Sensing system, transmission device, program, and sensing method

Abstract

This transmission device is provided with an optical signal generation unit for generating an optical signal having a plurality of frequencies, a signal conversion unit for converting a plurality of optical signals generated by the optical signal generation unit into an electrical signal having a plurality of frequency components, and at least one transmission antenna for wirelessly transmitting the electrical signal resulting from the conversion by the signal conversion unit.

Description

Sensing system, transmitting device, program, and sensing method

[0001] The present invention relates to a sensing system, a transmitting device, a program, and a sensing method.

[0002] Conventionally, sensing systems are known that transmit a wireless signal from a transmitting device to an object to be sensed, receive the wireless signal that has passed through the object with a receiving device, and obtain information about the object by analyzing the received signal (Non-Patent Document 1, Non-Patent Document 2).

[0003] Conventional sensing systems aim to improve the resolution in the thickness direction of the sensing target, expand the types of sensing targets, and enable high-speed compositional analysis by simultaneously using radio waves from multiple frequency bands. To achieve these effects, conventional sensing systems need to increase the number of usable frequency bands and the usable frequency range.

[0004] Ali Mostajeran, Member, SM Hossein Naghavi, Mohammad Emadi, Mohammed Aseeri, and Ehsan Afshari, “A High-Resolution 220-GHz Ultra-Wideband Fully Integrated ISAR Imaging System”, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 67, NO. 1, JANUARY 2019L. Tripodia*, M. Matters-Kammererb, H. Sch▲a▼ferc, PH Bolivarc, X. Hud, A. Rydbergd, R. G▲o▼tzene, “Broadband terahertz and sub-terahertz CMOS modules for imaging and spectroscopy applications”, https: / / www.researchgate.net / publication / 271617182_Broadband_Terahertz_and_Sub-terahertz_CMOS_Modules_for_Imaging_and_Spectroscopy_Applications

[0005] Conventional sensing systems have limitations on the frequency bandwidth that can be used simultaneously with a single radio frequency circuit due to the frequency characteristics of the radio frequency circuit. To use radio waves in multiple frequency bands for observation with a radio frequency circuit, a radio frequency circuit or mixer corresponding to the number of frequency bands used is required, resulting in increased power consumption in the radio frequency circuit. In other words, conventional sensing systems have problems with increased power consumption in the transmitting device and increased circuit size due to the need to prepare separate transmitting devices for multiple frequencies when sensing an object using radio signals transmitted from a transmitting device and received by a receiving device.

[0006] The present invention aims to provide a technology that reduces power consumption in a transmitting device and enables the construction of a compact circuit when sensing an object using a wireless signal transmitted from a transmitting device and received by a receiving device.

[0007] One aspect of the present invention is a sensing system comprising a transmitting device and a receiving device, wherein the transmitting device comprises an optical signal generating unit that generates a plurality of optical signals, a signal conversion unit that converts the plurality of optical signals generated by the optical signal generating unit into electrical signals having a plurality of frequency components, and at least one transmitting antenna that wirelessly transmits the electrical signals converted by the signal conversion unit, and the receiving device comprises at least one receiving antenna that wirelessly receives the electrical signals transmitted from the at least one transmitting antenna, and a sensing information acquisition unit that acquires information about an object to be sensed based on the plurality of electrical signals received by the at least one receiving antenna.

[0008] Another aspect of the present invention is a transmitting device comprising: an optical signal generation unit that generates optical signals of multiple frequencies; a signal conversion unit that converts the multiple optical signals generated by the optical signal generation unit into electrical signals having multiple frequency components; and at least one transmitting antenna that wirelessly transmits the electrical signals converted by the signal conversion unit.

[0009] Furthermore, yet another aspect of the present invention is a program that causes the computer of a transmitting device to execute an optical signal generation process that generates optical signals of multiple frequencies; a signal conversion process that converts the multiple optical signals generated in the optical signal generation process into electrical signals having multiple frequency components; and a wireless transmission process that wirelessly transmits the electrical signals converted in the signal conversion process from at least one transmitting antenna.

