JP6467993B2 - Synchronous circuit and master device - Google Patents

Description

  The present invention relates to a synchronization circuit and a master device, and more specifically, to a synchronization circuit that adjusts the transmission timing of a transmission frame to be transmitted to a connected slave device, and a master device including the circuit.

  When a private branch exchange (PBX) is installed to use multiple telephones in various facilities, the time division control transmission (Time Compression Multiplexing: TCM) is generally used between the PBX and the telephone terminal. Connected in a manner. The time division control transmission method is a method adopted for wired or wireless digital communication of PBX or Integrated Services Digital Network (ISDN). These digital communication systems have a master device and a slave device, and the slave device synchronizes with the operation timing of the master device.

  In communication by ISDN or PBX, an exchange or PBX serves as a master device, and a terminating device (Digital Service Unit: DSU) or a telephone terminal connected to the exchange or PBX serves as a slave device. The master device has ports for inputting / outputting data to / from the slave device as many as the number of slave devices connectable to the master device. Normally, one slave device is connected to each port. The master device sends transmission data to the slave device called a frame to each port at the same timing.

  The frame transmitted from the master device is composed of data shorter than half of the transmission cycle. The remaining time in the transmission cycle is allocated to reception from the slave device. Timing information (clock) required in the communication system is embedded in the frame.

  The slave device that has received the frames sent from the master device at the same time extracts a necessary clock and synchronizes with the clock. Therefore, any of the plurality of slave devices connected to one master device can be synchronized with the master device.

  Each telephone terminal connected to the PBX is configured as a base unit of a cordless telephone, and a cordless telephone unit corresponding to each base unit using a digital cordless telephone wireless communication system called the DECT (Digital Enhanced Cordless Telecommunications) system. Can be connected to the machine. Here, in order to realize a plurality of communications in the same area using the DECT method, it is necessary to match the timing for transmitting one frame at a cycle of 10 msec. When a telephone terminal is used cordlessly, the private branch exchange embeds 10msec timing, that is, wireless synchronization timing, necessary for execution of wireless communication using the DECT method, and is connected to each port of the private branch exchange via a wired cable. Distribute frames to each phone terminal that has

JP 2009-182659 A

  However, in the conventional cordless telephone system of the DECT system constructed by the PBX system, including the system using the circuit described in Patent Document 1, each slave device is connected to the private branch exchange with a different cable length. Problems arise when there is a delay difference. More specifically, even if the slave devices are synchronized, the wireless synchronization timing does not match due to a delay difference. Generally, electronic information is delayed by 4.5 nsec to 5.5 nsec per meter. That is, a delay difference of 45 to 55 nsec occurs at a difference of 10 meters, and a delay difference of 450 nsec to 550 nsec occurs at a difference of 100 meters. Therefore, if the cable length connecting the private branch exchange and each telephone terminal is different, there will be a delay difference in the timing of the frame sent from the PBX, and depending on the difference in each cable length, the radio synchronization timing will be the DECT frame. The accuracy required for synchronization (a delay difference of several μsec or less (eg, ± 50 μsec) at the timing of 10 msec frame period) could not be satisfied.

  In view of such a problem, the present invention provides a synchronization circuit and a master device that match the synchronization timing of each slave device even when different delay differences occur in communication between the master device and each slave device. For the purpose.

  In order to solve the above-described problems, the present invention provides a synchronization circuit that adjusts the transmission timing of a transmission frame to be transmitted to a slave device when performing frame communication with a connectable slave device. A counter that measures the interval from the generation timing of the transmission frame to the reception timing of the reception frame transmitted from the slave device in response to reception of the transmission frame as a delay amount, and the transmission timing of the transmission frame based on the delay amount And a delay adjustment circuit for delaying.

  The present invention also provides a master device including a synchronization circuit for adjusting a transmission timing of a transmission frame to be transmitted to a slave device when performing frame communication with a connectable slave device. For each transmission, a counter for measuring the interval from the generation timing of the transmission frame to the reception timing of the reception frame transmitted from the slave device in response to reception of the transmission frame as a delay amount, and the transmission timing of the transmission frame as a delay amount And a delay adjustment circuit for delaying based on the delay time.

  The present invention also provides a computer-readable synchronization program that causes a computer to function as a master device that adjusts the transmission timing of a transmission frame transmitted to a slave device when performing frame communication with a connectable slave device. The program measures, for each transmission of the transmission frame, a counter that measures, as a delay amount, an interval from the generation timing of the transmission frame to the reception timing of the reception frame transmitted from the slave device in response to reception of the transmission frame; and It functions as a delay adjusting means for delaying the transmission timing of the transmission frame based on the delay amount.

