KR102243876B1 - Remote unit in distributed antenna system - Google Patents

Abstract

A remote unit of a distributed antenna system, comprising: a power supply for supplying power for operation of the remote unit; A digital part for digital processing of a relay signal; And an output deactivation control signal for converting a digital output of the relay signal from the digital unit into a disabled state when a reset of the digital unit or a remote control command for driving the power of the remote unit is received. There is provided a remote unit including a control unit for outputting.

Description

Remote unit in distributed antenna system {REMOTE UNIT IN DISTRIBUTED ANTENNA SYSTEM}

The present invention relates to a distributed antenna system, and more particularly, to a method for stabilizing the operation of a remote unit when a remote control command such as a digital unit reset command or a power on/off command is received from an upper end. .

When a problem occurs in the remote unit in the DAS (Distributed Antenna System), reset the digital part (for example, a digital board) or/and the power supply unit (PSU). On/off may be necessary.

However, depending on the location where the remote unit is installed in the distributed antenna system, it is often difficult for a worker in the field to directly access the remote unit. Accordingly, there is a need for a function capable of remotely resetting a digital part or/and turning on/off a power supply unit from a remote unit in which a problem has occurred (or a problem is detected) at the upper end of the distributed antenna system.

In the process of performing the reset operation of the digital part of the remote unit or/and the ON/OFF operation of the power unit according to such a remote control command, an unnecessary wave is radiated to the digital output to cause damage to the PAU (Power Amplification Unit) and the system. Can give. Accordingly, there is a need for a technology capable of blocking unwanted waves that may be radiated during the reset operation of the digital part or/and the on/off operation of the power supply unit as described above.

An object of the present invention is to provide a remote unit capable of blocking unwanted waves from being radiated to a digital output when a reset operation of a digital part or an on/off operation of a power supply unit is performed in a remote unit in a distributed antenna system.

According to an aspect of the present invention, as a remote unit (Remote Unit) of a distributed antenna system (Distributed Antenna System),

A power supply for supplying power for the operation of the remote unit; A digital part for digital processing of a relay signal; And an output deactivation control signal for converting a digital output of the relay signal from the digital unit into a disabled state when a reset of the digital unit or a remote control command for driving the power of the remote unit is received. There is provided a remote unit including a control unit for outputting.

In one embodiment, the remote control command may be transmitted from an upper end unit constituting an upper end of the remote unit or a management system (NMS) connected through a network with a distributed antenna system.

In one embodiment, the digital unit comprises a digital signal processing unit that performs digital signal processing on a relay signal, and a digital signal that forms a final end of the digital unit based on a signal transmission path, and converts the digital signal processed into an analog signal. Including a terminal output,

The control unit may control at least one of the digital signal processing unit and the digital end output unit to be switched to a deactivated state through the output deactivation control signal.

In one embodiment, when the remote control command is a digital part reset command,

The control unit controls a reset operation of the digital unit and an initialization process of the digital unit according to a reset to be performed after the digital output is converted to an inactive state, and when the reset operation and the initialization process are completed, the digital output is activated ( enable), the output activation control signal can be output.

In one embodiment, when the remote control command is a power on/off command,

The controller controls the power on/off operation and the initialization process of the digital unit to be performed after the digital output is converted to an inactive state, and when the on/off operation and the initialization process are completed, the digital output is activated ( enable), the output activation control signal can be output.

In one embodiment, when the remote control command is received,

The control unit may control an operation of a power amplification unit (PAU) disposed at a rear end of the digital unit along a signal transmission path to be converted into an inactive state.

In one embodiment, when the remote control command is a digital part reset command,

The control unit controls a reset operation of the digital unit and an initialization process of the digital unit according to a reset after the operation of the digital output and the PAU is converted to an inactive state, and when the reset operation and the initialization process are completed, the A digital output and an output activation control signal for converting the PAU operation to an enable state may be output.

In one embodiment, when the remote control command is a power on/off command,

The control unit controls the power on/off operation and the initialization process of the digital unit to be performed after the operation of the digital output and the PAU is switched to an inactive state, and when the on/off operation and the initialization process are completed, the A digital output and an output activation control signal for converting the PAU operation to an enable state may be output.

