will briefly explain the traffic information system implemented in West Germany. Not all broadcasting stations broadcast traffic information, so in order to identify whether or not a station is broadcasting traffic information, a 57KHz identification signal called an SK signal is transmitted when broadcasting traffic information. Stations that are currently transmitting are constantly transmitting. Therefore, the receiver is configured to drive a display device upon detection of this SK signal, so that it is possible to easily select a station that carries out traffic information broadcasting. Also, since traffic information broadcasts are broadcast irregularly during the program, a 125Hz instruction signal called a DK signal that instructs the start of traffic information is amplitude-modulated into a 57KHz SK signal.
It is transmitted along with the SK signal. Therefore, upon detection of this DK signal, the receiver is configured to cancel muting, increase the volume, or switch from tape to radio to ensure reliable reception of traffic information broadcasts.

However, since this traffic information broadcast is carried out only on the FM band, MW,
I was unable to hear traffic information when receiving SW and LW bands. Therefore, if you try to receive traffic information broadcasts while receiving a band other than the FM band, it is necessary to keep the FM band receiving circuit in the receiving state at all times, but generally the receiver's tuning mechanism is tuned to each band. In car radio receivers that use a mechanical tuning method such as μ tuning, it is impossible to provide a separate μ tuning mechanism for the FM band due to space and cost considerations. Yes, it was not possible to listen to traffic information while receiving a band other than the FM band. In addition, in the recently popular synthesizer-type electronic tuning receiver with the configuration shown in Figure 1, in which the local oscillation circuit is configured with a PLL and a voltage variable capacitance element is used in the tuning circuit, the control section 1 of the PLL is configured to operate in the FM band. Receiving circuit 2 and
Since the MW band receiving circuit 3 is configured to be used interchangeably and switched, when switching to the MW band, the FM band becomes unreceivable, and traffic information cannot be received either.

Therefore, the present invention has been made in view of this point.
To provide a radio receiver configured to automatically switch to the FM band and receive traffic information when traffic information broadcasting starts even when a band other than the FM band is being received.

An embodiment of the present invention will be described below with reference to the drawings.
The FM band and MW band receiving circuits 2 and 3 include high frequency amplifier circuits 4 and 4', local oscillation circuits 5 and 5', mixing circuits 6 and 6', intermediate frequency amplifier circuits 7 and 7', and detection circuits 8 and 8, respectively. ' constitutes a heterodyne receiving circuit, and local oscillation circuits 5 and 5' are constituted by a voltage-controlled oscillator whose oscillation frequency is changed by controlling the applied voltage. It is configured to change the frequency and tune. 9 is a band changeover switch 10
a, 10b, 10c, and 10d are switched to the MW band, the voltage controlled oscillator of the FM band local oscillation circuit 5 and the tuning circuit of the high frequency amplifier circuit 4,
This is a receiving and holding circuit that supplies a control voltage in place of the PLL control unit 1, and is a stabilizing power supply circuit 1 as shown in FIG.
1 and a variable resistor 12, and supplies a voltage corresponding to the control voltage by the PLL controller 1. 13 is
In the SK signal and DK signal detection circuit provided in the FM band, the detected SK signal is applied to the switching transistor 14 to control the lighting of the light emitting diode 15, while the DK signal is applied to one input of the band switching switch. 10d is connected to the other input of the OR gate 16, which receives the high level in the FM band, and controls the conduction of the switching transistor 18 that controls the relay 17. 1
9 is a relay contact of the relay 17, and the detection circuit 8 of the FM band and MW band receiving circuits 2 and 3;
8' is switched and inputted to the low frequency amplifier circuit 20. Note that when the band changeover switch 10d is switched to the FM side, the relay 17 is always excited because the switching transistor 18 is always conductive, and the relay contact 19 is switched to the FM side. On the other hand, when the band selector switch 10d is switched to the MW side, the relay 17 is demagnetized due to the non-conduction of the transistor 18, and even when the relay contact 19 is switched to the MW side, the DK signal is detected by the detection circuit 13. Then,
When the relay 17 is excited by the conduction of the transistor 18, it is switched to the FM side. Although not shown, the FM band receiving circuit 2 is constantly supplied with power, and is maintained in an operating state even during reception of the MW band.

Next, the operation of the present invention having such a configuration will be explained.

First, the band changeover switches 10a to 10d are set to FM.
When the PLL control unit 1 is connected to the FM band receiving circuit 2, the voltage controlled oscillator of the local oscillation circuit 5 has its oscillation frequency controlled by the control voltage from the PLL control unit 1, and selects a station. Do this. At this time, if the tuned station is a station that broadcasts traffic information, the detection circuit 13 detects the SK signal, and the light emitting diode 15 lights up due to the conduction of the transistor 14, so that the tuned station broadcasts traffic information. Indicates that the station is a broadcasting station. At this time, the band selection switch 10d is on the FM side, the relay 17 is excited by the conduction of the transistor 18, and the relay contact 19 is held on the FM side, and the received signal is amplified by the low frequency amplifier circuit 20 and output to the speaker 21.
The sound will be louder. Therefore, if the traffic information starts in the middle of the program, the user can listen to the traffic information. Thus, in order to hear traffic information, the light emitting diode 15
Tune to the station where is lit.

