WO2022003844A1 - 拡声装置 - Google Patents
拡声装置 Download PDFInfo
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- WO2022003844A1 WO2022003844A1 PCT/JP2020/025737 JP2020025737W WO2022003844A1 WO 2022003844 A1 WO2022003844 A1 WO 2022003844A1 JP 2020025737 W JP2020025737 W JP 2020025737W WO 2022003844 A1 WO2022003844 A1 WO 2022003844A1
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- power
- voltage
- power supply
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 64
- 230000005236 sound signal Effects 0.000 claims abstract description 38
- 238000001514 detection method Methods 0.000 claims abstract description 20
- 230000007423 decrease Effects 0.000 description 18
- 238000010586 diagram Methods 0.000 description 7
- 230000006854 communication Effects 0.000 description 6
- 238000009434 installation Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000007175 bidirectional communication Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
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- 238000003199 nucleic acid amplification method Methods 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R27/00—Public address systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/08—Three-wire systems; Systems having more than three wires
- H02J1/082—Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/14—Balancing the load in a network
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
- H04R1/04—Structural association of microphone with electric circuitry therefor
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
- H02J2310/50—The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads
- H02J2310/56—The network for supplying or distributing electric power characterised by its spatial reach or by the load for selectively controlling the operation of the loads characterised by the condition upon which the selective controlling is based
- H02J2310/58—The condition being electrical
- H02J2310/60—Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
Definitions
- the present invention relates to a public address system, and more particularly to an improvement of a public address system that operates by receiving power supply from a power supply device.
- a loudspeaker broadcasting system that transmits information by voice to residents in indoor or outdoor broadcasting areas.
- the loudspeaker broadcasting system comprises one or more loudspeakers.
- Each loudspeaker includes a power amplifier that amplifies an audio signal to generate a speaker drive signal, and a speaker that converts the speaker drive signal into sound waves, and outputs audio according to the audio signal.
- Most of the power consumption of the public address system is the power consumption of the power amplifier. Therefore, the power consumption of the loudspeaker fluctuates according to the voice signal. Therefore, when the power is supplied from the external power supply device, the input power to the public address system fluctuates greatly.
- the power supply capacity of the power supply device may not be sufficient, and the upper limit power supply that can be supplied to the public address system may be smaller than the maximum power consumption of the public address system. In such a case, it is necessary to suppress the power consumption of the public address system so as not to exceed the upper limit power supply.
- the power consumption of the power amplifier can be suppressed.
- the power supply voltage is lowered, the speaker output is lowered, and there is a problem that it becomes difficult for the listener in the broadcasting area to distinguish and understand the voice.
- the sine wave power has a "distortion-free maximum power" of about 50% of the square wave power when there is no distortion. Therefore, the power supply voltage is a square wave signal. Even if it is a wave, it must be decided to a value that does not exceed the upper limit power supply. Therefore, when the audio signal is a sine wave, only 50% of the upper limit power supply can be used, and when the power supply capacity of the power supply device is not sufficient, it is difficult to secure the required speaker output. there were.
- PoE Power over Ethernet
- PoE + compliant power supply device defined by its higher standard IEEE802.3at
- the public address system as the power receiving device can generate power exceeding the supply upper limit power.
- the loudspeaker When consumed, the loudspeaker must be reset to immediately stop power supply and resume power supply. Therefore, when power is supplied from a PoE-compliant power supply device, there is a problem that it is difficult to secure sufficient speaker output.
- the present invention has been made in view of the above circumstances, and provides a public address system that facilitates voice discrimination while performing power control so that the input power does not exceed the supply upper limit power of the power supply device.
- the purpose is to be described in detail below.
- the loudspeaker is an electroacoustic converter that amplifies an audio signal by using a voltage conversion unit that converts a voltage of a DC power supply input from a power supply device and a DC power supply after the voltage conversion.
- a power amplifier that generates a drive signal for driving the power supply device, a power detection unit that detects input power from the power supply device, a threshold holding unit that holds a power determination threshold corresponding to the supply upper limit power of the power supply device, and the input. It is connected between the voltage control unit that controls the output voltage of the voltage conversion unit, the voltage conversion unit, and the power amplifier based on the power and the power determination threshold, and when the output voltage of the voltage conversion unit drops, the voltage is connected. It includes a charge storage unit that supplies power to the power amplifier.
- the DC power input from the power supply device is supplied to the power amplifier via the voltage conversion unit, and the output voltage of the voltage conversion unit is controlled based on the input power from the power supply device. can do. Therefore, the input power can be controlled so as not to exceed the supply upper limit power.
- audio can be output without being limited by the input power. Therefore, the listener in the broadcasting area can easily distinguish the sound output from the public address system.
- the power detection unit includes a current detection unit that detects the output current of the voltage conversion unit, and the output voltage and output of the voltage conversion unit. It is configured to obtain the input power based on the current.
- the supply upper limit power is combined with the power supply device based on a predetermined protocol before the start of power supply from the power supply device. It is configured to be determined in the negotiations that take place between.
