JPH11340758A - Remote control public address system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously perform broadcasting within a whole building, emergency broadcasting and local broadcasting from a multi-purpose speaker. SOLUTION: For a sound source 2 for the within-whole building broadcasting and the emergency broadcasting and a sound source 14 for the local broadcasting for respective facilities, a DC voltage is supplied from the variable resistors 17 and 16 of a control terminal 13 provided in a local equipment 10 to voltage controlled amplifiers VCAs 3 and 4 respectively, a sound volume is adjusted by varying respective amplification factors G and the multi-purpose speakers 11, 12 and 25 are rung through a speaker control part 7 in a control part 8 by a broadcasting activation switch 15. Thus, without the need of an emergency amplifier and a local amplifier as before, just by one center equipment 1 and the control terminal 13, the within-whole building broadcasting, the emergency broadcasting and the local broadcasting are simultaneously performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides, in schools, hotels, department stores, public facilities, etc., a whole-building broadcast, an emergency broadcast, and a local broadcast dedicated to each floor from speakers arranged on each floor through an amplifier provided in a center facility. Remote control loudspeakers, especially voltage controlled amplifiers (Vol.
The present invention relates to a remote control loudspeaker in which a control terminal is configured using a tage controlled amplifier (hereinafter referred to as VCA).

[0002]

2. Description of the Related Art In recent years, the trend of buildings in which the installation of emergency broadcast facilities is obligatory has been used for multiple purposes, and the demand for broadcasting is not limited to just general business broadcasting from emergency broadcast facilities.
Calling and BGM broadcasting have been diversified, such as broadcasting from a local amplifier installed in each facility to a dual-purpose speaker spanning each floor in the same facility. An example of broadcasting a speaker for both the whole building broadcasting and local broadcasting (hereinafter referred to as a dual-purpose speaker) is the “Emergency Broadcasting Equipment Manual” edited by the Emergency Broadcasting Equipment Committee (publisher 1st regulation).
Are described as the types of emergency cutoff circuits.

FIG. 18 shows a configuration in which an amplifier for a conventional emergency broadcast and a business broadcast in a building and a speaker for an amplifier for a local broadcast are also used. Amplifier 61,
It is composed of a switch 62, a shared speaker 63, and speakers 64 arranged on each floor. Normally, the switch 62 is connected to the local amplifier 61 side, and the output of the local amplifier 61 is connected to the dual speaker 63 via the switch 62 so that the dual speaker 63 sounds. At the time of emergency broadcast, a switching control signal 65 is supplied from the emergency broadcast amplifier 60 to the switch 62, and the switch 62 is connected to the emergency broadcast amplifier 60, so that the dual-purpose speaker 63 can emit an emergency broadcast. Also, at the time of the whole-building broadcast, the switch 62 is connected to the emergency broadcast amplifier 60 in the same manner, so that business broadcasting such as a paging broadcast to the whole building can be performed. Further, when it is desired to perform an emergency broadcast while the local broadcast is being performed by the switch 62, the broadcast is performed through each floor speaker 64.

[0004]

However, the above-mentioned conventional system for broadcasting by switching the speaker input by the switch 62 using the speaker 60 of the amplifier 60 for the emergency broadcast and the business broadcast in the whole building and the speaker 63 of the amplifier 61 for the local broadcast. In this case, there is a problem that only one of the inputs of the emergency broadcast amplifier 60 and the local amplifier 61 can be used. In addition, there is a problem that two broadcasting facilities, an emergency broadcast amplifier 60 and a local amplifier 61, must be installed. Furthermore, there is a problem that the local amplifier 61 cannot broadcast to the speakers 64 on each floor in the same facility that are not connected via the switch 62.