[0010] Furthermore, yet another aspect of the present invention is a sensing method using a transmitting device and a receiving device, comprising: an optical signal generation process in which the transmitting device generates optical signals of multiple frequencies; a signal conversion process in which the transmitting device converts the multiple optical signals generated in the optical signal generation process into electrical signals having multiple frequency components; a wireless transmission process in which the transmitting device wirelessly transmits the electrical signals converted in the signal conversion process from at least one transmitting antenna; a wireless reception process in which the receiving device wirelessly receives the electrical signals transmitted from the at least one transmitting antenna with at least one receiving antenna; and a sensing information acquisition process in which the receiving device acquires information about an object to be sensed based on the electrical signals received in the wireless reception process.

[0011] According to the present invention, when sensing an object using a wireless signal transmitted from a transmitting device and received by a receiving device, it is possible to reduce the power consumption of the transmitting device and to configure the circuit in a smaller size.

[0012] This is a schematic block diagram showing the configuration of a sensing system according to the first embodiment of the present invention. This is a diagram showing an example of a signal output from the optical signal generation unit to the photomixer. This is a diagram showing an example of a wireless signal output from the photomixer to the transmitting antenna. This is a flowchart showing an overview of the processing performed by the sensing system according to the first embodiment of the present invention. This is a sequence diagram showing an overview of the processing performed by the sensing system according to the first embodiment of the present invention. This is a schematic block diagram showing the configuration of a sensing system according to the second embodiment of the present invention. This is a diagram showing an example of a signal output from the optical signal generation unit to the photomixer. This is a diagram showing an example of a signal output from the bandpass filter to the transmitting antenna. This is a diagram showing an example of a signal output from the bandpass filter to the transmitting antenna. This is a schematic block diagram showing the configuration of a sensing system according to the third embodiment of the present invention. This is a diagram showing an example of a signal output from the weighting unit to the photomixer. This is a diagram showing an example of a signal output from the weighting unit to the photomixer. This is a flowchart showing an overview of the processing performed by the sensing system according to the third embodiment of the present invention. This is a schematic block diagram showing the configuration of a sensing system according to the fourth embodiment of the present invention.

[0013] Hereinafter, the first to fourth embodiments of the present invention will be described with reference to the drawings. First, the first embodiment of the present invention will be described.

[0014] [First Embodiment] First, a first embodiment of the present invention will be described. Figure 1 is a schematic block diagram showing the configuration of a sensing system 1000a according to the first embodiment of the present invention. The sensing system 1000a includes a transmitting device 100a and a receiving device 200a. In the first embodiment, a sensing object 300a is placed between the transmitting device 100a and the receiving device 200a. The wireless signal transmitted from the transmitting device 100a passes through the sensing object 300a and is received by the receiving device 200a.

[0015] The transmitting device 100a includes an optical signal generation unit 10a, a photomixer 11a, and a transmitting antenna 13a. The optical signal generation unit 10a generates multiple optical signals to be transmitted from the transmitting device 100a to the receiving device 200a and outputs them to the photomixer 11a. The photomixer 11a converts the optical signals into arbitrary wireless signals by intensity modulation and transmits the wireless signals via the transmitting antenna 13a. The sensing information acquisition unit 21a acquires some information about the sensing target object from the received signals corresponding to the wireless signals in the signal receiving units 20a-1 to 20a-N.

[0016] Figure 2A shows an example of a signal output from the optical signal generation unit 10a to the photomixer 11a. In Figure 2A, the horizontal axis represents the optical frequency. In Figure 2A, carrier waves A11, A12, and A13 exist on the frequency axis. Figure 2A also shows that signal A21, transmitted from the transmitter 100a to the receiver 200a, exists at a frequency f1 away from carrier wave A11. Furthermore, Figure 2A shows that signal A22, transmitted from the transmitter 100a to the receiver 200a, exists at a frequency f2 away from carrier wave A12. Furthermore, Figure 2A shows that signal A23, transmitted from the transmitter 100a to the receiver 200a, exists at a frequency f3 away from carrier wave A13.

