Wireless communication system, x-ray ct apparatus, and abnormality determination method

Abstract

To efficiently identify an abnormal location when an abnormality occurs in a wireless communication system.SOLUTION: A wireless communication system according to the present embodiment comprises a detection unit, an abnormality determination unit, and a notification unit. The detection unit detects a signal level of a communication signal transmitted from a transmission circuit to a transmission coupler. The abnormality determination unit determines an abnormality related to the transmission circuit or the transmission coupler on the basis of the signal level detected by the detection unit. The notification unit notifies different maintenance information depending on whether the determination result by the abnormality determination unit indicates an abnormality related to the transmission circuit or an abnormality related to the transmission coupler.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to a wireless communication system, an X-ray CT apparatus, and an abnormality determination method.

Background Art

[0002] A wireless communication system that performs wireless communication has been developed. For example, in a wireless communication system, there are a transmitting-side wireless communication device that transmits transmission data (communication signal) from a transmission coupler, and a receiving-side wireless communication device that receives the communication signal by electrostatic coupling or electromagnetic field coupling using a receiving coupler.

[0003] For example, when a communication error occurs in a wireless communication system, there may be an abnormality in either the transmitting-side wireless communication device or the receiving-side wireless communication device for some reason. In this case, first, an operator adjusts the alignment of the transmitting-side wireless communication device and the receiving-side wireless communication device (for example, the positional relationship between the transmission coupler and the receiving coupler). If the communication error is not resolved even after adjusting the alignment, the operator tries to identify the abnormal location by trial and error by replacing the transmitting-side wireless communication device or the receiving-side wireless communication device. However, it is inefficient for the operator to identify the abnormal location by trial and error.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to efficiently identify an abnormal location when an abnormality occurs in a wireless communication system. However, the problems solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. The problems corresponding to the effects of each configuration shown in the embodiments described later can also be regarded as other problems.

Means for Solving the Problem

[0006] The wireless communication system according to this embodiment includes a detection unit, an abnormality determination unit, and a notification unit. The detection unit detects the signal level of a communication signal transmitted from a transmission circuit to a transmission coupler. The abnormality determination unit determines an abnormality related to the transmission circuit and the transmission coupler based on the signal level detected by the detection unit. The notification unit notifies different maintenance information depending on whether the determination result by the abnormality determination unit is an abnormality related to the transmission circuit or an abnormality related to the transmission coupler.

Brief Description of the Drawings

[0007]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a wireless communication system, an X-ray CT apparatus, and an abnormality determination method will be described in detail with reference to the drawings. Note that the embodiments are not limited to the following embodiments. In addition, the content described in one embodiment is generally applicable to other embodiments as well.

[0009] The wireless communication system according to this embodiment is applied to, for example, an X-ray computed tomography (CT) apparatus.

[0010] FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus 1 to which the wireless communication system according to this embodiment is applied. The X-ray CT apparatus 1 collects CT image data of a subject. Specifically, the X-ray CT apparatus 1 rotates an X-ray tube and an X-ray detector around the subject substantially at the center, detects the X-rays transmitted through the subject, and collects projection data. Then, the X-ray CT apparatus 1 generates CT image data based on the collected projection data. As shown in FIG. 1, the X-ray CT apparatus 1 includes a gantry device 10, a couch device 30, and a console device 40.

[0011] In this embodiment, the rotation axis of the rotation frame 13 or the longitudinal direction of the top plate 33 of the couch device 30 in the non-tilt state is defined as the Z-axis direction. Also, the axial direction that is orthogonal to the Z-axis direction and horizontal with respect to the floor surface is defined as the X-axis direction. Further, the axial direction that is orthogonal to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction. Note that FIG. 1 is drawn from a plurality of directions for the purpose of explanation and shows the case where the X-ray CT apparatus 1 has one gantry device 10.

[0012] The gantry device 10 includes an X-ray tube 11, an X-ray detector 12, a rotation frame 13, an X-ray high voltage device 14, a control device 15, a wedge 16, a collimator 17, a data acquisition system (DAS) 18, and a fixed frame 19.

[0013] The X-ray tube 11 is a vacuum tube having a cathode (filament) that generates thermoelectrons and an anode (target) that generates X-rays upon receiving the impact of the thermoelectrons. The X-ray tube 11 generates X-rays to irradiate the subject P by irradiating thermoelectrons from the cathode toward the anode by applying a high voltage from the X-ray high-voltage device 14. For example, the X-ray tube 11 includes a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons.

[0014] The wedge 16 is a filter for adjusting the X-ray dose irradiated from the X-ray tube 11. Specifically, the wedge 16 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 11 so that the X-rays irradiated from the X-ray tube 11 to the subject P have a predetermined distribution. For example, the wedge 16 is a wedge filter or a bow-tie filter, and is a filter formed by processing aluminum or the like to have a predetermined target angle and a predetermined thickness.

[0015] The collimator 17 is a lead plate or the like for narrowing the irradiation range of the X-rays that have passed through the wedge 16, and forms a slit by combining a plurality of lead plates or the like. Note that the collimator 17 may also be referred to as an X-ray aperture. In FIG. 1, the case where the wedge 16 is disposed between the X-ray tube 11 and the collimator 17 is shown, but the collimator 17 may be disposed between the X-ray tube 11 and the wedge 16. In this case, the wedge 16 transmits and attenuates the X-rays irradiated from the X-ray tube 11 and whose irradiation range is limited by the collimator 17.

[0016] The X-ray detector 12 has a plurality of detection elements that detect X-rays. Each detection element in the X-ray detector 12 detects the X-rays irradiated from the X-ray tube 11 and passing through the subject P, and outputs a signal corresponding to the detected X-ray dose to the DAS 18. The X-ray detector 12 has, for example, a plurality of detection element arrays in which a plurality of detection elements are arranged in the channel direction (channel direction) along an arc centered on the focal point of the X-ray tube 11. The X-ray detector 12 has, for example, a structure in which a plurality of detection element arrays in which a plurality of detection elements are arranged in the channel direction are arranged in the column direction (slice direction, row direction).

[0017] For example, the X-ray detector 12 is an indirect conversion type detector having a grid, a scintillator array, and a photosensor array. The scintillator array has a plurality of scintillators. The scintillator has a scintillator crystal that outputs light in an amount of photons corresponding to the incident X-ray dose. The grid is disposed on the X-ray incident side surface of the scintillator array and has an X-ray shielding plate that absorbs scattered X-rays. Note that the grid may sometimes be called a collimator (one-dimensional collimator or two-dimensional collimator). The photosensor array has a function of converting the amount of light from the scintillator into an electrical signal, and has, for example, a photosensor such as a photodiode. Note that the X-ray detector 12 may be a direct conversion type detector having a semiconductor element that converts the incident X-rays into an electrical signal.

[0018] The X-ray high voltage device 14 has electric circuits such as a transformer (transformer) and a rectifier, and includes a high voltage generator that generates a high voltage to be applied to the X-ray tube 11, and an X-ray control device that controls the output voltage according to the X-rays generated by the X-ray tube 11. The high voltage generator may be a transformer type or an inverter type. Note that the X-ray high voltage device 14 may be provided on the rotating frame 13 or may be provided on the fixed frame 19. Here, the fixed frame 19 is a frame that rotatably supports the rotating frame 13 and has a rotation mechanism for rotating the rotating frame 13. The rotating frame 13 and the fixed frame 19 are each an example of a "rotating part" and a "fixed part", respectively.

