Phase stabilization circuit, phase synchronization system, and phase stabilization method

Abstract

To allow phase fluctuations of a reference signal in a target circuit to be suppressed when the reference signal is supplied to the target circuit.SOLUTION: A phase synchronization system includes a phase stabilization circuit including a transmission path 140 for transmitting a transmission signal, a loopback unit for branching the transmission signal input from the transmission path into two and outputting one of the branched transmission signals to the transmission path as a return signal, and a phase control unit for adjusting the phase difference between the reference signal and the return signal when a phase control signal is input so that the phase difference between the reference signal and a reception signal becomes 0 according to the phase control signal. The phase control unit includes a power detection unit for outputting the reception signal from the loopback unit and measuring the power and outputting a determination signal indicating whether or not the power is equal to or greater than a predetermined threshold, a determiner for outputting the phase control signal to the phase control unit when the determination signal indicates the power is equal to or greater than the threshold and not outputting the signal when the determination signal indicates the power is less than the threshold, and a phase comparator for outputting the phase control signal of the phase difference between the reference signal from the loopback unit and the reception signal from the power detection unit to the determiner.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a phase stabilization circuit, a phase synchronization system, and a phase stabilization method. [Background technology]

[0002] There is known a signal distribution system that branches a reference signal, which is an electric signal, and supplies it to other electric circuits via a transmission path such as a coaxial cable. In such a system, it is sometimes required that the phase of the reference signal is constant when the reference signal is received by the electric circuit (hereinafter referred to as the "target circuit") to which the reference signal is supplied.

[0003] However, when a signal is transmitted through a transmission line, the phase of the signal supplied from the transmission line to the target circuit may fluctuate due to temperature changes around the transmission line, vibrations applied to the transmission line, etc. Patent Document 1 describes a technology for stabilizing the phase of a reference signal output from the transmission line to the target circuit by controlling the phase difference between the reference signal before it propagates through the transmission line and a folded signal obtained by folding back the reference signal in the target circuit on the transmitting side of the reference signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7160212 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technique described in Patent Document 1, the return signal is a reference signal that has traveled back and forth through a transmission line to a target circuit, and therefore the longer the transmission line, the greater the attenuation of the return signal due to loss in the transmission line.

[0006] However, when the folded signal is attenuated, its power may become lower than the power of an unwanted reflected signal generated due to impedance mismatch in each part of the signal distribution system. In such a case where the power of the folded signal is small and the presence of the unwanted reflected signal cannot be ignored, if the phase difference between the reference signal and the folded signal is controlled when the reference signal is transmitted, erroneous phase control may be performed due to the influence of the reflected signal. This causes a significant loss of stability in the phase of the reference signal supplied to the target circuit.

[0007] (Objective of the Invention) An object of the present disclosure is to provide a technique for suppressing phase fluctuations of a reference signal in a target circuit when the reference signal is supplied to the target circuit. [Means for solving the problem]

[0008] The phase stabilization circuit according to the present disclosure comprises: A transmission path for transmitting a transmission signal; a branching means for branching an input reference signal into two signals and outputting the branched signals, and for outputting an input received signal; a return means for returning a part of the input transmission signal to the transmission line as a return signal; When a phase control signal is input, the following is performed in response to the phase control signal: adjusting a phase of the reference signal input from the branching means and outputting the adjusted phase as the transmission signal; adjusting the phase of the folded signal and outputting it to the branching means as a received signal; When the phase control signal is not input, the phase of neither the reference signal nor the folded signal is adjusted. A phase control means; a power detection means for outputting the received signal input from the branching means, measuring the power of the received signal output from the branching means, and outputting a determination signal indicating whether or not the power is equal to or greater than a predetermined threshold; a determination means for outputting the phase control signal to the phase control means when the determination signal indicates that the power is equal to or greater than a predetermined threshold, and for not outputting the phase control signal to the phase control means when the determination signal indicates that the power is less than the predetermined threshold; a phase comparison means for outputting to the determination means a phase control signal indicating a phase difference between the reference signal input from the branching means and the received signal input from the power detection means; Equipped with The phase control means adjusts the phase difference between the reference signal and the return signal so that the phase difference between the reference signal and the received signal becomes zero.

[0009] In addition, the phase stabilization method according to the present disclosure includes: A transmission signal is output from the phase control means; A part of the transmission signal propagated through a transmission line is folded back to the transmission line as a folding signal; When a phase control signal is input, the phase control means performs the following in response to the phase control signal: outputting the transmission signal with the phase of the reference signal adjusted; Outputting the received signal with the phase of the return signal adjusted; When the phase control signal is not input to the phase control means, the phase control means outputs the transmission signal and the reception signal without adjusting the phase of either the reference signal or the return signal; A phase difference between the reference signal and the received signal is obtained by a phase comparison means, and the phase control signal is output as an instruction that the phase difference is 0; measuring the power of the received signal, and outputting the phase control signal to the phase control means when the power is equal to a predetermined threshold value; When the power is less than the predetermined threshold, the phase control signal is not output to the phase control means. Includes instructions. Effect of the Invention

[0010] The present disclosure makes it possible to suppress phase fluctuations of a reference signal in a target circuit when the reference signal is supplied to the target circuit. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram illustrating a configuration example of a phase stabilization circuit. [Diagram 2] 5 is a flowchart showing an example of the operation of the phase stabilization circuit. [Diagram 3] 1 is an example of a flowchart of a phase stabilization method. [Figure 4] FIG. 1 illustrates an example of the configuration of a phase synchronization system. [Diagram 5] FIG. 1 illustrates an example of the configuration of a phase synchronization system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The embodiments of the present disclosure will be described below with reference to the drawings. Arrows shown in the drawings are intended to illustrate the direction of signals, etc., and are not intended to limit the nature of the signals, etc. In addition, in the embodiments and drawings, elements that have already been mentioned are given the same reference symbols, and duplicated descriptions may be omitted.

