JPS6123881Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a receiver equipped with an emergency broadcast receiving function suitable for receiving emergency broadcasts such as earthquake prediction information and warning declarations issued in the event of an emergency disaster such as an earthquake or tsunami. .

If it is possible to detect emergency abnormal situations such as earthquakes and tsunamis in advance and make emergency broadcasts to prevent or minimize disasters caused by such emergency situations, it would be extremely good news and meaningful from the standpoint of protecting human life and property. be.

For example, in Japan, there has recently been a movement to implement this under national control, and one such example is the field experiment of the NHK emergency warning system currently being conducted by the Japan Broadcasting Corporation (NHK).

According to this emergency warning system, prior to the emergency broadcast, a control signal for starting the warning is sent from the broadcasting station for a predetermined period of time, for example, 5 to 20 seconds. The control signal is encoded by combining two frequencies, for example around 1 kHz, which are the most sensitive to the audibility, and is used as an alarm sound in the receiver. When the emergency broadcast receiver receives this broadcast start control signal, the audio amplification unit, which had been turned off until then, is turned on, and a loud warning sound with a unique tone is emitted from the speaker, alerting the receiver. evoke. Following the broadcast start control signal, the broadcasting station broadcasts the contents of the alarm, and when the emergency broadcast announcement ends, a broadcast end control signal is sent out for a predetermined period of time, for example, one second. The emergency broadcast receiver turns off the audio amplifying section in response to this broadcast end control signal, and returns to the state of waiting for the broadcast start control signal.

By the way, with so-called dual-purpose receivers that can receive both general broadcasts and emergency broadcasts issued in the event of an emergency disaster, emergency broadcasts can always be received before the power switch is turned off. It is necessary to set the state.

Therefore, a separate receiver is built in for emergency broadcasting.
In other words, it is possible to use a receiver with two receivers and set one of the receivers so that it can always receive emergency broadcasts, but this would be expensive and
It is not practical because there are many problems such as countermeasures against mutual interference caused by the reception section of the receiver.

The present invention has been developed in view of these points, and uses a single receiving section, and has a simple configuration that can automatically set the state in which emergency broadcasts can be received at all times when the power switch is off, and has excellent operability. Moreover, the present invention provides a receiver equipped with a highly reliable emergency broadcast receiving function.

The following is an example of an embodiment of the present invention for emergency broadcasting.
As an example, when it is carried out using AM broadcast radio waves,
This will be explained in detail based on the attached drawings.

In the figure, AM captured by receiving antenna 1
The broadcast radio wave is supplied to a high frequency circuit 2 including a mixing circuit, where the high frequency signal is converted into an intermediate frequency signal and supplied to an intermediate frequency amplification circuit 3, and the intermediate frequency signal amplified here is sent to a detection circuit 4. The signal is detected and an audio frequency signal is extracted at its output. These high frequency circuit 2, intermediate frequency amplification circuit 3
The detection circuit 4 is always supplied with power from the positive power supply terminal +B and is always in a standby state with weak power. Note that the intermediate frequency amplification circuit 3 and the detection circuit 4 constitute demodulation means.

The audio frequency signal taken out to the output side of the detection circuit 4 is supplied to an audio frequency amplification circuit 5 serving as a signal amplification means, where it is amplified and emitted from a speaker 6.

The audio frequency amplification circuit 5 is always in operation by switching the power switch 10 serving as a mode selection means to the contact 10N side when receiving a normal general broadcast, and switching the power switch 10 to the contact 10A side when receiving an emergency broadcast. and is configured to operate selectively by a relay operation, which will be described later. That is, when receiving an emergency broadcast, a control signal detection circuit 7 such as a decoder is used as an emergency broadcast detection means to detect the above-mentioned control signal on the output side of the detection circuit 4.
will be provided. Like the high frequency circuit 2, the control signal detection circuit 7 is always energized with weak power and in a standby state, and when an emergency broadcast start control signal appears on the output side of the detection circuit 4, it detects this and, for example, a low level A so-called pulse-like energizing signal that changes to a higher level and maintains that level during the emergency broadcast is generated. When an emergency broadcast termination control signal issued following the end of the announcement of the contents of the emergency broadcast is detected, this energizing signal changes from a high level to a low level and ends. While this energizing signal is output from the control signal detection circuit 7, the relay 8 closes its contacts and sends the audio signal to the power terminal +B to the audio frequency amplification circuit 5.
When the energizing signal is no longer output, the contact is opened to cut off the power supply path of the audio frequency amplification circuit 5.

On the other hand, when receiving normal general broadcasts, press the power switch 10.
Switch to contact 10N side. In other words, by turning on the power switch 10, power is supplied to the audio frequency amplifier circuit 5 from the power terminal +B via the diode 9, and this circuit becomes operational.
Normal general broadcasts can be received. Note that the relay 8 and diode 9 constitute energization control means.

