Wireless communication system and processing method for wireless communication system

Abstract

To make it possible to speed up the communication speed of wireless communication.SOLUTION: A wireless communication system includes a first communication device and a second communication device. The first communication device includes a modulator 113 that performs modulation processing, and a first coupler 111 for wirelessly transmitting a signal. The second communication device includes a second coupler 121 for wirelessly receiving the signal by at least one of electric field coupling and magnetic field coupling to the first coupler, and a demodulator 122 that performs decoding processing. The first communication device or the second communication device includes an equalizer 112 that performs equalization processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to wireless communication systems and methods of operation for wireless communication systems. [Background technology]

[0002] In recent years, close proximity wireless communication systems have been proposed that perform wireless communication by electromagnetic coupling between nearby antennas. If wired connections using connectors and harnesses for communication between electronic circuit boards and modules could be made wireless, it would be possible to reduce the number of parts at the connection point and simplify the device manufacturing process.

[0003] Patent Document 1 discloses a wireless communication system that transmits binary baseband signals in a contactless manner using electromagnetic coupling. In this wireless communication system, couplers provided in a transmitter and a receiver are arranged facing each other and in close proximity, and wireless communication is achieved using electromagnetic coupling between the couplers. Specifically, when a baseband signal is input to the coupler on the transmitter side, a signal with an imperfect differential waveform is generated in the coupler on the receiver side due to electromagnetic coupling. The receiver reshapes this signal using a hysteresis comparator to restore the transmitted baseband signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-29785 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the amount of data transmitted within a device or between devices has increased, and there is a demand for faster communication speeds in wireless communication systems.

[0006] An object of the present disclosure is to enable an increase in communication speed in wireless communication. [Means for solving the problem]

[0007] The wireless communication system includes a first communication device and a second communication device, the first communication device having a modulator for performing modulation processing and a first coupler for wirelessly transmitting a signal, the second communication device having a second coupler for wirelessly receiving a signal by coupling with the first coupler through at least one of electric field coupling and magnetic field coupling, and a demodulator for performing demodulation processing, and the first communication device and the second communication device At least one of the communication devices has an equalizer that performs equalization processing. Regarding the amplification factor of the signal in the equalization process, the amplification factor of the signal in a frequency range lower than a predetermined frequency is higher than the amplification factor of the signal in a frequency range higher than the predetermined frequency. . [Effects of the Invention]

[0008] According to the present disclosure, the communication speed of wireless communication can be increased. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 2] FIG. 2 is a diagram for explaining a configuration example of a modulator. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a demodulator. [Figure 4] FIG. 2 is a diagram illustrating the structure of a coupler. [Figure 5] FIG. 1 is a diagram illustrating an equivalent circuit of a wireless communication system. [Figure 6] FIG. 10 is a diagram illustrating an example of transfer characteristics between couplers. [Figure 7] FIG. 10 is a diagram illustrating an example of the transfer characteristic of an equalizer. [Figure 8] 10A and 10B are diagrams for explaining the effect of widening the frequency bandwidth by an equalizer. [Figure 9] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 10] FIG. 1 illustrates an example of a multiplexer and a divider. [Figure 11] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) [System Configuration] The first embodiment will be described below with reference to the drawings. Fig. 1(a) is a diagram showing an example of the configuration of a wireless communication system 100 according to the first embodiment. Hereinafter, the wireless communication system 100 will be referred to as system 100. The system 100 has a wireless communication module 110 and a wireless communication module 120, and wireless communication is performed between the wireless communication module 110 and the wireless communication module 120. Hereinafter, the wireless communication module 110 will be referred to as module 110, and the wireless communication module 120 will be referred to as module 120. In other words, the module 110 and the module 120 each function as a communication device that performs wireless communication.

[0011] The module 110 includes a coupler 111, an equalizer 112, and a modulator 113. The module 120 includes a coupler 121, a demodulator 122, and termination resistors 126a and 126b.

[0012] The modulator 113 performs multi-symbol modulation processing on the multiple data signals Sig1 to Sig4 to compress the signal band and output the transmission signals TX+ and TX-. The transmission signals TX+ and TX- are differential signals with opposite phases to each other. The multi-symbol modulation may be, for example, quadrature phase-shift keying (QPSK), quadrature amplitude modulation (QAM), or orthogonal frequency division multiplexing (OFDM), etc.

[0013] If the module 110 did not have the modulator 113, it would be necessary to provide couplers 111 in numbers corresponding to the number of data signals Sig1 to Sig4. By providing the modulator 113, the module 110 can wirelessly transmit the multiple data signals Sig1 to Sig4 using one coupler 111. This allows the module 110 to reduce the number of couplers 111 and the area it occupies.

[0014] The equalizer 112 receives the transmission signals TX+ and TX- of the modulator 113 as transmission signals IN+ and IN-. The equalizer 112 performs equalization processing on the transmission signals IN+ and IN- and outputs transmission signals OUT+ and OUT- to the coupler 111. The transmission signals OUT+ and OUT- are a pair of differential signals.

[0015] The coupler 111 has two separate electrodes 111a and 111b. The electrode 111a receives a transmission signal OUT+. The electrode 111b receives a transmission signal OUT-. The coupler 121 has two separate electrodes 121a and 121b.