[0019] DAS18 collects the X-ray signals detected by each detection element of the X-ray detector 12. For example, DAS18 has an amplifier that performs an amplification process on the electrical signals output from each detection element, and an A / D converter that converts the electrical signals into digital signals, and generates detection data. DAS18 is realized by, for example, a processor. DAS18 is an example of a "data collection device".

[0020] The rotating frame 13 is an annular frame that oppositely supports the X-ray tube 11 and the X-ray detector 12 and rotates the X-ray tube 11 and the X-ray detector 12 by the control device 15. For example, the rotating frame 13 is a casting made of aluminum. Note that in addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 can further support an X-ray high voltage device 14, a wedge 16, a collimator 17, DAS18, etc. Further, the rotating frame 13 can further support various configurations not shown in FIG. 1.

[0021] Communication devices are provided on the rotating frame 13 and the fixed frame 19 which is a non-rotating part of the gantry device 10, respectively. For example, the data (collected X-ray signals) generated by DAS18 is transmitted from the communication device provided on the rotating frame 13 to the communication device provided on the fixed frame 19 by wireless communication and transferred to the console device 40. For example, the control signal for the rotating frame 13 transmitted by the console device 40 is transmitted from the communication device provided on the fixed frame 19 to the communication device provided on the rotating frame 13 by wireless communication. Note that the communication device provided on the rotating frame 13 and the communication device provided on the fixed frame 19 constitute a wireless communication system 100 described later.

[0022] FIG. 2 is a diagram showing a specific example when the wireless communication system 100 according to the present embodiment is applied to the X-ray CT apparatus 1.

[0023] In the example shown in FIG. 2, in the gantry device 10, as the communication devices on the transmission side, there are a communication device 111 arranged on the rotating frame 13 and a communication device 211 arranged on the fixed frame 19. As the communication devices on the reception side, there are a communication device 120 arranged on the fixed frame 19 and a communication device 220 arranged on the rotating frame 13. Further, in the gantry device 10, a slip ring capable of transmitting power, signals, etc. from the fixed frame 19 to the rotating frame 13 is provided. In the transmission-side communication device 111 and the reception-side communication device 120, the data to be transmitted (downlink data) is the X-ray signal collected by the DAS 18. In the transmission-side communication device 211 and the reception-side communication device 220, the data to be transmitted (uplink data) is the control signal for the rotating frame 13 transmitted by the console device 40.

[0024] Returning to FIG. 1, the control device 15 includes a processing circuit having a CPU (Central Processing Unit) etc. and a drive mechanism such as a motor and an actuator. The control device 15 receives an input signal from the input interface 43 and controls the operations of the gantry device 10 and the bed device 30. For example, the control device 15 controls the rotation of the rotating frame 13, the tilt of the gantry device 10, the operations of the bed device 30 and the top plate 33, etc. Taking an example, as the control for tilting the gantry device 10, the control device 15 rotates the rotating frame 13 about an axis parallel to the X-axis direction based on the input tilt angle information. Note that the control device 15 may be provided in the gantry device 10 or may be provided in the console device 40.

[0025] The bed device 30 is a device for placing and moving a subject P to be imaged, and includes a base 31, a bed driving device 32, a top plate 33, and a support frame 34. The base 31 is a housing that supports the support frame 34 so as to be movable in the vertical direction. The bed driving device 32 is a driving mechanism that moves the top plate 33 on which the subject P is placed in the major axis direction of the top plate 33, and includes a motor, an actuator, and the like. The top plate 33 provided on the upper surface of the support frame 34 is a plate on which the subject P is placed. Note that the bed driving device 32 may move the support frame 34 in the major axis direction of the top plate 33 in addition to the top plate 33.

[0026] The console device 40 includes a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 will be described as a separate body from the gantry device 10, the gantry device 10 may include the console device 40 or a part of each component of the console device 40.

[0027] The memory 41 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like. The memory 41 stores, for example, projection data and CT image data. Further, for example, the memory 41 stores a program for the circuits included in the X-ray CT apparatus 1 to realize their functions. Note that the memory 41 may be realized by a server group (cloud) connected to the X-ray CT apparatus 1 via a network.

[0028] The display 42 displays various types of information. For example, the display 42 displays various images generated by the processing circuit 44 or displays a GUI (Graphical User Interface) for receiving various operations from an operator. For example, the display 42 is a liquid crystal display or a CRT (Cathode Ray Tube) display. Note that the display 42 may be provided on the gantry device 10. Further, the display 42 may be a desktop type or may be configured by a tablet terminal or the like capable of wireless communication with the console device 40 main body.

[0029] The input interface 43 receives various input operations from the operator, converts the received input operations into electrical signals, and outputs them to the processing circuit 44. For example, the input interface 43 receives input operations from the operator such as the reconstruction conditions when reconstructing CT image data and the image processing conditions when generating a post-processed image from the CT image data. For example, the input interface 43 is realized by a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touch pad that performs an input operation by touching an operation surface, a touch screen in which a display screen and a touch pad are integrated, a non-contact input circuit using an optical sensor, a voice input circuit, and the like. Note that the input interface 43 may be provided in the gantry device 10. Also, the input interface 43 may be configured by a tablet terminal or the like that can communicate wirelessly with the console device 40 main body. Also, the input interface 43 is not limited to only those having physical operation parts such as a mouse and a keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the console device 40 and outputs this electrical signal to the processing circuit 44 is also included in the example of the input interface 43.

[0030] The processing circuit 44 controls the operation of the entire X-ray CT apparatus 1. For example, the processing circuit 44 executes a system control function 440, a scan control function 441, a pre-processing function 442, a reconstruction processing function 443, and a display control function 444.

[0031] The system control function 440 controls various functions of the processing circuit 44 based on the input operations received from the operator via the input interface 43.

[0032] The scan control function 441 performs a scan on the subject P using X-rays. For example, the scan control function 441 controls the scan based on an input operation received from an operator via the input interface 43. Specifically, the scan control function 441 controls the output voltage from the high voltage generator by transmitting a control signal to the X-ray high voltage device 14 based on the input operation. Also, the scan control function 441 controls the data collection by the DAS 18 by transmitting a control signal to the DAS 18.

[0033] The preprocessing function 442 generates preprocessed data by performing preprocessing on the X-ray detection data transmitted from the DAS 18. Specifically, the preprocessing function 442 generates preprocessed data by performing correction processes such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction. Note that the data before preprocessing (X-ray detection data) and the data after preprocessing may also be collectively referred to as projection data.

[0034] The reconstruction processing function 443 generates CT image data by reconstructing the projection data generated by the preprocessing function 442 using various reconstruction methods (for example, backprojection methods such as FBP (Filtered Back Projection) and sequential approximation methods). Also, the reconstruction processing function 443 stores the generated CT image data in the memory 41.