An object of the present invention is to solve such a conventional problem and to provide a remote control loudspeaker capable of simultaneously broadcasting a whole building broadcast, an emergency broadcast, and a local broadcast with one broadcasting facility. And

[0006]

In order to achieve the above-mentioned object, a remote control loudspeaker according to the present invention has a center having sound sources for whole-building and emergency broadcasts, and an amplifier for amplifying an audio signal from each sound source. Equipment comprising: a local facility having a plurality of speakers that output sound and are connected to a facility remote from the center facility by wire, a sound source for local broadcasting, and a control terminal that controls the center facility. In addition, by controlling the center facility with a local control terminal, it is possible to simultaneously broadcast the whole building, the emergency broadcast, and the local broadcast with one center facility.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a center facility having sound sources for whole-building broadcasting and emergency broadcasting, and an amplifier for amplifying an audio signal from each sound source;
A remote control loudspeaker that is connected to a facility distant from the center facility by wire and includes a plurality of speakers that output audio, a local broadcast sound source, and a local facility having a control terminal that controls the center facility. And
By controlling the center facility with a local control terminal, the whole facility broadcast, emergency broadcast, and local broadcast can be simultaneously broadcast by one center facility.

According to a second aspect of the present invention, a plurality of voltages are connected between each sound source of a center facility and a local facility and an amplifier and controlled by a DC voltage from a control terminal of the local apparatus. The remote control loudspeaker according to claim 1, wherein the control amplifier is provided in a center facility.
By controlling the gain of the voltage control amplifier by the control terminal, the volume from the speaker can be adjusted.

According to a third aspect of the present invention, there is provided the remote control loudspeaker according to the second aspect, further comprising a mixing amplifier connected between each of the voltage control amplifiers and the amplifier. And a local broadcast can be superimposed and broadcast.

According to a fourth aspect of the present invention, there is provided the remote control loudspeaker according to any one of the first to third aspects, wherein each of the DC voltages in the control terminal is controlled by a variable resistor. Is easily controlled.

According to a fifth aspect of the present invention, each variable resistor is connected in series and different DC voltages are inputted,
5. The remote control loudspeaker according to claim 4, wherein a difference between respective output voltages divided by said variable resistor is obtained by a balanced input circuit and input to a voltage control amplifier. This has the effect that external noise superimposed on the control line connecting to the control terminal on the side can be reduced.

According to a sixth aspect of the present invention, an output voltage of each variable resistor is branched through a balanced output circuit, and a difference between the branched output voltages is obtained by a balanced input circuit and input to a voltage control amplifier. The remote control loudspeaker according to claim 4, which has an effect of reducing external noise superimposed on a control line connecting a voltage control amplifier on the center facility side and a control terminal on the local facility side.

According to a seventh aspect of the present invention, the output voltage of each variable resistor is converted into a frequency and then branched through a balanced output circuit. 5. The remote control loudspeaker according to claim 4, wherein the external noise is superimposed on a control line connecting the voltage control amplifier on the center facility side and the control terminal on the local facility side. At the same time, the effect of the line resistance of the control line can be reduced, and the distance between the center facility and the local facility can be increased.

According to the invention described in claim 8 of the present invention, each variable resistor is connected in series and a different DC voltage is inputted, and a broadcast start switch is connected to one of the variable resistors, and another variable resistor is turned off when the variable resistor is turned off. A DC voltage of a value is applied, and when the broadcast start switch is turned on, a difference between respective output voltages divided by the two variable resistors is obtained by a balanced input circuit, and the output voltage is compared with a reference voltage. 5. The remote control loudspeaker according to claim 4, wherein an output of said balanced input circuit is input to a voltage control amplifier according to a comparison result, and a control line connecting a voltage control amplifier of a center facility to a control terminal of a local facility. Has the effect of reducing external noise superimposed on the broadcast control line and sharing the broadcast control line and the voltage control line.

According to a ninth aspect of the present invention, there is provided the remote control loudspeaker according to any one of the first to eighth aspects, further comprising means for displaying an output volume and an operation state on the control terminal. Has the effect that the volume can be easily adjusted while checking the output volume level display on the side.

According to a tenth aspect of the present invention, when a plurality of local facilities are connected to a center facility, a control terminal of each local facility controls a voltage control amplifier connected to a sound source of the center facility. 10. The remote control loudspeaker according to any one of claims 1 to 9, further comprising means for assigning priorities when performing, wherein the control terminal can assign and prioritize sound source broadcasts on the center facility side. .