[0016] Coupler 111 and coupler 121 are couplers that are electromagnetically coupled by being arranged close to each other so as to face each other. More specifically, electrode 111a and electrode 121a are arranged so as to face each other, and electrode 111b and electrode 121b are arranged so as to face each other.

[0017] Electromagnetic coupling includes both electric field coupling and magnetic field coupling. That is, wireless communication between modules 110 and 120 may be performed by electric field coupling, by magnetic field coupling, or by both electric field coupling and magnetic field coupling. However, the following description will be given assuming that coupler 111 and coupler 121 are coupled mainly by an electric field.

[0018] The electrode 111a wirelessly transmits a transmission signal OUT+ to the electrode 121a. The electrode 121a wirelessly receives a reception signal RX+ from the electrode 111a. The electrode 111b wirelessly transmits a transmission signal OUT- to the electrode 121b. The electrode 121b wirelessly receives a reception signal RX- from the electrode 111b. The demodulator 122 receives the reception signal RX+ from the electrode 121a and receives the reception signal RX- from the electrode 121b. The termination resistor 126a is connected to the interconnection point between the electrode 121a and one of the input terminals of the demodulator 122. The termination resistor 126b is connected to the interconnection point between the electrode 121b and the other of the input terminals of the demodulator 122.

[0019] The equalizer 112 wirelessly transmits the transmit signals OUT+ and OUT− to the demodulator 122 via the couplers 111 and 121. The demodulator 122 wirelessly receives the receive signals RX+ and RX− from the equalizer 112 via the couplers 111 and 121.

[0020] The transmission signals OUT+ and OUT- transmitted from the equalizer 112 are differential signals. The reception signals RX+ and RX- received by the demodulator 122 are also differential signals. That is, signals of opposite phases are input to the electrodes 111a and 111b, and signals of opposite phases are output from the electrodes 121a and 121b. When the transmission signals OUT+ and OUT- are input to the coupler 111, the reception signals RX+ and RX- are output from the coupler 121 due to the effect of electric field coupling.

[0021] The demodulator 122 restores a plurality of data signals Sig1 to Sig4 by performing multi-symbol demodulation processing on the received signals RX+ and RX- output from the coupler 121. The demodulation by the demodulator 122 corresponds to the modulation by the modulator 113. The data signals Sig1 to Sig4 output by the demodulator 122 are equivalent to the data signals Sig1 to Sig4 input to the modulator 113.

[0022] 2(a) is a diagram showing an example configuration of the modulator 113. The modulator 113 may receive one data signal Sig1 as input. The modulator 113 performs modulation processing on the data signal Sig1 and outputs transmission signals TX+ and TX-. The modulator 113 has an LPF (low pass filter) 200, and performs LPF (low pass filter) processing on the data signal Sig1 to limit the band and output the transmission signals TX+ and TX-.

[0023] FIG. 2(b) illustrates another exemplary configuration of the modulator 113. The modulator 113 performs modulation processing on the data signal Sig1 and outputs transmission signals TX+ and TX-. The modulator 113 includes a carrier generator 201 and a multiplier 202. The multiplier 202 performs frequency conversion by multiplying the carrier generated by the carrier generator 201 by the data signal Sig1, and outputs transmission signals TX+ and TX-. For example, if the data signal Sig1 is a rectangular signal (baseband data), a BPSK (Binary Phase Shift Keying) modulated signal is generated. Using a quadrature modulator as this modulator 113 enables a variety of modulation processes. The modulator 113 may be implemented using digital signal processing or electronic circuits.

[0024] The transfer characteristic between coupler 111 and coupler 121, which are coupled by electromagnetic field coupling, has a property that the gain (output signal strength of coupler 121) decreases as the frequency of the signal being transmitted decreases. Equalizer 112 performs equalization processing with a transfer characteristic that is the inverse of this transfer characteristic. In other words, equalizer 112 has a transfer characteristic that the output signal strength of equalizer 112 increases as the frequency of the input signal to equalizer 112 decreases. By multiplying the transfer characteristic of equalizer 112 by the transfer characteristic between coupler 111 and coupler 121, it is possible to expand the frequency bandwidth over which the gain (output signal strength of coupler 121) remains constant. The function of equalizer 112 can be implemented by an electronic circuit or digital signal processing.

[0025] The equalizer 112 may be placed before the modulator 113. In this case, the equalizer 112 performs equalization processing on the data signal. The modulator 113 performs modulation processing on the data signal after equalization processing by the equalizer 112, and outputs transmission signals TX+ and TX-. The electrode 111a wirelessly transmits the transmission signal TX+ to the electrode 121a. The electrode 111b wirelessly transmits the transmission signal TX- to the electrode 121b.

[0026] 3(a) is a diagram showing an example of the configuration of the demodulator 122. When the modulator 113 inputs one data signal Sig1, the demodulator 122 outputs one data signal Sig1. The demodulator 122 performs demodulation processing on the received signals RX+ and RX- and outputs the data signal Sig1. The demodulator 122 has a determiner 301, which determines the received signals RX+ and RX- and outputs the data signal Sig1. The determiner 301 outputs a signal Sig1 representing the determination result depending on the signs or intensities of the received signals (differential signals) RX+ and RX-.

