JPS6320195Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an emergency broadcast receiving device.

In recent years, the level of advanced prediction technology for large-scale earthquakes has improved, earthquake disaster prevention measures have been strengthened, and we have entered an era of emergency disaster forecasting and warnings. Broadcasters are also
We are actively promoting various emergency warning systems and automatic reception systems using existing broadcast radio waves.

For example, in the event of an emergency disaster, an emergency broadcast system is being considered in which a broadcasting station transmits a specific emergency alert signal by superimposing it onto existing broadcast radio waves in priority over normal broadcast program signals, and on the receiving side, power is only applied to the tuning unit and emergency alert signal detection unit, which consumes little power, and even if the audio amplifier unit, which consumes a lot of power, is turned off, the audio amplifier unit will automatically be powered on when an emergency alert signal is received.

FIGS. 1 and 2 are block diagrams respectively showing a transmitting device and a receiving device constituting such an emergency broadcast system.

That is, FIG. 1 is a block diagram showing a transmitting device, in which a normal broadcast program is interrupted in an emergency, and an emergency warning signal generator 1 generates an emergency warning signal (frequency shift keying modulation signal, for example, for determining the start of emergency broadcasting). Corresponding to the predetermined code pattern of "1" and "0", a signal with a frequency of 1024 Hz is transmitted at a rate of 64 bits/sec in an interval of code "1", and a signal with a frequency of 640 Hz is transmitted at a rate of 64 bits/sec in an interval of code "0". A signal that repeats at a speed of 2 seconds,
This emergency warning signal is applied to the broadcaster 3 via the changeover switch 2, superimposed on broadcast radio waves, and transmitted from the antenna 4. Thereafter, the transmitter transmits an emergency information signal superimposed on broadcast radio waves, and when the emergency information signal ends, an emergency warning signal (frequency shift keying modulation signal, for example, a predetermined "1" signal) is used to determine the end of the emergency broadcast. ”, corresponding to the code pattern of “0”, the frequency is 1024Hz in the section of code “1”
In the section where the code is "0", a signal with a frequency of 640 Hz repeats for 1 second at a rate of 64 bits/sec, pauses for the next 1 second, and continues after that if necessary). It is superimposed on radio waves and transmitted.

FIG. 2 is a block diagram showing the receiving device, where 5 is an antenna, 6 is a tuner section, 7 is an audio amplification section, and 8 is a block diagram showing a receiving device.
9 is a speaker, 9 is a detection unit for detecting whether an emergency warning signal is included in the detection output of the tuner unit 6, for example a decoder, and 10 is opened/closed by the control output from the decoder 9, and is connected to the audio amplification unit 7. A switching unit (first switching unit) (for example, a relay switch) for controlling the audio amplification unit that supplies and cuts off power supply voltage; 11 is a power supply unit; 12 is a power switch; 13 is a switch connected in parallel with the switching unit 10; It is.

In the receiving device shown in FIG.
When the switch 13 is turned on and the switch 13 is turned off, the tuner section 6 and the decoder 9 are supplied with power supply voltage and are in operation, but the audio amplification section 7 is not supplied with power supply voltage.

Therefore, when a normal broadcast program is being broadcast, even if the tuner section 6 receives the normal broadcast program signal, this broadcast program signal is not reproduced.

Next, in this state, the transmitter sends an emergency warning signal for determining the start of emergency broadcasting in place of the normal broadcast program signal.
Assuming that the emergency information signal and the emergency warning signal for determining the end of the emergency broadcast are transmitted in sequence, the tuner section 6 first receives the emergency warning signal for determining the start of the emergency broadcast. Then, the decoder 9 detects the emergency warning signal for determining the start of emergency broadcasting which is being output from the tuner section 6 and generates a control output, which turns the switching section 10 from off to on. Therefore, the power supply voltage is supplied to the audio amplifying section 7 via the switching section 10. Since the power supply voltage is supplied to the audio amplifying section 7 in this manner, the subsequently received emergency information signal passes through the tuner section 6 and the audio amplifying section 7 and is emitted from the speaker 8.