[0035] The display control function 444 causes various images generated by the processing circuit 44 to be displayed on the display 42. For example, the display control function 444 causes the CT image data generated by the reconstruction processing function 443 to be displayed on the display 42.

[0036] In the X-ray CT apparatus 1 shown in FIG. 1, each processing function is stored in the memory 41 in the form of a program executable by a computer. The processing circuit 44 is a processor that reads and executes a program from the memory 41 to realize the functions corresponding to the respective programs. In other words, the processing circuit 44 in the state of having read each program has the functions corresponding to the read program.

[0037] The term "processor" used in the above description means a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC). The term "processor" also means a circuit such as a programmable logic device. Examples of the programmable logic device include a simple programmable logic device (SPLD) and a complex programmable logic device (CPLD). Examples of the programmable logic device also include a field programmable gate array (FPGA). When the processor is, for example, a CPU, the processor realizes functions by reading and executing a program stored in the memory 41. On the other hand, when the processor is, for example, an ASIC, instead of storing a program in the memory 41, the program is directly incorporated into the circuit of the processor. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, and a plurality of independent circuits may be combined to be configured as one processor to realize its functions. Further, a plurality of components in FIG. 1 may be integrated into one processor to realize its functions.

[0038] As described above, the overall configuration of the X-ray CT apparatus 1 to which the wireless communication system 100 according to the present embodiment is applied has been described.

[0039] (First Embodiment) FIG. 3 is a diagram showing an example of the configuration of the wireless communication system 100 according to the first embodiment. FIG. 4 is a perspective view showing a configuration example of the wireless communication device 110 on the transmission side in FIG. 3.

[0040] As shown in FIG. 3, the wireless communication system 100 includes a wireless communication device 110 on the transmission side and a wireless communication device 120 on the reception side. In the wireless communication system 100, baseband wireless communication is performed between the wireless communication device 110 on the transmission side and the wireless communication device 120 on the reception side by electrostatic coupling or electromagnetic field coupling. That is, the wireless communication device 110 and the wireless communication device 120 each function as a communication device that performs baseband wireless communication. For example, the wireless communication device 110 is arranged on the rotating part (rotating frame 13), and the wireless communication device 120 is arranged on the fixed part (fixed frame 19).

[0041] First, the configuration of the wireless communication device 110 on the transmission side will be described. As shown in FIG. 3, the wireless communication device 110 on the transmission side includes a transmission circuit 101, a transmission line 108, a substrate 109, and a transmission coupler 111. For example, the substrate 109 is provided on the rotating frame 13, and the transmission circuit 101 is mounted on the substrate 109. For example, the transmission coupler 111 is fixed to the rotating frame 13 having an annular shape or the fixed frame 19 in the X-ray CT apparatus 1 shown in FIG. 2. In the present embodiment, the transmission coupler 111 is provided on the rotating frame 13 and formed in an annular shape. Configurations other than the transmission circuit 101, the transmission line 108, the substrate 109, and the transmission coupler 111 of the wireless communication device 110 on the transmission side will be described later.

[0042] Here, in the present embodiment, it is assumed that the communication signal input to the transmission coupler 111 is a baseband signal without modulation by a carrier wave. Further, the communication signal transmitted from the transmission circuit 101 is a differential signal, for example, a digital serial signal encoded by a code such as 8B10B or 64B66B. Therefore, the received signal received by the receiving circuit 122 is also a differential signal and a serial signal. The transmission line 108 is a transmission line for transmitting the signal output from the transmission circuit 101 to the transmission coupler 111, and includes a transmission line on the substrate 109 and a harness or the like connecting the transmission coupler 111 disposed at a location separated from the substrate 109. Its form may be a coaxial line, a differential transmission line, or a combination of both.

[0043] The transmission circuit 101 inputs transmission data (communication signal) including a transmission signal and a clock signal, performs clock signal recovery (restoration, repair) and encoding for ensuring DC balance on the transmission data, and transmits the transmission data. For example, in FIG. 4, the transmission circuit 101 is composed of differential transmission buffers and transmits communication signals SIG + and SIG- (not shown) as transmission data.

[0044] The transmission line 108 transmits the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111. For example, in FIG. 4, the transmission line 108 has transmission lines 108a and 108b constituting a differential transmission line, and the transmission lines 108a and 108b transmit the communication signals SIG + and SIG- (not shown) transmitted from the transmission circuit 101 to the transmission coupler 111, respectively.

[0045] The transmitting coupler 111 transmits the communication signal transmitted on the transmission line 108 to the wireless communication device 120 on the receiving side. For example, in FIG. 4, the transmitting coupler 111 has electrodes 111a and 111b which are two separated electrodes, and a reference potential conductor 111d (GND). One end of each of the electrodes 111a and 111b is connected to the transmission lines 108a and 108b respectively, and the other ends (terminals) 111C of the electrodes 111a and 111b are connected to a termination circuit terminated with an impedance substantially equal to the differential impedance of the transmission line 108. For example, the termination circuit is composed of a π-type termination circuit in which termination resistors Z1, Z2, and Z3 are arranged at the terminals 111C of the electrodes 111a and 111b. The termination resistor Z1 is arranged between the terminals 111C of the electrode 111a and the terminal 111C of the electrode 111b. The termination resistor Z2 is arranged between the terminal 111C of the electrode 111a and the reference potential conductor 111d (GND). The termination resistor Z3 is arranged between the terminal 111C of the electrode 111b and the reference potential conductor 111d (GND).

[0046] Here, in the present embodiment, the transmitting coupler 111 is formed, for example, as a pattern on a substrate such as a multilayer dielectric substrate or a flexible substrate. When it is formed of a flexible substrate, the reference potential may be supplied by a conductive support member.

[0047] Also, in the present embodiment, the electrodes 111a and 111b of the transmitting coupler 111 are arranged in a transmission line type coupler structure that acts as a transmission line extending as a planar conductor on a substrate such as a multilayer dielectric substrate or a flexible substrate. In the transmission line type coupler structure, a communication signal is supplied from one end of the electrodes 111a and 111b, and a termination resistor substantially equal to the characteristic impedance Z of the transmission line is arranged at the other end. With such a transmission line type coupler structure, the standing wave generated in the electrodes 111a and 111b can be suppressed. Therefore, the length in the longitudinal direction of the electrodes 111a and 111b can be set to an arbitrary value without limitation, and it becomes possible to form a transmitting coupler in the order of several meters such as the X-ray CT apparatus 1.

[0048] Next, the configuration of the receiving-side wireless communication device 120 will be described. As shown in FIG. 3, the receiving-side wireless communication device 120 includes a receiving coupler 121 and a receiving circuit 122. For example, the receiving coupler 121 is fixed to the rotating frame 13 having an annular shape or the fixed frame 19 in the X-ray CT apparatus 1 shown in FIG. 2. In the present embodiment, the receiving coupler 121 is provided on the fixed frame 19.