  According to the present invention, even when different delay differences occur in communication between the master device and each slave device, the synchronization timing of each slave device can be matched.

It is a circuit block diagram which shows the schematic structure of the Example of the synchronous circuit which concerns on this invention. FIG. 2 is a schematic diagram illustrating a private branch exchange system constructed using a private branch exchange including an embodiment of the synchronization circuit according to FIG. 1. It is a figure which shows the time chart regarding the frame timing of the slave apparatus from which transmission distance differs in a private branch exchange system. It is a figure which shows the time chart which contrasted before and after delay adjustment is performed by the synchronous circuit of FIG. It is a circuit block diagram which shows the schematic structural example of the telephone terminal connected with another Example of the synchronous circuit which concerns on this invention. It is a circuit block diagram which shows the schematic structure of another Example of the synchronous circuit which concerns on this invention. It is the schematic which shows the structure which operates a computer as a private branch exchange including the Example of the synchronous circuit which concerns on this invention.

  Next, embodiments of a synchronization circuit according to the present invention will be described in detail with reference to the accompanying drawings. The synchronization circuit 10 according to the embodiment of the present invention shown in FIG. 1 is mounted in a private branch exchange (PBX) that serves as a master device in a DECT PBX digital communication network, and serves as a slave device. This circuit adjusts the synchronization timing transmitted to each telephone terminal. Note that the configuration shown in this figure is limited to only components that are highly related to the synchronization of the radio synchronization timing.

  First, in order to clarify the overall image of the private branch exchange system in which the synchronization circuit 10 shown in FIG. 1 is used, the configuration of the private branch exchange system will be described with reference to FIG. A private branch exchange (PBX) system 12 includes a private branch exchange (PBX) 14 that functions as a master device and a synchronization circuit 10 and a plurality of telephone terminals 16 that serve as slave devices. The number of synchronization circuits 10 mounted in the private branch exchange 14 is the same as the number of telephone terminals 16 in the system 12. The private branch exchange 14 has the same number of ports 18 as the telephone terminals 16 and inputs / outputs data to / from the telephone terminals 16 via the ports 18. In the figure showing the present embodiment, three telephone terminals installed in the system 12 are represented by reference numerals 16a to 16c, and the number of synchronization circuits 10 and ports 18 installed is three according to the number of telephone terminals 18. It is said.

  Each of the synchronization circuits 10 is connected to one corresponding port 18. The respective ports 18a to 18c are connected to the corresponding telephone terminals 16a to 16c via the cables 20a to 20c. With this configuration, the synchronization circuit 10 can transmit a frame including a signal for adjusting the wireless synchronization timing to the corresponding telephone terminal 16. Further, the synchronization circuit 10 can receive a frame transmitted from the telephone terminal 16, and can further adjust the synchronization timing based on the received frame.

  In the present embodiment, the lengths of the cables 20a to 20c are different from each other. However, the time from when each telephone terminal 16a to 16c receives a frame from the private branch exchange 14 until the frame is returned (represented as T1 in FIG. 3 to be described later) and each telephone terminal 16a to 16c from the private branch exchange 14 It is assumed that the delay time (represented as T2 in FIG. 3 described later) from the reception of a frame to the generation of a synchronization signal necessary for DECT wireless communication is the same value for all telephone terminals 16.

  The telephone terminal 16 is a base unit of a cordless telephone that does not require a wired connection with a handset used by a user for a call by a curl cord or the like. Each of the telephone terminals 16a to 16c is connected to a corresponding cordless telephone cordless handset 22a to 22c by radio 24a to 24c. The wireless connection method is the DECT method, and the private branch exchange 14 embeds 10 msec wireless synchronization timing in the frame and connects to the telephone terminal 16 connected via the wired cable 20 in order to realize multiple communications in the same area. Distribute frames with embedded wireless synchronization timing.

  An area in which a plurality of wireless communications using the DECT method by the telephone terminals 16 and their slaves 22 using the private branch exchange system 12 as a master device is possible is represented as a DECT wireless area 26 in FIG.

  Following the overall description of the system 12 shown in FIG. 2, we will move on to a more detailed description of the configuration of the synchronization circuit 10 shown in FIG. The private branch exchange 14 has the same number of synchronization circuits 10 as the number of telephone terminals 16 to be connected, but the configuration of any of the synchronization circuits 10a to 10c may be essentially the same.