According to the remote unit in the distributed antenna system according to the embodiment of the present invention, damage to the PAU and the system is prevented by blocking unwanted waves from being radiated to the digital output when the reset operation of the digital part or/and the on/off operation of the power supply is performed. There is an effect that can prevent (demage).

1 is a diagram showing an example of a topology of a distributed antenna system to which the present invention can be applied.
2 is a block diagram of an embodiment of a remote unit in a distributed antenna system to which the present invention can be applied.
3 is a flow chart showing a method of cutting off unwanted wave output in a remote unit according to a first embodiment of the present invention.
4 and 5 are reference diagrams for explaining a method of blocking unwanted wave output according to the first embodiment.
6 is a flow chart showing a method of cutting off unwanted wave output in a remote unit according to a second embodiment of the present invention.

Since the present invention can apply various transformations and have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing the present invention, when it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, numbers (eg, first, second, etc.) used in the description of the present specification are merely identification symbols for distinguishing one component from other components.

In addition, in the present specification, when one component is referred to as "connected" or "connected" to another component, the one component may be directly connected or directly connected to the other component, but specially It should be understood that as long as there is no opposite substrate, it may be connected or may be connected via another component in the middle.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing an example of a topology of a distributed antenna system to which the present invention can be applied.

Referring to FIG. 1, a distributed antenna system (DAS) includes a base station interface unit (BIU) 10 and a main unit (MU) 20 constituting a headend node of a distributed antenna system, and an expansion node. It includes a (Extention Node) HUB (Hub Unit) 30, and a plurality of RU (Remote Unit) 40 disposed at each remote service location. Such a distributed antenna system may be implemented as an analog DAS or digital DAS, and in some cases, may be implemented as a hybrid type thereof (ie, some nodes perform analog processing and others perform digital processing).

However, FIG. 1 shows an example of a topology of a distributed antenna system, and the distributed antenna system includes an installation area and application fields (eg, In-Building, Subway, Hospital, Various topology modifications are possible in consideration of the specificity of the stadium (Stadium, etc.). To this effect, the number of BIUs 10, MUs 20, HUBs 30, and RUs 40, and a connection relationship between upper and lower ends thereof may be different from that of FIG. 1. In addition, in the distributed antenna system, the HUB 20 is used when the number of branches to be branched from the MU 20 to a star structure is limited compared to the number of RUs 40 required to be installed. Accordingly, the HUB 20 may be omitted when the number of RUs 40 required for installation can be sufficiently covered by only a single MU 20 or when a plurality of MUs 20 are installed.

Hereinafter, each node in the distributed antenna system applicable to the present invention and its functions will be sequentially described, centering on the topology of FIG. 1.

A base station interface unit (BIU) 10 serves as an interface between a base station transceiver system (BTS) such as a base station and the MU 20 in a distributed antenna system. 1 illustrates a case in which a plurality of BTSs are connected to a single BIU 10, the BIU 10 may be separately provided for each operator, for each frequency band, and for each sector.

In general, since the RF signal (Radio Frequency signal) transmitted from the BTS is a high power signal, in general, the BIU 10 converts such a high power RF signal into a signal of suitable power to be processed by the MU 20. It converts and transmits it to the MU 20. In addition, depending on the implementation method, the BIU 10 receives a signal of a mobile communication service for each frequency band (or for each operator, for each sector) as shown in FIG. 1 and combines it, and then the MU 20 It can also perform the function of passing to ).

If the BIU 10 lowers the high power signal of the BTS to low power and then combines each mobile communication service signal and delivers it to the MU 20, the MU 20 combines and transmits the mobile communication service signal (hereinafter, referred to as (Referred to as relay signal) is distributed by branch. At this time, when the distributed antenna system is implemented as a digital DAS, the BIU 10 converts the high-power RF signal of the BTS into a low-power RF signal, and the low-power RF signal as an IF signal (Intermediate Frequency signal). After conversion, digital signal processing is performed, and it can be divided into a unit that combines them. Unlike the above, if the BIU 10 performs only the function of lowering the high power signal of the BTS to low power, the MU 20 combines each transmitted relay signal and distributes it for each branch.