[0049] The receiving coupler 121 receives the communication signal transmitted from the transmitting coupler 111 by electrostatic coupling or electromagnetic field coupling. For example, the receiving coupler 121 has electrodes 121a and 121b (not shown) which are two separated electrodes. The electrodes 121a and 121b are respectively arranged in proximity so that the electrodes 111a and 111b of the transmitting coupler 111 face each other, and are coupled by, for example, an electromagnetic field. Since differential signals (communication signals SIG+ and SIG- (not shown)) having opposite phases to each other are input to the electrodes 111a and 111b, differential signals having opposite phases to each other are also output from the electrodes 121a and 121b. That is, when a communication signal is input to the transmitting coupler 111, a communication signal is output from the receiving coupler 121 due to the action of electromagnetic field coupling. The communication signal output from the receiving coupler 121 is subjected to various processes so that the communication signal is restored by the receiving circuit 122 and then output.

[0050] The receiving circuit 122 amplifies the communication signal received by the receiving coupler 121, recovers (restores, repairs) the clock signal included in the communication signal, and generates received data (communication signal) based on the transmission signal included in the communication signal and the recovered clock signal.

[0051] For example, the receiving circuit 122 has circuits such as an emitter follower circuit and a differential amplifier circuit. The input impedance of the circuit is set to be sufficiently larger than the impedance of the capacitance component generated by the coupling between the transmitting coupler 111 and the receiving coupler 121 at the lowest frequency of the communication signal. By setting the input impedance to such a value, it becomes possible to acquire a waveform according to the communication signal input to the transmitting coupler 111.

[0052] Further, the receiving circuit 122 has an amplification circuit for amplifying the communication signal received by the receiving coupler 121 at the subsequent stage of circuits such as an emitter follower circuit and a differential amplification circuit, and a function of correcting the frequency characteristics of the coupling state between the transmitting coupler 111 and the receiving coupler 121. Further, the receiving circuit 122 has a function of outputting the communication signal subjected to processing such as amplification as an output signal from the wireless communication device 120 at a signal level conforming to the external interface specification. For example, when the level of the communication signal becomes equal to or higher than the reference level, a limiting amplifier (limiting amplifier) that controls the output level to a predetermined value, that is, conforms to the external interface specification can be used.

[0053] Further, the receiving circuit 122 has a function of detecting the transition state of bits of the baseband signal using a hysteresis comparator or the like and restoring the transmitted communication signal. Further, the receiving circuit 122 has a function of reducing the jitter component by a CDR (Clock, Data, Recovery) circuit, and the combination thereof is selected according to the transmission speed and the characteristics of the system.

[0054] Note that in this embodiment, when the communication signal output from the receiving coupler 121 is at a waveform level that can be received by the receiving circuit 122, it is also possible to directly connect it without passing through the amplification circuit, and it is not limited to the above configuration. The electromagnetic field coupling in this embodiment includes both electric field coupling and magnetic field coupling. That is, the wireless communication between the wireless communication device 110 and the wireless communication device 120 may be performed by electric field coupling, may be performed by magnetic field coupling, or may be performed by both electric field coupling and magnetic field coupling. Further, the electrodes 121a and 121b (not shown) of the wireless communication device 120 on the receiving side can also be translated or rotated as long as they maintain a positional relationship facing the electrodes 111a and 111b of the wireless communication device 110 on the transmitting side.

[0055] In addition, in the present embodiment, the transmission coupler 111 is provided on the rotating frame 13, and the reception coupler 121 is provided on the fixed frame 19. However, the reception coupler 121 can also be applied to rotational movement. As long as the transmission coupler 111 and the reception coupler 121 maintain a positional relationship of being close to and facing each other, the wireless communication device 120 on the reception side may be rotationally moved, and there is no particular limitation on the coupler structure. Further, the electrodes 111a, 111b and the electrodes 121a, 121b (not shown) are formed in an annular conductor shape. These electrodes may have any shape as long as the change in the coupling degree can be suppressed to be small even when the transmission coupler 111 and the reception coupler 121 rotate relative to each other. For example, they may be polygonal or may have a shape with a slit (a shape in which the ring is partially interrupted). Also, the diameters of the electrode 111a and the electrode 121a (not shown) may be different from each other, and the diameters of the electrode 111b and the electrode 121b (not shown) may be different from each other.

[0056] In addition, the wireless communication system 100 according to the present embodiment can be applied not only to wireless communication between the rotating part (rotating frame 13) and the fixed part (fixed frame 19) of the X-ray CT apparatus 1. For example, the wireless communication system 100 according to the present embodiment can also be applied to wireless communication between the main body and the print head of an inkjet printer, wireless communication between the stage and the main body of a semiconductor exposure apparatus, or wireless communication between the drive part and the fixed part of a multi-axis actuator.

[0057] Here, data processing in the case where the wireless communication system 100 according to the present embodiment is also applied to wireless communication between the rotating part (rotating frame 13) and the fixed part (fixed frame 19) of the X-ray CT apparatus 1 will be described.

[0058] In the wireless communication system 100 according to this embodiment, the wireless communication device 110 on the transmission side is provided on the rotating frame 13, and the wireless communication device on the reception side is provided on the fixed frame 19. In this case, the transmission data (communication signal) is the X-ray signal (X-ray detection data) collected by the data acquisition device (DAS18). The wireless communication device 120 on the reception side recovers the clock signal included in the transmission data, and generates reception data (communication signal) based on the transmission data and the recovered clock signal. For example, in the processing circuit 44 of the console device 40, the preprocessing function 442 performs preprocessing on the reception data transmitted from the DAS18 to generate projection data. The reconstruction processing function 443 generates CT image data by reconstructing the projection data generated by the preprocessing function 442.

[0059] For example, when a communication error occurs in the wireless communication system, there may be an abnormality in either the wireless communication device on the transmission side or the wireless communication device on the reception side due to some reason. In this case, first, the operator adjusts the alignment (for example, the positional relationship between the transmission coupler and the reception coupler) of the wireless communication device on the transmission side and the wireless communication device on the reception side. If the communication error is not eliminated even after adjusting the alignment, the operator tries to identify the abnormal location by trial and error by replacing the wireless communication device on the transmission side or the wireless communication device on the reception side. For example, first, the operator replaces the wireless communication device on the reception side. If the communication error is not eliminated even after replacing the wireless communication device on the reception side, the operator replaces the wireless communication device on the transmission side. However, it is inefficient for the operator to identify the abnormal location by trial and error. In particular, replacing the transmission coupler 111 formed in an annular shape on the rotating frame 13 requires time-consuming work, so it is necessary to carefully consider whether replacement is necessary.

[0060] Therefore, in order to efficiently identify the location of an abnormality when an abnormality occurs in the wireless communication system 100 according to this embodiment, the wireless communication system 100 includes a detection unit, an abnormality determination unit, and a notification unit. The detection unit detects the signal level of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111. The abnormality determination unit determines an abnormality related to the transmission circuit 101 and the transmission coupler 111 based on the signal level detected by the detection unit. The notification unit notifies different maintenance information depending on whether the result of the determination by the abnormality determination unit is an abnormality related to the transmission circuit 101 or an abnormality related to the transmission coupler 111.

[0061] For example, in the wireless communication system 100 according to this embodiment, by adding a function to identify the location of an abnormality on the transmission side to the wireless communication device 110 on the transmission side, it is possible to automatically and quickly identify the location of an abnormality when an abnormality occurs in the wireless communication system 100.