[0013] (First embodiment) 1 is a diagram showing an example of the configuration of a phase stabilization circuit 100 according to the present disclosure. The phase stabilization circuit 100 includes a phase control section 110, a loopback section 120, and a transmission line 140.

[0014] A reference signal is input to the phase control section 110. The phase control section 110 adjusts the phase of the input reference signal, and sends the phase-adjusted reference signal as a transmission signal to the transmission path 140. The transmission path 140 is a transmission medium for an electric signal or an electromagnetic wave. The transmission path 140 is, for example, a coaxial cable, and transmits the transmission signal and a return signal, which will be described later.

[0015] The loopback unit 120 branches a transmission signal input from the transmission line 140 into two, and outputs (loops back) one of the branched transmission signals to the transmission line 140 as a return signal. That is, the return signal is a reference signal that has propagated through the transmission line 140 as a transmission signal, and has been returned by the loopback unit 120 (that is, a signal that has traveled back and forth through the transmission line 140). The other branched transmission signal is output to a target circuit (not shown) that is the supply destination of the transmission signal. The loopback unit 120 may be provided in the target circuit.

[0016] When the power of the received return signal is equal to or greater than a predetermined threshold, the phase control section 110 adjusts the phase of the transmission signal and the return signal based on the phase difference between the received return signal and the reference signal. When the power of the received return signal is less than the predetermined threshold, the phase control section 110 does not adjust the phase of either the transmission signal or the return signal. The configuration and operation of the phase stabilization circuit 100 will be described in detail below.

[0017] The phase control unit 110 includes a hybrid 101 , a phase comparator 102 , a phase adjuster 103 , a power detector 104 , and a determiner 105 .

[0018] Hybrid 101 has terminals 1011-1014. Hybrid 101 branches a reference signal input to terminal 1011 into two. One of the branched reference signals is output from terminal 1012, and the other is output from terminal 1014. Hybrid 101 also outputs the reference signal input to terminal 1012 from terminals 1011 and 1013. The reference signal input to terminal 1011 is not output from terminal 1013. The reference signal input to terminal 1012 is not output from terminal 1014.

[0019] Here, the hybrid 101 applies a phase shift of 90 degrees to the signal passing between the terminal 1011 and the terminal 1012. Also, the hybrid 101 applies a phase shift of 180 degrees to the signal passing between the terminal 1011 and the terminal 1014 and the signal passing between the terminal 1012 and the terminal 1013. For example, the hybrid 101 delays the phase of each of the input signals by the above-mentioned angle. A general 90-degree hybrid circuit having the above-mentioned functions may be used as the hybrid 101.

[0020] Hybrid 101 outputs the reference signal input to terminal 1011 from terminals 1012 and 1014. The reference signal output from terminal 1012 is input to terminal 1031 of phase adjuster 103. As described above, the phase of the reference signal output from terminal 1012 has changed by 90 degrees compared to when it was input to terminal 1011. Furthermore, the reference signal output from terminal 1014 is input to terminal 1022 of phase comparator 102. The phase of the reference signal output from terminal 1014 has changed by 180 degrees compared to when it was input to terminal 1011. Furthermore, the phase of the received signal output from terminal 1013 has changed by 180 degrees compared to when it was input to terminal 1012.

[0021] Phase adjuster 103 includes terminals 1031-1033. Phase adjuster 103 adjusts the phase of the signal input from terminal 1031 and the signal input from terminal 1032 based on the phase control signal input from terminal 1033, and outputs the adjusted signal. That is, phase adjuster 103 adjusts the phase of the reference signal input from terminal 1031, and outputs the adjusted signal from terminal 1032. The reference signal output from terminal 1032 is hereinafter referred to as a transmission signal. On the other hand, the signal input from terminal 1032 is output from terminal 1031 after the phase is adjusted. That is, phase adjuster 103 adjusts the phase of the return signal input from terminal 1032, and outputs the returned signal from terminal 1031. The return signal output from terminal 1031 is hereinafter referred to as a reception signal. The phase adjustment amount in phase adjuster 103 is the same for signals in either direction. The phase control signal input to terminal 1033 will be described later. There is no limitation on the configuration of phase adjuster 103. As phase adjuster 103, a general phase controller that is suitable for the frequency and power of the input / output signal can be used.