[0017] Returning to the explanation of Figure 1, the photomixer 11a converts the optical signals of multiple frequencies generated by the optical signal generation unit 10a (signals A21, A22, and A23 in Figure 2A) into electrical signals with multiple frequency components (signals A21, A22, and A23 in Figure 2B). By performing intensity modulation, the signals are converted into radio frequencies corresponding to the frequency differences of the input signals. Figure 2B shows an example of a radio signal output from the photomixer 11a. In Figure 2B, the horizontal axis represents radio frequency, and the vertical axis represents power. As shown in Figure 2B, the photomixer 11a positions signals A21, A22, and A23 at frequencies f1, f2, and f3 away from a predetermined frequency. This eliminates the need to provide a separate photomixer for each of the signals A21, A22, and A23 in Figure 2A. The photomixer 11a is composed of a photoelectric conversion device such as a photodiode.

[0018] Returning to the description of FIG. 1, the transmission antenna 13a transmits the electrical signal output from the photomixer 11a as a radio signal to the receiving device 200a. The signal output from the photomixer 11a may be amplified by an amplifier and then input to the transmission antenna 13a.

[0019] Note that the transmission device 100a also includes a control unit and a storage unit, but in FIG. 1, their illustration is omitted. The control unit included in the transmission device 100a is constituted by a CPU (Central Processing Unit) or the like and controls each part of the transmission device 100a. The storage unit included in the transmission device 100a is constituted by a RAM (Random Access Memory), a ROM (Read Only Memory) or the like and stores programs for driving the transmission device 100a, data for transmission from the transmission device 100a to the receiving device 200a, and the like.

[0020] The receiving device 200a includes signal receiving units 20a-1 to 20a-N (N is an integer of 2 or more) and a sensing information acquisition unit 21a. The signal receiving units 20a-1 to 20a-N include N receiving antennas. The signal receiving units 20a-1 to 20a-N receive the radio signal transmitted from the transmission antenna 13a of the transmission device 100a with the N receiving antennas and output it as an electrical signal to the sensing information acquisition unit 21a.

[0021] The sensing information acquisition unit 21a acquires sensing information of the sensing target unit 300a existing between the transmission device 100a and the receiving device 200a based on the N electrical signals output from the signal receiving units 20a-1 to 20a-N.

[0022] Note that the receiving device 200a also includes a control unit and a storage unit, but in FIG. 1, their illustration is omitted. The control unit included in the receiving device 200a is constituted by a CPU or the like and controls each part of the receiving device 200a. The storage unit included in the receiving device 200a is constituted by a RAM, a ROM or the like and stores programs for driving the receiving device 200a, data received by the receiving device 200a from the transmission device 100a, and the like.

[0023] Figure 3 is a flowchart showing an overview of the processing performed in the sensing system 1000a according to the first embodiment of the present invention. First, the optical signal generation unit 10a of the transmission device 100a generates optical signals corresponding to a plurality of radio frequency bands (for example, signals A11, A12, A13 shown in FIG. 2A) (step S101).

[0024] Next, the photomixer 11a of the transmission device 100a converts the plurality of optical signals (signals A11, A12, A13 in FIG. 2A) generated in step S101 into electrical signals (signals A21, A22, A23 in FIG. 2B) to generate radio signals in a plurality of radio frequency bands (step S102).

[0025] Next, the transmission antenna 13a of the transmission device 100a transmits the radio signals in a plurality of radio frequency bands generated in step S102 to the reception device 200a (step S103). Next, the sensing information acquisition unit 21a of the reception device 200a performs sensing of the sensing object 300a using the electrical signals in a plurality of radio frequency bands obtained by the signal reception units 20a-1 to 20a-N (step S104).

[0026] Figure 4 is a sequence diagram showing an overview of the processing performed in the sensing system 1000a according to the first embodiment of the present invention. First, the optical signal generation unit 10a of the transmission device 100a generates optical signals of a plurality of frequencies (signals A21, A22, A23 in FIG. 2A) (step S201).

[0027] Next, the photomixer 11a of the transmission device 100a converts the optical signals of a plurality of frequencies generated in step S201 into electrical signals having a plurality of frequency components (signals A21, A22, A23 in FIG. 2B) (step S202). Next, the transmission antenna 13a of the transmission device 100a wirelessly transmits the plurality of electrical signals converted in step S202 to the reception device 200a (step S203).