[0062] As shown in FIG. 3, the wireless communication device 110 on the transmission side further includes a waveform detection circuit 102, an abnormality determination unit 103, and a display unit 104 in addition to the transmission circuit 101. On the substrate 109, in addition to the transmission circuit 101, the waveform detection circuit 102, the abnormality determination unit 103, and the display unit 104 are mounted.

[0063] Here, the waveform detection circuit 102 and the abnormality determination unit 103 have a function of identifying the location of an abnormality on the transmission side.

[0064] The waveform detection circuit 102 detects the signal level of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111. The waveform detection circuit 102 is an example of the "detection unit". In the example shown in FIG. 4, among the transmission paths 108 (transmission paths 108a and 108b) for transmitting the communication signal from the transmission circuit 101 to the transmission coupler 111, the waveform detection circuit 102 is connected to the transmission path 108b, but the connection between the transmission path 108a and the waveform detection circuit 102 is not shown.

[0065] The abnormality determination unit 103 determines an abnormality related to the transmission circuit 101 and the transmission coupler 111 based on the signal level detected by the waveform detection circuit 102.

[0066] FIG. 5 is a diagram for explaining the processing of the abnormality determination unit 103 of the wireless communication device 110 on the transmission side of the wireless communication system 100 according to the first embodiment.

[0067] For example, the abnormality determination unit 103 determines whether the signal level detected by the waveform detection circuit 102 is within a predetermined signal level range. The signal level is the voltage value of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111. In this case, the predetermined signal level range is a range of predetermined voltages.

[0068] For example, the abnormality determination unit 103 determines whether the voltage value of the communication signal detected by the waveform detection circuit 102 is within a predetermined voltage range. Here, when the voltage value is within the predetermined voltage range, the abnormality determination unit 103 determines that there is no abnormality related to the transmission circuit 101 and the transmission coupler 111. That is, the abnormality determination unit 103 determines that the transmission circuit 101 and the transmission coupler 111 are normal.

[0069] On the other hand, when the voltage value of the communication signal detected by the waveform detection circuit 102 is below the predetermined voltage range, the abnormality determination unit 103 determines that an abnormality has occurred in the transmission circuit 101. Also, when the voltage value of the communication signal detected by the waveform detection circuit 102 is above the predetermined voltage range, the abnormality determination unit 103 determines that an abnormality has occurred in the transmission coupler 111.

[0070] The abnormality determination unit 103 converts the signal level (voltage value) detected by the waveform detection circuit 102 into a digital signal so that it becomes information that the notification unit can notify.

[0071] The display unit 104 notifies different maintenance information depending on whether the determination result by the abnormality determination unit 103 is an abnormality related to the transmission circuit 101 or an abnormality related to the transmission coupler 111. The display unit 104 is an example of the "notification unit".

[0072] The display unit 104 is a light-emitting element provided on the substrate 109 on which the transmission circuit 101 is mounted. Examples of the light-emitting element include an LED (Light Emitting Diode).

[0073] The abnormality determination unit 103 drives (lights up, turns off, blinks) the LED which is the display unit 104 to notify maintenance information. For example, when the result of the determination is an abnormality related to the transmission circuit 101, the abnormality determination unit 103 lights up the LED to notify maintenance information indicating that an abnormality has occurred in the transmission circuit 101. For example, when the result of the determination is an abnormality related to the transmission coupler 111, the abnormality determination unit 103 blinks the LED to notify maintenance information indicating that an abnormality has occurred in the transmission coupler 111.

[0074] Also, a plurality of LEDs may be provided as the display unit 104. For example, as shown in FIG. 4, the display unit 104 includes an LED 104a which is a first light-emitting element for notifying an abnormality related to the transmission circuit 101, and an LED 104b which is a second light-emitting element for notifying an abnormality related to the transmission coupler 111.

[0075] For example, when the result of the determination by the abnormality determination unit 103 is an abnormality related to the transmission circuit 101, the LED 104a is driven to notify maintenance information indicating that an abnormality has occurred in the transmission circuit 101. For example, the abnormality determination unit 103 lights up or blinks the LED 104a in red to notify the maintenance information.

[0076] Also, when the result of the determination by the abnormality determination unit 103 is an abnormality related to the transmission coupler 111, the LED 104b is driven to notify maintenance information indicating that an abnormality has occurred in the transmission coupler 111. For example, the abnormality determination unit 103 lights up or blinks the LED 104b in blue to notify the maintenance information.

[0077] Further, the abnormality determination unit 103 outputs the determination result from the wireless communication device 110 on the transmission side provided in the rotation frame 13, via the control device 15 in the gantry device 10 shown in FIG. 1, to the processing circuit 44 of the console device 40 shown in FIG. 1. The display control function 444 of the processing circuit 44 outputs maintenance information. The display control function 444 is an example of a "notification unit" provided in the console device 40.

[0078] For example, when the determination result is an abnormality related to the transmission circuit 101, the display control function 444 causes the display 42 to display maintenance information indicating that an abnormality has occurred in the transmission circuit 101. Also, when the determination result is an abnormality related to the transmission coupler 111, the display control function 444 causes the display 42 to display maintenance information indicating that an abnormality has occurred in the transmission coupler 111. The display 42 is an example of an "output unit".

[0079] Here, a process in which the voltage value of the communication signal detected by the waveform detection circuit 102 becomes equal to or greater than a predetermined voltage range when an abnormality occurs in the transmission coupler 111 will be described.

[0080] FIG. 6A is a diagram showing a simulation result when the terminating resistor Z3 disposed between the terminal 111C of the electrode 111b of the transmission coupler 111 and the reference potential conductor 111d (GND) in the wireless communication system 100 according to the first embodiment is short-circuited. FIG. 6B is a diagram showing a simulation result when the terminating resistor Z3 disposed between the terminal 111C of the electrode 111b of the transmission coupler 111 and the reference potential conductor 111d (GND) in the wireless communication system 100 according to the first embodiment is open.

[0081] In the example shown in FIGS. 6A and 6B, the transmission speed of the communication signal is 6.25 Gbps. In FIGS. 6A and 6B, the top figure shows the output waveform of the transmission circuit 101 (the output waveforms on the sides of electrodes 111a and 111b). Also, in FIGS. 6A and 6B, the middle figure shows the waveform at the termination 111C of the transmission coupler 111 (the waveforms of electrodes 111a and 111b). Further, in FIGS. 6A and 6B, the bottom figure shows the waveform on the transmission line 108 on the substrate 109 on which the transmission circuit 101 is mounted (the waveforms of transmission lines 108a and 108b).

[0082] In FIGS. 6A and 6B, when an abnormality such as an open or short circuit occurs at the termination 111C of the electrode 111b of the transmission coupler 111, it can be seen that the peak value of the waveform on the transmission line 108b is larger than that in the normal state (for example, the waveform of the transmission line 108a). This is because at the termination 111C of the transmission coupler 111, total reflection of the incident wave occurs in the case of an open circuit, and reverse reflection of the incident wave occurs in the case of a short circuit, resulting in interference between the traveling wave from the transmission circuit 101 and the reflected wave at the transmission termination 111C. The waveform detection circuit 102 can detect an abnormality of the transmission coupler 111 by detecting the peak value of the waveform in this abnormal state. As a detection method, it is possible to detect by picking up the voltage waveform with an impedance sufficiently higher than the characteristic impedance of the transmission line 108 and performing half-wave rectification or full-wave rectification.