The invention according to claim 11 of the present invention is the remote control loudspeaker according to any one of claims 1 to 10, wherein another speaker different from the speaker in the local facility is connected to the center facility. , A speaker can be arbitrarily added, and the speaker can be arranged arbitrarily.

A twelfth aspect of the present invention is the remote control loudspeaker according to any one of the first to eleventh aspects, wherein each sound source includes a microphone, a BGM, a cassette, a CD player, a wireless receiver, and a chime. This has the effect that a wide variety of sound sources can be used.

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a remote control loudspeaker according to Embodiment 1 of the present invention. This remote control loudspeaker is composed of a center facility 1 for performing a whole-building broadcast and an emergency broadcast with one broadcast facility and a local facility 10 for performing a local broadcast. Center equipment 1
Is the sound source 2 (microphone, B
GM, cassette, CD player, wireless receiver, chime, etc.), VCA3, 4 as variable amplifying means, mixed amplifier 5, amplifier 6, speaker control section 7, mixing means as control means, and control section 8 as control means. Also,
The local equipment 10 provided in the same facility area existing in a remote place includes dual-purpose speakers 11, 12 connected to the speaker control unit 7 of the center equipment 1, a control terminal 13 for controlling the center equipment 1, a local broadcast (A microphone, a BGM, a cassette, a CD player, a wireless receiver, a chime, etc.) are connected. Control terminal 13
Is the control unit 8 of the center equipment 1 through the broadcast control line 21.
Start switch 15 and DC voltage control line 2 connected to
2, a variable resistor 16 connected to the VCA 4 of the center facility 1 via a DC voltage control line 23, and a variable resistor 17 connected to the VCA 3 of the center facility 1 via the DC voltage control line 23. Further, the sound source 14 is connected to the VCA 4 of the center facility 1 through the audio signal line 24. Further, the speaker control unit 7 of the center facility 1 is connected to a dual-purpose speaker 25 outside the same facility area.

The operation of the remote control loudspeaker configured as described above will be described with reference to FIG. The audio signal output from the sound source 14 of the local facility 1 in the same facility area where the local amplifier is conventionally installed is connected to the audio signal line 2.
4 to the input of VCA4. The audio signal is supplied to the control voltage CV by the variable resistor 16 of the control terminal 13.
Is supplied to the VCA 4 through the DC voltage control line 22, the volume is adjusted by the VCA 4, that is, the amplification factor (gain) G is controlled. 5 is output.

On the other hand, an audio signal from a sound source 2 in a center facility 1 for whole-broadcasting and emergency broadcasting is connected to an input of a VCA 3. In the VCA 3, the control voltage CV is varied by the variable resistor 17 of the control terminal 13 in the same facility area located in the remote place and supplied through the DC voltage control line 23, and the business broadcast from the whole building, that is, the sound source 2 and the remote place , The volume of the sound source 14 can be adjusted by the control terminal 13 of the local facility 10.

The broadcast start switch 1 of the control terminal 13
5 to the control unit 8 through the broadcast control line 21 by adding a DC voltage presence / absence signal. Dual-purpose speakers 11, 12
Alternatively, the dual-purpose speaker 25 other than the area within the same facility sounds.

As described above, according to the first embodiment of the present invention, the two sound sources 2,
14 can be broadcast simultaneously, and the center equipment 1
It is possible to adjust the volume from the control terminal 13 installed in a place away from the center, to broadcast to the shared speaker 25 outside the same facility area connected to the center facility 1, and to further control the local amplifier. And an excellent effect such as that the whole facility broadcast, the emergency broadcast, and the local broadcast can be performed with only one center facility 1 without the need for the central facility.

