JP2004173138A - Synchronous system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronous system in which a plurality of devices to be driven which need a timing signal for synchronization of a long period use commercial power to synchronize each other and operate. <P>SOLUTION: In this synchronous system, a power supply device 2 outputs to a radio base station device 3 power supply power subjected to omission processing about one cycle of commercial power waveform inputted through a power supply plug 1 by every predetermined commercial power period. The radio base station device 3 generates a frame timing signal on the basis of a part subjected to omission processing of output power of the power supply device 2. This realizes the synchronous system in which the plurality of devices to be driven which need the timing signal for synchronization of a long period use commercial power to synchronize each other and operate with the same power source. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a synchronization system, and more particularly to a synchronization system that synchronizes and operates using commercial power.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a pedestrian ITS (Intelligent Transport System: Intelligent Transportation System) that provides detailed digital map data information and provides a route guidance service considering barrier-free access to a destination for the purpose of pedestrian navigation. Is being developed.
[0003]
In the pedestrian ITS, a service as a highly accurate position locating system is required. In a position locating system using radio waves, it is necessary to synchronize a plurality of wireless base stations. When a pedestrian terminal moves from the service zone of one wireless base station to the service zone of another wireless base station, if the synchronization between the wireless base stations before and after the movement is not established, the communication condition becomes poor due to interference, and Communication failures such as deterioration of orientation accuracy occur. As a method of synchronizing the wireless base stations, a method of transmitting a timing signal over a wired line, a method of transmitting a timing signal over a wireless line, a method of receiving a standard radio wave or a GPS (Global Positioning System) signal, and transmitting the timing signal An extraction method, a method of generating a timing signal using the frequency of commercial power, and the like can be considered.
[0004]
In the case of a CDMA (Code Division Multiple Access) system using GPS or pseudoride (a system in which a device that generates a signal similar to GPS is placed on the ground), a high-precision reference clock is built into the system. There is a need to. Further, the CDMA system has a near-far problem that the receiving terminal does not operate properly if there is a level difference between signals received from a plurality of wireless base stations.
[0005]
The method of generating the timing signal using the frequency of the commercial power is very convenient because the commercial power is supplied to each wireless base station apparatus in common. Further, since it is not necessary to supply the synchronization signal through a separate line, the cost and size of the entire system can be reduced. There is a monitor system that is not a pedestrian ITS but synchronizes a plurality of television cameras by supplying a timing signal synchronized with commercial power to a plurality of television cameras together with power supply power (for example, see Patent Document 1).
[0006]
[Patent Document 1]
JP-A-7-123293
[Problems to be solved by the invention]
As described above, the method of generating the timing signal using the frequency of the commercial power is very convenient, but since the frequency of the commercial power in Japan is 50 Hz or 60 Hz, TDMA (Time Division Multiple Access) is used. When applied to the pedestrian ITS using the connection) method, the timing interval (frame length) is limited. That is, when the rising zero cross point of the commercial power waveform is extracted, the frame length becomes 20 ms or 16.7 ms. In practical use, it is necessary to consider that the polarity changes (the phase shifts by 180 degrees) when the insertion direction of the power plug changes, and when the rising and falling zero cross points of the commercial power waveform are extracted, the frame length is reduced to half of that. 10 ms or 8.3 ms.
[0008]
Therefore, the method of generating the timing signal using the frequency of the commercial power is used in a communication system having a long frame period (a period longer than 10 ms) such as a pedestrian ITS using the TDMA method. Driven device) could not be synchronized.
[0009]
Therefore, a main object of the present invention is to provide a synchronization system in which a plurality of driven devices requiring a long-period synchronization timing signal can synchronize and operate using commercial power. is there.
[0010]
[Means for Solving the Problems]
A synchronous system according to the present invention is a synchronous system that synchronizes and operates using commercial power, and outputs power from a part of a commercial power waveform that has been truncated every predetermined commercial power cycle. The power supply apparatus includes a plurality of driven devices, each driven by the output power of the power supply device, and operating in synchronization with the portion of the output power of the power supply device that has been subjected to the loss processing.
[0011]
Preferably, the power supply device counts the number of zero cross points extracted by the point extracting means for extracting rising and falling zero cross points of the commercial power waveform, and counts the number of zero cross points extracted by the point extracting means. A counter means for outputting a control signal for one cycle period, and an input terminal for receiving commercial power, an output terminal connected to a plurality of driven devices, and a non-conductive state during a period when the control signal is output from the counter means. Switch means.
[0012]
Preferably, the plurality of driven devices each convert a waveform of an output power of the power supply device into a pulse signal sequence and output the same, and detect a waveform missing portion based on the pulse signal sequence, and Loss detecting means for generating a timing signal for synchronizing the plurality of driven devices based on the result.