[0083] FIG. 7 is a diagram showing an example of a specific configuration of the waveform detection circuit 102 of the wireless communication device 110 on the transmission side in the wireless communication system 100 according to the first embodiment.

[0084] The waveform detection circuit 102 includes a half-wave rectification circuit for detecting a voltage value as a signal level. In this case, in order to detect the signal level (voltage value) of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111, the waveform detection circuit 102 is connected to the transmission line 108 with an impedance higher than the characteristic impedance of the transmission line 108 through which the communication signal is transmitted from the transmission circuit 101 to the transmission coupler 111.

[0085] The waveform detection circuit 102 includes a resistor 102A which is a resistive element, a diode 102B, and a capacitor 102C which is a capacitive element, and the resistor 102A, the diode 102B, and the capacitor 102C are configured as a series circuit. Specifically, one end of the resistor 102A is connected to the transmission line 108, the other end of the resistor 102A is connected to the anode of the diode 102B, and the capacitor 102C is connected between the cathode of the diode 102B and the reference potential conductor (GND), and is connected to the input of the abnormality determination unit 103.

[0086] The resistor 102A is selected to have an impedance sufficiently higher than the characteristic impedance of the transmission line 108. For example, when the characteristic impedance of the transmission line 108 is 50 Ω, it is preferably selected to have a resistance value of about 200 Ω or more. In this embodiment, the resistance value used in the simulation is 510 Ω.

[0087] The diode 102B uses, for example, a Schottky diode or the like. If a diode with a small forward voltage and a small parasitic capacitance is selected, it is possible to cope with the waveforms of higher-speed transmission data (communication signals). In the simulation of this embodiment, an ideal diode is used. If the transmitted communication signal is a digital serial signal encoded by a code such as 8B10B or 64B66B, the mark rate is 50%. The mark rate indicates the ratio of the time occupied by the voltage representing "1 (mark)" within a certain period of time. When the mark rate is 50%, the voltage value charged in the capacitor 102C by half-wave rectification becomes a voltage value proportional to the peak value of the waveform of the transmission data (communication signal).

[0088] FIGS. 8A and 8B are diagrams showing the simulation results of the voltage charged in the capacitor 102C from the timing when an abnormality occurs in the transmission coupler 111 in the waveform detection circuit 102 of the wireless communication device 110 on the transmission side of the wireless communication system 100 according to the first embodiment.

[0089] As shown in FIG. 8A, it can be seen that the voltage charged in the capacitor 102C rises from the timing when an abnormality occurs. Since the speed of this rise is determined by the time constant of the resistor 102A and the capacitor 102C, the capacitance of the capacitor 102C may be selected according to the system requirements.

[0090] When an abnormality such as an open circuit or a short circuit occurs in the transmission coupler 111, the voltage value detected by the waveform detection circuit 102 ideally becomes about twice that in the normal state, as shown in FIG. 8B. In this case, the voltage value detected by the waveform detection circuit 102 is, for example, equal to or higher than a predetermined voltage range. Realistically, a drop due to the mark rate of the communication signal and the forward voltage of the diode 102B (the voltage generated when a current flows in the forward direction in which the diode is turned on) occurs, but it is larger than that in the normal state.

[0091] Thus, when the waveform detection circuit 102 detects the voltage value of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111, if the voltage value is equal to or higher than a predetermined voltage range, the abnormality determination unit 103 determines that an abnormality has occurred in the transmission coupler 111.

[0092] In this case, since it is necessary to replace the transmission coupler 111, the notification unit (display unit 104, display control function 444) notifies maintenance information indicating that an abnormality has occurred in the transmission coupler 111.

[0093] Next, a process in which the voltage value of the communication signal detected by the waveform detection circuit 102 becomes equal to or lower than a predetermined voltage range when an abnormality occurs in the transmission circuit 101 will be described.

[0094] FIG. 9 is a diagram for explaining a case where an abnormality occurs in the transmission circuit 101 in the wireless communication device 110 on the transmission side of the wireless communication system 100 according to the first embodiment.

[0095] The transmission circuit 101 is, for example, a differential driver circuit. When an abnormality such as an open circuit, a short circuit, or a breakdown of a transistor occurs in the output impedance of this driver circuit, the output of the transmission circuit 101 becomes small. In this case, the voltage value detected by the waveform detection circuit 102 becomes equal to or less than a predetermined voltage range. Also, even when the transmission circuit 101 does not output to the transmission coupler 111, the voltage value detected by the waveform detection circuit 102 becomes equal to or less than a predetermined voltage range.

[0096] In this case, since it is necessary to replace the transmission circuit 101, the notification unit (display unit 104, display control function 444) notifies maintenance information indicating that an abnormality has occurred in the transmission circuit 101.

[0097] Note that, as an example for detecting the signal level (voltage value) of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111, in FIG. 7, an example of detecting with an impedance sufficiently higher than the characteristic impedance of the transmission line 108 has been described, but it is also possible to detect with a directional coupler or a power divider.

[0098] FIG. 10 is a diagram showing another example of the configuration of the wireless communication system 100 according to the first embodiment.

[0099] As shown in FIG. 10, the wireless communication device 110 on the transmission side further includes a detector 105. The detector 105 is further mounted on the substrate 109.

[0100] The detector 105 is provided on the substrate 109 in order to detect the signal level (voltage value) of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111. The detector 105 inputs the communication signal transmitted from the transmission circuit 101, transmits the communication signal to the transmission coupler 111, and outputs the communication signal to the waveform detection circuit 102. The waveform detection circuit 102 and the detector 105 are examples of a "first detection unit" and a "second detection unit", respectively.

[0101] Detector 105 is, for example, a power divider. A power divider inputs a single signal and outputs two or more signals. The power level of the output signals is 1 / N of the input power level, where N corresponds to the number of outputs of the divider. In the example shown in FIG. 10, the power divider inputs a single signal and outputs two signals. As a power divider, a resistive divider, which is the most common implementation form of the power divider, can be mentioned. When the power divider outputs two signals, in the example shown in FIG. 10, when the input impedance is Zo, a resistive divider, which is an example of the power divider, uses three resistors with equal resistance values (R = Zo / 3). In FIG. 10, the port on the transmission circuit 101 side of the transmission line 108 is the input port of the power divider, the port on the transmission coupler 111 side of the transmission line 108 is the output port 1 of the power divider, and the port on the waveform detection circuit 102 side is the output port 2 of the power divider. The power divider inputs the communication signal transmitted from the transmission circuit 101, transmits the communication signal to the transmission coupler 111, and outputs the communication signal to the waveform detection circuit 102.