- the supply device supplies power in accordance with the IEEE802.3 standard having a plurality of power classes, and is in accordance with the IEEE802.3 standard.
- the PoE interface unit that determines one of the power classes from the plurality of power classes through negotiation with the power supply device before the start of power supply from the power supply device is provided, and the supply upper limit is provided.
- the electric power is configured to be the supply upper limit electric power defined by the IEEE802.3 standard corresponding to the electric power class determined by the PoE interface unit.
- the voltage control unit controls the output voltage to be the first voltage when the input power exceeds the power determination threshold.
- the output voltage is controlled to be a second voltage higher than the first voltage, and the first voltage is the maximum power of the drive signal.
- the input power is configured to be a value that does not exceed the supply upper limit power.
- the amplitude of the voice signal is limited based on the comparison result of the terminal voltage of the charge storage unit and the predetermined voltage determination threshold.
- a limiting unit is provided, and the voltage determination threshold is configured to be a value between the first voltage and the second voltage.
- the amplitude limiting unit of the charge storage unit is configured to end after the elapse of a predetermined amplitude limiting period.
- FIG. 1 It is a figure which showed one configuration example of the loudspeaker broadcasting system 100 including the loudspeaker 2 by Embodiment 1 of this invention.
- FIG. 1 is a diagram showing a configuration example of a loudspeaker broadcasting system 100 including a loudspeaker 2 according to the first embodiment of the present invention.
- the loudspeaker broadcasting system 100 includes a sound source device 1 that generates audio data, a loudspeaker 2 that reproduces audio, and a switching hub 3 that relays audio data between the sound source device 1 and the loudspeaker device 2.
- the public address system 100 is a system that transmits information by voice to residents in a predetermined indoor or outdoor broadcasting area, for example, an office building, a shopping center, a station, an airport, a school, a concert hall, or the like. It is a PA system (public address system) installed on the ground.
- the voice used for information transmission is composed of utterance sounds, music, alarm sounds such as disaster alarms, sound effects such as chimes, and the like.
- the sound source device 1 is a device that generates packet data including voice data or control data, and for example, an IP packet capable of Internet protocol communication is generated.
- the voice data includes voice information such as input voice input from a microphone or the like, recorded voice stored in advance in a storage medium, and synthetic voice generated by an electronic sound source.
- the control data is control data for the loudspeaker 2, and is data for designating voice data (built-in voice data) such as recorded voice held in the loudspeaker 2, for example.
- the generated packet data is transmitted from the sound source device 1 to the public address device 2. Packet data is sent by designating a destination, and when two or more public address devices 2 are connected to one sound source device 1, the same packet data or different packet data is sent to each public address device 2. Can be done.
- the public address system 2 is a voice reproduction device that reproduces voice, and emits the reproduced voice to the broadcasting area.
- the loudspeaker 2 receives packet data from the sound source device 1 and reproduces voice by extracting voice data and control data from the packet data.
- the public address system 2 is used, for example, for public address broadcasting such as business broadcasting and emergency broadcasting.
- the switching hub 3 is a relay device that receives packet data from the sound source device 1 and transmits it to the public address system 2 according to the destination.
- the sound source device 1 is connected to the switching hub 3 by wire or wirelessly, and the public address system 2 is connected to the switching hub 3 by using a cable 4. It is also possible to connect the sound source device 1 and the public address device 2 with two or more switching hubs 3 interposed therebetween. Further, the sound source device 1 and the loudspeaker device 2 can be directly connected by using the cable 4 without interposing the switching hub 3.
- the public address system 2 receives packet data and is supplied with power via the cable 4.
- the power supply between the loudspeaker 2 and the switching hub 3 conforms to, for example, PoE (Power over Ethernet) defined by the IEEE802.3af standard and PoE + defined by the IEEE802.3at standard, and the switching hub 3 is the power supply device.
- PoE Power over Ethernet
- PoE + defined by the IEEE802.3at standard
- the switching hub 3 is the power supply device.
- PSE PowerSourceDevice
- the public address system 2 is used as a power receiving device
- PD PoweredDevice
- the cable 4 contains four pairs of twisted pairs composed of twisted two conductors, and these twisted pairs are assigned for data communication or power supply. Also, one twisted pair can be used for both data communication and power supply. Therefore, power supply and data communication can be simultaneously performed between the public address system 2 and the switching hub 3 only by connecting using a single cable 4.
- the cable 4 By using the cable 4, it is not necessary to lay a power supply line when installing the public address system 2, and the installation work of the public address system 2 can be facilitated.
- the installation of the power supply line can be omitted, so that the installation cost can be suppressed and the public address system 2 can be installed in the place where the public address system 2 is installed.
- the degree of freedom can be improved.
- FIG. 2 is a block diagram showing a configuration example of the public address system 2 of FIG.
- the public address system 2 includes an interface unit 200, a voice processing unit 201, a power amplifier 202, a speaker 203, a voltage conversion unit 204, a power detection unit 205, a voltage control unit 206, a threshold holding unit 207, a charge storage unit 208, and a voice input terminal 209.
- a power supply device 10 such as a sound source device 1 and a switching hub 3 is connected via a cable 4.