[0013]
Preferably, the plurality of driven devices are a plurality of wireless base station devices for performing wireless communication with a plurality of receiving terminals.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing the overall configuration of a pedestrian ITS of the TDMA system according to an embodiment of the present invention. In FIG. 1, the pedestrian ITS includes a power plug 1, a power supply device 2, radio base station devices (transmitters) 3-1 to 3-n, antennas 4-1 to 4-n, a pedestrian Terminals (receivers) 5-1, 5-2,...
[0015]
The power supply device 2 has an input terminal receiving commercial power via the power plug 1 and an output terminal connected to the plurality of wireless base station devices 3-1 to 3-n. Each of the wireless base station devices 3-1 to 3-n receives power from the power supply device 2, and each of the pedestrian terminals 5-1, 5-2,... To Pn are radiated via the antennas 4-1 to 4-n according to the TDMA method. Each of the pedestrian terminals 5-1, 5-2,... Transmits a reference radio wave radiated from a wireless base station device having a service zone including its own terminal position among the wireless base station devices 3-1 to 3-n. Receive and localize your terminal.
[0016]
When each of the wireless base station devices 3-1 to 3-n broadcasts (reports) to a pedestrian terminal located in the service zone of the own base station device, and the pedestrian terminal moves between service zones during communication. However, they are arranged at predetermined intervals so that notification can be performed. However, in the case of the TDMA system, since a plurality of wireless base station devices use one wireless channel in a time-division manner, each of the wireless base station devices 3-1 to 3-n must avoid overlapping of the timing of radiating the reference radio wave. Must be synchronized with each other.
[0017]
FIG. 2 is a diagram illustrating radiation timing for each frame of the wireless base station devices 3-1 to 3-n illustrated in FIG. In FIG. 2, one wireless channel is shared by n wireless base station devices 3-1 to 3-n. Each of the reference radio waves P1 to Pn radiated from the radio base station devices 3-1 to 3-n is set so as to radiate sequentially for each time slot Ts so that the radiation timings do not overlap. Here, the frame length is a length obtained by multiplying the time slot Ts by n.
[0018]
FIG. 3 is a block diagram showing a main part of the power supply device 2 and the wireless base station device 3 shown in FIG. In FIG. 3, a power plug 1 is connected to a wireless base station device 3 via a power supply device 2, and an antenna 4 is connected to the wireless base station device 3. The waveform loss processing circuit 6 included in the power supply device 2 includes a point extraction circuit 7, a counter circuit 8, and a switch circuit 9. The timing generation circuit 10 included in the wireless base station device 3 includes a waveform conversion circuit 11 And a missing detection circuit 12.
[0019]
In the waveform loss processing circuit 6, the point extraction circuit 7 extracts the rising and falling zero cross points of the commercial power waveform input via the power plug 1.
[0020]
The counter circuit 8 counts the number of zero cross points extracted by the point extraction circuit 7 and outputs a control signal every time the number reaches the set number of zero cross points. This control signal is output for one cycle (a cycle from the rising zero cross point to the next rising zero cross point or a cycle from the falling zero cross point to the next falling zero cross point).
[0021]
The switch circuit 9 receives the commercial power through the power plug 1 and becomes non-conductive during a period in which the control signal is being input from the counter circuit 8, thereby outputting the power of the power which is obtained by partially removing the commercial power waveform. I do.
[0022]
FIG. 4 is a diagram showing an output power waveform of the power supply device 2 shown in FIG. In FIG. 4, one cycle of the output power waveform is deleted for every six cycles. With such a waveform loss, no problem occurs in power supply to the wireless base station device 3. Here, the description has been made on the assumption that the cycle of the waveform drop processing is every six cycles, but the same applies to the case where the cycle of the waveform drop processing is every integer multiple of cycles.
[0023]
Returning to FIG. 3, in the timing generation circuit 10, the waveform conversion circuit 11 converts a sine wave waveform of the power supply power input from the power supply device 2 into a pulse signal train and outputs it. The loss detection circuit 12 detects a waveform loss portion based on the pulse signal train input from the waveform conversion circuit 11, and generates a frame timing signal for synchronizing frames of the wireless base station device 3 based on the detection result. I do. The wireless base station device 3 radiates, via the antenna 4, a reference radio wave synchronized by the generated frame timing signal.