Next, when the emergency information signal ends and an emergency warning signal for determining the end of the emergency broadcast is received, the decoder 9 detects the emergency warning signal for determining the end of the emergency broadcast and generates a control output. The section 10 is turned off again, and the power supply voltage to the audio amplification section 7 is cut off. Therefore, even if a normal broadcast program signal is received by the tuner section 6 following the emergency warning signal for determining the end of the emergency broadcast, it will not be reproduced. In this way, the tuner section 6 and decoder 9 have low power consumption.
Even if the power supply voltage to the audio amplification unit 7, which consumes a large amount of power, is cut off, the power supply voltage will be automatically supplied to the audio amplification unit 7 when an emergency warning signal is received. , it is possible to prevent a large amount of power from being wasted.

Next, when receiving a normal broadcast program signal, both the switch 12 and the switch 13 are turned on, and the power supply voltage is supplied to the tuner section 6 and the audio amplification section 7.

However, with the receiving apparatus shown in FIG. 2, there is a risk that the decoder 9 may malfunction due to noise or the like when the electric field strength input to the receiving apparatus is weak or when the receiving apparatus is not tuned.

In view of this, the present invention proposes an emergency broadcast receiving device that eliminates the above-mentioned drawbacks.An embodiment of the present invention will be described below with reference to FIG. In addition, in FIG. 3, the same part numbers as in FIG. 2 will be used for the same parts as in FIG.

The receiving device shown in FIG. 3 includes a voltage generating circuit that generates an output voltage corresponding to (approximately proportional to) the received input signal level (input electric field strength) input to the antenna 5;
For example, a switching section (second switching section) 15 for controlling a decoder is provided, which is controlled on and off by the output voltage from the signal indicator driving voltage generating circuit 14. When the received input signal level is below a predetermined level, the decoder control switching section 15 is turned off by the output voltage from the signal indicator drive voltage generation circuit 14, and the power supply voltage to the decoder 9 is cut off. The decoder 9 is made inactive.

In this way, if the receiving device is not tuned, or if the input electric field strength to the receiving device is weak, etc., the received input signal level is below a predetermined level, the decoder 9
There is no risk of malfunction due to noise etc.

Incidentally, by changing the characteristics of the switching section 15 for controlling the decoder, the threshold level at which the switching section 15 is turned on can be arbitrarily set. In other words, the magnitude of the received input signal level when the decoder 9 starts operating can be arbitrarily set by changing the characteristics of the switching section 15.

When the received input signal level input to the antenna 5 exceeds a predetermined level, the decoder control switching unit 15 is turned on by the output voltage from the signal indicator drive voltage generation circuit 14, and the power supply voltage is applied to the decoder 9. is supplied to operate the decoder 9.

In the embodiment shown in FIG. 3, a signal indicator driving voltage generation circuit is used as a voltage generation circuit that generates an output voltage according to the received input signal level. However, the present invention is not limited to this embodiment. , an AGC circuit may be used as a voltage generation circuit that generates an output voltage according to the received input signal level.

As described above, according to the emergency broadcast receiving device according to the present invention, the operation of the detection circuit that detects the presence or absence of an emergency warning signal is stopped when the received input signal level is below a predetermined level, so that the receiving device It is possible to prevent the detection circuit from malfunctioning due to noise etc. when the input electric field strength is weak or when the receiving device is out of tune.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a transmitting device constituting an emergency broadcast system, FIG. 2 is a block diagram showing a conventional emergency broadcast receiving device, and FIG. 3 is a block diagram showing an emergency broadcast receiving device according to the present invention. . 6... tuner section, 7... audio amplification section, 9...
...decoder (detection section), 10... switching section for controlling the audio amplification section (first switching section),
11...Power supply section, 14...Signal indicator driving voltage generation circuit (voltage generation section), 15...
Decoder control switching section (second switching section).

Claims (1)

[Scope of utility model registration request] In order to receive emergency warning signals and emergency information signals that are transmitted with priority over normal broadcast program signals using the same carrier waves as those for normal broadcasting, a tuner section, an audio amplification section, and an output terminal of the tuner section are connected to the It includes a detection section that detects whether or not an alarm signal is included, and a first switching section whose opening/closing is controlled by the output of the detection section, and when the detection section detects the emergency alarm signal, the first switching section In the receiving device, the power supply voltage is supplied to the audio amplification section through the switching section 1, and the reception a second device that stops the operation of the detection unit when the input signal level is below a predetermined level;
An emergency broadcast receiving device comprising a switching section.