- the interface unit 200 performs bidirectional communication with the power supply device 10, and DC power is supplied from the power supply device 10. Further, the interface unit 200 outputs voice data or control data to the voice processing unit 201, outputs a power class to the threshold value holding unit 207, and further supplies DC power to each block in the loudspeaker 2.
- the DC power supplied from the power supply device 10 is input to the voltage conversion unit 204, and is also supplied to the voice processing unit 201, the voltage control unit 206, the threshold value holding unit 207, and the like as a drive power source.
- the interface unit 200 negotiates with the power supply device 10 to determine the power class, and outputs the threshold power Pth corresponding to the determined power class to the threshold holding unit 207.
- the negotiation with the power supply device 10 is performed according to a predetermined protocol when the public address system 2 is connected to the power supply device 10 and the power supply from the power supply device 10 is started. For example, negotiation is performed between the power feeding device and the power receiving device defined by the IEEE802.3af standard or the IEEE802.3at standard.
- the power class is associated with the supply upper limit power Pmax, and if the power class is determined, the maximum power that can be supplied from the power supply device 10 to the public address device 2 is determined. Therefore, if the power consumption of the loudspeaker 2 exceeds the supply upper limit power Pmax corresponding to the power class after the power class is determined, the power supply from the power supply device 10 is immediately stopped. That is, the power feeding device 10 is configured to detect the power consumption of the loudspeaker 2 at a predetermined cycle and stop the power supply when the detected power consumption exceeds the supply upper limit power Pmax according to the power class.
- the threshold power Pth is determined based on the supply upper limit power Pmax.
- the power determination threshold value Pth is a threshold value for controlling the voltage of the voltage conversion unit 204 so that the input power of the loudspeaker 2 does not exceed the supply upper limit power Pmax. For example, the same value as the supply upper limit power Pmax corresponding to the power class, or a value considering a predetermined margin can be set as the power determination threshold value Pth.
- FIG. 3 is a diagram showing an example of a power class set across the three standards PoE, PoE + and PoE ++, and a supply upper limit power Pmax set for each power class.
- the supply upper limit power Pmax corresponding to the power class is known.
- the supply upper limit power Pmax is 25.5 W, and a value of 25.5 W or a value slightly lower than this is determined as the threshold power Pth.
- the interface unit 200 holds a table in which a plurality of power classes that can be specified by negotiation and the supply upper limit power Pmax for each power class are associated with each other as shown in FIG. 3, and the interface unit 200 refers to this table for negotiation.
- the threshold power Pth is determined in advance based on the supply upper limit power Pmax corresponding to each power class, a table in which each power class is associated with the threshold power Pth is maintained, and the table is referred to by negotiation. It is also possible to determine the threshold power Pth corresponding to the specified power class.
- the interface unit 200 when the interface unit 200 receives the packet data from the power feeding device 10, the interface unit 200 extracts the voice data or the control data from the packet data and outputs the voice data or the control data to the voice processing unit 201.
- the voice processing unit 201 generates a voice signal as an analog signal or a digital signal based on the voice data or control data input from the interface unit 200.
- the voice signal can be generated based on the voice data received from the power feeding device 10. Further, it is also possible to generate a voice signal based on the voice data designated by the control data among the two or more voice data (built-in voice data) held in advance by the voice processing unit 201.
- the voice processing unit 201 includes a voice signal based on the voice data and a voice signal based on the built-in voice data designated by the control data. It is also possible to generate an audio signal by mixing.
- the audio input terminal 209 is a terminal that is connected to an external sound source such as a microphone and receives an audio signal input from the external sound source.
- the voice input terminal 209 is connected between the voice processing unit 201 and the power amplifier 202, and the voice signal input via the voice input terminal 209 is supplied to the power amplifier 202.
- the power amplifier 202 is an amplifier circuit that amplifies the power of the audio signal and generates a speaker drive signal for driving the speaker 203, and the drive power is supplied via the voltage conversion unit 204.
- the power amplifier 202 amplifies the audio signal input from the audio processing unit 201, the audio signal input from the audio input terminal 209, or the audio signal mixed with these.
- the speaker 203 is a means for converting the speaker drive signal from the power amplifier 202 into sound waves and outputting them to the broadcasting area.
- the output power of the speaker 203 (hereinafter referred to as speaker output) can be regarded as the power consumption of the power amplifier 202.
- the power consumption of the power amplifier 202 changes according to the audio signal and also changes according to the power supply voltage supplied to the power amplifier 202. Therefore, for example, if the amplitude of the audio signal increases, the speaker output also increases, and if the amplitude decreases, the speaker output also decreases. Further, if the voltage of the drive power supply of the power amplifier 202 increases, the maximum output power of the speaker 203 increases, and if it decreases, the maximum output power of the speaker 203 also decreases.
- the voltage conversion unit 204 is a DC-DC converter that converts the voltage of the DC power supply, and converts the voltage of the input power supply from the interface unit 200 into a different voltage.