[0028] The signal receiving units 20a-1 to 20a-N of the receiving device 200a wirelessly receive the electrical signal transmitted in step S203 using the receiving antenna (step S204). Next, the sensing information acquisition unit 21a of the receiving device 200a acquires information about the sensing target object based on the electrical signal received in step S204 (step S205). For example, the sensing information acquisition unit 21a acquires sensing information by identifying the state of the sensing target object 300a that exists between the transmitting antenna 13a and the N receiving antennas of the signal receiving units 20a-1 to 20a-N, based on the reception strength of the N receiving antennas of the signal receiving units 20a-1 to 20a-N.

[0029] In the first embodiment described above, by inputting optical signals (signals A11, A12, and A13 in Figure 2A) to the photomixer 11a and generating multiple radio frequency signals (signals A21, A22, and A23 in Figure 2B) at once, the power consumption of the transmitting device 100a can be reduced by supplying the excitation current with only one photomixer 11a, regardless of the number of frequency bands used or the magnitude of the frequencies. Therefore, when sensing an object 300a using radio signals transmitted from the transmitting device 100a and received by the receiving device 200a, the power consumption of the transmitting device 100a can be reduced, and the circuit can be made more compact.

[0030] [Second Embodiment] Next, a second embodiment of the present invention will be described. Figure 5 is a schematic block diagram showing the configuration of a sensing system 1000b according to the second embodiment of the present invention. The sensing system 1000b includes a transmitting device 100b and a receiving device 200b. In the second embodiment, a sensing object 300b is placed between the transmitting device 100b and the receiving device 200b. The wireless signal transmitted from the transmitting device 100b passes through the sensing object 300b and is received by the receiving device 200b.

[0031] The transmitting device 100b includes an optical signal generation unit 10b, a photomixer 11b, a signal branching unit 14b, bandpass filters 12b-1 to 12b-K (where K is an integer of 2 or more), and transmitting antennas 13b-1, 13b-2, ..., 13b-K. The receiving device 200b includes signal receiving units 20b-1 to 20b-N (where N is an integer of 2 or more) and a sensing information acquisition unit 21b.

[0032] Note that the configuration and processing of the signal receiving units 20b-1 to 20b-N and the sensing information acquisition unit 21b of the receiving device 200b according to the second embodiment (Figure 5) are the same as those of the signal receiving units 20a-1 to 20a-N and the sensing information acquisition unit 21a of the receiving device 200a according to the first embodiment (Figure 1), so their explanation will be omitted.

[0033] The optical signal generation unit 10b generates multiple optical signals to be transmitted from the transmitting device 100b to the receiving device 200b and outputs them to the photomixer 11b. Figure 6A shows an example of the signals output from the optical signal generation unit 10b to the photomixer 11b. In Figure 6A, the horizontal axis represents optical frequency. In Figure 6A, carrier waves A31, A32, and A33 exist on the frequency axis. Figure 6A also shows that signal A41, transmitted from the transmitting device 100b to the receiving device 200b, exists at a frequency f1 away from carrier wave A31. Figure 6A also shows that signal A42, transmitted from the transmitting device 100b to the receiving device 200b, exists at a frequency f2 away from carrier wave A32. Figure 6A also shows that signal A43, transmitted from the transmitting device 100b to the receiving device 200b, exists at a frequency f3 away from carrier wave A33.

[0034] Returning to the explanation of Figure 5, the photomixer 11b converts the optical signals of multiple frequencies generated by the optical signal generation unit 10b (signals A21, A22, A23 in Figure 2A) into electrical signals with multiple frequency components (signals A21, A22, A23 in Figure 2B) and outputs them to the signal branching unit 14b. The signal branching unit 14b branches the electrical signals output from the photomixer 11b into K electrical signals and outputs them to the bandpass filters 12b-1 to 12b-K. Figures 6B and 6C show examples of signals output from the bandpass filters 12b-1 and 12b-K. In Figures 6B and 6C, the horizontal axis represents radio frequency and the vertical axis represents power. For example, the bandpass filter 12b-1 outputs signal A43 as shown in Figure 6C, and the bandpass filter 12b-K outputs signal A41 as shown in Figure 6B. If a device with both signal branching and bandpass filtering functions, such as an array waveguide grating, is used in the signal branching section 14b, the bandpass filters 12b-1 to 12b-K may be omitted.