  The synchronization circuit 10 includes a frame generation circuit 32 that generates a transmission frame for transmission to the telephone terminal 16 connected to each circuit 10. The frame generation circuit 32 is mounted on the private branch exchange 14 and is connected to a transmission data generation circuit 36 (see FIG. 2) that generates transmission data 34 to be transmitted to the telephone terminal 16 or a similar circuit. With this configuration, the frame generation circuit 32 generates a transmission frame 38 based on the transmission data 34 received from the transmission data generation circuit 36.

  The synchronization circuit 10 includes a frame reception circuit 42 that receives a reception frame 40 from the telephone terminal 16 via the cable 20 and the port 18 and processes the reception frame 40. The frame reception circuit 42 extracts information necessary for communication from the reception frame 40 and generates reception data 44. Subsequently, the frame reception circuit 42 transmits the generated reception data 44 to a reception data processing circuit 46 (see FIG. 2) that is mounted in the private branch exchange 14 and performs necessary processing of the reception data.

  The frame generation circuit 32 and the frame reception circuit 42 are connected to a reference timing circuit 52 (see FIG. 2) that is mounted on the private branch exchange 14 and generates and transmits a reference timing 50 necessary for DECT wireless communication, or a similar circuit. Yes. In accordance with the received reference timing 50, for example, an operation such as the generation of the transmission frame 38 in the frame generation circuit 32 and the generation of the reception data 44 in the frame reception circuit 42 may be performed.

  The frame generation circuit 32 includes a transmission timing generation circuit 56 that generates a transmission timing signal 54 used for calculation of a delay time generated in communication between the private branch exchange 14 and the telephone terminal 16. In accordance with the reference timing 50 received from the reference timing circuit 52 by the frame generation circuit 32, the transmission timing signal 54 generated by the transmission timing generation circuit 56 is output from the transmission timing generation circuit 56.

  Note that the transmission data generation circuit 36, the reception data processing circuit 46, and the timing circuit 52 mounted on the private branch exchange 14 and connected to the synchronization circuit 10 are only connected to the synchronization circuit 10a for the sake of convenience in FIG. However, these circuits are naturally connected to the synchronization circuits 10b and 10c in the same manner as the synchronization circuit 10a.

  The frame reception circuit 42 includes a reception timing extraction circuit 60 that extracts a reception timing from the reception frame 40 received from the telephone terminal 16 and generates a reception timing signal 58 based on the extracted reception timing. The reception timing signal 58 is also used for calculating a delay time generated in communication between the private branch exchange 14 and the telephone terminal 16.

  The synchronization circuit 10 is connected to the transmission timing generation circuit 56 and the reception timing extraction circuit 60, and has a counter 62 that receives the transmission timing signal 54 and the reception timing signal 58 from these circuits 56, 60. The counter 62 is a circuit or the like device that measures a delay time generated in communication via the cable 20 based on the transmission timing signal 54 and the reception timing signal 58. More specifically, the counter 62 starts counting with reception of the transmission timing signal 54 as a start condition, and stops counting with reception of the reception timing signal 58 as an end condition. The count value 64 at the time of stop is a so-called measured delay amount, and is held in the counter 62. The initial value of the delay amount counted by the counter 62 is set to zero.

  The synchronization circuit 10 includes a delay adjustment circuit 66 connected to a frame generation circuit 32 that outputs a transmission frame 38 and a counter 62 that outputs a count value 64. The delay adjustment circuit 66 generates a transmission frame 68 obtained by delaying the received transmission frame 38 by an amount of time calculated based on the count value 64. Subsequently, the delay adjustment circuit 66 transmits the generated transmission frame 68 to the telephone terminal 16. Referring to FIG. 2, the transmission frame 68 output from the delay adjustment circuit 66 in the synchronization circuit 10 is transmitted to the telephone terminal 16 via the port 18 and the cable 20.

  Subsequently, the frame synchronization operation executed by the synchronization circuit 10 according to the embodiment of the present invention will be described. First, in general transmission / reception of the frame between the private branch exchange 14 and the telephone terminals 16a and 16b by the DECT method, when the length of the cable 20a is different from the length of the cable 20b, wireless synchronization transmitted by the telephone terminals 16a and 16b is performed. The phenomenon that the timings do not match will be schematically described with reference to FIG. That is, it can be said that the communication state of the private branch exchange system 12 before the synchronization by the synchronization circuit 10 according to the embodiment of the present invention is performed.