[0024]
In this embodiment, a part of the commercial power waveform is subjected to the missing process at every arbitrary integral multiple of the commercial power cycle, and a frame timing signal is generated based on the missing part. Therefore, within the same power supply range, a plurality of wireless base station devices 3-1 to 3-n can be synchronized in a communication system in which the frame cycle is an arbitrary integral multiple of the commercial power cycle. Since the power supply power is used in common for each of the wireless base station devices 3-1 to 3-n, the method using commercial power is very convenient. In addition, since an expensive synchronization signal generator is not required, and there is no need to supply a synchronization signal through a separate line, the cost and size of the entire system can be reduced.
[0025]
The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0026]
【The invention's effect】
As described above, the synchronization system according to the present invention is a synchronization system that synchronizes and operates using commercial power, in which a part of the commercial power waveform is deleted for each predetermined commercial power cycle. The power supply includes a power supply that outputs power, and a plurality of driven devices that are each driven by the output power of the power supply and operate in synchronization with a portion of the power supply that has been subjected to the output power loss processing. Therefore, according to this embodiment, a plurality of driven devices that require a long-period synchronization timing signal can synchronize and operate using commercial power within the same power supply range. A simple synchronous system can be realized. Since power supply power is commonly used for each driven device, the method using commercial power is very convenient. In addition, since an expensive synchronization signal generator is not required, and there is no need to supply a synchronization signal through a separate line, the cost and size of the entire system can be reduced.
[0027]
Preferably, the power supply device counts the number of zero cross points extracted by the point extracting means for extracting the rising and falling zero cross points of the commercial power waveform, and counts the number of zero cross points each time the predetermined number of zero cross points is reached. A counter means for outputting a control signal for one cycle period, and an input terminal for receiving commercial power, an output terminal connected to a plurality of driven devices, and a non-conductive state during a period when the control signal is output from the counter means. Switch means. In this case, it is possible to supply a plurality of driven devices with power supply power in which the waveform has been subjected to one cycle period missing processing at every arbitrary multiple of the commercial power cycle.
[0028]
Preferably, the plurality of driven devices each convert a waveform of an output power of the power supply device into a pulse signal sequence and output the same, and detect a waveform missing portion based on the pulse signal sequence, and Loss detecting means for generating a timing signal for synchronizing the plurality of driven devices based on the result. In this case, a plurality of driven devices can be synchronized by a timing signal having a cycle that is an arbitrary integral multiple of the commercial power cycle.
[0029]
Preferably, the plurality of driven devices are a plurality of wireless base station devices for performing wireless communication with a plurality of receiving terminals. In this case, a plurality of wireless base station apparatuses can be synchronized in a communication system in which the frame cycle is an arbitrary integral multiple of the commercial power cycle.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of a TDMA pedestrian ITS according to an embodiment of the present invention.
FIG. 2 is a diagram showing radiation timing for each frame of the wireless base station devices 3-1 to 3-n shown in FIG.
FIG. 3 is a block diagram showing a main part of the power supply device 2 and the wireless base station device 3 shown in FIG.
FIG. 4 is a diagram showing an output power waveform of the power supply device 2 shown in FIG.
[Explanation of symbols]
1 power plug, 2 power supply device, 3,3-1,3-2,... 3-n wireless base station device, 4,4-1,4-2,. 2 Pedestrian terminal, 6 waveform loss processing circuit, 7 point extraction circuit, 8 counter circuit, 9 switch circuit, 10 timing generation circuit, 11 waveform conversion circuit, 12 loss detection circuit, P1, P2,.

Claims (4)

A synchronous system that synchronizes and operates using commercial power,
A power supply device that outputs a power supply obtained by removing a part of a commercial power waveform for each predetermined commercial power cycle, and each of the power supply devices is driven by an output power of the power supply device, and outputs power of the power supply device. A synchronization system including a plurality of driven devices that operate in synchronization with a portion subjected to the missing processing. The power supply device,
Point extraction means for extracting rising and falling zero cross points of the commercial power waveform,
The counter means for counting the number of zero cross points extracted by the point extracting means and outputting a control signal for one cycle period every time the number of zero cross points becomes a predetermined number of zero cross points, and an input terminal thereof receives the commercial power, 2. The synchronization system according to claim 1, further comprising switch means connected to an output terminal of said plurality of driven devices and becoming non-conductive while said control signal is being output from said counter means. The plurality of driven devices each convert an output power waveform of the power supply device into a pulse signal train and output the same, and a waveform missing portion is detected based on the pulse signal train, and a detection result is output. 3. The synchronization system according to claim 1, further comprising a missing detection unit that generates a timing signal for synchronizing the plurality of driven devices based on the missing signal. 4. 4. The synchronization system according to claim 1, wherein the plurality of driven devices are a plurality of wireless base station devices for performing wireless communication with a plurality of receiving terminals. 5.

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