[0035] Returning to the explanation of Figure 5, the bandpass filters 12b-1 to 12b-K amplify the electrical signals branched into K parts by the signal branching section 14b, passing only a predetermined bandwidth through each, and outputting them to the multiple transmitting antennas 13b-1 to 13b-K. For example, the bandpass filter 12b-1 has a center frequency of frequency f1 and passes only a bandwidth that is sufficiently wider than the signal A41. The multiple transmitting antennas 13b-1 to 13b-K transmit the K electrical signals output from the bandpass filters 12b-1 to 12b-K to the receiving device 200b. The power of the radio waves radiated from the transmitting antennas 13b-1 to 13b-K may be increased by adding an amplifier before or after the bandpass filters 12b-1 to 12b-K.

[0036] According to the sensing system 1000b of the second embodiment, similar to the sensing system 1000a of the first embodiment, when sensing an object 300b using a wireless signal transmitted from the transmitting device 100b and received by the receiving device 200b, the power consumption of the transmitting device 100b can be reduced and the circuit can be made smaller.

[0037] Furthermore, compared to the first embodiment, the sensing system 1000b according to the second embodiment allows for an increase in the transmitting antenna area by increasing the number of transmitting antennas provided by the transmitting device 200b, thereby increasing the resolution of the sensing processing performed by the sensing information acquisition unit 21b of the receiving device 200b.

[0038] [Third Embodiment] Next, a third embodiment of the present invention will be described. Figure 7 is a schematic block diagram showing the configuration of a sensing system 1000c according to the third embodiment of the present invention. The sensing system 1000c includes a transmitting device 100c and a receiving device 200c. In the third embodiment, a sensing object 300c is placed between the transmitting device 100c and the receiving device 200c. The wireless signal transmitted from the transmitting device 100c passes through the sensing object 300c and is received by the receiving device 200c.

[0039] The transmitting device 100c includes an optical signal generation unit 10c, a weighting unit 15c, photomixers 11c-1 to 11c-M (where M is an integer of 2 or more), and transmitting antennas 13c-1, 13c-2, ..., 13c-M. The receiving device 200c includes signal receiving units 20c-1 to 20c-N (where N is an integer of 2 or more) and a sensing information acquisition unit 21c.

[0040] Note that the configuration and processing of the signal receiving units 20c-1 to 20c-N and the sensing information acquisition unit 21c in the receiving device 200c according to the third embodiment (Figure 7) are the same as those of the signal receiving units 20a-1 to 20a-N and the sensing information acquisition unit 21a in the receiving device 200a according to the first embodiment (Figure 1), so their explanation will be omitted.

[0041] The optical signal generation unit 10c generates a plurality of optical signals transmitted from the transmission device 100c to the reception device 200c, and outputs them to the weight application unit 15c. The weight application unit 15c adds a weight to the plurality of optical signals output from the optical signal generation unit 10c by modulating the amplitude or the phase or both, and outputs them to the photomixers 11c-1 to 11c-M. FIG. 8A is a diagram showing an example of a signal output from the weight application unit 15c to the photomixer 11c-1. In FIG. 8A, the horizontal axis represents the optical frequency. In FIG. 8A, carrier waves A51, A52, and A53 exist on the frequency axis. Also, in FIG. 8A, a case is shown where a signal A61 to be transmitted from the transmission device 100c to the reception device 200c exists at a position separated from the carrier wave A51 by a frequency f1. Also, in FIG. 8A, a case is shown where a signal A62 to be transmitted from the transmission device 100c to the reception device 200c exists at a position separated from the carrier wave A52 by a frequency f2. Also, in FIG. 8A, a case is shown where a signal A63 to be transmitted from the transmission device 100c to the reception device 200c exists at a position separated from the carrier wave A53 by a frequency f3.