  In this example, the length of the cable 20a connecting the private branch exchange 14 and the telephone terminal 16a is assumed to be longer than the length of the cable 20b connecting the private branch exchange 14 and the telephone terminal 16b. In addition, as described above, T1 shown in the figure is the time from when each telephone terminal 16a to 16c receives a frame from the private branch exchange 14 until the frame is returned, and T2 is each telephone terminal 16a to 16c is a private branch exchange. The delay time from when the frame 14 is received until the synchronization signal necessary for DECT wireless communication is generated. In this embodiment, it is assumed that T1 and T2 are set at the same time for both the telephone terminals 16a and 16b.

  The private branch exchange 14 as a master device transmits a master transmission frame 74 to each telephone terminal 16 as a slave device once every frame period 72. The time at which the master transmission frame 74 transmitted from the private branch exchange 14 arrives at each telephone terminal 16 as the slave reception frame 76 has a time difference proportional to the transmission distance. In this figure, the delay time required for the master transmission frame 74 transmitted from the private branch exchange 14 to arrive at the telephone terminal 16a is T0, and similarly, the delay time for the telephone terminal 16b required to arrive at the telephone terminal 16b is T3. Represent. In the example of this figure, since the cable 20a is longer than the cable 20b, the delay time T0 is longer than the delay time T3. That is, the difference of T3−T0 becomes the difference T4 of the time for transmitting the frame synchronization signal 78 conforming to the DECT method from the telephone terminal 16 to the handset 22 of the terminal 16.

  Similarly, the time when the slave transmission frame 80 transmitted from each telephone terminal 16 arrives at the private branch exchange 14 as the master reception frame 82 also has a delay time of T0 or T3 depending on the length of the cable 20.

  The operation of the synchronization circuit 10 that eliminates the mismatch in the transmission timing of the frame synchronization signal that occurs in this way will be described in more detail below. First, the frame generation circuit 32 of the synchronization circuit 10 generates a transmission frame 38 according to the reference timing 50 supplied from the private branch exchange 14. The transmission timing generation circuit 56 in the frame generation circuit 32 outputs the transmission timing signal 54 to the counter 62 according to the reference timing 50. The counter 62 starts counting the amount of delay with the reception of the transmission timing signal 54 as a trigger.

  When the synchronization circuit 10 is supplied with the reception frame 40 from the telephone terminal 16, the reception timing extraction circuit 60 in the frame reception circuit 42 extracts the reception timing from the reception frame 40, and receives the reception timing based on the extracted reception timing. A signal 58 is generated and output to the counter 62.

  When the counter 62 receives the reception timing signal 58 from the reception timing extraction circuit 60, the counter 62 stops counting and holds the measured count value 64.

  The counter 62 outputs the held count value 64 to the delay adjustment circuit 66 in synchronization with the timing at which the frame generation circuit 32 outputs the transmission frame 38 to the delay adjustment circuit 66.

  The delay adjustment circuit 66 delays the transmission frame 38 supplied from the frame generation circuit 32 based on the input count value 64 and transmits it to the telephone terminal 16 as a transmission frame 68. The delay time (T) inserted into the transmission frame 68 by the delay adjustment circuit 66 is a value obtained by subtracting the delay amount 64 measured by the counter 62 from the maximum delay amount.

  The maximum delay amount can be based on the amount of time that is the longest delay time until the radio synchronization timing signal is received from the private branch exchange 14 among the telephone terminals 16 used in the private branch exchange system 12. In that case, each synchronization circuit 10 may receive information on the maximum delay amount from the private branch exchange 14. In addition, when the maximum delay amount is known in advance, information regarding the maximum delay amount may be held in the synchronization circuit 10 in advance.

As for the maximum delay amount, the maximum maximum delay amount (TL) allowable by the private branch exchange system 12 is defined in advance, and based on the difference from the actual delay amount (T0) based on the measurement by the counter 62. Thus, a method for setting the delay time (T) to be inserted can be taken. In this case, for example,
Delay amount (T) = (TL−T0) / 2
The delay time to be inserted into the transmission frame 68 can be obtained by the following equation. According to the delay time calculation method using this equation, for example, when the actual delay amount (T0) is equal to the maximum delay amount (TL), that is, when the delay amount (T0) is the maximum, the delay amount that is set (T) is 0. On the other hand, when the delay amount (T0) is close to 0, the set delay amount (T) is very close to the value of TL / 2.