(Embodiment 2) FIG. 2 is a block diagram showing a configuration of a main part of a remote control loudspeaker according to Embodiment 2 of the present invention. Embodiments 2 to 6 solve the problem caused by the control terminal in the local facility being connected to the center facility by wire. FIG. 2 shows one of the systems for broadcasting the sound source 2 for the whole building and the emergency broadcast or the sound source 14 for the local broadcast in FIG. 1, and the audio signal output from the sound source 31 is shown in FIG. This shows a configuration in which the level is adjusted by the VCA 32, supplied to the speaker 34 via the amplifier 33, and the sound is amplified, and the activation and volume adjustment are performed from the control terminal 35A located at a remote place.

In FIG. 2, a remote control terminal 35
A is a double variable resistor 37, 38 and a broadcast start switch 3
9, variable resistors 37, 3 serving as volume control means.
Output voltage V _R of 8, is input to the balanced input circuit 36 provided in the center facility side, the output of the balanced input circuit 36,
The control voltage is input to the VCA 32 as the control voltage CV. VCA3
2, that is, the amplification factor (gain) G is a DC control voltage CV input to the VCA 32 as shown in FIG.
For example, when the voltage level of the control voltage CV increases, the amplification factor of the VCA 32 also increases.

As shown in FIG. 3, a constant DC voltage V ₁ at the control terminal 35A is divided by a variable resistor 38 into an output voltage V _R1 and a constant DC voltage V ₂ is divided by a variable resistor 37. The output voltage _VR2 is supplied to the balanced input circuit 36,
As shown in FIG. 4, the output voltage CV of the balanced input circuit 36 varies with the difference between the output voltages V _{R2 and} V _R1 , that is, the control voltage C V is adjusted by adjusting the variable resistors 37 and 38.
It is possible to arbitrarily adjust the volume (volume) of the sound amplified from the speaker 34 by V.

As described above, according to the second embodiment, D
The external noise induced on the C voltage control lines 37b and 38b and the external noise superimposed on the GNDs 37a and 38a of the variable resistors are output from the balanced input circuit 36 composed of a differential amplifier circuit or the like.
, Common mode noise can be eliminated, and it is possible to prevent the noise from being superimposed on the control voltage CV and changing the volume from the speaker.

(Embodiment 3) FIG. 6 is a block diagram showing a configuration of a main part of a remote control loudspeaker according to Embodiment 3 of the present invention. Control terminal 35B in the present embodiment
Is composed of a variable resistor 37 and a balanced output circuit 40,
Other configurations are the same as those in FIG. 2, and the same reference numerals are given to the same parts as in FIG. 2, and the description thereof will be omitted.

Constant DC voltage V at control terminal 35B
The output voltage V _{R obtained by} dividing the voltage by the variable resistor 37 is input to the balanced output circuit 40, and as shown in FIG.
The output voltages V _R1 and V _{R2 of} 0 are the output voltage V of the variable resistor 37.
_R , the output voltage V _R1 of the balanced output circuit 40,
_VR2 is supplied to the balanced input circuit 36, and as shown in FIG. 8, the control voltage CV changes with the difference voltage of the output voltage _VR2 - _VR1 . That is, by adjusting the variable resistor 37, the control voltage CV and thus the volume from the speaker 34 can be arbitrarily adjusted, and the same operation and effect as those of the second embodiment can be obtained.

(Embodiment 4) FIG. 9 is a block diagram showing a configuration of a main part of a remote control loudspeaker according to Embodiment 4 of the present invention. Control terminal 35C in the present embodiment
Is composed of a variable resistor 37, a voltage / frequency conversion circuit 42, and a balanced output circuit 40, and has a frequency / voltage conversion circuit 41 added between the parallel input circuit 36 and the VCA 32 on the center facility side. The other configuration is the same as that of FIG. 2, and the same reference numerals are given to the same parts as those of FIG. 2, and the description thereof will be omitted.