[0042] Note that the signal (FIG. 8A) output from the weight application unit 15c to the photomixer 11c-1 is exp(i2πf ｃ１ t) + exp(i2πf ｃ２ t) + exp(i2πf ｃ３ t) + {(s １ (t) exp(i2π(f ｃ１ + f1)t) + s ２ (t) exp(i2π(f ｃ２ + f2)t) + s ３ (t) exp(i2π(f ｃ３ + f3)t))}. exp(i2πf ｃ１ t) indicates the carrier wave A51. exp(i2πf ｃ２ t) indicates the carrier wave A52. exp(i2πf ｃ３ t) indicates the carrier wave A53. s １ (t) exp(i2π(f ｃ１ + f1)t) indicates the signal A61. s ２ (t) exp(i2π(f ｃ２ + f1)t) indicates the signal A62. s３ (t)exp(i2π(f ｃ３ +f1)t) indicates signal A63.

[0043] Figure 8B shows an example of a signal output from the weighting unit 15c to the photomixer 11c-M. In Figure 8B, the horizontal axis represents the optical frequency. In Figure 8B, carrier waves A71, A72, and A73 exist on the frequency axis. Figure 8B also shows that signal A81, transmitted from the transmitter 100c to the receiver 200c, exists at a frequency f1 away from carrier wave A71. Furthermore, Figure 8B shows that signal A82, transmitted from the transmitter 100c to the receiver 200c, exists at a frequency f2 away from carrier wave A72. Furthermore, Figure 8B shows that signal A83, transmitted from the transmitter 100c to the receiver 200c, exists at a frequency f3 away from carrier wave A73.

[0044] The signal output from the weighting unit 15c to the photomixer 11c-M (Figure 8B) is exp(i2πf ｃ１ t)+exp(i2πf ｃ２ t)+exp(i2πf ｃ３ t) + s １ (t)exp(i2π(f ｃ１ +f1)t+θ Ｍ ) + s ２ (t)exp(i2π(f ｃ２ +f²)t+θ Ｍ ) + s ３ (t)exp(i2π(f ｃ３ +f3)t+θ Ｍ It is expressed as exp(i2πf). ｃ１ t) represents the carrier wave A71. exp(i2πf ｃ２ t) represents the carrier wave A72. exp(i2πf ｃ３ t) represents the carrier wave A53. exp(i2πf ｃ１ t) shows carrier wave A73. １ (t)exp(i2π(f ｃ１ +f1)t+θ Ｍ ) indicates signal A81, θ Ｍ The phase is added. ２(t)exp(i2π(f ｃ２ +f²)t+θ Ｍ ) indicates signal A82, θ Ｍ The phase is added. ３ (t)exp(i2π(f ｃ３ +f3)t+θ Ｍ ) indicates signal A83, θ Ｍ The phase is added.

[0045] Returning to the explanation of Figure 7, the photomixers 11c-1 to 11c-M convert the optical signal output from the weighting unit 15c into an electrical signal and output it to the transmitting antennas 13c-1 to 13c-M. The transmitting antennas 13c-1 to 13c-M transmit the electrical signal to the receiving device 200c.

[0046] Figure 9 is a flowchart illustrating the overview of the processing performed by the sensing system 1000c according to the third embodiment of the present invention. First, the optical signal generation unit 10c of the transmitting device 100c generates a plurality of optical signals corresponding to a plurality of radio frequency bands (for example, signals A11, A12, and A13 shown in Figure 2A) (step S301).

[0047] Next, the weighting unit 15c of the transmitting device 100c adds weight to the multiple optical signals generated in step S301 (step S302). For example, the weighting unit 15c adds weight to signals A61, A62, and A63 shown in Figure 8A by applying a phase rotation.

[0048] Next, the photomixers 11c-1 to 11c-M generate radio signals in multiple radio frequency bands by converting the multiple optical signals generated in step S302 into electrical signals (signals A81, A82, and A83 in Figure 8B) (step S303).

[0049] Next, the transmitting antennas 13c-1 to 13c-M of the transmitting device 100c transmit the radio signals of multiple radio frequency bands generated in step S303 to the receiving device 200c (step S304). Next, the signal receiving units 20c-1 to 20c-M of the receiving device 200c obtain channel information of multiple radio frequency bands from the transmitting device 100c from the radio signals of multiple radio frequency bands received in step S304 (step S305).