As described above, the combined relay signal distributed from the MU 20 is transmitted through the HUB 20 or directly to the RU 40 for each branch, and each RU 40 transmits the combined relay signal to the frequency band. Separate each and perform signal processing (analog signal processing in the case of analog DAS, and digital signal processing in the case of digital DAS). Accordingly, each RU 40 transmits a relay signal to a user terminal within its service coverage through a service antenna. In this case, a detailed functional configuration of the RU 40 will be described later in detail with reference to FIG. 2.

In the case of FIG. 1, it is shown that the BTS and the BIU 10 and the BIU 10 and the MU 20 are connected by an RF cable, and all from the MU 20 to the lower end thereof are connected by an optical cable. The signal transport medium between each node is also capable of various other modifications. For example, the BIU 10 and the MU 20 may be connected through an RF cable, but may be connected through an optical cable or a digital interface. As another example, the MU (20) and the HUB (30) and the RU (40) directly connected to the MU (20) is connected by an optical cable, and the cascade-connected RU (40) is connected to each other by an RF cable, a twisted cable, and a UTP. It can be implemented in a way that is connected through a cable or the like. As another example, as another example, the RU 40 directly connected to the MU 20 may also be implemented in a manner that is connected through an RF cable, a twist cable, a UTP cable, or the like.

However, hereinafter, it will be described with reference to FIG. 1. Therefore, in the present embodiment, the MU 20, HUB 30, and RU 40 may include an optical transceiver module for electro-optical conversion/photoelectric conversion, and when nodes are connected by a single optical cable, WDM ( Wavelength Division Multiplexing) device may be included. This will be clearly understood through the functional description of the RU 40 in FIG. 2 to be described later.

This distributed antenna system can be connected to an external management device (Network Management Server or System (NMS) of Fig. 1) through a network. Accordingly, the administrator can remotely monitor the status and problems of each node of the distributed antenna system through the NMS. And, you can remotely control the operation of each node.

2 is a block diagram of an embodiment of a remote unit in a distributed antenna system to which the present invention can be applied. Here, the block diagram of FIG. 2 illustrates an implementation form of the RU 40 in the digital DAS in which node-to-node connections are made through an optical cable.

Referring to FIG. 2, the RU 40 includes an optical to electrical converter 50, a serializer (SERDES), based on a downlink signal transmission path (ie, a forward path). /Deserializer (44), Deframer (52), Digital Signal Processing Unit (DSP) (70), Digital/Analog Converter (DAC) (54), Up Converter (56), PAU (Power) Amplification Unit) 58.

Accordingly, in the forward path, the optical relay signal digitally transmitted through the optical cable is converted into an electric signal (serial digital signal) by the optical/electric converter 50, and the serial digital signal is converted to a parallel digital signal by the SERDES 44. It is converted into a signal, and the parallel digital signal is reformatted by the deframer 52 so that the digital signal processing unit 70 can process each frequency band. The digital signal processing unit 70 performs functions such as digital signal processing, digital filtering, gain control, and digital multiplexing for each frequency band of a relay signal. The digital signal processing unit 70 may be implemented as a Field Programmable Gate Array (FPGA). The digital signal passed through the digital signal processing unit 70 is converted into an analog signal through a digital/analog converter 54 constituting the final stage of a digital part based on a signal transmission path. At this time, since the analog signal is an IF signal, the frequency is up-converted to an analog signal of the original RF band through the up converter 56. In this way, the analog signal (ie, RF signal) converted to the original RF band is heavy through the PAU 58 and transmitted through a service antenna (not shown).

Based on the uplink signal transmission path (ie, reverse path), the RU 40 includes a low noise amplifier (LNA) 68, a down converter 66, and an analog/digital converter (ADC). (64), a digital signal processing unit (DSP) 70, a framer (62), SERDES (44), and an electric/optical converter (Electrical to Optical Converter) 60.

Accordingly, in the reverse path, the RF signal (i.e., the terminal signal) received through the service antenna (not shown) from the user terminal (not shown) within the service coverage is low-noise amplified by the LNA 68, which is a down converter ( 66), the converted IF signal is converted into a digital signal by the analog/digital converter 64 and transmitted to the digital signal processing unit 70. The digital signal passed through the digital signal processing unit 70 is formatted into a format suitable for digital transmission through the framer 62, which is converted into a serial digital signal by the SERDES 44, and the electric/optical converter 60 It is converted into an optical digital signal and transmitted to the upper end through an optical cable.