Further, in this embodiment, a conventional PLL synthesizer circuit 11 including a PLL circuit and a preset memory (not shown) is used to automatically perform the channel selection operation. For example, eight preset keys SW1 to _{SW8 are} provided to the presettable memory of the synthesizer circuit 11.
will be provided. For example, the eighth preset key _SW8 is used for emergency broadcast reception settings.

12 is a capacitor 12a and a resistor 12, for example.
A reset pulse generating circuit consisting of circuit 10b generates a reset pulse when the power switch 10 is switched to the contact 10N side, that is, when the power switch is turned on, and supplies this pulse to the last channel selection terminal of the synthesizer circuit 11 to select the last channel. will be selected. 13 stores the broadcast station received before the power switch is turned off, for example, as frequency division ratio information, and when the power switch is turned on, it is possible to re-tune to the previously received broadcast station based on the stored frequency division ratio information. This is channel memory.

With the power switch 10 turned on, press the write button (not shown) and press the preset key SW ₁ ~
By pressing SW ₈ , the received frequency is displayed as the corresponding frequency division ratio information in the synthesizer circuit 1.
1 preset memory. At this time, the last channel memory 13 is connected to the AND circuit 14.
Frequency division ratio information corresponding to the frequency that is constantly received via is stored. Then, when receiving normal general broadcasting to turn on the receiver, turn on the power switch 10.
When turned on, the frequency division ratio information stored in the last channel memory 13 as described above is supplied to the PLL circuit of the synthesizer circuit 11, converted into a corresponding local oscillation signal, and then supplied to the mixing circuit of the high frequency circuit 2. The receiver then starts operating in the last channel reception state, that is, in the state tuned to the broadcast station received before the power switch was turned off.

15 is an OR circuit for band switching, and the synthesizer circuit 11 is configured so that when the output of the OR circuit 15 is logically "1", it is in the AM broadcast reception state, and when it is "0", it is in the FM broadcast reception state. has been done.
That is, when the power switch 10 is in the ON state with the power switch 10 connected to the contact 10N side, when the band changeover switch 17 is switched to the AM side, the output of the OR circuit 15 becomes "1", and when it is switched to the FM side, the output of the OR circuit 15 becomes "0". ”, allowing switching between the AM band and FM band. For convenience of explanation
Various circuits related to the FM band, such as the front end, are omitted.

Meanwhile, the power switch is off, i.e. the receiver 10
In the emergency broadcast reception standby state where is connected to the contact 10A side, it is assumed that the emergency broadcast is carried out using AM broadcast radio waves, so even if the band switching switch 17 is switched to the FM side, such AM It must be set to receive emergency broadcast signals. Therefore, in this embodiment, the contact 10A of the power switch 10 is connected to one input terminal of the OR circuit 15, and the OR circuit 15 is always in the emergency broadcast reception standby state, that is, when the power switch 10 is connected to the contact 10A side. Set the output to “1”,
Switch the synthesizer circuit 11 to the AM band. In addition, a high frequency circuit 2, a PLL synthesizer circuit 11, a reset pulse generation circuit 12, a last channel memory 13, an AND circuit 14, an OR circuit 1
5 and the band changeover switch 17 constitute frequency tuning means.

There is also a preset key SW ₈ for emergency broadcast reception settings.
One end of the power switch 10 is connected to the contact 10A of the power switch 10 at the connection point 16, so that when the power switch is off, the preset key SW ₈ is essentially always closed. It is set to a state in which it is synchronized with. In this state, no input is made to the last channel memory 13. In other words, when an emergency broadcast is actually received in the emergency broadcast standby state, if the frequency division ratio information related to this is input into the last channel memory 13, when the power switch is turned on to receive a normal general broadcast, that is, when the power switch 10 is turned on at contact 10N, As soon as the switch is made, the receiver will start operating from the station that made the emergency broadcast, causing an inconvenience. Therefore, in the emergency broadcast reception standby state when the power switch 10 is switched to the contact 10A side, the AND circuit 1
Since gate No. 4 is closed, even if an emergency broadcast is received, such frequency division ratio information will not be input to the last channel memory 13. Note that in order to energize the synthesizer circuit 11 in the emergency broadcast reception standby state, it is not necessary to constantly supply power from the power supply terminal +B, and there is no need to constantly supply power from the power terminal +B. A configuration may also be adopted in which a trigger pulse generation circuit is provided and the level is set to high level only for an initial predetermined time.

Next, the operation of this embodiment will be explained. First, when receiving a normal general broadcast, the power switch 10 is connected to the contact 10N side to turn on the power switch.
Then, the last channel selection signal is supplied to the synthesizer circuit 11 by the reset pulse generated by the reset pulse generation circuit 12, and the gate of the AND circuit 14 is opened and the last channel is selected. The frequency ratio information is supplied to the synthesizer circuit 11, and the receiver starts operating in a state tuned to the broadcast station received before the power switch is turned on.

By pressing the preset keys _SW1 to _SW8 in sequence while pressing the write button (not shown), the corresponding reception frequency is stored in the preset memory of the synthesizer circuit 11 as frequency division ratio information. That is, the received broadcast stations are assigned to preset keys _SW1 to _SW8 . Therefore, in the case of reproduction, by pressing any of the preset keys _SW1 to _SW8 , normal broadcasting from the corresponding broadcasting station can be easily and quickly received.