- the output voltage of the voltage conversion unit 204 is controlled based on the voltage control signal S1 of the voltage control unit 206, and outputs either a high voltage V2 or a low voltage V1. For example, when the input voltage is 44 to 57V, the output voltage can be 17V for the high voltage V2 and 12V for the low voltage V1.
- the power detection unit 205 is a means for detecting the input power Pi from the power feeding device 10.
- Power detection unit 205 a current detecting unit 205e for detecting an output current i D of the voltage conversion unit 204, based on the detected current value to determine the input power Pi from the power supply device 10.
- the output current i D of the voltage conversion unit 204 is, for example, a small resistance connected in series to the output terminal of the voltage converter 204, is detected by measuring the voltage between the terminals of the resistor.
- the output power of the voltage conversion unit 204 can be regarded as the input power from the power feeding device 10.
- Output power of the voltage conversion unit 204 can be determined from the output voltage and output current i D of the voltage converter 204, the output voltage of the voltage conversion unit 204 is a known value that is controlled by the voltage control unit 206. Therefore, the input power from the power feeding device 10 can be obtained based on the detection current of the current detection unit 205e.
- the voltage control unit 206 is a means for controlling the output voltage of the voltage conversion unit 204 according to the input power from the power supply device 10, and controls the input power so as not to exceed the supply upper limit power Pmax. ..
- the voltage control unit 206 generates a voltage control signal S1 based on the input power obtained by the power detection unit 205, and controls the output voltage of the voltage conversion unit 204.
- the voltage control signal S1 is generated by comparing the input power from the power feeding device 10 with the power determination threshold value Pth held by the threshold value holding unit 207. For example, if the input power is equal to or less than the power determination threshold Pth, the voltage control signal S1 indicating the high voltage V2 (second voltage) is generated, and if the input power exceeds the power determination threshold Pth, the low voltage V1 (first voltage) is generated. ) Is output as a voltage control signal S1.
- the low voltage V1 is predetermined as the power supply voltage of the power amplifier 202 whose speaker output does not exceed the supply upper limit power Pmax even when the audio signal that maximizes the speaker output is output from the audio processing unit 201.
- the threshold value holding unit 207 is a means for holding the power determination threshold value Pth.
- the power determination threshold value Pth is determined based on the power class determined by the interface unit 200. For example, a value in which a predetermined margin is taken into consideration for the supply upper limit power Pmax corresponding to the power class can be set as the power determination threshold value Pth, but in the present embodiment, the power determination threshold value Pth is one with the supply upper limit power Pmax for convenience. An example of the case where it is done will be described.
- the charge storage unit 208 is a capacitive element connected between the power amplifier 202 and the power detection unit 205, and the terminal voltage of the charge storage unit 208 becomes the power supply voltage of the power amplifier 202.
- the charge storage unit 208 is charged when the voltage conversion unit 204 outputs the high voltage V2. Further, the charge storage unit 208 discharges when the voltage conversion unit 204 outputs the low voltage V1 and supplies the stored charge to the power amplifier 202. That is, the speaker output is supplied by the voltage conversion unit 204 and the charge storage unit 208.
- FIG. 4 is a timing chart showing an example of the operation of the public address system 2 of FIG. 2, and shows, for example, a state when an audio signal for outputting a short sound of less than 1 second at a loud volume is given. ..
- (a) is the output power of the speaker 203
- (b) is the input power Pi supplied from the power feeding device 10
- (c) is the voltage control signal S1 generated by the voltage control unit 206.
- (D) shows the terminal voltage of the charge storage unit 208, respectively.
- the characteristic L1 shown by the solid line in (a) in the figure shows the change in the speaker output in the loudspeaker 2 in FIG. 2, and the characteristic L2 shown by the broken line drives the speaker 203 according to the audio signal. It shows the change of the speaker output when it is assumed that it was possible.
- the characteristic L1 of the solid line and the characteristic L2 of the broken line shown in (b) in the figure are also shown for the input power Pi in the same manner.
- the audio signal changes so that the speaker output is increased from low output to high output and then returned to low output, and the speaker output at the time of high output exceeds the supply upper limit power Pmax.
- P1 in the figure is the output power of the speaker 203 at the time of low output, and is a value smaller than the power determination threshold value Pth.
- P2 in the figure is the output power of the speaker 203 at the time of high output, and is a value larger than the power determination threshold value Pth.
- the audio signal straddles the power determination threshold Pth at time t1, changes the speaker output from the low power P1 to the high power P2, and then straddles the power determination threshold Pth again at the time t3, and outputs the speaker from the high power P2. Change to low power P1.
- Ts in the figure is a continuous sound output period Ts in which continuous sound is output when the speaker is driven according to the voice signal to output voice.
- the continuous sound in the present specification refers to a series of sounds in which the speaker output continues to exceed the supply upper limit power Pmax.
- the continuous sound output period Ts is such a continuous sound output period, and is a period separated by a pause period in which the speaker output becomes the supply upper limit power Pmax or less.
- the voltage control unit 206 If the input power Pi is a low power P1 smaller than the power determination threshold Pth, the voltage control unit 206 generates a voltage control signal S1 instructing the high voltage V2, and the voltage conversion unit 204 outputs the high voltage V2. In FIG. 4, such a state continues at first, and the charge storage unit 208 is in a state of being charged to the high voltage V2.