[0022] The power detector 104 includes terminals 1041-1043. A received signal is input from the hybrid 101 to the terminal 1041 of the power detector 104. The power detector 104 outputs a determination signal corresponding to the power of the input received signal from the terminal 1043 to the terminal 1053 of the determiner 105. Specifically, the power detector 104 measures the power (received power Pr) of the signal output from the terminal 1013 of the hybrid 101 when it is input to the terminal 1041. Then, the power detector 104 compares the received power Pr with a predetermined threshold value Pth. The threshold value Pth may be stored in advance as data in an internal memory or the like of the power detector 104.

[0023] When the received power Pr is equal to or greater than the threshold Pth, the power detector 104 outputs, as a determination signal, a signal (start signal) including an instruction to start phase control by the phase adjuster 103. On the other hand, when the input power is less than the predetermined threshold, the power detector 104 outputs, as a determination signal, a signal (stop signal) including an instruction to stop phase control by the phase adjuster 103.

[0024] The received power can be obtained, for example, by measuring the current and voltage of the input signal using a current shunt resistor and converting the result into a numerical value using an A / D (analog / digital) converter. Furthermore, the power detector 104 outputs the input received signal from a terminal 1042 to a terminal 1021 of the phase comparator 102.

[0025] The phase comparator 102 includes terminals 1021-1023. The received signal is input to the terminal 1021 from the terminal 1042 of the power detector 104, and the reference signal is input to the terminal 1022 from the terminal 1014 of the hybrid 101. The phase comparator 102 calculates a phase difference between the input reference signal and the received signal, and outputs a phase control signal according to the calculated phase difference from the terminal 1023 to the terminal 1051 of the determiner 105. The phase control signal is a signal that instructs the phase adjuster 103 to adjust the phase, with the goal of making the phase difference calculated in the phase comparator 102 zero. For example, the phase control signal is a signal that includes information on the phase difference calculated in the phase comparator. Alternatively, the phase control signal is a signal that notifies the phase adjuster 103 of the amount of phase adjustment required to make the calculated phase difference zero.

[0026] The determiner 105 includes terminals 1051-1053. The terminal 1051 receives a phase control signal from a terminal 1023 of the phase comparator 102. The terminal 1053 receives a determination signal from a terminal 1043 of the power detector 104. When the determination signal input to the terminal 1053 is a start signal, the determiner 105 outputs the phase control signal input from the phase comparator 102 directly from the terminal 1052 to the terminal 1033 of the phase adjuster 103. On the other hand, when the determination signal input to the terminal 1053 is a stop signal, the determiner 105 does not output the phase control signal input from the phase comparator 102 to the phase adjuster 103.

[0027] When the determination signal is a start signal, the phase adjuster 103 receives a phase control signal from the phase comparator 102 via the determiner 105. When a phase control signal is input to the terminal 1033 of the phase adjuster 103, the phase adjuster 103 controls the phase of the reference signal input from the terminal 1031 and the phase of the return signal input from the terminal 1032 in accordance with the phase control signal. For the same phase control signal, the phase adjuster 103 changes the phases of the reference signal and the return signal by the same angle. For example, when the phase adjuster 103 delays the phase of the reference signal by θ degrees, the phase adjuster 103 also delays the phase of the return signal by θ degrees. Furthermore, when the phase control signal is not input from the determiner 105, the phase adjuster 103 does not perform phase control of the transmission signal and the return signal. When the phase adjuster 103 does not perform phase control, it may notify an alarm to the outside of the phase stabilization circuit 100. The alarm may be notified by an electric signal, sound generation, or lighting of a lamp. That is, when the received power Pr is less than the threshold value Pth, the phase adjuster 103 may issue an alarm to the outside.

[0028] The transmission signal output from the terminal 1032 of the phase adjuster 103 is transmitted to the loopback unit 120 via the transmission path 140. The loopback unit 120 loops back a part of the transmission signal received from the transmission path 140 to the transmission path 140. The loopback unit 120 includes a hybrid 121. As the hybrid 121, a 90-degree hybrid similar to the hybrid 101 included in the phase control unit 110 can be used. The hybrid 121 includes a terminal 1211-terminal 1214. When the transmission signal output from the phase adjuster 103 and propagated through the transmission path 140 is input to the terminal 1211, the input transmission signal is output from the terminal 1212. At this time, the phase of the transmission signal changes by 90 degrees. The transmission signal output from the terminal 1212 is branched into two, and one of the transmission signals is input to the terminal 1214. The transmission signal input to the terminal 1214 is output from the terminal 1211 as a loopback signal. Here, hybrid 121 shifts the phase of the signal input from terminal 1214 by 180 degrees and outputs it from terminal 1211. Therefore, the phase of the return signal output from terminal 1211 is shifted by 270 degrees compared to the phase of the transmission signal input to terminal 1211.

[0029] The other branched transmission signal is output from terminal 1212 of hybrid 121 and output to the outside of phase stabilization circuit 100 as the output of loopback unit 120. The transmission signal output from loopback unit 120 is used as a reference signal in the target circuit. Since terminal 1213 of hybrid 121 is not used, terminal 1213 is preferably terminated with resistor 1215.

[0030] 2 is a flowchart showing an example of the operation of the phase stabilization circuit 100. The operation of the phase stabilization circuit 100 will be described with reference to FIG.

[0031] Hybrid 101 branches a reference signal inputted from terminal 1011 into two (step S01 in FIG. 2). The branched reference signals are outputted from terminals 1012 and 1014. In addition, hybrid 101 outputs the signal inputted to terminal 1012 from terminal 1013.