  As described above, according to the present embodiment of the invention, the counter 62 starts counting the delay amount using the transmission timing signal 54 as a trigger and stops counting using the reception timing signal 58 as a trigger. It is possible to measure the interval between the transmission frame and the reception frame. The delay adjustment circuit 66 can adjust the output timing of the transmission frame 68 based on the measured count value 64. Since the output timing adjustment of the transmission frame 68 is executed for each slave device 16, the arrival times of the transmission frames output to the respective slave devices 16 can be matched.

  The delay adjustment of the wireless synchronization timing executed by the synchronization circuit 10 is represented by the time chart shown in FIG. In the example shown in the figure, it is assumed that the delay time required until the master transmission frame 74 transmitted from the private branch exchange 14 arrives at the telephone terminal 16a is the maximum delay amount TL. On the other hand, it is assumed that the delay time of the telephone terminal 16b required until the master transmission frame 74 transmitted from the private branch exchange 14 arrives at the telephone terminal 16b is a delay amount Tb shorter than the maximum delay amount TL.

  According to FIG. 4, before the delay adjustment by the synchronization circuit 10 is performed 86, the transmission timings of the frame synchronization signals 78a and 78b according to the DECT method transmitted from the telephone terminals 16a and 16b differ by the time of T4. Yes. However, in 88 after the synchronization circuit 10 performs the delay adjustment, since the delay time (T) to be adjusted is obtained, the transmission time of the master transmission frame 74 for the telephone terminal 16b that needs to delay transmission is the time T. Delayed by minutes. As a result, the transmission timings of the frame synchronization signals 78a and 78b transmitted from the telephone terminals 16a and 16b coincide with each other.

  As described above, according to the present embodiment, the synchronization timings of the slave devices can be matched even when the transmission distances of the slave devices connected to the master device are different.

  Subsequently, a synchronous circuit according to another embodiment of the present invention will be described. In the above-described embodiment, T1 (the time from when each slave device 16a to 16c receives a frame from the master device 14 until it returns a frame) and T2 (each slave device 16a to 16c is the master device) shown in FIG. Explained the technique to adjust the transmission timing of the synchronization signal when the delay time from receiving the frame from 14 to generating the synchronization signal necessary for DECT wireless communication is the same in all slave devices 16 . On the other hand, in the embodiment described below, even when the settings of T1 and T2 are different for each slave device 16, it is possible to adjust the transmission timing of the synchronization signal transmitted from the slave device 16 to the slave device 22.

  In addition to the configuration of the synchronization circuit 10d according to the present embodiment, the configuration of the telephone terminal 16d, which is a slave device connected corresponding to the synchronization circuit 10d, will also be described. FIG. 5 shows a schematic configuration of a cordless telephone terminal 16d connected to the synchronization circuit 10d via the port 18 and the cable 20 in the private branch exchange system 12. The configuration shown in this figure is limited to only components that are highly related to the synchronization of the radio synchronization timing. On the other hand, FIG. 6 shows a schematic configuration of a synchronization circuit 10d connected to the telephone terminal 16d shown in FIG. Note that, among the components of the synchronization circuit 10d shown in FIG. 6, the same components as those included in the synchronization circuit 10 shown in FIG.

  First, the configuration of the telephone terminal 16d shown in FIG. 5 will be described. The telephone terminal 16d receives a transmission frame 68 emitted from the private branch exchange 14 having the synchronization circuit 10d as a reception frame 102 for the slave device side, A frame receiving circuit 104 for processing is included. The frame reception circuit 104 extracts information necessary for communication from the reception frame 102 and generates reception data 106. Subsequently, the frame reception circuit 104 transmits the generated reception data 106 to a processing circuit (not shown) that is mounted on the telephone terminal 16d and that processes the reception data 106 necessary for communication.

  In addition, the telephone terminal 16d includes a frame generation circuit 110 that is mounted on the telephone terminal 16d and connected to a transmission data generation circuit (not shown) that generates transmission data 108 to be transmitted to the private branch exchange 14. The frame generation circuit 110 generates a transmission frame 112 based on the transmission data 108 received from the transmission data generation circuit and transmits it to the private branch exchange 14. The transmission frame 112 transmitted from the telephone terminal 16d is processed by the frame reception circuit 42 as the reception frame 40 for the synchronization circuit 10d via the cable 20 and the port 18.