Next, when receiving the MW band, the band changeover switches 10a to 10d are switched to the MW side.
By switching to the MW side, the PLL control section 1 is connected to the MW band receiving circuit 3, thereby controlling the local oscillation circuit 5' and making it possible to select a channel in the MW band. At this time, relay contact 1 is demagnetized by relay 17.
9 is switched to the MW side, and the received signal in the MW band is reproduced from the speaker 21. Note that when switching to the MW band, the PLL control section 1 is separated from the FM band receiving circuit 2, but by connecting the receiving holding circuit 9 to the local oscillation circuit 5 instead,
The FM band receiving circuit 2 is maintained in a receivable state. That is, from the reception holding circuit 9, the variable resistor 12
By adjusting, it is possible to supply a voltage corresponding to the control voltage supplied by the PLL control unit 1. Therefore, by adjusting the variable resistor 12, the voltage controlled oscillator of the local oscillation circuit 5 can be controlled and channel selection can be performed. . Therefore, by adjusting the variable resistor 12 of the reception holding circuit 9 so that the light emitting diode 15 lights up, the FM band reception circuit 2 can be tuned to the station implementing the traffic information broadcast and held in the receiving state.

Therefore, when the traffic information broadcast is started while the MW band is being received while the FM band is kept in the reception state of the traffic information broadcast, the detection circuit 13
When the DK signal is detected, the transistor 18 is turned on via the OR gate 16, so that the relay 1 is turned on.
7 excitation switches the relay contact 19 to the FM side,
Traffic information is reproduced from the speaker 21. Since the DK signal is transmitted during the period when traffic information is being broadcast, the relay contact 19 is switched to the FM side during the period of traffic information, but since the DK signal also disappears when the traffic information ends, the DK signal is Due to the disappearance, the relay 17 is demagnetized and the relay contact 19 is returned to the MW side, and reception of the MW band is performed again. Thus, if traffic information broadcasting starts even while receiving the MW band, the user can stop receiving the MW band and listen to the traffic information.

Although the above embodiment was for the MW band, the SW band or LW band can also be configured in the same way.
You can listen to traffic information broadcasts while receiving the LW band.

As described above, the radio receiver of the present invention uses a tuning control unit that is used for both the FM band receiving circuit that performs traffic information broadcasting and the receiving circuit for other bands such as the MW band, and is controlled by switching. , the band
reception holding means for holding the FM band receiving circuit in a receiving operating state in place of the tuning control means when switching from the FM band to a band other than the FM band and the tuning control means is connected to the receiving circuit of the other band; is provided, and configured to selectively connect the tuning control means and the reception holding means to the FM band reception circuit by means of a band changeover switch, and the means for detecting the traffic information start signal in the FM band, and the means for detecting the traffic information start signal in the FM band. The configuration is simplified by automatically switching the band to the FM band upon detection, and providing a switching means for controlling a band switching switch to connect the receiving circuit of the FM band from the reception holding means to the tuning control means. When receiving traffic information on a band other than the FM band, when traffic information broadcasting starts, the system automatically switches to the FM band and allows you to listen to traffic information.

[Brief explanation of the drawing]

Figure 1 shows a conventional example of a radio receiver, Figure 2 shows a conventional example of a radio receiver.
Figure 3 shows the configuration of the radio receiver of the present invention.
The figure is a diagram showing the configuration of the main part of FIG. 2. 1...PLL control unit, 2...FM band receiving circuit, 3
...MW band receiving circuit, 9...Reception holding circuit, 13
...Detection circuit.

Claims (1)

[Claims] 1. It is composed of multiple bands including the FM band and other bands such as the MW band, and the tuning control means is also used as the receiving circuit for each band, and is selectively connected to the receiving circuit for the band selected by band switching. In a radio receiver equipped with a band switching switch, when the band is switched from the FM band to a band other than the FM band and the tuning control means is connected to a receiving circuit of another band, the tuning control means a reception holding means for holding the FM band receiving circuit in a receiving operation state, and the tuning control means and the reception holding means are configured to be selectively connected to the FM band receiving circuit by the band changeover switch; Detecting means for detecting a traffic information start signal in the FM band, and automatically switching the band to the FM band upon detection by the detecting means, and connecting an FM band receiving circuit from the reception holding means to the tuning control means. What is claimed is: 1. A radio receiver comprising a switching means for controlling the band switching switch, and receiving traffic information even when receiving a band other than the FM band.