[0027] FIG. 3(b) shows another example of the configuration of the demodulator 122. The demodulator 122 demodulates the received signals RX+ and RX- and outputs a data signal Sig1. The demodulator 122 in FIG. 3(b) is operated in conjunction with the modulator 113 in FIG. 2(b). The demodulator 122 has a local oscillator 302 and a multiplier 303. The multiplier 303 multiplies the received signals RX+ and RX- by the output signal of the local oscillator 302 to perform frequency conversion and output a data signal Sig1. Note that using the demodulator 122 as a quadrature demodulator enables a variety of demodulation processes. Note that the demodulator 122 may be implemented using digital signal processing or electronic circuits.

[0028] 4(a) and 4(b) are diagrams showing structural examples of couplers 111 and 121. Fig. 4(a) is a perspective view showing the structures of couplers 111 and 121. Fig. 4(b) is a plan view of the structures of couplers 111 and 121 as viewed from the Z-axis direction. Connections P1, P2, P3, and P4 are connection parts (power supply parts) between electrodes 111a, 111b, 121a, and 121b and the transmission lines, respectively.

[0029] Electrodes 111a and 111b are formed on one surface of dielectric 119. Electrodes 121a and 121b are formed on one surface of dielectric 129 (the surface facing dielectric 119). In this embodiment, couplers 111 and 121 are formed as patterns on a substrate such as a rigid substrate or a flexible substrate. Couplers 111 and 121 may also be formed from sheet metal or the like. As shown in FIGS. 4(a) and 4(b), by arranging couplers 111 and 121 closely facing each other, electric field coupling occurs between couplers 111 and 121. The distance between couplers 111 and 121 in the Z-axis direction is Z1.

[0030] System 100 having the above-described configuration can be implemented, for example, in an imaging device or a machine driven by a motor. When system 100 is implemented in a camera serving as an imaging device, module 110 may be included in the main body of the camera, module 120 may be included in an accessory part of the camera, and a transmission signal representing image data acquired by the main body may be wirelessly transmitted to the accessory part. Furthermore, the imaging device is not limited to a camera, and may also be a CT (computed tomography) device. Specifically, module 110 may be included in a rotating part of the CT device, module 120 may be included in a fixed part of the CT device, and a transmission signal representing image data acquired by the rotating part may be wirelessly transmitted to the fixed part.

[0031] Furthermore, when the system 100 is implemented in a robot arm as a motor-driven machine, the module 110 may be included in the arm, the module 120 may be included in the hand, and a control signal for controlling the operation of the hand may be transmitted wirelessly from the arm. The module 120 may then control the operation of the hand in accordance with a signal received by the demodulator 122. The motor-driven machine is not limited to a robot arm, but may also be a semiconductor exposure apparatus. Specifically, the module 120 may control the operation of a movable stage of the exposure apparatus in accordance with a signal received wirelessly. As another example, the module 110 may be included in the main body of an inkjet printer, the module 120 may be included in the print head, and the module 120 may control the ejection of ink in accordance with a signal received wirelessly. Note that the target on which the system 100 is implemented is not limited to these examples.

[0032] FIG. 5 is a diagram showing an equivalent circuit of the system 100. The transfer characteristics between the coupler 111 and the coupler 121, which are coupled by electromagnetic field coupling, will be explained using the equivalent circuit shown in FIG. 5. The equalizer 112 has a signal source 500 and a resistor 501. The resistor 501 corresponds to the output impedance of the equalizer 112. Here, the value of the resistor 501 is set to R t The signal source 500 outputs a voltage V t Assume that the coupler 111 and the coupler 121 are coupled by an electric field, and the degree of coupling (electrostatic capacitance) is C [F]. The resistor 503 is the combined resistance of the termination resistors 126a and 126b in FIG. 1(a). Here, the value of the resistor 503 is R L The output signal voltage of the coupler 121 generated across the resistor 503 is V r Using this equivalent circuit, the output signal voltage V of the coupler 121 is r and the output signal voltage V of the signal source 500 t The ratio of this to Equation (1) is obtained.

[0033]

number

[0034] Voltage V r and voltage V t The ratio of ∑ ∑ a ∑ b ...

[0035]

number

[0036] Fig. 6 is a graph showing the transfer characteristics shown in equation (2). In Fig. 6, ω1 and ω2 are respectively expressed by equations (3) and (4).

[0037]

number

[0038]

number

[0039] At frequencies above ω1, the resistance R L and resistance value R t becomes large enough that the output signal voltage V t is the resistance value R L and resistance value R t The voltage divided by is the output signal voltage V of coupler 121. r Therefore, at frequencies equal to or greater than ω1, the gain is approximately constant.

[0040] On the other hand, at frequencies below ω1, the impedance of the coupling coefficient C is L and resistance value R t The impedance of the coupling factor C increases as the frequency decreases, and the output signal voltage V of the coupler 121 also decreases accordingly. r decreases.

[0041] In order to wirelessly transmit wideband data using the system 100, it is desirable that the gain be constant over a wide band and that this constant gain be as high as possible. For example, the degree of coupling C between the coupler 111 and the coupler 121 is approximately several fF to several pF when the coupler 111 and the coupler 121 are separated by a space of several mm. L and resistance value R t Assuming that both are 100 Ω, ω1 will be a few GHz at the very least. The gain becomes constant, and ω1 is the lowest frequency in the frequency band that is advantageous for wireless data transmission. If the frequency bandwidth is not expanded by the equalizer 112, the modulator 113 and demodulator 122 that make up the system 100 must be applicable to at least ω1 (several GHz), which creates problems in terms of cost, power consumption, etc. Furthermore, the frequency band below ω1 will be discarded as a frequency band that is disadvantageous for wireless data transmission, reducing frequency utilization efficiency. To solve the above problems, the equalizer 112 is introduced.