[0032] The reference signal output from terminal 1012 of hybrid 101 (i.e., one of the branched reference signals) is input to phase adjuster 103. Phase adjuster 103 adjusts the phase of the input reference signal in accordance with the phase control signal input from determiner 105, and outputs the phase-adjusted reference signal as a transmission signal to transmission path 140 (S02). However, if no phase control signal is input from determiner 105, phase adjuster 103 does not adjust the phase of the input reference signal.

[0033] The loopback unit 120 branches the transmission signal propagated through the transmission line 140, and loops one of the branches back to the transmission line 140 (S03). As a result, the return signal propagated through the transmission line 140 is input to the terminal 1032 of the phase adjuster 103. The phase adjuster 103 adjusts the phase of the return signal in accordance with the phase control signal, and outputs the phase-adjusted return signal as a received signal to the terminal 1012 of the hybrid 101 (S04). If the phase control signal is not input from the determiner 105, the phase adjuster 103 does not adjust the phase of the input return signal. The hybrid 101 outputs the received signal input from the phase adjuster 103 from the terminal 1013 to the power detector 104.

[0034] The power detector 104 measures the received power Pr of the received signal output from the hybrid 101 (S05). Then, the power detector 104 compares the received power Pr with a predetermined threshold Pth (S06). If the received power Pr is equal to or greater than the threshold Pth (S05: YES), the power detector 104 outputs a start signal to the determiner 105 (S07). If the received power Pr is less than the threshold Pth (S05: NO), the power detector 104 outputs a stop signal to the determiner 105 (S08). In addition, the power detector 104 outputs the received signal to the phase comparator 102. However, when outputting the stop signal to the determiner 105, the power detector 104 does not have to output the received signal to the phase comparator 102.

[0035] The phase comparator 102 compares the phase of the reference signal with that of the received signal and detects the phase difference (S09). The reference signal is input from a terminal 1014 of the hybrid 101. The received signal is input from a terminal 1042 of the power detector 104. The phase comparator 102 outputs a phase control signal to the determiner 105 (S10).

[0036] A start signal or a stop signal is input to a terminal 1053 of the determiner 105 as a determination signal. The determiner 105 determines the type of the input determination signal (S11). When a start signal is input to the determiner 105 (S11: start signal), the determiner 105 outputs the phase control signal input from the phase comparator 102 to the phase adjuster 103 (S12). On the other hand, when a stop signal is input to the terminal 1053 (S11: stop signal), the determiner 105 does not output the phase control signal input from the phase comparator 102 to the phase adjuster 103 (S13). When it is unclear whether the control signal is a start signal or a stop signal, the determiner 105 does not need to output the phase control signal to the phase adjuster 103.

[0037] Then, as described above, when a phase control signal is input from determiner 105, phase adjuster 103 adjusts the phase of the reference signal, and outputs the phase-adjusted reference signal to transmission path 140 as a transmission signal (S02). Phase adjuster 103 also adjusts the phase of the return signal, and outputs the phase-adjusted return signal to hybrid 101 as a reception signal (S04). Here, phase adjuster 103 adjusts the phase of the return signal and the reference signal in response to the phase control signal so that the phase difference between the reference signal input to phase comparator 102 and the reception signal becomes zero.

[0038] The procedure for controlling the phase of a return signal and a reference signal described in Patent Document 1 can be applied to the phase control using the hybrid 101, the hybrid 121, the phase comparator 102, and the phase adjuster 103. The control described in Patent Document 1 keeps the phase of the transmission signal output from the terminal 1211 of the hybrid 121 constant regardless of the phase difference occurring in the transmission path 140. Therefore, the phase stabilization circuit 100 in the present disclosure can keep the phase of the transmission signal propagated through the transmission path 140 constant.

[0039] When the power of the return signal is small, if the phase comparator 102 tries to detect the phase difference between the reference signal and the received signal, the phase of the received signal may not be detected accurately due to the influence of noise such as a reflected signal generated on the transmission path through which the transmission signal and the return signal propagate. In this case, the accuracy of the phase difference detected by the phase comparator 102 decreases, so that if the phase is adjusted by the phase adjuster 103 using the detected phase difference, an erroneous adjustment may be performed. For example, the phase difference between the reference signal and the received signal may converge to a value other than 0, or the phase difference may fluctuate greatly over time. This means that the stability of the phase of the reference signal supplied to the target circuit is greatly impaired. For this reason, when the power of the received signal is small, it is preferable to stop the phase control rather than continue the phase control using inaccurate phase difference information. For this reason, the phase stabilization circuit 100 includes a power detector 104 and a determiner 105.

[0040] The power detector 104 detects the received power Pr of the return signal, and when the received power Pr is less than the threshold value Pth, outputs a stop signal to the determiner 105. When the stop signal is input from the power detector 104, the determiner 105 does not output a phase control signal to the phase adjuster 103. Furthermore, when the phase control signal is not input from the determiner 105, the phase adjuster 103 does not perform phase control of the transmission signal and the return signal.

