JPS5816768B2 - Wireless receiver with selective call function - Google Patents

Abstract

PURPOSE:To realize a small capacity as well as a long life for the emergency power source, by switching the power source to the speaker system for low power consumption use at the service interruption time of the commercial power source.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radio receiver having a selective calling function that switches between commercial power supply and emergency power supply.

In a system where a master station and multiple slave stations are connected via a wireless line that uses the same general transmission wave, the requirement is that the audio signal from the master station is played only on a specific slave station. In this case, a selective calling function is required to call only a specific slave station.

FIG. 1 is a block diagram showing an example of a radio receiver having such a selective calling function.

In the figure, 1 is a receiving antenna, 2 is a wireless receiving section, and 3 is a receiving antenna.
is a high-power low-frequency amplifier, 4 is a high-power loudspeaker, 5 is a selective calling device, 6 is a rectifier that converts commercial power input into direct current,
7 is an emergency power source consisting of a battery, a charger, etc., and is normally charged with a commercial power source.

8 is a power outage detector that detects a power outage in the commercial power supply; 9 is a switch that switches based on the output of the power outage detector 8; and 10 is a selective calling device 5.
This is a switch that operates on the output of

The switch 9 connects the terminals a and c during a period when the power outage detector 8 is not detecting a power outage of the commercial power supply.

For this reason, the output of the rectifier 6 that converts the commercial power input into DC is supplied to the wireless receiving section 2 and the selective calling device 5, and the selective calling device 5 constantly monitors the reception demodulation output of the wireless receiving section 2. There is.

When the selective calling device 5 detects its own calling signal, it turns on the switch, connects the terminals de, and starts supplying power to the high power low frequency amplifier 3.

As a result, the output of the radio receiving section 2, that is, the audio signal following the calling signal is amplified by the amplifier 3 and broadcast from the loudspeaker 4.

On the other hand, when the power outage detector 8 detects a power outage in the commercial power supply, regardless of the operation of the selective calling device 5, it controls the switching device 9 to connect the terminals be to the output of the rectifier 6 from the emergency power source 7. A similar power supply is provided.

Then, when the commercial power supply is restored, the switch 9 is controlled again to connect terminals a and c.

However, in the uninterruptible power supply system as described above, the power consumption at the load for each operating state of the selective calling device 5 does not change during a power outage of the commercial power supply and during normal operation.

Therefore, there is a drawback that the capacity of the emergency power source 7 must be increased in order to ensure that the high power low frequency amplifier 3 operates for a long time when receiving a call during a power outage of the commercial power source, for example.

The present invention has been made in view of the above-mentioned points, and provides a radio receiver having a selective calling function, which can operate for a long time with a small capacity emergency power source.

In the present invention, a first loudspeaker broadcasting system that consumes a large amount of power and a second loudspeaker system that is driven by a small amount of power are separately provided, and the first loudspeaker system is always selected, and after a power outage, the system remains constant. A power supply mode is adopted in which the second loudspeaker system is selected after a period of time or after the output level of the emergency power source falls below a certain value, thereby reducing the capacity and extending the life of the emergency power source.

The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention, and the same parts as in FIG. 1 are given the same reference numerals and detailed explanations will be omitted.

This embodiment differs from FIG. 1 in that, firstly, in addition to the first loudspeaker system consisting of a high-power low-frequency amplifier 3 and a high-power loudspeaker 4, a low-power low-frequency amplifier 12 and a low-power loudspeaker 4 are provided. A second loudspeaker system consisting of a loudspeaker 13 is provided, secondly a switch 14 is provided downstream of the switch 10 for exclusive use of the first and second loudspeaker systems, and thirdly a switch 14 is provided after the switch 10; The switching control of the circuit 14 is performed by the output of the timer circuit 15 which receives the output of the power failure detector 8.

The switch 14 normally connects terminals g and h, and when the selective calling device 5 detects a calling signal and turns on the switch 10, the output of the rectifier 6 can be supplied to the high power low frequency amplifier 3. state.

The timer circuit 15 controls switching of the switch 14 after a certain period of time when the power failure detector 8 sends out the power failure detection signal, and switches the terminals g and i.
Connect between.

In addition, when the power failure detector 8 sends out a power failure recovery signal, the switch 14 is switched to connect the terminals g and h again.