[0042] 7 is a graph showing an example of the transfer characteristic of the equalizer 112. This transfer characteristic is expressed by equation (5).

[0043]

number

[0044] The transfer characteristic from the input of the equalizer 112 to the output of the coupler 121 is expressed as the product of equations (2) and (5). The product of equations (2) and (5) is expressed as equation (6).

[0045]

number

[0046] As can be seen from equation (6), by introducing the equalizer 112, the transfer characteristic does not depend on the frequency and is t and resistance value R LThat is, in principle, the gain is constant over all frequency bands, making it possible to transmit wideband data wirelessly.

[0047] However, in reality, loss occurs in the high frequency range due to the physical shapes of coupler 111 and coupler 121. Furthermore, equalizer 112 saturates at a finite gain, so it is not possible to maintain a completely constant gain in the low frequency range.

[0048] 8(a) is a diagram showing which section of the system 100 each transfer characteristic in FIG. 8(b) corresponds to. FIG. 8(b) is a graph showing, from top to bottom, the transfer characteristic shown in equation (5), the transfer characteristic shown in equation (2), and the transfer characteristic shown in equation (6). The transfer characteristic shown in equation (5) is the transfer characteristic between A and B in FIG. 8(a), and the transfer characteristic G EQ The transfer characteristic shown in equation (2) is the transfer characteristic between B and C in FIG. 8(a), and the transfer characteristic G between the coupler 111 and the coupler 121 is Cap The transfer characteristic shown in equation (6) is the transfer characteristic between A and C in FIG. 8(a), and is the transfer characteristic G(s) from the input of the equalizer 112 to the output of the coupler 121.

[0049] In addition, the transfer characteristic G(s) has a reduced gain in the high and low frequencies, taking into consideration the loss in the high frequencies caused by the physical shapes of the couplers 111 and 121 and the saturation of the gain of the equalizer 112. As described above, by introducing the equalizer 112, the transfer characteristic G(s) is Cap For transfer characteristic G(s), the lower limit of the frequency band advantageous for wireless data transmission can be extended to frequencies below ω1, making it possible to wirelessly transmit wideband data. Also, by extending the lower limit of the frequency band advantageous for wireless data transmission to frequencies below ω1, the modulator 113 and demodulator 122 that make up system 100 can operate at low frequencies, which is advantageous in terms of cost, power consumption, etc.

[0050] FIG. 1(b) is a diagram showing another example of the configuration of the system 100. The system 100 in FIG. 1(b) differs from the system 100 in FIG. 1(a) in the position of the equalizer 112. The system 100 includes a module 110 and a module 120. The module 110 includes a modulator 113 and a coupler 111. The coupler 111 includes electrodes 111a and 111b. The module 120 includes a coupler 121, termination resistors 126a and 126b, the equalizer 112, and a demodulator 122. The coupler 121 includes electrodes 121a and 121b.

[0051] The modulator 113 compresses the signal band by performing multi-symbol modulation processing on the multiple data signals Sig1 to Sig4, and outputs the transmission signals TX+ and TX-. The transmission signals TX+ and TX- are a pair of differential signals. The electrode 111a wirelessly transmits the transmission signal TX+ to the electrode 121a. The electrode 111b wirelessly transmits the transmission signal TX- to the electrode 121b.

[0052] Termination resistor 126a is connected to the interconnection point between electrode 121a and one input terminal of equalizer 112. Termination resistor 126b is connected to the interconnection point between electrode 121b and the other input terminal of equalizer 112. Electrode 121a wirelessly receives reception signal IN+ from electrode 111a. Electrode 121b wirelessly receives reception signal IN- from electrode 111b.

[0053] The equalizer 112 performs equalization processing on the received signals IN+ and IN− and outputs received signals OUT+ and OUT−. The transmitted signals OUT+ and OUT− are a pair of differential signals. The equalization processing has an inverse transfer characteristic to the transfer characteristic between the couplers 111 and 121.

[0054] The demodulator 122 receives the received signals OUT+ and OUT- from the equalizer 112 as received signals RX+ and RX-. The demodulator 122 performs multi-symbol demodulation processing on the received signals RX+ and RX- to restore a plurality of data signals Sig1 to Sig4. The data signals Sig1 to Sig4 output by the demodulator 122 are equivalent to the data signals Sig1 to Sig4 input by the modulator 113.

[0055] The system 100 in FIG. 1(b) can achieve the same effects as the system 100 in FIG. 1(a).

[0056] 2(a) and 2(b), the modulator 113 can input one line of data signal Sig1, and the demodulator 122 can output one line of data signal Sig1. In this case, the module 110 has the modulator 113 that performs modulation processing and a coupler (combiner) 111 that wirelessly transmits a signal. The module 120 has a coupler 121 that wirelessly receives a signal from the coupler 111 using at least one of electric field coupling and magnetic field coupling, and a demodulator 122 that performs demodulation processing. The module 110 or 120 has an equalizer 112 that performs equalization processing.