[0041] By providing the power detector 104 and the determiner 105, the phase adjuster 103 stops adjusting the phase of the reference signal and the return signal when the power of the return signal (received power Pr) is less than the threshold Pth. Therefore, the phase stabilization circuit 100 can suppress inaccurate phase control in the phase adjuster 103 caused by an increase in detection error of the phase difference between the reference signal and the received signal due to a small received power Pr.

[0042] In this way, the phase stabilization circuit 100 can not only keep constant the phase of the transmission signal propagated through the transmission line 140, but also suppress phase fluctuations caused by noise. The reason is that the phase stabilization circuit 100, which is provided with the power detector 104 and the determiner 105, does not adjust the phase in the phase adjuster 103 when the power of the return signal drops below a predetermined threshold value through the transmission line 140.

[0043] The effect of the phase stabilization circuit 100 can also be obtained by a phase stabilization circuit having the following configuration: The reference numerals in parentheses indicate the corresponding components in FIG.

[0044] The phase stabilization circuit (100) includes a branching means (101), a loopback means (120), a phase comparison means (102), a phase control means (103), a power detection means (104), a determination means (105), and a transmission path (140). The transmission path (140) transmits a transmission signal. The branching means (101) branches an input reference signal into two signals and outputs the signals, and outputs an input reception signal. In other words, the hybrid 101 functions as a branching means that branches an input reference signal into two signals and outputs the signals, and also outputs an input reception signal. The loopback means (120) loops back a portion of the input transmission signal to the transmission path (140) as a loopback signal. In other words, the loopback unit 120 functions as a loopback means that loops back a portion of the input transmission signal to the transmission path 140 as a loopback signal.

[0045] When a phase control signal is input, the phase control means (103) adjusts the phase of the reference signal input from the branching means (101) in accordance with the phase control signal and outputs the signal as a transmission signal. The phase control means (103) also adjusts the phase of the return signal and outputs the signal as a reception signal to the branching means (101). Note that when a phase control signal is not input, the phase control means (103) does not adjust the phase of either the reference signal or the return signal.

[0046] The power detection means (104) outputs the received signal input from the branching means (101). In addition, the power detection means (104) measures the power of the received signal input from the branching means (101) and outputs a determination signal indicating whether or not the power is equal to or greater than a predetermined threshold.

[0047] The determination means (105) outputs a phase control signal to the phase control means (103) when the determination signal indicates that the power of the received signal is equal to or greater than a predetermined threshold, and does not output the phase control signal to the phase control means (103) when the determination signal indicates that the power is less than the predetermined threshold.

[0048] The phase comparison means (102) outputs a phase control signal indicating the phase difference between the reference signal input from the branching means (101) and the received signal input from the power detection means (104) to the determination means (105). Then, the phase control means (103) adjusts the phase difference between the reference signal and the return signal so that the phase difference between the reference signal and the received signal becomes zero.

[0049] The phase stabilization circuit 100 also discloses the following phase stabilization method: Fig. 3 is an example of a flowchart of the phase stabilization method in the present disclosure.

[0050] In the phase stabilization method, a transmission signal is output from the phase control means (step S51 in FIG. 3), and a part of the transmission signal that has propagated through the transmission line is folded back onto the transmission line as a folding back signal (S52).

[0051] When a phase control signal is input to the phase control means (S53: YES), the phase control means outputs the transmission signal with the phase of the reference signal adjusted and the reception signal with the phase of the return signal adjusted in response to the phase control signal (S54).On the other hand, when a phase control signal is not input to the phase control means (S53: NO), the phase control means outputs the reference signal and the return signal without adjusting the phase (S55).

[0052] The phase comparison means detects the phase difference between the reference signal and the received signal, and outputs a phase control signal that indicates that the phase difference is 0 (S56). The power detection means measures the power (received power) Pr of the received signal (S57).

[0053] If the received power Pr is equal to or greater than the predetermined threshold (S58: YES), the determination means outputs a phase control signal to the phase control means (S59). If the received power is less than the predetermined threshold Pth (S58: NO), the determination means does not output a phase control signal to the phase control means (S60).

[0054] Second Embodiment Fig. 4 is a diagram showing a configuration example of a phase synchronization system 1 according to the present disclosure. The phase synchronization system 1 includes a signal source 11, a distributor 12, phase stabilization circuits 100a and 100b, and target circuits 200a and 200b. In Fig. 4, two phase stabilization circuits 100a and 100b are arranged in parallel. However, the number of parallel phase stabilization circuits is not limited to two. In the phase synchronization system 1, the number of parallel phase stabilization circuits can be increased by increasing the number of distributions of the distributor 12 to three or more.

[0055] The following mainly describes the phase stabilization circuit 100a and its related parts. The configuration and operation of the phase stabilization circuit 100b are similar to those of the phase stabilization circuit 100a. Therefore, unless otherwise necessary, the description of the phase stabilization circuit 100b will be omitted. In addition, in FIG. 4, the components of the phase stabilization circuits 100a and 100b are given the reference characters a or b to the corresponding components in FIG. 1, and the description will be omitted. In addition, in FIG. 4, the blocks showing the components of the phase stabilization circuits 100a and 100b are simply drawn.

