JPH02158220A - Broadcast receiver - Google Patents

Abstract

PURPOSE:To surely listen to traffic information with simple constitution by devising the receiver such that remaining front end circuits not selected are kept to receive a tuning frequency just before the selection so as to continue the reception even when the selected front end circuit is changed over. CONSTITUTION:A radio receiver 1 is provided with a 1st front end circuit 2 and a 2nd front end circuit 3, the 1st front end circuit 2 receives a frequency modulated broadcast, while the 2nd front end circuit 3 receives an amplitude- modulated broadcast. The radio receiver 1 gives a control voltage to the 1st front end circuit 2 for the frequency modulation broadcast to receive the frequency modulation broadcast and when the transmission of the traffic information is detected, the receiver 1 selects the reception of the frequency modulation broadcast automatically. Moreover, a phase comparator 43 and a reference signal generating circuit 44 being components of a phase locked loop partial circuit are realized as a simple circuit each. Thus, the traffic information is surely listened to with simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a broadcast receiving device that can be advantageously implemented for reliably listening to radio broadcast traffic information.

Conventional technology In so-called electronically tuned radio receivers, the front-end circuit for receiving radio broadcasts includes only a single phase-locked loop circuit, so that traffic information is not broadcast on stations other than the radio broadcast being received. However, you cannot listen to traffic information broadcast from other stations.

In order to solve this problem, a plurality of phase-locked loop circuits are provided to simultaneously receive a plurality of radio broadcasts, and each broadcast station receives an identification signal that is transmitted before the traffic information is broadcast. A conceivable configuration is to switch to the phase-locked loop circuit that is receiving the traffic information so that when the identification signal is received, the radio broadcast that received the identification signal is converted into sound.

Problems to be Solved by the Invention However, phase-locked loop circuits are generally expensive, and therefore the configuration described above becomes complicated and large in size.

An object of the present invention is to provide a broadcast receiving device that can receive a plurality of broadcasts and reliably obtain desired information with a simple configuration.

Means for Solving the Problems The present invention provides at least two front-end circuits that receive broadcasting in a superheterodyne manner at a tuning frequency corresponding to an input voltage, and one front-end circuit of the front-end circuits. a phase-locked loop subcircuit that forms a phase-locked loose frequency synthesizer and derives the voltage; and the output voltage of the phase-locked loop subcircuit is memorized and held, and the held voltage is applied to the phase-locked loop frequency. 4. Remaining front-end circuits that do not constitute the synthesizer. - a voltage holding circuit that causes the remaining front end circuit to receive a tuned frequency corresponding to the holding voltage;
The remaining front-end circuit and the phase-locked loop partial circuit are switched to configure a phase-locked loop frequency synthesizer, and the output voltage of the phase-locked loop partial circuit immediately before the switching operation is held in the voltage holding circuit. - A broadcast receiving device characterized by including a control means.

According to the present invention, at least two front-end circuits for receiving broadcasting in a superheterodyne manner are provided, and a phase-locked loop partial circuit that constitutes a phase-locked loop frequency synthesizer together with these front-end circuits is provided. It will be done. Among the front end circuits, one front end circuit selected by the switching/control means and this phase locked loop partial circuit constitute the phase locked loop frequency synthesizer, and the reception frequency is locked to ensure stable reception. state can be maintained.

The front-end circuit performs a reception operation using a superheterodyne method at a tuning frequency corresponding to the input voltage, and the one selected by the switching and control means.
The two front-end circuits are provided with the output voltage of the phase-locked loop subcircuit, and the receiving frequency is locked and held as described above. This output voltage is also given to a voltage holding circuit, and when the front-end circuit is switched by the switching/control means, the switching/control means outputs the output voltage of the phase-locked loop partial circuit immediately before the switching operation. is held by the voltage holding circuit. The holding voltage held in this manner is applied to the remaining front end circuits different from the front end circuit selected by the switching operation.

Therefore, the remaining front-end circuit remains at the tuned frequency immediately before the switching operation, and continues the receiving operation. Thereby, when an identification signal transmitted prior to the traffic information is received in response to the received output of the remaining unselected front-end circuit, the identification signal from the currently selected front-end circuit is received. By switching to the received residual front-end circuit, the traffic information can be reliably heard. In this way, the desired information can be reliably obtained with a simple configuration using a single phase lock loop 1 partial circuit.

Embodiment FIG. 1 is a block diagram showing the electrical configuration of a radio reception filter according to an embodiment of the present invention. This radio receiver 1 is provided with two front end circuits, a first front end circuit 2 and a second front end circuit 3. The first front end circuit 2 receives frequency modulated broadcasting, and the second front end circuit 3 receives amplitude modulated broadcasting.

Each of these front end circuits 2.3 receives each radio broadcast in a superheterodyne or double superheterodyne system.
Including the perheterodyne method, it is collectively called the superheterodyne method.