[0050] Next, the sensing information acquisition unit 21c of the receiving device 200c performs sensing of the sensing target object 300c using the channel information converted in step S305 (step S306). For example, the sensing information acquisition unit 21c identifies whether the electrical signal output from the signal receiving unit 20c-l (where l is an integer between 1 and L) is based on a radio signal transmitted from one of the transmitting antennas 13a-1 to 13a-M by referring to the channel information. Then, the sensing information acquisition unit 21c acquires sensing information by identifying the state of the sensing target object 300c that exists between the transmitting antennas 13c-1 to 13c-M and the L receiving antennas of the signal receiving units 20c-1 to 20c-L, based on the received signal strength at the L receiving antennas provided by the signal receiving units 20c-1 to 20c-L.

[0051] According to the third embodiment of the sensing system 1000c, similar to the first embodiment of the sensing system 1000a, when sensing an object 300c using a wireless signal transmitted from the transmitting device 100c and received by the receiving device 200c, the power consumption of the transmitting device 100c can be reduced and the circuit can be made smaller.

[0052] Furthermore, compared to the first embodiment, the sensing system 1000c according to the third embodiment allows for an increase in the transmitting antenna area by increasing the number of transmitting antennas provided in the transmitting device 200c, thereby increasing the resolution of the sensing processing performed by the sensing information acquisition unit 21c of the receiving device 200c.

[0053] [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described. Figure 10 is a schematic block diagram showing the configuration of a sensing system 1000d according to the fourth embodiment of the present invention. The sensing system 1000d includes a transmitting device 100d and a receiving device 200d. In the fourth embodiment, a sensing object 300d is placed between the transmitting device 100d and the receiving device 200d. The wireless signal transmitted from the transmitting device 100d passes through the sensing object 300d and is received by the receiving device 200d.

[0054] The transmitting device 100d includes an optical signal generation unit 10d, a weighting unit 15d, photomixers 11d-1-1, 11d-1-2, ..., 11d-1-M (where M is an integer of 2 or more), ..., 11d-N-1 (where N is an integer of 2 or more), 11d-N-2, ..., 11d-N-M, and transmitting antennas 13d-1-1, 13d-1-2, ..., 13d-1-M, ..., 13d-N-1, 13d-N-2, ..., 13d-N-M. The receiving device 200d includes signal receiving units 20d-1 to 20d-L (where L is an integer of 2 or more) and a sensing information acquisition unit 21d.

[0055] The configuration and operation of the receiving device 200d in the fourth embodiment are the same as those of the receiving device 200c in the third embodiment, so their description will be omitted. The transmitting device 200d in the fourth embodiment differs from the transmitting device 100c in the third embodiment in that the photomixer and transmitting antenna are arranged in an M x N matrix.

[0056] According to the sensing system 1000d of the fourth embodiment, similar to the sensing system 1000a of the first embodiment, when sensing an object 300d using a wireless signal transmitted from the transmitting device 100d and received by the receiving device 200d, the power consumption of the transmitting device 100d can be reduced and the circuit can be made smaller.

[0057] Furthermore, compared to the first embodiment, in the sensing system 1000d according to the fourth embodiment, the transmitting antennas 13d-1-1, 13d-1-2, ..., 13d-1-M, ..., 13d-N-1, 13d-N-2, ..., 13d-N-M of the transmitting device 100d are arranged in an M row x N column matrix, thereby increasing the transmitting antenna area and improving the resolution of the sensing processing performed by the sensing information acquisition unit 21d of the receiving device 200d.

[0058] In the fourth embodiment, the case in which the transmitting antennas 13d-1-1, 13d-1-2, ..., 13d-1-M, ..., 13d-N-1, 13d-N-2, ..., 13d-N-M of the transmitting device 100d are arranged in an M x N matrix, was described, but the embodiment is not limited to this. For example, the receiving antennas of the receiving device 200d may also be arranged in a matrix.