- the speaker output increases and reaches the power determination threshold value Pth (time t1). After that, the output voltage of the voltage conversion unit 204 vibrates so as to reciprocate between the low voltage V1 and the high voltage V2, so that the input power is suppressed.
- the voltage control unit 206 If the speaker output reaches the power determination threshold value Pth while the voltage conversion unit 204 is outputting the high voltage V2, the input power Pi also reaches the power determination threshold value Pth. Therefore, the voltage control unit 206 generates the voltage control signal S1 instructing the low voltage V1, and the output voltage of the voltage conversion unit 204 is switched to the low voltage V1. However, when the output voltage of the voltage conversion unit 204 is switched to the low voltage V1, the output voltage becomes lower than the terminal voltage of the charge storage unit 208. Therefore, the power supply to the power amplifier 202 is performed by the charge storage unit 208, the output current i D is zero, the input power Pi also becomes substantially zero. As a result, the voltage control unit 206 generates the voltage control signal S1 instructing the high voltage V2, and the output voltage of the voltage conversion unit 204 is switched to the high voltage V2 again.
- the voltage control signal S1 alternately switches between the high voltage V2 and the low voltage V1, and the output voltage of the voltage conversion unit 204 vibrates so as to reciprocate between the high voltage V2 and the low voltage V1. do. For example, it vibrates with a cycle of 20 ⁇ sec. This cycle is set to be sufficiently earlier than the cycle in which the supply device 10 detects the power consumption of the loudspeaker 2, for example, several msec to several tens of msec. By vibrating the output voltage in this way, the power can be limited so that the input power Pi does not exceed the power determination threshold value Pth.
- the charge storage unit 208 After the time t1, the charge storage unit 208 is discharged, the terminal voltage of the charge storage unit 208 gradually decreases from the high voltage V2, and reaches the low voltage V1 at the time t2. That is, from time t1 to t2, the power supply to the power amplifier 202 is mainly performed by the charge storage unit 208. Therefore, it is possible to realize a speaker output that exceeds the power determination threshold Pth while suppressing the input power so as not to exceed the power determination threshold Pth.
- the speaker output decreases according to the audio signal, and the power determination threshold value Pth is reached at time t3. Further, the speaker output is lowered and falls below the power determination threshold value Pth.
- the power used for charging the charge storage unit 208 is newly added to the input power. Therefore, even if the speaker output becomes equal to or less than the power determination threshold value Pth, the input power does not become equal to or less than the power determination threshold value Pth, and the output voltage of the voltage conversion unit 204 continues to vibrate.
- the change in which the output voltage of the voltage conversion unit 204 decreases from the high voltage V2 to the low voltage V1 is rapidly performed, while the change in which the output voltage from the low voltage V1 to the high voltage V2 is gradually increased according to a predetermined time constant. .. Therefore, even if the output voltage of the voltage conversion unit 204 is vibrating, if the speaker output is less than the power determination threshold Pth, the charge storage unit 208 can be charged.
- the speaker output further decreases, and the charging current of the charge storage unit 208 increases accordingly (time t3 to t4).
- the terminal voltage of the charge storage unit 208 gradually rises due to the charge storage, and the charging current starts to decrease.
- the output voltage of the voltage conversion unit 204 becomes the high voltage V2, and the vibration is stopped (time t5).
- Charging of the charge storage unit 208 is continued thereafter, and charging ends when the terminal voltage reaches the high voltage V2 (time t6).
- 5 and 6 are diagrams showing comparative examples to be compared with the public address system 2 according to the embodiment of the present invention. Both are diagrams showing changes in speaker output in a conventional public address system.
- FIG. 5 shows the speaker output when the power limit is not applied.
- the characteristic L1 of the solid line and the characteristic L2 of the broken line shown in the figure are the same as in the case of (a) of FIG. Since the power is not limited, the power supply from the power supply device 10 is stopped when the speaker output reaches the supply upper limit power Pmax. Therefore, after that, the operation cannot be resumed unless the loudspeaker 2 is reset and the power class negotiation with the power supply device 10 is started.
- FIG. 6 shows the speaker output when the voltage is limited.
- the characteristic L1 of the solid line and the characteristic L2 of the broken line shown in the figure are the same as in the case of (a) of FIG.
- the low voltage V1 is the power supply voltage of the power amplifier 202 whose speaker output does not exceed the supply upper limit power Pmax regardless of the audio signal. Therefore, by fixing the output voltage of the voltage conversion unit 204 to the low voltage V1, it is possible to prevent the input voltage from exceeding the supply upper limit power Pmax. In this case, the speaker output is simply reduced and the supply upper limit power Pmax is not exceeded, so that it becomes difficult to hear the voice.
- the public address system 2 supplies power to the power amplifier 202 via the voltage conversion unit 204, and controls the output voltage of the voltage conversion unit 204 based on the input power from the power supply device 10 to input.