[0057] The equalizer 112 performs equalization processing to increase the gain in the low frequency range of the transfer characteristic between the coupler 111 and the coupler 121. The module 120 has termination resistors 126a and 126b connected to the coupler 121.

[0058] 1(a), the module 110 includes an equalizer 112. The equalizer 112 performs equalization processing on the signal modulated by the modulator 113, and outputs the equalized signal to the coupler 111. The demodulator 122 performs demodulation processing on the signal wirelessly received by the coupler 121.

[0059] 1(b), the module 120 includes an equalizer 112. The modulator 113 outputs the modulated signal to the coupler 111. The equalizer 112 performs equalization on the signal wirelessly received by the coupler 121. The demodulator 122 demodulates the signal that has been equalized by the equalizer 112.

[0060] The equalizer 112 may be provided in the preceding stage of the modulator 113. In that case, the module 110 includes the equalizer 112. The modulator 113 performs modulation processing on the signal that has been equalized by the equalizer 112, and outputs the modulated signal to the coupler 111. The demodulator 122 performs demodulation processing on the signal that has been wirelessly received by the coupler 121.

[0061] According to this embodiment, the equalizer 112 can expand the transmission bandwidth (transmittable frequency bandwidth) between the couplers 111 and 121. This allows the system 100 to achieve the effect of increasing the communication speed of wireless communication and the amount of data that can be transmitted. Note that the modulator 113 may receive input of a single line of data signal Sig1, or may receive input of multiple lines of data signals Sig1 to Sig4.

[0062] Next, a case where modulator 113 receives multiple data signals Sig1 to Sig4 will be described. Module 110 includes modulator 113 that generates one signal by performing modulation processing on the multiple data signals, and coupler 111 for wirelessly transmitting the signal. Module 120 includes coupler 121 that wirelessly receives a signal from coupler 111 using at least one of electric field coupling and magnetic field coupling, and demodulator 122 that restores the multiple data signals by performing demodulation processing. Module 110 or 120 includes equalizer 112 that performs equalization processing. Note that equalizer 112 is optional.

[0063] 1(a), the module 110 includes an equalizer 112. The equalizer 112 performs equalization processing on one line of signals generated by the modulator 113, and outputs the one line of signals that has undergone the equalization processing to the coupler 111. The demodulator 122 performs demodulation processing on the one line of signals wirelessly received by the coupler 121, thereby restoring the multiple lines of data signals.

[0064] 1(b), the module 120 includes an equalizer 112. A modulator 113 outputs the generated one channel of signals to a coupler 111. The equalizer 112 performs equalization processing on the one channel of signals wirelessly received by the coupler 121. A demodulator 122 performs demodulation processing on the one channel of signals that has been equalized by the equalizer 112, thereby restoring the multiple channels of data signals.

[0065] The equalizer 112 may be provided in a stage preceding the modulator 113. In this case, the module 110 includes the equalizer 112. The equalizer 112 performs equalization processing on the multiple lines of data signals. The modulator 113 generates one line of signal by performing modulation processing on the multiple lines of data signals that have been equalized by the equalizer 112, and outputs the generated one line of signal to the coupler 111. The demodulator 122 restores the multiple lines of data signals by performing demodulation processing on the one line of signal wirelessly received by the coupler 121.

[0066] According to this embodiment, the modulator 113 performs modulation processing on data signals of multiple systems, thereby increasing the amount of data per unit frequency band. As a result, the system 100 has the effect of increasing the amount of data that can be transmitted within the limited transmission bandwidth (transmittable frequency bandwidth) between the couplers 111 and 121, thereby increasing the communication speed of wireless communication. Note that the equalizer 112 is optional.

[0067] (Second embodiment) Fig. 9 is a diagram showing an example of the configuration of a system 100 according to the second embodiment. The system 100 in Fig. 9 is configured by providing a multiplexer 900 and a divider 901 instead of the modulator 113 and demodulator 122 of the system 100 in Fig. 1. The following describes the differences between the second embodiment and the first embodiment.

[0068] The system 100 includes a module 110 and a module 120. The module 110 includes a multiplexer 900, an equalizer 112, and a coupler 111. The coupler 111 includes an electrode 111a and an electrode 111b. The module 120 includes a coupler 121, termination resistors 126a and 126b, and a divider 901. The coupler 121 includes an electrode 121a and an electrode 121b.

[0069] The multiplexer 900 multiplexes a plurality of data signals Sig1 to Sig4 and outputs transmission signals TX+ and TX-. The transmission signals TX+ and TX- are differential signals with opposite phases. The multiplexing may be, for example, code division multiple access (CDMA), time division multiple access (TDMA), or frequency division multiple access (FDMA). TDMA includes a SerDes (serializer / deserializer).

[0070] If the module 110 does not include the multiplexer 900, it would be necessary to provide couplers 111 in numbers corresponding to the number of data signals Sig1 to Sig4. By providing the multiplexer 900, the module 110 can wirelessly transmit the multiple data signals Sig1 to Sig4 using one coupler 111. This allows the module 110 to reduce the number of couplers 111 and the area they occupy.