Constant DC voltage V at control terminal 35C
The output voltage V _{R obtained by} dividing the voltage by the variable resistor 37 is input to the voltage / frequency conversion circuit 42, converted into a control frequency CF as shown in FIG. 10 and supplied to the balanced output circuit 40. The output of the balanced output circuit 40 is supplied to the frequency / voltage conversion circuit 41 via the balanced input circuit 36, and the control voltage CV changes at the control frequency CF as shown in FIG. That is, by adjusting the variable resistor 37, the control voltage CV, and thus the volume from the speaker 34, can be arbitrarily adjusted, the influence of the line resistance of the DC voltage control line is reduced, and the installation distance of the control terminal 35C is increased. As well as
The third embodiment has the same function and effect as the second embodiment.

(Embodiment 5) FIG. 12 is a block diagram showing a configuration of a main part of a remote control loudspeaker according to Embodiment 5 of the present invention. Control terminal 35 in the present embodiment
D connects a broadcast start switch 39 to the output side of the two variable resistors 37 shown in FIG.
Is applied during off a constant DC voltage V ₃ to 9, it is a DC voltage for controlling the DC voltage and volume to start power and the broadcast selected ones transmitted as different DC voltages. In addition, a voltage comparison circuit 44 for detecting the voltage difference and an electronic switch circuit 45 for turning on and off the control voltage CV are added to the center equipment side.
2 are the same as those in FIG. 2, and the same parts as those in FIG.

The output voltages V _R1 , V _R of the variable resistors 37, 38
_R2 is broadcast start switch 39 as shown in FIG. 13 is off, a constant DC voltage V ₃ is the output voltage V _R2. When the broadcast start switch is on, the output voltage V _{R1 obtained by} dividing the constant DC voltage V ₁ at the control terminal 35D by the variable resistor 38 and the constant DC voltage V ₂ are connected to the variable resistor 37.
In dividing the output voltage V _R2 is applied to the balanced input circuit 36, the control voltage CV is the difference between the output voltage V _R2 over V _R1 since the broadcasting start switch 39 as shown in FIG. 14 is turned on The voltage is supplied to the VCA 32. That is, by adjusting the variable resistors 37 and 38, the sound volume from the control voltage CV and thus the speaker 34 is adjusted. Balanced input circuit 36
Differential voltage output from the CV is compared to a reference voltage V ₅ in the voltage comparator circuit 44, is higher than the reference voltage V _5, the differential voltage CV by turning on the electronic switch circuits 45
To the VCA 32.

As described above, according to the fifth embodiment, the voltage comparison circuit 44 detects the voltage difference of the DC voltage that controls the various broadcasts of the amplifier 33 and controls the electronic switch circuit 45. Broadcast control line and D on line
The C voltage control line can be shared, the number of control lines can be reduced, and the same operation and effect as in the second embodiment can be obtained.

(Embodiment 6) FIG. 15 is a block diagram showing a configuration of a main part of a remote control loudspeaker according to Embodiment 6 of the present invention. Control terminal 35 in the present embodiment
E is a signal for connecting a broadcast start switch 39 to the output side of the variable resistor 37 shown in FIG.
While adding a display drive circuit 50 and a balanced input amplifier circuit 49 and ED51, start the broadcast start switch 39, the DC voltage V ₃ constant as in the fifth embodiment is applied to an off, the power and the broadcast selection The DC voltage to be transmitted and the DC voltage to control the volume are transmitted as different DC voltages. On the center equipment side, a balanced output amplifier circuit 47 for superimposing the DC voltage and an electronic switch circuit 46 are provided.
And a low-pass filter circuit 48 are added. The other configuration is the same as that of FIG. 2, and the same reference numerals are given to the same parts as those of FIG. 2, and the description thereof will be omitted.

In the sixth embodiment, the same operation as in the fifth embodiment is performed, and the output of the VCA 32 is applied to the balanced output amplifier circuit 47 via the electronic switch circuit 46.
The output volume signal is superimposed on the DC voltage control line as shown in FIG. On the control terminal 35E side, only the output volume signal is extracted and amplified in the balanced input amplifier circuit 49 by the superimposed output volume signal, and the volume level is displayed by the LED 51 via the display drive circuit 50.