[0102] Alternatively, detector 105 is, for example, a directional coupler. The directional coupler has a first transmission line that is part of the transmission line 108 and a second transmission line 105A parallel to the first transmission line. In FIG. 10, the port on the transmission circuit 101 side of the transmission line 108 is the input port of the directional coupler, the port on the transmission coupler 111 side of the transmission line 108 is the output port of the directional coupler, and the output port of the second transmission line 105A is the coupling port of the directional coupler. When the communication signal transmitted from the transmission circuit 101 is input to the input port, it is transmitted from the output port to the transmission coupler 111 while slightly attenuating on the transmission line 108. At this time, a part of the energy of the traveling wave is output from the coupling port to the waveform detection circuit 102 by electromagnetic coupling in the second transmission line 105A.

[0103] Note that in the wireless communication system 100 according to the present embodiment, the receiving-side wireless communication device 120 is also provided with a function for identifying an abnormal part on the receiving side. For example, the receiving-side wireless communication device 120 has a function capable of notifying an abnormality as LOS (Loss of Signal) when the received signal level falls below a predetermined value.

[0104] For example, as shown in FIGS. 3 and 10, the receiving circuit 122 includes an abnormality determination unit 122A. The abnormality determination unit 122A determines an abnormality on the receiving side based on the signal level when the receiving coupler 121 receives the communication signal transmitted from the transmission coupler 111. The abnormality determination unit 122A is an example of a "receiving-side abnormality determination unit".

[0105] When the abnormality determination unit 122A determines an abnormality on the receiving side and the abnormality determination unit 103 determines that no abnormality has occurred in the transmission circuit 101 and the transmission coupler 111, the display control function 444 in the console device 40 notifies the abnormality on the receiving side. For example, it is assumed that the display control function 444 receives the determination result from the transmission-side wireless communication device 110 of the rotary frame 13 via the control device 15 in the gantry device 10 that the abnormality determination unit 103 has determined that no abnormality has occurred in the transmission circuit 101 and the transmission coupler 111. In this case, the display control function 444 causes the display 42 to display maintenance information indicating that an abnormality has occurred on the receiving side. The display control function 444 is an example of a "receiving-side notification unit" provided in the console device 40.

[0106] As described above, the receiving circuit 122 includes circuits such as an emitter follower circuit and a differential amplifier circuit. The emitter follower circuit and the differential amplifier circuit are circuits that operate so that the output voltage follows the input voltage. Therefore, when the receiving coupler 121 receives the communication signal transmitted from the transmission coupler 111, the receiving circuit 122 can follow the signal level (voltage value) of the communication signal.

[0107] However, when the signal level (voltage value) of the communication signal received by the receiving coupler 121 falls below a predetermined value (predetermined voltage value), for example, as an abnormality on the receiving side, there may be an abnormality in the receiving coupler 121. Therefore, in the wireless communication system 100 according to the present embodiment, when the signal level of the communication signal received by the receiving coupler 121 falls below the predetermined value in a state where no abnormality on the transmitting side is detected, it can be determined that there is an abnormality in the wireless communication device 120 on the receiving side.

[0108] From the above description, in the wireless communication system 100 according to the first embodiment, the waveform detection circuit 102 detects the signal level of the communication signal transmitted from the transmission circuit 101 to the transmission coupler 111. The abnormality determination unit 103 determines an abnormality related to the transmission circuit 101 and the transmission coupler 111 based on the signal level detected by the waveform detection circuit 102. The notification unit (display unit 104, display control function 444) notifies different maintenance information depending on whether the determination result by the abnormality determination unit 103 is an abnormality related to the transmission circuit 101 or an abnormality related to the transmission coupler 111. Thereby, in the present embodiment, when an abnormality occurs in the wireless communication system 100, the abnormal location can be efficiently specified.

[0109] (Second Embodiment) FIG. 11A is a diagram showing an example of a specific configuration of the waveform detection circuit 102 of the wireless communication device 110 on the transmitting side in the wireless communication system 100 according to the second embodiment.

[0110] The waveform detection circuit 102 includes a full-wave rectification circuit for detecting a voltage value as the signal level. That is, in the second embodiment, the waveform detection circuit 102 includes a full-wave rectification circuit instead of the half-wave rectification circuit (FIG. 7) in the first embodiment.

[0111] The waveform detection circuit 102 includes, as a full-wave rectifier circuit, resistors 102Aa and 102Ab which are resistance elements, diodes 102Ba and 102Bb, and a capacitor 102C which is a capacitance element. For example, one end of resistor 102Aa is connected to transmission line 108a, the other end of resistor 102Aa is connected to the anode of diode 102Ba, one end of resistor 102Ab is connected to transmission line 108b, and the other end of resistor 102Ab is connected to the anode of diode 102Bb. Further, capacitor 102C is connected between the cathodes of diodes 102Ba and 102Bb and the reference potential conductor (GND), and is connected to the input of the abnormality determination unit 103.

[0112] FIG. 11B is a diagram showing another example of the specific configuration of the waveform detection circuit 102 of the wireless communication device 110 on the transmission side in the wireless communication system 100 according to the second embodiment.

[0113] The waveform detection circuit 102 includes a full-wave rectifier circuit for detecting a voltage value as a signal level, and a common-mode filter 102D for suppressing noise (noise current) transmitted as a common mode in the full-wave rectifier circuit. In this case, a common-mode filter 102D is provided between the other ends of resistors 102Aa and 102Ab and the anodes of diodes 102Ba and 102Bb.

[0114] In the examples shown in FIGS. 11A and 11B, it is assumed that the configuration of the transmission line is differential. By adopting the configurations shown in FIGS. 11A and 11B, it is possible to detect the voltage value not only for each of the transmission lines 108a and 108b alone, but also for each differential electric line (a pair of transmission lines 108a and 108b).

[0115] Therefore, in the wireless communication system 100 according to the second embodiment, it is possible to reduce the number of components such as capacitor 102C as compared with the first embodiment. Further, in the wireless communication system 100 according to the second embodiment, by using the common-mode filter 102D as one of the components of the waveform detection circuit 102, it is possible to suppress malfunction due to common-mode noise.

[0116] (Third Embodiment) FIG. 12 is a diagram for explaining a wireless communication system 100 according to the third embodiment. In the wireless communication system 100, there may be a configuration in which a transmission path 108 for transmitting transmission data (communication signal) is divided into a plurality of transmission paths 108_1 to 108_N (N is an integer of 2 or more). In this case, in the third embodiment, a plurality of waveform detection circuits 102_1 to 102_N are provided as waveform detection circuits 102 for the plurality of transmission paths 108_1 to 108_N, respectively, so that the abnormality determination unit 103 can switch the outputs of the respective waveform detection circuits 102_1 to 102_N and perform an abnormality determination.

[0117] For example, the abnormality determination unit 103 includes a selector 103A and an MCU (Micro Controller Unit) 103B. The MCU 103B outputs a control signal CTL for sequentially switching the outputs of the respective waveform detection circuits 102_1 to 102_N. The selector 103A sequentially switches the outputs of the respective waveform detection circuits 102_1 to 102_N according to the control signal CTL. The MCU 103B determines an abnormality related to the transmission circuit 101 and the transmission coupler 111 based on the signal levels detected by the respective waveform detection circuits 102_1 to 102_N.