[0071] The equalizer 112 receives the transmit signals TX+ and TX- of the multiplexer 900 as transmit signals IN+ and IN-. The equalizer 112 performs equalization processing on the transmit signals IN+ and IN- and outputs transmit signals OUT+ and OUT-. The transmit signals OUT+ and OUT- are a pair of differential signals. The equalization processing has an inverse transfer characteristic to the transfer characteristic between the couplers 111 and 121.

[0072] The electrode 111a wirelessly transmits a transmission signal OUT+ to the electrode 121a, and the electrode 111b wirelessly transmits a transmission signal OUT- to the electrode 121b.

[0073] Termination resistor 126a is connected to the interconnection point between electrode 121a and one input terminal of divider 901. Termination resistor 126b is connected to the interconnection point between electrode 121b and the other input terminal of divider 901. Electrode 121a wirelessly receives a reception signal RX+ from electrode 111a. Electrode 121b wirelessly receives a reception signal RX- from electrode 111b.

[0074] Divider 901 performs division processing on received signals RX+ and RX- to restore multiple data signals Sig1 to Sig4. Data signals Sig1 to Sig4 output by divider 901 are equivalent to data signals Sig1 to Sig4 input to multiplexer 900. Divider 901 is, for example, a divider for CDMA, TDMA, FDMA, or the like.

[0075] 10(a) is a diagram showing an example of the configuration of a multiplexer 900, for example, an FDMA (Frequency Division Multiple Access) multiplexer 900. The multiplexer 900 has a plurality of multipliers 902, a plurality of subcarrier generators 903, and an adder 904. The plurality of multipliers 902 perform frequency conversion by multiplying the subcarrier signals generated by the plurality of subcarrier generators 903 by the data signals Sig1 to Sig3, respectively. The adder 904 adds the output signals of the plurality of multipliers 902 and outputs transmission signals TX+ and TX-.

[0076] Since the frequencies of the subcarrier signals generated by the multiple subcarrier generators 903 are different (separate), the data signals Sig1 to Sig3 do not interfere with each other even when the adder 904 adds the output signals of the multiple multipliers 902. As a result, the divider 901 performs division processing to restore the data signals Sig1 to Sig3.

[0077] 10(b) is a diagram showing an example of the configuration of the divider 901, and shows an example of the divider 901 for FDMA (Frequency Division Multiple Access). The divider 901 has a plurality of multipliers 906, a plurality of subcarrier generators 905, and a plurality of LPFs (low pass filters) 907. The plurality of multipliers 906 multiply the received signals RX+ and RX- by subcarrier signals generated by the plurality of subcarrier generators 905, respectively, thereby converting the received signals RX+ and RX- in frequency. The plurality of LPFs 907 restore a plurality of data signals Sig1 to Sig3 by attenuating unnecessary frequency bands in the output signals of the plurality of multipliers 906, respectively.

[0078] As described above, according to this embodiment, the multiplexer 900 multiplexes multiple data signals Sig1 to Sig4, the equalizer 112 expands the frequency band advantageous for wireless data transmission, and outputs the transmission signals OUT+ and OUT− to the coupler 111. By using the multiplexer 900, the module 110 can, for example, multiplex low-speed data signals and transmit high-speed transmission signals of several kbps to several Gbps using the pair of couplers 111. By transmitting multiple data signals Sig1 to Sig4 with different properties using the pair of couplers 111, the module 110 can reduce the ratio of data bandwidth to coupler area. The multiplexer 900 and the divider 901 may use CDMA (Code Division Multiple Access) or TDMA (Time Division Multiple Access). Furthermore, by using a combination of these multiplexing technologies, the ratio of data bandwidth to coupler area can be further optimized.

[0079] The equalizer 112 may be inserted between the termination resistors 126a and 126b and the divider 901. In this case, the multiplexer 900 performs multiplexing processing on a plurality of data signals Sig1 to Sig4 to output transmission signals TX+ and TX-. The electrode 111a wirelessly transmits the transmission signal TX+ to the electrode 121a. The electrode 111b wirelessly transmits the transmission signal TX- to the electrode 121b. The termination resistor 126a is connected to the interconnection point between the electrode 121a and one of the input terminals of the equalizer 112. The termination resistor 126b is connected to the interconnection point between the electrode 121b and the other input terminal of the equalizer 112. The electrode 121a wirelessly receives the reception signal IN+ from the electrode 111a. The electrode 121b wirelessly receives the reception signal IN- from the electrode 111b. The equalizer 112 performs equalization processing on the received signals IN+ and IN- and outputs received signals OUT+ and OUT-. The divider 901 inputs the received signals OUT+ and OUT- of the equalizer 112 as received signals RX+ and RX-. The divider 901 performs division processing on the received signals RX+ and RX- to restore multiple data signals Sig1 to Sig4. In this case, the same effect as above can be obtained.

[0080] As described above, system 100 includes multiplexer 900 and divider 901. Module 110 includes multiplexer 900 that generates one signal by performing multiplexing processing on multiple data signals, and coupler 111 that wirelessly transmits the signal. Module 120 includes coupler 121 that wirelessly receives a signal from coupler 111 using at least one of electric field coupling and magnetic field coupling, and divider 901 that restores the multiple data signals by performing division processing. Module 110 or 120 includes equalizer 112 that performs equalization processing. Note that equalizer 112 is optional.