As described above, according to the sixth embodiment, when the output volume at the local facility and various controls are performed from the remote control terminal 35E, the control of the output volume level is visually confirmed on the control terminal 35E side. In addition to this, it can be easily performed, and has the same operation and effect as the fifth embodiment.

(Seventh Embodiment) FIG. 17 is a block diagram showing a configuration of a main part of a remote control loudspeaker according to a seventh embodiment of the present invention. In the seventh embodiment, a VCA that controls the sound source 2 by installing a plurality of control terminals 10 of the first embodiment
A dual broadcast start switch 52 is provided so that the volume control and various controls can be performed by a plurality of control terminals 35F through the DC voltage control line 23 and the amplifier 6 through the broadcast control line 21. First control terminal 35
In the broadcast start switch 52-1 of F-1, the movable terminals a and b are respectively connected to the VCA 3 and the amplifier 6, and the fixed terminals c and d on one side are connected to the movable terminal of the variable resistor 17 and the ground, respectively. The fixed terminals e and f on the opposite side are connected to the movable terminals a and b in the next stage, respectively.

When the broadcast start switch 52-1 of the first control terminal 35F-1 is off, the connection between the broadcast control line 21 and the DC voltage control line 23 is connected to the second control terminal 35F-2. Start switch 5 of the second control terminal 35F-2
When 2-2 is on, volume control and broadcast control by the second control terminal 35F-2 are possible. 1 in the above state
Broadcast start switch 52-1 of the control terminal 35F-1
When is turned on, this is given priority and the volume control and broadcast control can be performed from the first control terminal 35F-1. Similarly, control can be performed from the second and subsequent control terminals.

As described above, according to the seventh embodiment, 1
When controlling the volume of the VCA 3 from the plurality of control terminals 35F and performing various controls, the priority is given to the control terminals, so that there is an effect that broadcasting can be performed in accordance with the form of broadcasting of the building.

[0041]

As described above, according to the present invention, a center facility having a sound source for whole-building and emergency broadcasts, an amplifier for amplifying an audio signal from each sound source, and a facility distant from the center facility are provided. A local equipment having a plurality of speakers connected to each other by a wire to output sound, a sound source for local broadcasting, and a control terminal for controlling the center equipment, wherein the center equipment is a local control terminal. , It is possible to simultaneously broadcast the whole building, the emergency broadcast, and the local broadcast with one center facility.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a remote control loudspeaker according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a partial configuration of a remote control loudspeaker according to Embodiment 2 of the present invention;

FIG. 3 is a characteristic diagram showing a change in an output voltage according to a variable resistor rotation angle according to the second embodiment of the present invention;

FIG. 4 is a characteristic diagram showing a change in a control voltage supplied to a VCA according to a second embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a change in the amplification factor of VCA according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a partial configuration of a remote control loudspeaker according to Embodiment 3 of the present invention.

FIG. 7 is a characteristic diagram showing a change in a balanced output voltage according to a variable resistor rotation angle in the third embodiment of the present invention.

FIG. 8 is a characteristic diagram showing a change in a control voltage supplied to a VCA according to a third embodiment of the present invention.

FIG. 9 is a block diagram showing a partial configuration of a remote control loudspeaker according to a fourth embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a change in control frequency depending on a variable resistor rotation angle according to a fourth embodiment of the present invention.

FIG. 11 is a characteristic diagram showing a change in a control voltage supplied to a VCA according to a fourth embodiment of the present invention.

FIG. 12 is a block diagram showing a partial configuration of a remote control loudspeaker according to a fifth embodiment of the present invention.

FIG. 13 is a characteristic diagram showing a change in output voltage according to a variable resistor rotation angle according to the fifth embodiment of the present invention.

FIG. 14 is a characteristic diagram showing a change in a control voltage supplied to a VCA according to the fifth embodiment of the present invention.

FIG. 15 is a block diagram showing a partial configuration of a remote control loudspeaker according to a sixth embodiment of the present invention.

FIG. 16 is a characteristic diagram showing a change in an output voltage according to a variable resistor rotation angle in the sixth embodiment of the present invention.