[0118] The MCU 103B has an ADC (Analog to Digital Converter, A / D converter). The ADC converts the signal levels (voltage values) detected by the respective waveform detection circuits 102_1 to 102_N into digital signals so that the notification unit (display unit 104, display control function 444) can notify the information. The notification unit (display unit 104, display control function 444) notifies different maintenance information depending on whether the determination result by the abnormality determination unit 103 is an abnormality related to the transmission circuit 101 or an abnormality related to the transmission coupler 111.

[0119] Here, in the example shown in FIG. 12, one LED is illustrated as the display unit 104, but a plurality of LEDs may be provided as the display unit 104. When the display unit 104 is one LED, the abnormality determination unit 103 drives (lights up, turns off, blinks) the LED that is the display unit 104 to notify maintenance information. For example, when the result of the determination is an abnormality related to the transmission circuit 101, the abnormality determination unit 103 lights up the LED to notify maintenance information. For example, when the result of the determination is an abnormality related to the transmission coupler 111, the abnormality determination unit 103 blinks the LED to notify maintenance information.

[0120] Note that when a plurality of LEDs are provided as the display unit 104, as described above, the display unit 104 includes LEDs 104a and 104b (FIG. 4). For example, when the result of the determination is an abnormality related to the transmission circuit 101, the abnormality determination unit 103 drives the LED 104a to notify maintenance information. Also, when the result of the determination is an abnormality related to the transmission coupler 111, the abnormality determination unit 103 drives the LED 104b to notify maintenance information.

[0121] In the configuration of the wireless communication system 100 according to the third embodiment, since the abnormality determination unit 103 switches the outputs of the respective waveform detection circuits 102_1 to 102_N for abnormality determination, it is not necessary to provide the abnormality determination unit 103 for each of the transmission lines 108_1 to 108_N. Therefore, in the wireless communication system 100 according to the third embodiment, compared with the first embodiment and the second embodiment, the number of components can be further reduced.

[0122] Note that each component of each device illustrated in this embodiment is a functional concept, and it is not necessarily physically configured as illustrated. That is, the specific form of the distribution and integration of each device is not limited to that illustrated, and all or part of it can be functionally or physically distributed and integrated in an arbitrary unit according to various loads and usage situations. Furthermore, each processing function performed by each device can be realized in whole or in any part by a CPU and a program analyzed and executed by the CPU, or can be realized as hardware by wired logic.

[0123] In addition, the method described in this embodiment can be realized by executing a pre-prepared program on a computer such as a personal computer or a workstation. This program can be distributed via a network such as the Internet. Further, this program can be recorded on a non-transitory recording medium readable by a computer such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, or a DVD, and can also be executed by being read from the recording medium by the computer.

[0124] According to at least one of the embodiments described above, when an abnormality occurs in the wireless communication system, the abnormal location can be efficiently specified.

[0125] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations of the embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0126] 100 Wireless communication system 101 Transmission circuit 102 Waveform detection circuit 103 Abnormality determination unit 104 Display unit 111 Transmission coupler

Claims

1. A detection unit that detects the signal level of a communication signal transmitted from a transmission circuit to a transmission coupler; An abnormality determination unit that determines an abnormality related to the transmission circuit and the transmission coupler based on the signal level detected by the detection unit; An informing unit that informs different maintenance information depending on whether the determination result by the abnormality determination unit is an abnormality related to the transmission circuit or an abnormality related to the transmission coupler; A wireless communication system comprising the above.

2. When the signal level detected by the detection unit is equal to or lower than a predetermined signal level range, the abnormality determination unit determines that an abnormality related to the transmission circuit has occurred, and when the signal level is equal to or higher than the predetermined signal level range, the abnormality determination unit determines that an abnormality related to the transmission coupler has occurred. The wireless communication system according to Claim 1.

3. The detection unit is connected to the transmission line with an impedance higher than the characteristic impedance of the transmission line that transmits the communication signal from the transmission circuit to the transmission coupler. The wireless communication system according to Claim 1.

4. The detection unit includes a half-wave rectifier circuit or a full-wave rectifier circuit for detecting a voltage value as the signal level. The wireless communication system according to Claim 1.

5. The detection unit includes a full-wave rectifier circuit for detecting a voltage value as the signal level and a common-mode filter for suppressing noise transmitted in the common mode in the full-wave rectifier circuit. The wireless communication system according to Claim 1.

6. The transmission line is a differential transmission line. The wireless communication system according to Claim 3.

7. A second detection unit that inputs the communication signal transmitted from the transmission circuit, transmits the communication signal to the transmission coupler, and outputs the communication signal to a first detection unit that is the detection unit. The wireless communication system according to Claim 1, further comprising the above.

8. The second detection unit is a power divider or a directional coupler. The wireless communication system according to Claim 7.

9. The informing unit is a light-emitting element provided on a substrate on which the transmission circuit is mounted. The abnormality determination unit drives the light-emitting element to inform the maintenance information. The wireless communication system according to Claim 1.

10. The light-emitting element includes a first light-emitting element for informing an abnormality related to the transmission circuit and a second light-emitting element for informing an abnormality related to the transmission coupler. The abnormality determination unit When the result of the determination by the abnormality determination unit is an abnormality related to the transmission circuit, the first light-emitting element is driven to notify the maintenance information. When the result of the determination by the abnormality determination unit is an abnormality related to the transmission coupler, the second light-emitting element is driven to notify the maintenance information. The wireless communication system according to claim 9.

11. The notification unit is provided on the console and causes the output unit to output the maintenance information. The wireless communication system according to claim 1.

12. A reception-side abnormality determination unit that determines a reception-side abnormality based on a signal level when the reception coupler receives the communication signal transmitted from the transmission coupler; When the reception-side abnormality determination unit determines the reception-side abnormality and the abnormality determination unit determines that no abnormality has occurred in the transmission circuit and the transmission coupler, a reception-side notification unit that notifies the reception-side abnormality; The wireless communication system according to claim 1, further comprising:

13. The reception-side notification unit is provided on the console and causes the output unit to output the reception-side abnormality. The wireless communication system according to claim 12.

14. An X-ray CT apparatus comprising: a rotating unit having an X-ray tube, an X-ray detector that detects X-rays irradiated from the X-ray tube, and a data collection device that collects X-ray signals detected by the X-ray detector; A fixing unit that rotates the rotating unit; A detection unit provided in the rotating unit for detecting a signal level of a communication signal transmitted from a transmission circuit to a transmission coupler; An abnormality determination unit provided in the rotating unit for determining an abnormality related to the transmission circuit and the transmission coupler based on the signal level detected by the detection unit; A notification unit that notifies different maintenance information depending on whether the result of the determination by the abnormality determination unit is an abnormality related to the transmission circuit or an abnormality related to the transmission coupler; An X-ray CT apparatus comprising:

15. Transmitting a communication signal from a transmission circuit to a transmission coupler, Detecting a signal level of the communication signal transmitted from the transmission circuit to the transmission coupler, Determining an abnormality related to the transmission circuit and the transmission coupler based on the detected signal level, Notifying different maintenance information depending on whether the result of the determination is an abnormality related to the transmission circuit or an abnormality related to the transmission coupler. An abnormality determination method including:

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