[0081] 9, the module 110 includes an equalizer 112. The equalizer 112 performs equalization processing on one line of signals generated by the multiplexer 900, and outputs the one line of signals that has undergone the equalization processing to the coupler 111. The divider 901 performs division processing on the one line of signals wirelessly received by the coupler 121, thereby restoring the multiple lines of data signals.

[0082] The equalizer 112 may be provided in a stage preceding the divider 901. In that case, the module 120 includes the equalizer 112. The multiplexer 900 outputs the generated single channel signal to the coupler 111. The equalizer 112 performs equalization processing on the single channel signal wirelessly received by the coupler 121. The divider 901 performs demodulation processing on the single channel signal that has been equalized by the equalizer 112, thereby restoring the multiple channels of data signals.

[0083] Furthermore, the equalizer 112 may be provided in a stage preceding the multiplexer 900. In this case, the module 110 includes the equalizer 112. The equalizer 112 performs equalization processing on the multiple data signals. The multiplexer 900 generates a single signal by multiplexing the multiple data signals that have been equalized by the equalizer 112, and outputs the generated single signal to the coupler 111. The divider 901 restores the multiple data signals by dividing the single signal received wirelessly by the coupler 121.

[0084] According to this embodiment, the multiplexer 900 performs multiplexing processing on data signals of multiple systems, thereby increasing the amount of data that can be transmitted within the limited transmission bandwidth (transmittable frequency bandwidth) between the couplers 111 and 121. This enables the system 100 to increase the communication speed of wireless communication. Note that the equalizer 112 can be omitted.

[0085] (Third embodiment) 11 is a diagram showing an example of the configuration of a system 100 according to the third embodiment. The system 100 includes a module 110 and a module 120. The module 110 is configured by adding a reference signal generator 908 and a coupler 909 to the module 110 of the first or second embodiment. The module 120 is configured by adding a coupler 910 and a reference signal receiver 911 to the module 120 of the first or second embodiment.

[0086] Module 110 includes a reference signal generator 908 and a coupler 909. Coupler 909 is an electrode. Module 120 includes a reference signal receiver 911 and a coupler 910. Coupler 910 is an electrode. Reference signal generator 908 is preferably a reference frequency source (clock source) for system 100, and generates a reference frequency signal (clock signal).

[0087] Modulator 113 or multiplexer 900 included in module 110 performs predetermined signal processing using the reference frequency signal generated by reference signal generator 908 as a reference frequency source. Couplers 909 and 910 are coupled by an electromagnetic field, similar to couplers 111 and 121. Reference signal generator 908 outputs a reference frequency signal to coupler 909. The reference frequency signal input to coupler 909 is transmitted to coupler 910 by electromagnetic field coupling.

[0088] Reference signal receiver 911 performs waveform shaping processing and the like on the reference frequency signal output from coupler 910. Demodulator 122 or divider 901 included in module 120 performs predetermined signal processing using the reference frequency signal output from reference signal receiver 911 as a reference frequency source.

[0089] If the modules 110 and 120 are spatially separated and do not share a common reference frequency source, a pseudo reference frequency signal must be generated using the data signal to transmit the data signal between the coupler 111 and the coupler 121. The function of generating this pseudo reference frequency signal is generally complex and requires a large circuit scale, which can increase the cost and size of the module.

[0090] By providing a new function for sharing a reference frequency signal between module 110 and module 120 as in this embodiment, the previously mentioned function for generating a pseudo reference frequency signal is no longer necessary, thereby reducing the cost and size of the module. Because the reference frequency signal transmitted between coupler 909 and coupler 910 is a signal with a constant frequency, there are very few restrictions on its transfer characteristics. Therefore, the cost and size of the module required for transmitting the reference frequency signal between coupler 909 and coupler 910 can be reduced compared to when a function for generating a pseudo reference frequency signal is added.

[0091] As described above, module 110 has reference signal generator 908 that generates a reference signal (clock signal), and coupler 909 that wirelessly transmits the reference signal generated by reference signal generator 908. Module 120 has coupler 910 that wirelessly receives the reference signal from coupler 909 using at least one of electric field coupling and magnetic field coupling, and reference signal receiver 911 that performs waveform shaping processing on the reference signal wirelessly received by coupler 910.

[0092] This embodiment can be applied to the first embodiment. In this case, the modulator 113 performs modulation processing based on the reference signal generated by the reference signal generator 908. The demodulator 122 performs demodulation processing based on the reference signal that has been subjected to waveform shaping processing by the reference signal receiver 911.

[0093] This embodiment can also be applied to the second embodiment. In that case, multiplexer 900 performs multiplexing processing based on a reference signal generated by reference signal generator 908. Divider 901 performs division processing based on a reference signal that has been waveform-shaped by reference signal receiver 911.

[0094] According to this embodiment, the system 100 can reduce costs and size compared to when a function for generating a pseudo reference frequency signal is added.