FIG. 17 is a block diagram showing a partial configuration of a remote control loudspeaker according to a seventh embodiment of the present invention.

FIG. 18 is a block diagram showing a configuration of a conventional loudspeaker.

[Explanation of symbols]

Reference Signs List 1 center equipment 2 sound source 3, 4 VCA 5 mixing amplifier 6 amplifier 7 speaker control unit 8 control unit 9 speaker control line 10 local equipment 11, 12 shared speaker 13 control terminal 14 sound source 15 broadcast start switch 16, 17 variable resistor 21 broadcast Control line 22, 23 DC voltage control line 24 Audio signal line 31 Sound source 32 VCA 33 Amplifier 34 Speaker 35A, 35B, 35C, 35D, 35E, 35F Control terminal 36 Balanced input circuit 37, 38 Variable resistor 39 Broadcast start switch 40 Balanced Output circuit 41 Frequency / voltage conversion circuit 42 Voltage / frequency conversion circuit 44 Voltage comparison circuit 45 Electronic switch circuit 48 Low pass filter circuit 49 Balanced input amplifier circuit 50 Display drive circuit 51 LDE 52 Broadcast start switch 60 Emergency broadcast amplifier 61 Local amplifier 62 switch 63 shared speaker 64 speaker on each floor 65 switching control signal

Claims (12)

[Claims] 1. A center facility having a sound source for whole-broadcasting and emergency broadcasting, an amplifier for amplifying an audio signal from each sound source, and a cable connected to a facility distant from the center facility to output sound. A remote control loudspeaker comprising a plurality of speakers, a local broadcast source, and a local facility having a control terminal for controlling the center facility. 2. The center equipment includes a plurality of voltage-controlled amplifiers connected between the sound sources of the center equipment and the local equipment and the amplifiers, and each of which is controlled by a DC voltage from a control terminal of the local equipment. 2. The remote control loudspeaker according to claim 1. 3. The remote controlled loudspeaker of claim 2, further comprising a mixing amplifier connected between each voltage controlled amplifier and the amplifier. 4. The remote control loudspeaker according to claim 1, wherein each of the DC voltages in the control terminal is controlled by a variable resistor. 5. A method in which each variable resistor is connected in series and different DC voltages are input, and a difference between respective output voltages divided by the variable resistor is obtained by a balanced input circuit and input to a voltage control amplifier. Item 5. A remote control loudspeaker according to Item 4. 6. The remote control loudspeaker according to claim 4, wherein an output voltage of each variable resistor is branched through a balanced output circuit, and a difference between the branched output voltages is obtained by a balanced input circuit and input to a voltage control amplifier. . 7. The output voltage of each variable resistor is converted into a frequency and then branched through a balanced output circuit. The difference between the branched frequencies is obtained by a balanced input circuit, converted into a voltage, and then input to a voltage control amplifier. The remote control loudspeaker according to claim 4. 8. Each of the variable resistors is connected in series and a different DC voltage is input, and a broadcast start switch is connected to one of the variable resistors to apply a further different DC voltage when the variable resistor is turned off. When the start switch is turned on, a difference between respective output voltages divided by the two variable resistors is obtained by a balanced input circuit, and the output voltage is further compared with a reference voltage. 5. The remote control loudspeaker according to claim 4, wherein an output of said remote control loudspeaker is input to a voltage controlled amplifier. 9. The remote control loudspeaker according to claim 1, further comprising means for displaying an output volume and an operation state on a control terminal. 10. When a plurality of local facilities are connected to the center facility, the control terminal of each local facility is provided with means for prioritizing control of a voltage control amplifier connected to a sound source of the center facility. The remote control loudspeaker according to any one of claims 1 to 9. 11. A loudspeaker different from the loudspeaker in the local equipment connected to the center equipment.
The remote control loudspeaker according to any one of the above. 12. The remote control loudspeaker according to claim 1, wherein each sound source includes a microphone, a BGM, a cassette, a CD player, a wireless receiver, and a chime.