[0056] Signal source 11 is an oscillator that generates a reference signal. The reference signal is input to distributor 12. Distributor 12 distributes the input reference signal in phase to phase stabilization circuits 100a and 100b. Even when three or more phase stabilization circuits are connected in parallel, distributor 12 distributes the reference signal in phase to each phase stabilization circuit.

[0057] The phase stabilization circuit 100a operates in the same manner as the phase stabilization circuit 100 described in the first embodiment. Therefore, the phase stabilization circuit 100a transmits the reference signal input from the distributor 12 via the transmission line 140a, and controls the phase adjuster 103a to make the phase difference between the reference signal and the received signal 0. The same applies to the phase stabilization circuit 100b.

[0058] The phase stabilization circuit 100a includes a power detector 104a and a determiner 105a. As described in the first embodiment, by including the power detector 104a and the determiner 105a, the phase stabilization circuit 100a can stabilize the phase control operation of the phase adjuster 103a. This is because the power detectors 104a and 104b output a stop signal to the determiner 105a when the received power Pr is less than the threshold Pth. When the determiner 105a receives a stop signal, it does not output a phase control signal to the phase adjusters 103a and 103b. When the phase adjuster 103a does not receive a phase control signal, it stops the phase control for the reference signal and the return signal.

[0059] In this way, when the received power Pr is less than the threshold Pth, the phase synchronization system 1 stops the phase control of the phase adjuster 103a. As a result, even if an accurate phase difference cannot be detected due to the influence of noise from a reflected signal or the like because the power of the return signal is small, it is possible to prevent the phase control in the phase adjuster 103a from becoming unstable.

[0060] The above-mentioned effects of the phase stabilization circuit 100a can be obtained in the phase stabilization circuit 100b as well. Therefore, in a system in which a reference signal is distributed to different target circuits 200a and 200b using different transmission paths, the phase of the transmission signal supplied to each target circuit can be stabilized in the phase of the transmission signal.

[0061] In this way, since the phase synchronization system 1 includes the phase stabilization circuits 100a and 100b, the phase of the transmission signal propagated through the transmission lines 140a and 140b is kept constant by phase control by the phase adjusters 103a and 103b. Therefore, the phase of the transmission signal supplied to the target circuits 200a and 200b connected to the phase stabilization circuits 100a and 100b, respectively, is stabilized. The stabilization of the phase of the transmission signal contributes to the stabilization of the operation of the target circuits 200a and 200b.

[0062] Furthermore, the phase synchronization system 1 includes power detectors 104a and 104b and determiners 105a and 105b. With this configuration, the phase synchronization system 1 can stop phase adjustment in the phase adjuster 103 for each phase stabilization circuit when the power (received power Pr) of the return signal is small. Here, a phase stabilization circuit whose received power Pr is equal to or greater than the threshold Pth is not affected even when another phase stabilization circuit stops phase adjustment. For example, even if the phase adjuster 103a does not perform phase control in the phase stabilization circuit 100a because the power of the received signal is less than the threshold Pth, the phase adjuster 103b performs phase control when the power of the received signal is equal to or greater than Pth in the phase stabilization circuit 100b. The threshold Pth in the phase stabilization circuit 100a and the threshold Pth in the phase stabilization circuit 100b may be the same or may not be the same. When the requirements for phase stability differ for each target circuit or when there are individual differences in the characteristics of the phase adjusters, a different threshold value Pth may be set for each phase stabilization circuit depending on the situation in which each phase stabilization circuit is used.

[0063] (Modification of the second embodiment) FIG. 5 is a diagram showing a configuration example of a phase synchronization system 2. The phase synchronization system 2 is a modified example of the phase synchronization system 1. The phase synchronization system 2 includes phase stabilization circuits 100c and 100d instead of the phase stabilization circuits 100a and 100b of the phase synchronization system 1. The phase stabilization circuit 100c is different from the phase stabilization circuit 100a described in FIG. 4 in that it includes a multiplier unit 130a. Similarly, the phase stabilization circuit 100d is different from the phase stabilization circuit 100b in that it includes a multiplier unit 130b. However, the configurations and operations of the parts of the phase stabilization circuits 100c and 100d other than the multiplier units 130a and 130b are the same as those of the phase stabilization circuits 100a and 100b.

[0064] The phase stabilization circuit 100c includes a loopback unit 120a that receives a transmission signal propagated through a transmission line 140a. The transmission signal output from the loopback unit 120a is input to the multiplier unit 130a. That is, the transmission signal output from the loopback unit 120a is input to the multiplier unit 130a. The multiplier unit 130a multiplies the frequency of the input transmission signal and outputs the multiplied signal to the target circuit 200a.

[0065] In the phase synchronization system 2, the transmission signals output from the loopback units 120a and 120b are multiplied in frequency by n in the multiplier units 130a and 130b, respectively. n is a natural number, and the value of n may be different for each phase stabilization circuit. This makes it possible to supply transmission signals with stabilized phases and different frequencies to the target circuits 200a and 200b. The multiplier units 130a and 130b are a form of multiplication means that multiplies the frequency of the transmission signals output without being folded back in the loopback units 120a and 120b, respectively, and outputs the multiplied signal.

[0066] Here, n may be an even number. As described in Patent Document 1, by multiplying the frequency of the transmission signal by an even number, when a reference signal generated in one signal source 11 is distributed to multiple target circuits, the phases of the transmission signals supplied to the respective target circuits can be made the same.