In addition, although not clearly shown in FIG. 2, in a state in which the RUs 40 are cascaded with each other as in the example of FIG. 1, the relay signal transmitted from the upper end is transferred to the adjacent RU of the lower end cascaded Can be done in the following way. For example, when transmitting an optical relay signal digitally transmitted from the upper end to the adjacent RU of the lower end connected to the casecade, the optical relay signal digitally transmitted from the upper end is an optical/electric converter 50 -> SERDES 44- > Deframer 52 -> Framer 62 -> SERDES 44 -> All/optical converter 60 may be transferred to the adjacent RU through the sequence.

In FIG. 2, the SERDES 44 and the digital signal processing unit (DSP) 70 are shown to be shared in the downlink and uplink signal transmission paths, but these may be separately provided for each path. In addition, in FIG. 2, although the photo/electric converter 50 and the electro/optical converter 60 are separately provided, this may be implemented in a single optical transceiver module.

In the above, a topology of a form of a distributed antenna system and a configuration example of an RU have been described with reference to FIGS. 1 and 2. Referring to the above-described distributed antenna system, it is often difficult for workers in the field to directly access depending on the installation location and area of the RU, and accordingly, the RU in which a problem has occurred (or a problem has been detected through a monitoring process) is remotely controlled. It needs to be controlled at. However, when the power on/off of the RU or the digital part reset operation is performed according to the remote control command from the upper level, an unnecessary wave is radiated to the digital output, causing damage to the entire system such as the PAU. Accordingly, in each embodiment of the present invention to be described later, a remote unit capable of blocking the unwanted wave output will be described with reference to FIGS. 3 to 6.

First Example

3 is a flow chart showing a method of cutting off unwanted wave output in a remote unit according to a first embodiment of the present invention, and FIGS. 4 and 5 are reference diagrams for explaining a method of blocking unwanted wave output according to the first embodiment. Hereinafter, with reference to FIGS. 4 and 5 together with the flow chart of FIG. 3, a method of cutting off the unwanted wave output in the remote unit will be described in detail.

Here, FIG. 3 is a flowchart illustrating a case where a reset command for a digital part (refer to 200 in FIGS. 4 and 5) is received by the RU as a remote control command. At this time, the remote reset command of the digital part is transmitted from the upper end of the distributed antenna system (for example, the MU 20, HUB 30 of FIG. 1) or the NMS of FIG. 1 connected to the distributed antenna system through a network. I can. In some cases, the remote reset command may be transmitted from an adjacent RU. This is the same even in the case of the power on/off command of FIG. 6 to be described later.

Referring to steps S110 and S120 of FIG. 3, when a remote reset command instructing to reset the digital part of the RU is received, the output of the digital part of the RU and the PAU of the RU are switched to a disabled state.

In step S120 of FIG. 3, it is exemplified that the digital output of the digital part 200 and the PAU 130 are both switched to the inactive state according to the remote reset command, but the PAU 130 is switched to the inactive state together. Whether to do this may be up to the system designer's option. That is, a method of converting only the output of the digital part to an inactive state, and a method of converting only the PAU to an inactive state may also be selected. However, hereinafter, it will be described based on the flow chart of FIG. 3 (this is the same in FIG. 6).

This will be described with reference to FIG. 4 as follows. FIG. 4 shows only the components involved in implementing the unwanted wave output blocking function according to an embodiment of the present invention, for convenience of illustration and for the concentration of explanation, and this is the same in the case of FIG. 5 to be described later. In addition, in this embodiment, the digital termination processing unit 220 is a digital to analog converter (DAC), the control unit 230 is implemented as a central processing unit (CPU), and the digital signal processing unit 210 is a field programmable gate array (FPGA). ) Is assumed to be implemented. In addition, the digital end output unit defined below refers to a digital configuration unit constituting the digital end end when the signal transmission path in the digital part in the RU is referenced. In addition, hereinafter, the digital output is referred to as a term collectively referring to signal output through a digital component, and whether the output signal itself is an analog signal or a digital signal is irrelevant.