When traffic information is received in the radio broadcast being received by the first front-end circuit 2, this radio receiver 1 stops converting the received content into sound by the second front-end circuit 3, and the front-end circuit 2 Traffic information, which is the received content, is converted into audio.

In West Germany, a traffic information system called SDK has been put into practical use. This traffic information system is implemented using frequency modulation broadcasting as described above, and the frequency spectrum of the frequency modulation broadcasting is shown in FIG. In this figure, reference numeral 4 represents an audible acoustic signal, and an identification signal indicated by reference numeral 5 is, for example, 57 KHz, indicating that this radio broadcast is a radio broadcast that may transmit traffic information. The identification signal 5 is constantly transmitted. When traffic information is transmitted during the broadcasting period of the acoustic signal 4 and the identification signal 5, for example, 1 indicated by reference numeral 6,
A 25Hz identification signal is transmitted.

The frequency modulated broadcast signal received by the antenna 10 is transmitted from the first front end circuit 2 to the intermediate frequency amplification circuit 11.
The acoustic signal 4 is frequency-discriminated by the detection circuit 12, separated into left and right channels, and guided to one individual contact 13a of the changeover switch 13.

Furthermore, the amplitude modulation broadcast signal received by the antenna 10 is
The signal is led out from the second front end circuit 3 to the other individual contact 13b of the changeover switch 13. In this way, the audio signals for frequency modulation broadcasting and amplitude modulation broadcasting are selectively derived from the common contact 13c of the changeover switch 13, and the audio signals are given from the low frequency amplifier circuit 14 to the speaker 15,
It becomes acoustic.

The first front-end circuit 2 includes a tuning circuit 21, a local oscillation circuit 22, and a mixing circuit 23. The first front-end circuit 2 includes a tuning circuit 21, a local oscillation circuit 22, and a mixing circuit 23. , the frequency modulated broadcasting signal received by the antenna 10 oscillates at a frequency corresponding to the DC voltage level input via the line 11.
It is given to the mixing circuit 23 via the tuning circuit 21,
This mixing circuit 23 mixes the signal with the local oscillation signal from the local oscillation circuit 22 and outputs it to the intermediate frequency amplification circuit 11 as an intermediate frequency signal.

The second front end circuit 3 includes a tuning circuit 31, a local oscillation circuit 32, a mixing circuit 33, and a detection circuit 34. Similarly to the local oscillation circuit 22, the @ section oscillation circuit 32 oscillates at a frequency corresponding to the DC voltage level input via the line 12.The amplitude modulation broadcast signal received by the antenna 10 is tuned. The signal is supplied to a mixing circuit 33 via a circuit 31, where it is mixed with the local oscillation signal from the local oscillation circuit 32,
The intermediate frequency signal generated in this way is demodulated into an acoustic signal by the detection circuit 34, and the individual contact 13 of the changeover switch 13
b. An acoustic signal for frequency modulation broadcasting or amplitude modulation broadcasting is selectively derived from the common contact 13c of the changeover switch 13, and is applied to the low frequency amplification circuit 14.

The local oscillator signal from local oscillator circuit 22.32 is also connected to line 13. The signals are input to a processing circuit 40 realized by a microcomputer or the like through the respective terminals 14 and 14. In the processing circuit 40, the line 13 is connected to the frequency dividing circuit 42.
The line 14 is connected to one individual contact 41a of the changeover switch 41 via the changeover switch 41, and the line 14 is connected to the other individual contact 41b of the changeover switch 41. A common contact 41c of the changeover switch 41 is connected to one input of a phase comparator 43, and a reference signal from a reference signal generation circuit 44 is input to the other input of the phase comparator 43.

The phase comparator 43 detects the phase shift between the local oscillation signal from the local oscillation circuit 22, 32 that is selectively inputted via the changeover switch 41 and the reference signal from the reference signal generation circuit 44, and A duty pulse signal based on the difference is led out to line 15, this pulse signal is converted to a DC voltage level by low pass filter 50, and is led out to line 16 as a control voltage. This line 16 is connected to the line 12 and also to one individual contact 51a of the changeover switch 51. A common contact 51c of the changeover switch 51 is connected to the line 11. In this way, the control voltage corresponding to the difference between the local oscillation signal input from the lines 13 and 14 and the reference signal is transmitted to the tuned circuit 21 and the local oscillation circuit 22, or to the tuned circuit 31 and the local oscillation circuit, via the lines IL and 12. 32 to maintain a stable reception state in which the reception frequency of radio broadcasting is locked.