[0067] Some or all of the functions and procedures described in each of the above embodiments may be realized by a central processing unit (CPU) included in the phase stabilization circuit executing a program. The program is recorded on a fixed, non-transitory recording medium. The recording medium may be, but is not limited to, a semiconductor memory or a fixed magnetic disk device. The CPU is, for example, a computer included in the phase control unit 110.

[0068] The embodiments of the present invention can be described as follows, but are not limited to these.

[0069] (Appendix 1) A transmission path for transmitting a transmission signal; a branching means for branching an input reference signal into two signals and outputting the branched signals, and for outputting an input received signal; a return means for returning a part of the input transmission signal to the transmission line as a return signal; When a phase control signal is input, the following is performed in response to the phase control signal: adjusting a phase of the reference signal input from the branching means and outputting the adjusted phase as the transmission signal; adjusting the phase of the folded signal and outputting it to the branching means as a received signal; When the phase control signal is not input, the phase of neither the reference signal nor the folded signal is adjusted. A phase control means; a power detection means for outputting the received signal input from the branching means, measuring the power of the received signal output from the branching means, and outputting a determination signal indicating whether or not the power is equal to or greater than a predetermined threshold; a determination means for outputting the phase control signal to the phase control means when the determination signal indicates that the power is equal to or greater than a predetermined threshold, and for not outputting the phase control signal to the phase control means when the determination signal indicates that the power is less than the predetermined threshold; a phase comparison means for outputting to the determination means a phase control signal indicating a phase difference between the reference signal input from the branching means and the received signal input from the power detection means; Equipped with the phase control means adjusts the phase difference between the reference signal and the return signal so that the phase difference between the reference signal and the received signal becomes zero. Phase stabilization circuit.

[0070] (Appendix 2) The branching means is imparting a phase difference of 90 degrees to the reference signal input to the phase control means; imparting a phase difference of 180 degrees to the reference signal input to the phase comparison means; imparting a phase difference of 180 degrees to the received signal output from the phase control means; the return means gives a phase difference of 270 degrees to the input transmission signal and outputs the signal as the return signal to the transmission line. Phase stabilization circuit described in Appendix 1.

[0071] (Appendix 3) 3. The phase stabilization circuit of claim 2, wherein the branching means and the folding means each include a 90-degree hybrid.

[0072] (Appendix 4) 4. The phase stabilization circuit according to claim 1, further comprising: a multiplier for multiplying and outputting a frequency of the transmission signal output from the folding back means without being folded back by the folding back means.

[0073] (Appendix 5) 5. A phase stabilization circuit as described in claim 4, wherein the multiplying means multiplies the frequency of the transmission signal by an even number.

[0074] (Appendix 6) a signal source generating the reference signal; At least one phase stabilization circuit according to any one of claims 1 to 5, to which the reference signal is input from the signal source; a target circuit that receives the transmission signal output from the folding circuit.

[0075] (Appendix 7) 7. The phase synchronization system of claim 6, wherein the predetermined threshold is set according to requirements of the target circuit.

[0076] (Appendix 8) A plurality of the phase stabilization circuits; a distributor that distributes the reference signal output from the signal source to two or more; The distributed reference signals are connected to different phase stabilization circuits, 8. A phase-locked system according to claim 6 or 7.

[0077] (Appendix 9) 9. A phase synchronization system as described in claim 8, wherein the predetermined threshold values ​​of the power detection means of each of the plurality of phase stabilization circuits are not the same.

[0078] (Appendix 10) A transmission signal is output from the phase control means; A part of the transmission signal propagated through a transmission line is folded back to the transmission line as a folding signal; When a phase control signal is input, the phase control means performs the following in response to the phase control signal: outputting the transmission signal with the phase of the reference signal adjusted; Outputting the received signal with the phase of the return signal adjusted; When the phase control signal is not input to the phase control means, the phase control means outputs the transmission signal and the reception signal without adjusting the phase of either the reference signal or the return signal; A phase difference between the reference signal and the received signal is obtained by a phase comparison means, and the phase control signal is output as an instruction that the phase difference is 0; measuring the power of the received signal, and outputting the phase control signal to the phase control means when the power is equal to a predetermined threshold value; When the power is less than the predetermined threshold, the phase control signal is not output to the phase control means. Phase stabilization method.

[0079] (Appendix 11) imparting a phase difference of 90 degrees to the reference signal input to the phase control means; a phase difference of 180 degrees is applied to the reference signal before the phase difference is calculated; a phase difference of 180 degrees is further imparted to the received signal output from the phase control means; giving a phase difference of 270 degrees to the transmission signal propagated through the transmission line and outputting the signal as the return signal to the transmission line; 11. A phase stabilization method as described in claim 10.

[0080] (Appendix 12) 12. The phase stabilization method according to claim 10 or 11, further comprising multiplying a frequency of the transmission signal propagated through the transmission line and outputting the multiplied frequency.

[0081] (Appendix 13) 13. The phase stabilization method of claim 12, further comprising multiplying the frequency of the transmission signal by an even number.