  Also, the frame receiving circuit 104 extracts a reference timing 114 that is mounted on the telephone terminal 16d and necessary for DECT wireless communication from the received frame 102. The frame reception circuit 104 is connected to the frame transmission circuit 110, and transmits the extracted reference timing 114 to the frame circuit. Similarly, the frame reception circuit is also connected to a processing circuit such as a transmission data generation circuit (not shown) mounted in the telephone terminal 16d, and transmits the reference timing 114 to the processing circuit in the telephone terminal 16d. In accordance with the received reference timing 114, for example, the reception data 106 is generated in the frame reception circuit 104, and the transmission data 108 is generated in the transmission data generation circuit.

  The configuration of the telephone terminal 16d described so far is provided not only in the present embodiment but also in the telephone terminal 16 connected to the synchronization circuit of the above-described embodiment. However, the telephone terminal 16d connected to the synchronization circuit 10d according to the present embodiment further includes T1 (time from when the telephone terminal 16d receives a frame from the private branch exchange 14 until it returns a frame) and T2 (telephone terminal). The information input circuit 116 or the same type of circuit is used to input information related to the delay time (from when the frame 16d is received from the private branch exchange 14 until the synchronization signal necessary for DECT wireless communication is generated) to the transmission data 108. Have.

  The information input circuit 116 provides T1 and T2 areas in the data format of the transmission data 108 supplied from the transmission data generation circuit of the telephone terminal 16d to the frame generation circuit, and T1 and T2 specific to the telephone terminal 16d are provided in that area. Information 118 about is inserted. The amount of time T1 and T2 is a value determined according to the design of each telephone terminal 16d. Therefore, the information 118 regarding T1 and T2 is a fixed value for each terminal.

  It is possible to include the information 118 in the transmission data 108 supplied to the frame generation circuit 110 by mounting the information input circuit 116 on the telephone terminal 16d from the beginning of manufacture or additionally incorporating it into the existing telephone terminal. Of course. Alternatively, the transmission data 34 is sent to the private branch exchange 14 including the synchronization circuit 10d or the same circuit 10d as an instruction signal that also serves as the information input circuit 116 for an existing circuit such as a transmission data generation circuit provided in the telephone terminal 16d. Alternatively, a circuit that is inserted into the transmission frame 38 may be provided. A circuit for inserting a command signal to be sent to the telephone terminal 16d may be realized by, for example, the frame generation circuit 32 of the synchronization circuit 10d, the transmission data generation circuit 36 of the private branch exchange 14, or the like. If such a circuit is provided on the master device 14b side, even if a conventional private branch exchange system has already been constructed, the present embodiment can be used without any processing on the telephone terminal side. System is built. This is because the synchronization circuit 10d according to the present embodiment can be incorporated into the private branch exchange or the private branch exchange 14 including the circuit 10d can be re-installed.

  A synchronization circuit 10d shown in FIG. 6 is an example of a circuit connected to the telephone terminal 16d shown in FIG. 5, and the synchronization circuit 10d according to the present embodiment also has a frame reception circuit 42 as in the previous embodiment. . However, the frame receiving circuit 42 of this embodiment further includes an information extracting circuit 122 that extracts information 118 relating to T1 and T2 inserted in the received frame 40 received from the telephone terminal 16d. The information extraction circuit 122 is connected to the delay adjustment circuit 66. The information extraction circuit 122 obtains the delay adjustment value 124 based on the extracted information regarding T1 and T2, and then outputs the obtained delay adjustment value 124 to the delay adjustment circuit 66.

An example of a method for calculating the delay adjustment value 124 by the information extraction circuit 122 will be described below. For both T1 and T2, the maximum delays assumed in advance are set as T1max and T2max, respectively. The information extraction circuit 122 extracts the information 118 regarding T1 and T2 from the received frame 40, obtains the difference between T1max and T1, and the difference between T2max and T2, respectively, and sets the obtained values as the delay adjustment value 124. The calculation method of the delay adjustment value 124 for T1 and T2 is, for example, the following equation:
Delay adjustment value 124 (T1) = T1max-T1
Delay adjustment value 124 (T2) = T2max-T2
Represented by

  The delay adjustment circuit 66 in this embodiment transmits a transmission frame 38 delayed by an amount of time calculated based on the count value (delay amount) 64 received from the counter 62 and the delay adjustment value 124 received from the information extraction circuit 122. A frame 68 is generated. Subsequently, the delay adjustment circuit 66 transmits the generated transmission frame 68 to the telephone terminal 16d.

  The delay adjustment circuit 66 subtracts the delay time (T) inserted in the transmission frame 68 from the maximum delay amount (TL) by the count value 64, and further reduces the amount of each delay adjustment value 124 related to T1 and T2. Can be calculated.