The control voltage derived from the line 16 is inputted to an analog input terminal of a processing circuit 40 via a line 17, and its voltage level is digitally converted by an analog/digital converter 46 and stored in a memory 47 which is a voltage holding circuit. The memory 47 reads the control voltage when the radio receiver 1 receives the amplitude modulated broadcast. The control voltage level data thus obtained is read out, converted into the control voltage by the digital/analog converter 52, and led out to the other individual contact 51b of the changeover switch 51.

A switch 53 for switching between frequency modulation broadcasting and amplitude modulation broadcasting is provided in association with the processing circuit 40, and each time this switch 53 is operated, the switching control circuit 48 switches the changeover switch 41. As the state changes, the output level delivered to line 18 changes. The line 18 is connected to one terminal of a relay coil 55 via a buffer 54, and the other terminal of this relay coil 55 is connected to a high level power supply B. Therefore, each time the output level led out to line 18 by switching control circuit 48 changes, relay coil 55
is energized/demagnetized, and the switching state of the changeover switch 13.51 is switched in conjunction.

When reception of frequency modulation broadcasting is selected in this way, the changeover switches 13.51 each have individual contacts 13a.
, 51a, and the changeover switch 41 is connected to the individual contact 41.
Conducted to a. Further, when reception of amplitude modulation broadcasting is selected, the changeover switches 13.51 each have individual contacts 13b.

51b, and the changeover switch 41 is connected to the individual contact 41b.
conducts to.

The intermediate frequency signal from the intermediate frequency amplification circuit 11 also has the following characteristics:
It is applied to the identification signal detection circuit 61. The identification signal detection circuit 61 is composed of a first detection section 62 and a second detection section 63, and when the 57 KHz identification signal 5 is detected, the first detection section 62 detects the input intermediate frequency signal. It is derived to the second detection section 63. The second detection unit 63 includes the 12
When the 5Hz identification signal 6 is detected, the line 19
derive a signal indicating that traffic information is being sent to
The signal is applied to the switching control circuit 48 of the processing circuit 40. A switch 56 is interposed in this line 19, and by keeping this switch 56 conductive, a switching operation when receiving traffic information as described later is performed, and when this switch 56 is cut off, Even if traffic information is being transmitted, the switching operation described below will not be performed.

In the radio receiver 1 configured as described above, when the switch 53 is operated to select reception of frequency modulated broadcasting, the changeover switch 13 conducts to the individual contact 13a as described above, and the changeover switch 51 becomes conductive. Individual contact 51
a, and the selector switch 41 is connected to the individual contact 4.
It is electrically connected to 1a. As a result, a phase-locked loop circuit consisting of the first front-end circuit 2, the frequency dividing circuit 42, the phase comparator 43, the low-pass filter 50, and the first front-end circuit 2 is configured, and it is possible to stably receive frequency modulated broadcasting. Can be done.

When receiving frequency modulation broadcasting, after selecting the broadcasting station that is transmitting the 57 KHz identification signal 5, if the switch 53 is operated to switch to the reception state of amplitude modulation broadcasting, the memory 47 stores that information. The control voltage corresponding to the tuned broadcasting station is stored. Also @I! When modulated broadcasting is selected, the changeover switch 13 conducts to the individual contact 13b, and the changeover switch 41 conducts to the individual contact 41b.

In this way, the second front end circuit 3 - phase comparator 43 -
A phase-locked loop circuit consisting of the low-pass filter 50 and the second front-end circuit 3 is configured, and can stably receive amplitude modulated broadcasting.

At this time, the changeover switch 51 is electrically connected to the individual contact 51b, and as a result, a pulse signal with a duty corresponding to the control voltage stored in the memory 47 is derived from the processing circuit 40, and the digital/analog converter 52 is A control voltage is applied to the first front end circuit 2 via the first front end circuit 2. In this way, even when amplitude modulation broadcasting is received, frequency modulation broadcasting is received, and as mentioned above, the identification signal 5.6 is received.
is detected and the switch 56 is turned on,
The changeover control circuit 48 connects the changeover switch 13 to the individual contact 13a.
By electrically conducting the changeover switch 51 to the individual contact 51a, and further conducting the changeover switch 41 to the individual contact 41a, it is possible to reliably receive the transmitted frequency modulated broadcast of traffic information.

FIG. 3 is a flowchart for explaining the operation when receiving frequency modulation broadcasting. In step nO, the reception state of frequency modulation broadcasting is established. In step n1, it is determined whether the switch 53 has been operated, and if not, the process returns to step no to continue receiving the frequency modulation broadcast, and if the switch 53 has been operated, step n2
Move to.

In step n2, the switching control circuit 48
, 41 and 51 respectively as individual contacts 13b.

41b and 51b, and the amplitude modulated broadcast is made into sound from the speaker 15.

In step n3, the control voltage immediately before the switching operation in step n2 is stored and held in the memory 47, and the control voltage 91 held in the digital/analog converter 52 is derived.