[0095] It should be noted that the above-described embodiments merely illustrate specific examples of implementing the present disclosure, and the technical scope of the present disclosure should not be construed as being limited by these embodiments. The present disclosure is not limited to the above-described embodiments, and various changes and modifications are possible. [Explanation of symbols]

[0096] 100 wireless communication system, 110, 120 wireless communication module, 111, 121 coupler, 112 equalizer, 113 modulator, 122 demodulator, 126a, 126b termination resistor

Claims

1. a first communication device; a second communication device; the first communication device, a modulator for performing modulation processing; a first coupler for wirelessly transmitting a signal; the second communication device, a second coupler for wirelessly receiving a signal by at least one of electric field coupling and magnetic field coupling with the first coupler; a demodulator for performing demodulation processing, At least one of the first communication device and the second communication device has an equalizer that performs equalization processing, A wireless communication system characterized in that, regarding the signal amplification factor in the equalization process, the amplification factor of signals in a frequency range lower than a predetermined frequency is higher than the amplification factor of signals in a frequency range higher than the predetermined frequency.

2. the first communication device has the equalizer; the equalizer performs equalization processing on the signal modulated by the modulator, and outputs the equalized signal to the first combiner; 2. The wireless communication system according to claim 1, wherein the demodulator performs demodulation processing on the signal wirelessly received by the second combiner.

3. the second communication device has the equalizer; the modulator outputs the modulated signal to the first combiner; the equalizer performs equalization processing on the signal wirelessly received by the second combiner; 2. The wireless communication system according to claim 1, wherein the demodulator performs demodulation processing on the signal that has been equalized by the equalizer.

4. the first communication device has the equalizer; the modulator modulates the signal that has been equalized by the equalizer, and outputs the modulated signal to the first coupler; 2. The wireless communication system according to claim 1, wherein the demodulator performs demodulation processing on the signal wirelessly received by the second combiner.

5. The modulator performs modulation processing on a plurality of data signals, 5. The wireless communication system according to claim 1, wherein the demodulator restores the plurality of data signals by performing demodulation processing.

6. A wireless communication system described in any one of claims 1 to 5, characterized in that the second communication device further has a termination resistor connected to the second coupler.

7. A wireless communication system described in any one of claims 1 to 6, characterized in that the specified frequency is based on at least the capacitance between the first coupler and the second coupler.

8. a first communication device; a second communication device; the first communication device, a multiplexer that performs multiplexing processing on a plurality of input data signals; a first coupler for wirelessly transmitting a signal; the second communication device, a second coupler for wirelessly receiving a signal by at least one of electric field coupling and magnetic field coupling with the first coupler; a divider for dividing a received signal into the plurality of data signals; At least one of the first communication device and the second communication device has an equalizer that performs equalization processing, A wireless communication system characterized in that, regarding the signal amplification factor in the equalization process, the amplification factor of signals in a frequency range lower than a predetermined frequency is higher than the amplification factor of signals in a frequency range higher than the predetermined frequency.

9. the first communication device has the equalizer; the equalizer performs equalization processing on the signal multiplexed by the multiplexer, and outputs the equalized signal to the first combiner; The wireless communication system according to claim 8, wherein the divider divides the received signal into the plurality of data signals by performing division processing on the signal wirelessly received by the second combiner.

10. the second communication device has the equalizer; outputting the signal multiplexed by the multiplexer to the first combiner; the equalizer performs equalization processing on the signal wirelessly received by the second combiner; 9. The wireless communication system according to claim 8, wherein the divider divides the received signal into the plurality of data signals by performing demodulation processing on the signal that has been equalized by the equalizer.

11. the first communication device has the equalizer; the equalizer performs equalization processing on a plurality of data signals; the multiplexer performs a multiplexing process on the plurality of data signals that have been equalized by the equalizer, and outputs the multiplexed signal to the first combiner; The wireless communication system according to claim 8, wherein the divider divides the received signal into the plurality of data signals by performing division processing on the signal wirelessly received by the second combiner.

12. The multiplexer is a serializer, 12. The wireless communication system according to claim 8, wherein the divider is a deserializer.

13. A wireless communication system described in any one of claims 8 to 11, characterized in that the second communication device further has a termination resistor connected to the second coupler.

14. A wireless communication system described in any one of claims 8 to 11, characterized in that the specified frequency is based on at least the capacitance between the first coupler and the second coupler.

15. the first communication device, a reference signal generator for generating a reference signal; a third combiner for wirelessly transmitting the reference signal generated by the reference signal generator; the second communication device, a fourth coupler for wirelessly receiving a reference signal by at least one of electric field coupling and magnetic field coupling with the third coupler; The wireless communication system according to any one of claims 1 to 13, further comprising a reference signal receiver that performs waveform shaping processing on the reference signal wirelessly received by the fourth coupler.

16. The wireless communication system according to claim 1, 16. The wireless communication system according to claim 1, wherein the wireless communication system is implemented in a CT (Computed Tomography) device.

17. a first communication device; a second communication device, a step in which a multiplexer of the first communication device performs a multiplexing process of multiplexing a plurality of signals; a first coupler of the first communication device wirelessly transmitting a signal; a step of receiving a signal wirelessly from the first coupler by at least one of electric field coupling and magnetic field coupling using a second coupler of the second communication device; a step in which a divider of the second communication device performs a division process to divide the signal into a plurality of signals; an equalizer of the first communication device or the second communication device performing an equalization process; A processing method for a wireless communication system, characterized in that, regarding the signal amplification factor in the equalization processing, the amplification factor of signals in a frequency range lower than a predetermined frequency is higher than the amplification factor of signals in a frequency range higher than the predetermined frequency.

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