  Subsequently, the frame synchronization operation executed by the synchronization circuit 10d according to the embodiment of the present invention will be briefly described with respect to the difference from the operation of the previous embodiment. First, the telephone terminal 14d provides areas T1 and T2 in the data format of the transmission data 108 by the information input circuit 116, and inserts information 118 relating to T1 and T2 specific to the telephone terminal 16d into the area. Alternatively, upon receiving a command signal from the private branch exchange 14 having the synchronization circuit 10d, the telephone terminal 14d inserts information 118 regarding T1 and T2 unique to the transmission data 108.

  The telephone terminal 16d generates a transmission frame 112 based on the transmission data 108 including the information 118, and transmits it to the synchronization circuit 10d of the private branch exchange 14. The transmission frame 112 is received by the frame reception circuit 42 as the reception frame 40 on the synchronization circuit 10d side.

  In the frame receiving circuit 42, information 118 relating to T1 and T2 is extracted from the received frame 40 by the information extracting circuit 122, and a delay adjustment value 124 is calculated based on the extracted information 118 and transmitted to the delay adjusting circuit 66.

  Similarly to the previous embodiment, the counter 62 receives the transmission timing signal 54 from the transmission timing generation circuit 56, then receives the reception timing signal 58 from the reception timing extraction circuit 60, and uses the measured reception interval as the count value 64. The data is transmitted to the delay adjustment circuit 66.

  The delay adjustment circuit 66 generates a transmission frame 68 obtained by delaying the transmission frame 38 based on the received count value 64 and delay adjustment value 124, and transmits this transmission frame 68 to the telephone terminal 16d.

  According to the present embodiment, the synchronization timing of each slave device can be matched even when slave devices with different frame response times and different synchronization signal generation times are connected to the master device due to different designs. Will be able to.

  By the way, the private branch exchange 14 including the synchronization circuit 10 and the circuit 10 according to the embodiment of the present invention can also be realized by installing a program for executing the synchronization method described above in a computer. An embodiment in this case will be briefly described with reference to FIG. A program for causing the computer 152 to function as the private branch exchange 14 having the synchronization circuit 10 according to the embodiment of the present invention described above is stored in the storage medium 154. Here, the storage medium 154 includes any device or component capable of storing a program, such as an optical disk, a magnetic disk, or a flash memory.

  The computer 152 has a drive 156 that can read the storage contents of the storage medium 154. The drive 156 may be fixedly built in the computer 152 or may be an external device that is independent from the computer 152 and can be connected to the computer 152. The computer 152 includes a central processing unit (CPU) 158 that performs information processing such as computation and control of the computer itself, and a storage device 160 that stores programs, data, and the like. For convenience, the storage device 160 shown in this figure includes both a device that temporarily stores data and a device that permanently stores data. The CPU 158 is connected to the drive 156 via the connection line 162 and is also connected to the storage device 160 via the connection line 164.

  The program stored in the storage medium 154 is read by the computer 152 via the drive 156, and the read program is stored in the storage device 160 of the computer 152 under the control of the CPU 158. The computer 152 in which the program is incorporated in this way can operate as the private branch exchange 14 equipped with the synchronization circuit 10 according to the above-described embodiment of the present invention by executing the program. This program causes the CPU 158 in the computer 152, the storage device 160, and other various internal devices not shown to function as the frame generation circuit 32, the frame reception circuit 42, the counter 62, and the delay adjustment circuit 66 included in the synchronization circuit 10. It can be said that.

  Although several embodiments of the present invention have been described so far, specific methods for implementing the present invention are not limited to the above-described embodiments. As long as the present invention can be implemented, the design, operation procedure, and the like can be changed as appropriate. For example, circuits and other devices used for assisting the function of the components used in the present invention can be added and omitted as appropriate. Also, the frame delay time calculation process executed by the delay adjustment circuit, the delay adjustment value calculation process executed by the information extraction circuit, and the like are not limited to the processes of the above-described embodiments, and are used in the private branch exchange system. Various settings by those skilled in the art are possible depending on the design of each device, the usage environment of the system, and the like.