[0082] (Appendix 14) On the computer, a step of outputting a transmission signal from a phase control means; When a phase control signal is input, the phase control means performs the following in response to the phase control signal: a step of outputting the transmission signal having a phase adjusted to a reference signal; a step of outputting a received signal obtained by adjusting a phase of a return signal obtained by returning a part of the transmission signal to a transmission line as a return signal; a step of outputting the transmission signal and the reception signal without adjusting the phase of either the reference signal or the return signal in the phase control means when the phase control signal is not input to the phase control means; a step of determining a phase difference between the reference signal and the received signal by a phase comparison means, and outputting the phase control signal which is an instruction that the phase difference is 0; measuring the power of the received signal, and outputting the phase control signal to the phase control means if the power is equal to a predetermined threshold value; a step of not outputting the phase control signal to the phase control means when the power is less than the predetermined threshold; A program for executing the above.

[0083] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. The description of the phase stabilization circuit in each embodiment also discloses the configuration of a phase synchronization system including the phase stabilization circuit, and a phase stabilization method used in the phase stabilization circuit.

[0084] In addition, the configurations described in the respective embodiments are not necessarily mutually exclusive. The actions and effects of the present disclosure may be achieved by a configuration that combines all or part of the above-described embodiments. [Explanation of symbols]

[0085] 1, 2 Phase Synchronous System 11 Signal source 12 Distributor 100, 100a-100d phase stabilization circuit 101, 121 Hybrid 102 Phase comparator 103, 103a, 103b Phase adjuster 104, 104a, 104b Power detector 105, 105a, 105b judger 110 Phase control section 120, 120a, 120b Loopback section 130a, 130b Multiplier section 140, 140a, 140b Transmission lines 200a, 200b target circuit

Claims

1. A transmission path for transmitting a transmission signal; a branching means for branching an input reference signal into two signals and outputting the branched signals, and for outputting an input received signal; a return means for returning a part of the input transmission signal to the transmission line as a return signal; When a phase control signal is input, the following is performed in response to the phase control signal: adjusting a phase of the reference signal input from the branching means and outputting the adjusted phase as the transmission signal; adjusting the phase of the folded signal and outputting it to the branching means as a received signal; When the phase control signal is not input, the phase of neither the reference signal nor the folded signal is adjusted. A phase control means; a power detection means for outputting the received signal input from the branching means, measuring the power of the received signal output from the branching means, and outputting a determination signal indicating whether or not the power is equal to or greater than a predetermined threshold; a determination means for outputting the phase control signal to the phase control means when the determination signal indicates that the power is equal to or greater than a predetermined threshold, and for not outputting the phase control signal to the phase control means when the determination signal indicates that the power is less than the predetermined threshold; a phase comparison means for outputting to the determination means a phase control signal indicating a phase difference between the reference signal input from the branching means and the received signal input from the power detection means; Equipped with the phase control means adjusts the phase difference between the reference signal and the return signal so that the phase difference between the reference signal and the received signal becomes zero. Phase stabilization circuit.

2. The branching means is imparting a phase difference of 90 degrees to the reference signal input to the phase control means; a phase difference of 180 degrees is given to the reference signal input to the phase comparison means; imparting a phase difference of 180 degrees to the received signal output from the phase control means; the folding back means gives a phase difference of 270 degrees to the input transmission signal and outputs the resultant signal to the transmission line as the folding back signal.

2. A phase stabilization circuit as claimed in claim 1.

3. 3. The phase stabilization circuit of claim 2, wherein said branching means and said folding means each include a 90 degree hybrid.

4. 4. A phase stabilization circuit according to claim 1, further comprising a frequency multiplier for multiplying and outputting a frequency of said transmission signal output from said folding back means without being folded back by said folding back means.

5. 5. A phase stabilization circuit according to claim 4, wherein said multiplying means multiplies the frequency of said transmission signal by an even number.

6. a signal source generating the reference signal; At least one phase stabilization circuit according to any one of claims 1 to 3, to which the reference signal is input from the signal source; a target circuit that receives the transmission signal output from the folding circuit.

7. 7. The phase synchronization system of claim 6, wherein the predetermined threshold is set by requirements of the target circuit.

8. A plurality of the phase stabilization circuits; a distributor that distributes the reference signal output from the signal source to two or more signals; The distributed reference signals are connected to different phase stabilization circuits, 7. A phase synchronization system according to claim 6.

9. 9. The phase synchronization system according to claim 8, wherein the predetermined threshold values ​​of the power detection means of each of the plurality of phase stabilization circuits are not the same.

10. A transmission signal is output from the phase control means; A part of the transmission signal propagated through a transmission line is folded back to the transmission line as a folding signal; When a phase control signal is input, the phase control means performs the following in response to the phase control signal: outputting the transmission signal with the phase of the reference signal adjusted; Outputting the received signal with the phase of the return signal adjusted; When the phase control signal is not input to the phase control means, the phase control means outputs the transmission signal and the reception signal without adjusting the phase of either the reference signal or the return signal; A phase difference between the reference signal and the received signal is obtained by a phase comparison means, and the phase control signal is output as an instruction that the phase difference is 0; measuring the power of the received signal, and outputting the phase control signal to the phase control means when the power is equal to a predetermined threshold value; When the power is less than the predetermined threshold, the phase control signal is not output to the phase control means. Phase stabilization method.

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