JPS6282727A - Emergency broadcast receiver - Google Patents

Abstract

PURPOSE:To receive stably an emergency broadcast even when a voltage supply to a main power circuit is disconnected by providing a power failure detection section generating a detection output when a voltage applied to the main power supply circuit is interrupted. CONSTITUTION:A power failure detection section 11 is to detect that a power voltage of a main power supply circuit 7 always fed to a signal reception section 2 and a decoder section 3 is lowered remarkably because of the disconnection of the voltage fed to the main power supply circuit 7 and the power failure detection section 11 generates a detection output signal. One of the detection output signals is fed to an electronic switch 10 to control a drive power supply so as to be switched from the main power supply circuit 7 into a secondary battery 8. If the voltage (in general a voltage on a home use lighting line) fed to the main power supply circuit is disconnected in such a way, the secondary battery 8 provided separately with a driving power supply is switched and controlled to continue the emergency broadcast reception function.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides an emergency system for receiving emergency broadcasts with start and end codes transmitted from a broadcasting station when an emergency situation such as an earthquake or tsunami is expected to occur. The present invention relates to broadcast receivers, and is particularly effective when applied to equipment having a power supply circuit that utilizes household power lines.

BACKGROUND OF THE INVENTION FIG. 2 shows an example of the configuration of an emergency broadcast receiver that receives emergency broadcasts with start and end codes.

In FIG. 2, the broadcast signal induced in antenna 1 is
Generally, the signal is added to the signal receiving section 2, which is composed of a high frequency amplifier, 9 local oscillators, 2 frequency mixers, an intermediate frequency amplifier, an envelope detector, etc., where it is restored to an audio signal, amplified by a low frequency amplifier 4, and then output to a speaker. 6 is output. The aforementioned antenna 1. Signal receiving section 2. Low frequency amplifier 4
．． The speaker 5 has a function similar to that of a general medium wave broadcast receiver. The decoder section 3 detects the code indicating the start and end of the emergency broadcast, and at the same time controls the electronic switch 6 composed of a transistor or the like to be in a conductive or cut-off state. When a sign indicating , the switch 6 is controlled to be conductive, and the main power supply circuit 7
Power is supplied from On the other hand, when the decoder section 3 detects a code indicating the end of the emergency broadcast, the switch 6 is controlled to be in a cutoff state, and the power supply to the low frequency amplifier 4 is cut off. That is, the low frequency amplifier 4 operates normally during the period from the start to the end of the emergency broadcast. In the standby state in which emergency broadcasts are not received, the signal receiving section 2 and decoder section 3 are constantly supplied with power from the main power supply circuit 7 and are fully operational, but the power supply to the low frequency amplifier 4 is Since the supply is controlled so that the electronic switch 6 is in a cutoff state, the normal broadcast cannot be heard from the speaker 6.

Problems to be Solved by the Invention As described above, in the configuration shown in FIG. 2, the signal receiving section 2 and the decoder section 3 are constantly supplied with power from the main power supply circuit 7. At this time, the voltage supplied to the main power circuit 7 (mainly from the household power line)
If the emergency broadcast receiver is cut off due to a power outage or the like, it will be difficult to perform its original function as an emergency broadcast receiver.

The present invention solves these conventional problems, and aims to provide an emergency broadcast receiver that can stably receive emergency broadcasts even when the voltage supply to the main power circuit is cut off. It is something.

Means for Solving the Problems The emergency broadcast receiver of the present invention includes a power failure detection section that generates a detection output when the voltage supplied to the main power circuit is cut off, and a power supply for the receiver that uses this detection output. Equipped with an electronic switch that switches the supply from the main power circuit to a separately provided secondary battery (such as a nickel-cadmium battery), allowing normal emergency broadcast reception even if the voltage supplied to the main power circuit is cut off. The present invention detects the power supply voltage of the main power supply circuit, and when the voltage supplied to the main power supply circuit is cut off, the drive power supply is switched to a separately provided secondary battery. By switching, normal emergency broadcast reception function can be continued.

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.0 Figure 1 shows an embodiment of the present invention, and blocks whose functions are the same as those in Figure 2 are designated by the same numbers as those in the block. , and further detailed explanation will be omitted.

In FIG. 1, a power outage detection unit 11 detects that the power supply voltage of a main power circuit 7 that is constantly supplied to a signal receiving unit 2 and a decoder unit 3 is a voltage that is supplied to the main power circuit 7 (generally, it is This is to detect that the power supply voltage of the main power supply circuit 7 is significantly reduced due to the disconnection of the main power supply circuit 7. At this time, the power failure detection section 11 generates a detection output signal. One of the detection output signals is supplied to the electronic switch 1o to control the driving power source to be switched from the main power supply circuit 7 to the secondary battery 8. Furthermore, when the voltage of the main power supply circuit 7 is higher than the predetermined voltage of the secondary battery 8, the charging circuit 9 is connected to the main power supply circuit 7.
This is to supply charging current to the secondary battery 8, and generally prevents reverse current from the secondary battery 8 to the main power circuit 7 when the power supply voltage of the main power supply circuit 7 becomes lower than the voltage of the secondary battery 8. A resistor that limits the charging current, and a constant voltage diode that prevents overvoltage when the power supply voltage of the main power supply circuit 7 becomes significantly higher than the voltage of the secondary battery 8. It is.

Effects of the Invention As described above, the emergency broadcast receiver of the present invention uses a separately provided secondary battery as a driving power source when the voltage supplied to the main power circuit (generally a household power line) is cut off. The emergency broadcast reception function can be continued by controlling the switch.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an emergency broadcast receiver according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional emergency broadcast receiver. 2... Signal receiving section, 3... Decoder section, 4... Low frequency amplifier, 6, 1o...
Electronic switch, 7... Main power circuit, 8...
...Secondary battery, 9...Charging circuit section, 11...
...Power outage detection unit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
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Claims (2)

[Claims] (1) In a receiver compatible with a broadcasting system that interrupts and transmits emergency broadcasts in the middle of audio broadcasts, detects the power supply voltage of the main power circuit built into the receiver body and driven by household power lines, a power outage detection unit that generates a detection output when the power supply voltage is cut off due to a power outage in a household power line; and a secondary battery provided separately from the main power circuit to supply power to the receiver main body based on the detection output. What is claimed is: 1. An emergency broadcast receiver comprising an electronic switch section that is switched and controlled so that normal emergency broadcast reception can be continued even if the voltage supplied to the main power supply circuit is cut off. (2) When the voltage of the main power supply circuit is equal to or higher than a predetermined voltage of the secondary battery, a charging current is supplied from the main power supply circuit to the secondary battery via a charging circuit. Emergency broadcast receiver described in section.