Referring to FIG. 4, a remote reset command of the RU digital part transmitted from an upper end of the distributed antenna system may be transmitted to the controller 230 of the digital part 200. Accordingly, the control unit 230 outputs a digital output related to the relay signal in the digital part 200 and an output deactivation control signal (refer to Disable CS in FIG. 4) for converting the PAU 130 of the RU into an inactive state. Output as (120).

The output control circuit unit 120 may include a circuit configuration capable of controlling the digital output of the digital component in the digital part 200 to a deactivated and activated state. For example, when the output deactivation control signal according to a remote reset command is transmitted, a signal (low or high signal) for deactivating the digital output from the output control circuit unit 120 to each output control terminal of the digital component is forcibly applied. The circuit can be implemented as possible (see Disable 1 and Disable 2 in FIG. 4).

In this case, the digital configuration unit in which the digital output is converted to an inactive state may be at least one of the digital signal processing unit 210 and the digital end output unit 220 shown in FIG. 4. That is, the output control circuit unit 120 may be implemented in a circuit such that the digital output is converted to an inactive state in all of the above digital components, or a circuit may be implemented such that any one of the digital outputs is converted into an inactive state. That is, based on the signal transmission path, the designer's decision to switch the digital output of any digital component to the inactive state is to the extent that the purpose of preventing unwanted waves from being transmitted to the final output terminal such as the PAU 130 at the rear stage is achieved. May be optional. However, since the digital configuration unit that directly transmits the unwanted wave to the final output terminal such as the PAU 130 is the digital terminal output unit 220 in FIG. 4, the digital output of the digital terminal output unit 220 is converted to an inactive state. The way to do it may be considered (preferred) first. However, in the present embodiment, it is assumed that, when a remote resend command of a digital part is performed, the digital outputs of the digital signal processing unit 210 and the digital end output unit 220 are all converted to an inactive state.

In addition, the output control circuit unit 120 may also include a circuit configuration capable of controlling the PAU 130 of the RU in a deactivated and activated state. For example, the output control circuit unit 120 includes an operation on/off terminal of the PAU 130 or a circuit configuration connected to the output control terminal, and when the output deactivation control signal is transmitted from the control unit 230, the above operation is turned on. A circuit may be implemented such that a signal (low or high signal) for deactivating the operation or output of the PAU 130 is forcibly applied to the /off terminal or the output control terminal (see Disable 3 in FIG. 4).

According to step S120 of FIG. 3, when the digital output of the digital part 200 and the PAU 130 are converted to the inactive state, the controller 230 performs a reset operation of the digital part 200 and the digital part 200 in step S130. Control so that the initialization process of is performed.

Accordingly, when the output deactivation control signal is transmitted from the control unit 230, the output control circuit unit 120 allows the digital output of the digital part 200 and the PAU 130, which were previously converted to the deactivated state, to be converted back to the activated state. Outputs an output activation control signal (see Enable CS in FIG. 5). According to the output activation control signal, the output control circuit unit 120 may transmit a digital output of the digital part 200 and a signal for activating the PAU 130 to each digital component unit and the PAU as shown in FIG. 5. (See Enable 1, Enable 2, and Enable 3 in Fig. 5).

As described above, in the first embodiment of the present invention, when the remote reset command of the digital part of the RU is received, before performing the reset operation of the digital part, the output of the digital part or/and the PAU are first set to an inactive state. By switching, an unnecessary wave is generated as a digital output of a digital part in the process of performing the reset operation and initialization, thereby preventing a problem of damaging the PAU of the rear stage or the entire system.

Second Example

6 is a flow chart showing a method of cutting off unwanted wave output in a remote unit according to a second embodiment of the present invention. Hereinafter, in the description of the second embodiment with reference to FIG. 6, detailed descriptions thereof will be omitted for overlapping contents as in the first embodiment described above.

The second embodiment of the present invention provides a procedure when an on/off command for RU power (that is, an on/off command for the power supply unit 110 in FIGS. 4 and 5 of the previous example) is received from an upper end. Show. Here, the power on/off command may be a power reset command that is immediately turned on after the power is turned off, but may also be a remote command instructing only the power-off operation or the power-on operation. If the remote command instructs only the power-off operation, only the processes from FIG. 6 to step S230 may be performed. In addition, in the case of the remote command indicating only the power-on operation, and the case of the power reset command described above, all the steps of FIG. 6 will be performed. Hereinafter, the flowchart of FIG. 6 will be described.