10 Synchronous circuit
12 Private branch exchange system
14 Private branch exchange (PBX)
16 Telephone terminal
32 Frame generation circuit
42 Frame receiver circuit
56 Transmission timing generator
60 Reception timing extraction circuit
62 counter
66 Delay adjustment circuit
122 Information extraction circuit
152 computer

Claims (9)

In a synchronization circuit that adjusts the transmission timing of a transmission frame to be transmitted to the slave device when performing frame communication with a connectable slave device, the circuit includes:
A counter that measures, as a delay amount, an interval from the generation timing of the transmission frame to the reception timing of the reception frame transmitted from the slave device in response to reception of the transmission frame for each transmission of the transmission frame;
A delay adjustment circuit that delays the transmission timing of the transmission frame based on the delay amount ;
Possess an information extraction circuit for extracting information about the time required from when the slave device receives the transmission frame to execute a predetermined process from the received frame,
The information extracted by the information extraction circuit includes at least
A time from when the slave device receives the transmission frame until it returns the reception frame;
The slave device, the synchronization circuit according to claim Rukoto includes the time required from reception of the transmission frame to the generation of the synchronizing signal subjected to radio communications. The synchronization circuit of claim 1, wherein the circuit further comprises:
A transmission timing generation circuit that generates a transmission timing signal in accordance with the generation timing of the transmission frame as a signal for starting measurement by the counter, and supplies the transmission timing signal to the counter;
A reception timing extraction circuit for extracting a reception timing of the reception frame, generating a reception timing signal based on the reception timing as a signal for ending the measurement by the counter, and supplying the reception timing signal to the counter; Synchronous circuit characterized. 3. The synchronization circuit according to claim 1 or 2 , wherein the circuit notifies the slave device of information related to a time required for the slave device to execute a predetermined process after receiving the transmission frame. Synchronous circuit characterized by ordering to be provided. In a master device including a synchronization circuit that adjusts transmission timing of a transmission frame transmitted to the slave device when performing frame communication with a connectable slave device, the synchronization circuit includes:
A counter that measures, as a delay amount, an interval from the generation timing of the transmission frame to the reception timing of the reception frame transmitted from the slave device in response to reception of the transmission frame for each transmission of the transmission frame;
A delay adjustment circuit that delays the transmission timing of the transmission frame based on the delay amount ;
Possess an information extraction circuit for extracting information about the time required from when the slave device receives the transmission frame to execute a predetermined process from the received frame,
The information extracted by the information extraction circuit includes at least
A time from when the slave device receives the transmission frame until it returns the reception frame;
The slave device, a master device for the required time includes said Rukoto from the reception of the transmission frame to the generation of the synchronizing signal subjected to radio communications. 5. The master device according to claim 4 , wherein the synchronization circuit further includes:
A transmission timing generation circuit that generates a transmission timing signal based on the reference timing of the communication as a signal for starting measurement by the counter, and supplies the transmission timing signal to the counter;
A reception timing extraction circuit for extracting a reception timing of the reception frame, generating a reception timing signal based on the reception timing as a signal for ending the measurement by the counter, and supplying the reception timing signal to the counter; Feature master device. 6. The master device according to claim 4 or 5 , wherein the synchronization circuit transmits, to the slave device, information related to a time required for the slave device to execute a predetermined process after receiving the transmission frame. A master device characterized by commanding a circuit to provide. In a computer-readable synchronization program for causing a computer to function as a master device for adjusting the transmission timing of a transmission frame to be transmitted to the slave device when performing frame communication with a connectable slave device, the program is The computer,
A counter that measures, as a delay amount, an interval from the generation timing of the transmission frame to the reception timing of the reception frame transmitted from the slave device in response to reception of the transmission frame for each transmission of the transmission frame ;
Delay adjusting means for delaying based on the delay amount the transmission timing of the previous SL transmit frame and,
Allowing the slave device to function as information extraction means for extracting information about the time required from the reception of the transmission frame to executing a predetermined process from the reception frame ;
The information extracted by the information extracting means includes at least
A time from when the slave device receives the transmission frame until it returns the reception frame;
The slave device, the contains the required time from the reception of the transmission frame to the generation of the synchronizing signal subjected to the radio communication synchronization program characterized Rukoto. The master device according to claim 7 , wherein the program further includes:
A transmission timing signal is generated as a signal for starting measurement by the counter based on the reference timing of the communication, a transmission timing generation means for supplying the transmission timing signal to the counter, and a reception timing of the reception frame is extracted, A synchronization program for generating a reception timing signal based on the reception timing as a signal for ending the measurement by the counter and also functioning as reception timing extraction means for supplying the reception timing signal to the counter. In synchronization program according to claim 7 or 8, the program is the computer to provide information about the time required from when the slave device receives the transmission frame to execute a predetermined process on the computer A synchronization program comprising a program for transmitting an instruction to the slave device.

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