- the power is limited. For example, if the input power is equal to or higher than the power determination threshold value Pth, the output voltage of the voltage conversion unit 204 is lowered from the high voltage V2 to the low voltage V1. Therefore, the input power can be suppressed so as not to exceed the supply upper limit power Pmax.
- the charge storage unit 208 between the voltage conversion unit 204 and the power amplifier 202, power is supplied to the power amplifier 202 from the charge storage unit 208 immediately after the output voltage of the voltage conversion unit 204 is lowered. be able to. Therefore, it is possible to realize a speaker output larger than the input power while limiting the input power from the power feeding device 10. That is, it is possible to output the speaker that exceeds the supply upper limit power Pmax while suppressing the input power so as not to exceed the supply upper limit power Pmax.
- the charge storage unit 208 by using the charge storage unit 208, it is possible to output sound at least at the beginning of the continuous sound output period Ts without being limited by the supply upper limit power Pmax. In general, it is said that it is important to clearly hear the beginning of a continuous sound when distinguishing it. Therefore, since the opening portion is not limited by the supply upper limit power Pmax, the listener in the broadcasting area can easily distinguish and understand the sound output from the public address system 2.
- the current detector 205e between the voltage converter 204 and the charge storage portion 208, it detects the output current i D of the voltage conversion unit 204, based on the output current i D, the input power from the power supply device 10 I'm looking for it. Therefore, the input power can be quickly detected without being affected by the discharge of the charge storage unit 208.
- the output voltage of the voltage conversion unit 204 is controlled based on the result of comparing the input power with the power determination threshold value Pth, and the power determination threshold value Pth is determined based on the power class determined in the negotiation with the power supply device 10. .. Therefore, it is possible to limit the power according to the power class.
- Embodiment 2 In the first embodiment, an example of the public address system 2 for limiting the input power has been described. On the other hand, in the present embodiment, an example will be described in which charging of the charge storage unit 208 is promoted by further limiting the amplitude of the audio signal during the power limitation.
- FIG. 7 is a diagram showing a configuration example of the public address system 2 according to the second embodiment of the present invention.
- the public address system 2 is different from the public address system 2 of FIG. 2 in that it includes a voltage detection unit 210 and an amplitude limiting unit 211 as compared with the public address system 2 (Embodiment 1).
- the configurations corresponding to the configurations shown in FIG. 2 are designated by the same reference numerals, and duplicate description will be omitted.
- the voltage detection unit 210 is a means for detecting the power supply voltage supplied to the power amplifier 202, and is connected between the charge storage unit 208 and the power amplifier 202.
- the detected voltage Va is output to the amplitude limiting unit 211.
- the amplitude limiting unit 211 is a means for limiting the amplitude of the audio signal based on the detected voltage Va.
- the amplitude limitation is a process of clipping the amplitude of an audio signal by a predetermined value. That is, among the amplitudes of the audio signals, the amplitude exceeding the predetermined clip value is replaced with the clip value, and the excess portion is deleted. By limiting the amplitude, the reproduced sound is greatly distorted, but the speaker power can be suppressed. For example, 1/3 of the maximum amplitude of the audio signal can be set as the clip value.
- the amplitude limiting unit 211 compares the detected voltage Va with a predetermined voltage determination threshold value Vth, limits the amplitude of the audio signal based on the comparison result, and outputs the amplitude-limited audio signal to the power amplifier 202.
- the voltage determination threshold value Vth is predetermined as a value lower than the high voltage V2 and higher than the low voltage V1. For example, when the high voltage V2 is 17V and the low voltage V1 is 12V, the voltage threshold value can be set to 14V.
- the amplitude limiting unit 211 If the detected voltage Va exceeds the voltage determination threshold value Vth, the amplitude limiting unit 211 outputs the input audio signal to the power amplifier 202 as it is without limiting the amplitude. On the other hand, if the detected voltage Va is equal to or less than the voltage determination threshold value Vth, the amplitude-limited audio signal is output to the power amplifier 202. This amplitude limitation is continued until the amplitude limitation time Td elapses after the detection voltage Va exceeds the voltage determination threshold value Vth.
- the amplitude time limit Td is, for example, a predetermined fixed time.
- FIG. 8 is a timing chart showing an example of the operation of the public address system 2 of FIG. 7, and shows, for example, a state when an audio signal for outputting a short sound of less than about 1 second at a loud volume is given.
- (a) is the output power of the speaker 203
- (b) is the input power Pi supplied from the power feeding device 10
- (c) is the voltage control signal S1 generated by the voltage control unit 206.
- (D) shows the amplitude limiting process in the amplitude limiting unit 211
- (e) shows the terminal voltage of the charge storage unit 208.
- the difference between the characteristic L1 of the solid line and the characteristic L2 of the broken line shown in (a) and (b) in the figure is the same as in the case of FIG.
- the operation up to time t12 is the same as the operation up to time t2 in FIG. Initially, both the speaker power and the input power are low power P1 smaller than the power determination threshold Pth, the voltage conversion unit 204 outputs the high voltage V2, and the charge storage unit 208 is in a state of being charged to the high voltage V2. ing. After that, when the speaker output increases and the input power reaches the power determination threshold Pth at time t11, the output voltage of the voltage conversion unit 204 vibrates so as to reciprocate between the high voltage V2 and the low voltage V1, and the input power becomes It is suppressed so as not to exceed the power determination threshold Pth.