As in step S210 of FIG. 6, when a remote command for turning on/off the RU power is received, the digital output and PAU are switched to the inactive state as in the first embodiment (step S220 of FIG. 6). The digital output and PAU deactivation conversion method in step S220 may be performed by the same method as in step S120 of FIG. 3.

After switching to the digital output and PAU inactive state in step S220, a power on/off operation according to a remote command is performed in step S230. When the power on/off operation is completed, the operation of the digital part 200 of the RU is initialized according to step S240. Step S240 may be performed in the same manner as in the related description in step S130 of FIG. 3.

When the initialization of the digital part 200 is completed through the above process, the digital output and PAU previously converted to the inactive state through step S250 are converted back to the active state. Step S250 may also be performed in the same manner as in step S140 of FIG. 3.

Even in the second embodiment of the present invention as described above, when a remote command for power on/off of the RU is received, before performing the power on/off operation, the output of the digital part or/and the PAU are first disabled. By converting to, it is possible to prevent a problem in which an unnecessary wave is generated as a digital output of the digital part in the process of performing the initialization of the digital part afterwards, causing damage to the PAU at the rear stage or the entire system.

Although the above has been described with reference to the embodiments of the present invention, those of ordinary skill in the relevant technical field variously modify the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. And it will be easily understood that it can be changed.

110: power supply
120: output control circuit part
130: PAU
200: digital part
210: digital signal processing unit
220: digital termination processing unit
230: control unit

Claims (8)

As a remote unit of a distributed antenna system,
A power supply for supplying power for the operation of the remote unit;
A digital part for digital processing of a relay signal; And
When a reset of the digital unit or a remote control command related to power driving of the remote unit is received, an output deactivation control signal for converting the digital output of the relay signal from the digital unit into a disabled state is provided. A control unit that outputs;
Including,
The remote control command is transmitted from an upper end unit constituting the upper end of the remote unit or a management system (NMS: Network Management System) connected through a network with a distributed antenna system,
The control unit controls an operation corresponding to the remote control command to be performed after the digital output is switched to an inactive state, and when the operation corresponding to the remote control command is completed, the digital output is turned into an enabled state. A remote unit that outputs an output activation control signal to be switched.
delete The method of claim 1,
The digital unit includes a digital signal processing unit that performs digital signal processing on a relay signal, and a digital terminal output unit that constitutes a final end of the digital unit based on a signal transmission path and converts the processed digital signal into an analog signal. ,
The control unit controls the output of at least one of the digital signal processing unit and the digital end output unit to be switched to a deactivated state through the output deactivation control signal.
The method of claim 1,
When the remote control command is a digital part reset command,
The control unit controls a reset operation of the digital unit and an initialization process of the digital unit according to a reset to be performed after the digital output is converted to an inactive state, and when the reset operation and the initialization process are completed, the digital output is activated ( enable), a remote unit that outputs an output activation control signal that switches to the state.
The method of claim 1,
When the remote control command is a power on/off command,
The controller controls a power on/off operation and an initialization process of the digital unit to be performed after the digital output is converted to an inactive state, and when the power on/off operation and the initialization process are completed, the digital output is activated ( enable), a remote unit that outputs an output activation control signal that switches to the state.
The method of claim 1,
When the remote control command is received,
The control unit controls the operation of a power amplification unit (PAU) disposed at a rear end of the digital unit along a signal transmission path to be switched to an inactive state.
The method of claim 6,
When the remote control command is a digital part reset command,
The control unit controls a reset operation of the digital unit and an initialization process of the digital unit according to a reset after the operation of the digital output and the PAU is converted to an inactive state, and when the reset operation and the initialization process are completed, the digital unit The remote unit for outputting an output and an output activation control signal for converting the PAU operation to an enable state.
The method of claim 6,
When the remote control command is a power on/off command,
The control unit controls a power on/off operation and an initialization process of the digital unit to be performed after the operation of the digital output and the PAU is switched to an inactive state, and when the on/off operation and the initialization process are completed, the digital output And outputting an output activation control signal for converting the PAU operation to an enabled state.

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