Of course, even in this normal general broadcast reception state, at least when the program broadcast of the broadcast station where the emergency broadcast is being performed is being received, that is, when the preset key SW ₈ is being pressed, the above-mentioned emergency broadcast start control signal will sound an alarm. The following warning message can be heard.

On the other hand, in a standby state where only emergency broadcasts are received without receiving general broadcasts, the power switch 10 is set to contact 1.
Switch to the 0A side to turn off the power switch.
In such a state, regardless of the position of the band changeover switch 17, a positive signal, ie, "1", is supplied to the synthesizer circuit 11 from the power supply terminal +B via the OR circuit 15, and this circuit switches to the AM band, and at the same time, the power supply terminal A positive signal from +B selects the preset memory of the synthesizer circuit 11 corresponding to the preset key _SW8 . Then, the corresponding frequency division ratio information is stored in the synthesizer circuit 11 from this memory.
After being converted into a corresponding local oscillation signal, the signal is supplied to the mixing circuit of the high frequency circuit 2, and the receiver is tuned to the broadcasting station where the emergency broadcast is being made.

Then, when the emergency broadcast starts, the broadcast radio waves are captured by the antenna 1 like normal broadcast radio waves, passed through the high frequency circuit 2, the intermediate frequency amplification circuit 3, and the detection circuit 4.
It is derived as a detection output signal on the output side of . Since this detection output signal includes the above-mentioned control signal in the case of an emergency broadcast, the control signal detection circuit 7 detects the broadcast start control signal, and the contact of the relay 8 is closed by the energizing signal based on this signal. As a result, power is supplied to the audio frequency amplification circuit 5, and this circuit enters the operating state.

Therefore, the emergency broadcast start control signal amplified by the audio frequency amplification circuit 5 is emitted from the speaker 6 as an alarm sound to call the user's attention. Furthermore, the alarm content is emitted from speaker 6 following the alarm sound, and when the emergency broadcast announcement is finished, approximately 1
The control signal detection circuit 7 detects an emergency broadcast end control signal lasting about 1 second. When this emergency broadcast termination control signal is detected, the control signal detection circuit 7 no longer outputs the energizing signal, so the contacts of the relay 8 are released to cut off the power to the audio frequency amplifier circuit 5, and the receiver returns to the standby state for receiving emergency broadcasts.

As described above, according to the present invention, the power switch can be switched to the emergency broadcast reception standby state, that is, the receiver can be automatically set to the state where the emergency broadcast can be received at the same time as the power switch is turned off, so that it is easy to handle and has excellent operability. Moreover, relevant information can be transmitted reliably and reliability is high.

Furthermore, since the receiving section can be shared for normal general broadcasts and emergency broadcasts, the configuration is simple and inexpensive.

Furthermore, in a conventional system in which a control signal detection circuit is simply combined with a synthesizer receiver, the receiver always waits for and receives emergency broadcasts while tuned to the previously received station (last channel). In such cases, there is a possibility of malfunction due to insufficient field strength or tuning being off depending on the station being received. However, with this device, emergency broadcasts are fixed to the desired channel that has been set in advance regardless of normal receiving operations, allowing for good reception.

In the above embodiment, the case where the emergency broadcast is carried out using AM broadcast radio waves has been explained as an example, but when the emergency broadcast is carried out via other broadcast radio waves, for example, FM broadcast radio waves, control is required at the subsequent stage of the frequency discrimination circuit. Similar effects can also be obtained by providing a signal detection circuit.

[Brief explanation of the drawing]

The attached figure is a circuit configuration diagram showing an embodiment of the present invention. 2 is a high frequency circuit, 4 is a detection circuit, 5 is an audio frequency amplification circuit, 7 is a control signal detection circuit, 8 is a relay,
10 is a power switch, 11 is a PLL synthesizer circuit, 12 is a reset pulse generation circuit, 13 is a last channel memory, 14 is an AND circuit, 15 is an OR circuit, 17 is a band selection switch, SW ₁ to
SW ₈ is a preset key.

Claims (1)

[Claims for Utility Model Registration] Frequency tuning means to which a tuning control signal for setting a tuning frequency is supplied; demodulation means for demodulating a tuning signal output from the frequency tuning means; and from the demodulation means. Signal amplification means for amplifying the demodulated signal to be demodulated; Emergency broadcast detection means for detecting that the emergency broadcast has been received; Mode selection means for selecting the normal broadcast mode or the emergency broadcast mode; and the mode. When the normal broadcast mode is selected by the selection means, power is also supplied to the signal amplification means, and when the emergency broadcast mode is selected, power is also supplied to the signal amplification means in response to the detection output of the emergency broadcast detection means. and supplying a preset predetermined channel selection control signal to the frequency tuning means in response to the emergency broadcast mode being selected by the mode selection means. A receiver equipped with an emergency broadcast reception function.