- the power supply to the power amplifier 202 is mainly performed by the charge storage unit 208. Therefore, the terminal voltage of the charge storage unit 208 gradually decreases and reaches the voltage determination threshold value Vth (time t12). At this time, the amplitude limitation of the audio signal by the amplitude limiting unit 211 is started. As a result, the speaker output is significantly reduced to a value lower than the power determination threshold value Pth, but as the speaker output is reduced, charging of the charge storage unit 208 is started. As a result, since the power used for charging the charge storage unit 208 is newly added to the input power, the output voltage of the voltage conversion unit 204 continues to vibrate.
- the terminal voltage of the charge storage unit 208 gradually rises due to the charge storage, and the charging current gradually decreases.
- the input power becomes equal to or less than the power determination threshold value Pth, and the power limit is released (time t13). That is, the output voltage of the voltage conversion unit 204 stops vibration and becomes a high voltage V2.
- the charge storage unit 208 continues to be charged, but the charging current gradually decreases, and the input power gradually decreases accordingly. Then, when the terminal voltage of the charge storage unit 208 becomes the high voltage V2, charging is completed (time t14). Therefore, after that, the input power matches the speaker output.
- the amplitude limit is released after the amplitude limit time Td has elapsed.
- the speaker output since it is an audio signal that outputs a short sound, the speaker output reaches the power determination threshold value Pth at time t15, but the amplitude limitation is released at time t16 after that. Become.
- charging of the charge storage unit 208 can be started before the end of the continuous sound output period Ts, and charging of the charge storage unit 208 can be terminated at an early stage.
- the public address system 2 is a sufficient speaker by using the charge storage unit 208 while suppressing the input power by limiting the power.
- the output is secured.
- the period during which sufficient speaker output can be secured depends on the capacity of the charge storage unit 208 and is limited to only the beginning portion during the continuous sound output period Ts. Therefore, when the terminal voltage of the charge storage unit 208 drops to the voltage determination threshold value Vth, the amplitude is limited to reduce the speaker output, and charging of the charge storage unit 208 is started.
- FIG. 9 is a timing chart showing another example of the operation of the public address system 2 of FIG. 7, and is a state when an audio signal for outputting a sound slightly longer than that of FIG. 8 is given. It is shown.
- the operation up to time t24 is the same as the operation up to time t14 in FIG. In FIG. 9, since the audio signal outputs a sound slightly longer than that in FIG. 8, the amplitude limitation is released at time t25, but the speaker output decreases and the power determination threshold Pth is reached at a subsequent time. It is t26.
- the speaker output exceeds the power determination threshold Pth, so that the power limitation is started again (time t25). ). That is, the output voltage of the voltage conversion unit 204 vibrates, and the input power is suppressed so as not to exceed the power determination threshold value Pth.
- the power supply to the power amplifier 202 is mainly performed by the discharge of the charge storage unit 208, and the terminal voltage of the charge storage unit 208 gradually decreases.
- the speaker output drops and falls below the power determination threshold value Pth, so that charging of the charge storage unit 208 is started (time t26).
- the terminal voltage of the charge storage unit 208 gradually increases due to charging, and the charging current gradually decreases.
- the input power becomes equal to or less than the power determination threshold value Pth, and the power limitation is released (time t27).
- the charge storage unit 208 is continuously charged thereafter, and charging ends at time t28.
- the second power limit is started, but the continuous sound output period Ts ends immediately after that. Therefore, although the second amplitude limitation is not started, the terminal voltage of the charge storage unit 208 does not drop significantly, so that the high voltage V2 can be returned to the high voltage V2 by charging in a relatively short time without performing the amplitude limitation. can.
- FIG. 10 is a timing chart showing still another example of the operation of the public address system 2 of FIG. 7, when an audio signal for outputting a sound longer than that of FIG. 9 at a loud volume is given. The situation is shown.
- the operation up to time t35 is the same as the operation up to time t25 in FIG. Further, the operation until the time t39 thereafter is a repetition of the operation until the time t35. That is, if the continuous sound output period Ts becomes long, the same operation is periodically repeated. Then, since the continuous sound output period Ts ends at time t40 after the amplitude limitation is released at time t39, the operation at times t39 to t42 is the same as that of t25 to 28 in FIG.
- the loudspeaker 2 conforming to PoE, PoE + and PoE ++ defined in the IEEE802.3 standard has been described, but the device to which the present invention is applicable is not limited to the device conforming to the above standard.
- the device to which the present invention is applicable is not limited to the device conforming to the above standard.
- it can be applied to various public address systems in which the drive power of the power amplifier is supplied from an external power supply device in which the upper limit power supply is determined.
- USB Universal Serial Bus
- the application target of the present invention is not limited to the public address system constituting such a system.
- the present invention can be applied to various public address systems including a power amplifier and amplifying input sound.