In step n4, it is determined whether the switch 53 has been operated, and if not, the step r+3
is repeated, and when the switch 53 is operated, the process moves to step n5. In step rr5, the changeover control circuit 48 connects the changeover switches 13, 41, and 51 to the individual contacts 13a and 13a, respectively.
41a and 51a, the frequency modulation broadcast is thus converted into sound from the speaker 15, and the process returns to step no.

FIG. 4 is a flowchart for explaining the operation of interrupting traffic information reception when receiving amplitude modulated broadcasting. In step rnO, the reception state of amplitude modulation broadcasting is established. In step m1, it is determined whether the switching control circuit 48 has output from the identification signal detection circuit 61 indicating that the 125 Hz identification signal 6 has been detected;
Otherwise, the process returns to step mO to continue receiving the amplitude modulation broadcast, and when the identification signal 6 is received, the process moves to step m2. In step m2, the switching control circuit 48 connects the changeover switches 13, 41.51 to the individual contacts 13, 41.
a, 41a, and 51a, and the frequency modulated broadcast of traffic information is made into sound from the speaker 15.

In step rn3, it is determined whether or not the identification signal 6 is continuously detected. If so, step m3 is repeated, and when the identification signal 6 is no longer detected, the process moves to step m4. In step rn4, the changeover control circuit 48 switches the changeover switches 13, 41, 51 to the respective individual contacts 13b.

41b and 51b, and thus the amplitude modulated broadcast originally received from the speaker 15 is converted into sound.

As described above, in the radio receiver 1 according to the present invention, even when receiving amplitude modulation broadcasting, the first
A control voltage is applied to the front end circuit 2 to receive the frequency modulated broadcast, and when it is detected that traffic information has been transmitted, the state is automatically switched to receive the frequency modulated broadcast. Information can be received reliably.

Furthermore, the phase comparator 43, reference signal generation circuit 44, etc. that constitute the phase-locked loop subcircuit can be realized as a single configuration, and the configuration can be simplified.

Note that by providing the second front end circuit 3 with an identification circuit that identifies the presence or absence of an acoustic signal, it is possible to receive traffic information that has been put into practical use in Japan.

That is, when receiving frequency modulation broadcasting, a control voltage corresponding to 1620 KHz is derived from the memory 47 via the digital/analog converter 52, and the front end circuit 3
When an acoustic signal is detected at the carrier frequency of 1620 KHz, a switching operation for receiving the acoustic signal is automatically performed, and traffic information can be reliably received. In this case, by using the first front end circuit 2 for both frequency modulation broadcasting and amplitude modulation broadcasting, traffic information can be reliably received even when receiving amplitude modulation broadcasting.

Effects of the Invention As described above, according to the present invention, at least two front-end circuits receive broadcasting in a superheterodyne manner.
One front-end circuit selected by the switching/control means and the phase-locked loop partial circuit constitute a phase-locked loop frequency synthesizer to lock the reception frequency and maintain a stable reception state. At this time, the output voltage of the phase-locked loop subcircuit that is being applied to the selected front-end circuit is also applied to the voltage holding circuit, and the holding voltage held in this way is applied to the front-end circuit selected by the switching operation. is applied to different remaining front end circuits, so even if the front end circuits are switched, the remaining front end circuits are maintained at the tuned frequency immediately before the switching operation and continue receiving operations. ing.

Therefore, in response to the received output of the remaining unselected front-end circuit, when an identification signal, e.g. transmitted prior to said traffic information, is received, this identification signal from the currently selected front-end circuit is received. By switching to the received residual front-end circuit of
The traffic information can be reliably heard. In this way, desired information can be reliably obtained with a simple configuration using a single phase-locked loop subcircuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of a radio receiver 1 according to an embodiment of the present invention, FIG. 2 is a diagram showing the frequency spectrum of frequency modulation broadcasting when traffic information is being transmitted,
3 and 4 are flowcharts for explaining the operation.

Claims (1)

[Scope of Claims] At least two front-end circuits that receive broadcasting in a superheterodyne manner at a tuned frequency corresponding to an input voltage; and a phase-locked front-end circuit with one of the front-end circuits. A phase-locked loop sub-circuit that configures a loop frequency synthesizer to derive the voltage; and an output voltage of the phase-locked loop sub-circuit is memorized and held, and the held voltage is used to input the phase-locked loop frequency synthesizer. a voltage holding circuit that responds to the received output of the remaining front end circuit, and sets the remaining front end circuit to a receiving state of a tuned frequency corresponding to the holding voltage; hand,
The remaining front end circuit and the phase-locked loop partial circuit are switched to form a phase-locked loop frequency synthesizer, and the output voltage of the phase-locked loop partial circuit immediately before the switching operation is held in the voltage holding circuit. What is claimed is: 1. A broadcast receiving device comprising a switching/control means for controlling the broadcast signal.