If the timer circuit 15 is provided with this control function, the switch 14 will maintain the connection state between the terminals g and h when the power is restored within the set time of the timer circuit 15 due to a temporary power outage, for example.

With the radio receiver configured as described above, for example, when the selective calling device 5 turns on the switch 10 and loudspeaker broadcasting is being carried out from the high-power loudspeaker 4, if the commercial power supply fails, the switching 9 is immediately switched and power supply from the emergency power source 7 is started.

However, at this point, the high-power low-frequency amplifier 3 is still being supplied with power, so the loudspeaker 4 continues to broadcast at a high volume.

Then, when the timer circuit 15 is activated after a certain period of time, the power supply of the emergency power source 7 is switched to the low power low frequency amplifier 12, so that a low volume broadcast is made from the loudspeaker 13 until the power outage is restored.

A radio receiver that operates in this manner consumes less power most of the time when the emergency power source γ is used, so the capacity of the emergency power source 7 can be reduced and its lifespan can be extended.

Furthermore, even if the emergency power source 7 is switched on, the system does not immediately switch to low-volume loudspeaker broadcasting, so during a certain period when high-volume loudspeaker broadcasting is possible using the emergency power source, a command may be issued to call listeners to the vicinity of the receiver. Therefore, even if the volume is subsequently switched to a low volume, the effectiveness of the information transmission function will not be impaired.

Although it is assumed that a call will be made after switching to the second loudspeaker broadcasting system after a certain period of time has elapsed after a power outage is detected, the system of the present invention is intended for emergency broadcasting, and this emergency broadcasting and power outage are generally closely related.

In other words, emergency broadcasts are made when a failure occurs due to a disaster, etc., and if a power outage occurs as one of the failures, there is a large time difference between this power outage and the emergency broadcast. This rarely occurs, and in most cases, an emergency broadcast is made within a short time after a power outage occurs.

Therefore, in practice, it is rare that a call is made after switching to the second loudspeaker broadcasting system after a certain period of time has elapsed after a power outage occurs, and the broadcast is always carried out at a loud volume.

FIG. 3 is a block diagram showing another embodiment of the invention.

This embodiment differs from the previous embodiment in that the timer circuit 15
Instead, a level detector 16 is provided to detect the output (DC) level of the switch 9, and when the level detector 16 detects that the output level of the emergency power supply 7 has fallen below a certain value, the switch is activated. The point is that the switch 14 is switched to connect the contacts g and i.

Even in this case, loudspeaker broadcasting is performed at a high volume using the loudspeaker 4 for a certain period of time after the power outage until the output level of the emergency power source 7 decreases to a certain value.

Furthermore, when the level detector 16 is activated, the loudspeaker 13 is switched to a low-volume amplified broadcast, so even with a small capacity emergency power source 7, communication with the master station can be maintained for a long time.

When the power outage is restored, the output of the switch 9 is switched to the output of the rectifier 6, and at the same time, upon receiving a power outage recovery signal from the power outage detector 8, the switch 14 immediately switches to connect terminals g and h. Then, the broadcast will return to loud amplification.

Then, while using the output of the rectifier 6, the emergency power supply 7
Charging is the same as in the previous embodiment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional radio receiver having a selective calling function, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. It is a diagram. 1... Receiving antenna, 2... Radio receiving section, 3... High power low frequency amplifier, 4...
・High-power loudspeaker, 5...Selective calling device, 6.
... Rectifier, 7 ... Emergency power supply, 8 ...
...Power failure detector, 9...Switcher, 10...
... Switch, 12 ... Low power low frequency amplifier, 13 ... Low power loudspeaker, 14 ...
・Switcher, 15...Timer circuit, 16...
...Level detector.

Claims (1)

[Claims] 1. In a wireless receiver that uses commercial power at all times and switches to emergency power in the event of a power outage, the first loudspeaker system, which uses high power to amplify received audio signals, and this first loudspeaker system are exclusive. a second loudspeaker broadcasting system that broadcasts the used and received audio signals using low power; and a selective calling device that can supply power to the first or second loudspeaker system only when a selective call is received. , enabling power to be supplied to the first loudspeaker system at all times, and to supply power to the second loudspeaker system after a certain period of time after a power outage or when the output level of the emergency power supply drops below a certain value. What is claimed is: 1. A wireless receiver having a selective calling function, characterized in that it is equipped with a switching system that enables power feeding.