- the present invention is a public address system to which electroacoustic converters such as speakers, headphones, and earphones are connected, and amplifies an audio signal to generate a drive signal, and outputs the drive signal to these electroacoustic converters. It can be applied to what is output.
- the present invention can also be applied to a communication device such as a telephone (speakerphone), an intercom, or an intercom having a hands-free communication function.
- Audio processing section 202 Power amplifier 203 Speaker 204 Voltage conversion section 205 Power detection section 205e Current detection section 206 Voltage control section 207 Threshold holding section 208 Charge storage unit 210 Voltage detection unit 211 Amplification limit unit P1 Low power P2 High power Pmax Supply upper limit power Pth Power judgment threshold S1 Voltage control signal Td Voltage limit time Ts Continuous sound output period V1 Low voltage V2 High voltage Va Detection voltage Vth Voltage Judgment threshold i D output current
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Abstract
Description
図1は、本発明の実施の形態1による拡声装置2を含む拡声放送システム100の一構成例を示した図である。拡声放送システム100は、音声データを生成する音源装置1と、音声を再生する拡声装置2と、音源装置1及び拡声装置2間において音声データを中継するスイッチングハブ3とを備える。
実施の形態1では、入力電力の電力制限を行う拡声装置2の例について説明した。これに対し、本実施の形態では、電力制限中にさらに音声信号の振幅制限を行うことにより、電荷蓄積部208の充電を促進する場合の例について説明する。
2 拡声装置
3 スイッチングハブ
4 ケーブル
10 給電装置
100 拡声放送システム
200 インターフェース部
201 音声処理部
202 パワーアンプ
203 スピーカ
204 電圧変換部
205 電力検出部
205e 電流検出部
206 電圧制御部
207 閾値保持部
208 電荷蓄積部
210 電圧検出部
211 振幅制限部
P1 低電力
P2 高電力
Pmax 供給上限電力
Pth 電力判定閾値
S1 電圧制御信号
Td 振幅制限時間
Ts 連続音出力期間
V1 低電圧
V2 高電圧
Va 検出電圧
Vth 電圧判定閾値
iD 出力電流
Claims (7)
- 給電装置から入力される直流電源の電圧変換を行う電圧変換部と、
電圧変換後の直流電源を用いて音声信号を増幅し、電気音響変換器を駆動する駆動信号を生成するパワーアンプと、
前記給電装置からの入力電力を検出する電力検出部と、
前記給電装置の供給上限電力に対応する電力判定閾値を保持する閾値保持部と、
前記入力電力及び前記電力判定閾値に基づいて、前記電圧変換部の出力電圧を制御する電圧制御部と、
前記電圧変換部及び前記パワーアンプの間に接続され、前記電圧変換部の出力電圧の低下時に前記パワーアンプに電源を供給する電荷蓄積部とを備えたことを特徴とする拡声装置。 - 前記電力検出部は、前記電圧変換部の出力電流を検出する電流検出部を備え、前記電圧変換部の出力電圧及び出力電流に基づいて前記入力電力を求めることを特徴とする請求項1に記載の拡声装置。
- 前記供給上限電力は、前記給電装置からの電源供給の開始前に、予め定められたプロトコルに基づいて、前記給電装置との間で行われるネゴシエーションにおいて決定されることを特徴とする請求項1に記載の拡声装置。
- 前記供給装置は、複数の電力クラスを有するIEEE802.3規格に準拠して給電を行うものであり、
IEEE802.3規格に準拠して、前記給電装置からの電源供給の開始前に前記給電装置との間で行われるネゴシエーションを通じて、前記複数の電力クラスからいずれかの電力クラスを決定するPoEインターフェース部を備え、
前記供給上限電力は、前記PoEインターフェース部により決定された電力クラスに対応する、IEEE802.3規格で定められた供給上限電力であることを特徴とする請求項1に記載の拡声装置。 - 前記電圧制御部は、前記入力電力が前記電力判定閾値を超える場合に、前記出力電圧が第1電圧となるように制御し、前記入力電力が前記電力判定閾値以下の場合に、前記出力電圧が第1電圧よりも高い第2電圧となるように制御し、
第1電圧は、前記駆動信号が最大電力である場合に、前記入力電力が前記供給上限電力を超えない値であることを特徴とする請求項1に記載の拡声装置。 - 前記電荷蓄積部の端子電圧及び予め定められた電圧判定閾値の比較結果に基づいて、前記音声信号の振幅制限を行う振幅制限部を備え、
前記電圧判定閾値が、前記第1電圧及び前記第2電圧の間の値であることを特徴とする請求項1に記載の拡声装置。 - 前記振幅制限部は、予め定められた振幅制限期間の経過後に終了することを特徴とする請求項6に記載の拡声装置。
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JP2022532901A JPWO2022003844A1 (ja) | 2020-06-30 | 2020-06-30 | |
CA3184257A CA3184257A1 (en) | 2020-06-30 | 2020-06-30 | Public address device |
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US10122545B2 (en) * | 2014-08-08 | 2018-11-06 | Philips Lighting Holding B.V. | Power forwarding via a powered device |
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