[0059] In the first to fourth embodiments, the case in which the transmitting antenna of the transmitting device and the receiving antenna of the signal receiving unit of the receiving device are arranged opposite each other with the sensing object in between was described. However, the invention is not limited to this, and multiple transmitting antennas can be arranged at any position. Similarly, the receiving antennas can also be arranged at any position.

[0060] In addition, the sensing information acquisition units 21a, 21b, 21c, and 21d in the first to fourth embodiments may use machine learning algorithms to acquire information on the sensing target. The sensing target may be learned in advance by machine learning. When learning to sense the sensing target, training data including information on the radio frequency, bandwidth, and transmission weight used in the transmitting devices 100a, 100b, 100c, and 100d may be generated by actual measurement or simulation, and the sensing accuracy of the sensing information acquisition units 21a, 21b, 21c, and 21d may be improved using this training data.

[0061] Furthermore, at least some of the functions of the transmitting and receiving devices in the first to fourth embodiments described above may be implemented by a computer. In this case, the functions may be implemented by recording a program for implementing these functions on a computer-readable recording medium, loading the program recorded on this recording medium into a computer system, and executing it. Here, "computer system" includes hardware such as an OS (Operating System) and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), CD-ROMs, and storage devices such as hard disks built into a computer system. Moreover, "computer-readable recording medium" may also include those that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside a computer system that acts as a server or client in such cases. Furthermore, the above-mentioned program may be for implementing some of the functions described above, or it may be a program that can implement the above-mentioned functions in combination with a program already recorded in the computer system, or it may be implemented using a programmable logic device such as an FPGA.

[0062] Furthermore, we have demonstrated that it is possible to output RF signals of multiple frequencies from a single photomixer, such as the photomixer 11b shown in Figure 1 and the photomixer 11b shown in Figure 5, as shown in Figure 2B. When using a V-band UTC-PD, as an example, when the optical frequencies input to the photomixer were 196.075 THz, 196.103 THz, 196.1 THz, and 196.128 THz, the photomixer output RF signals with frequencies of 3 GHz, 25 GHz, and 28 GHz. In this case, the frequency of 53 GHz, which is the difference between 196.075 THz and 196.128 THz, was not output because it exceeded the RF frequency range that the photomixer can convert photoelectrically. However, by using a broadband photomixer, it is possible to support an even wider range of RF frequencies.

[0063] Furthermore, we have demonstrated through experiments using actual equipment a method in which weights are generated in the optical domain using the weighting unit 15c shown in Figure 7 and the weighting unit 15d shown in Figure 10, and photoelectric conversion is performed using the photomixers 11c-1 to 11c-M shown in Figure 7 and the photomixers 11d-1-1 to 11d-N-M shown in Figure 10, and the weights are reflected in the output RF signal.

[0064] Although the first to fourth embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0065] The present invention can be applied to sensing systems, transmitting devices, programs, and sensing methods that require reducing power consumption in the transmitting device or miniaturizing the circuit when sensing an object using a wireless signal transmitted from a transmitting device and received by a receiving device.

[0066] 10a, 10b, 10c, 10d... Optical signal generation unit, 11a, 11b, 11c-1 to 11c-M, 11d-1 to 11d-N-M... Photo mixer, 12b-1 to 12b-K... Bandpass filter, 13a, 13b-1 to 13b-K, 13c-1 to 13c-M, 13d-1 to 13d-N-M... Transmitting antenna, 14b... Signal splitting unit, 15c, 15d... Weighting unit, 20a-1 to 20a-L, 20b-1 to 20b-L, 20c-1 to 20c-L, 20d-1 to 20d-L... Signal receiving unit, 21a, 21b, 21c, 21d... Sensing information acquisition unit, 100a, 100b, 100c, 100d... Transmitting devices; 200a, 200b, 200c, 200d... Receiving devices; 1000a, 1000b, 1000c, 1000d... Sensing systems

Claims

1. A sensing system comprising a transmitting device and a receiving device, wherein the transmitting device comprises: an optical signal generating unit that generates optical signals of multiple frequencies; a signal conversion unit that converts the multiple optical signals generated by the optical signal generating unit into electrical signals having multiple frequency components; and at least one transmitting antenna that wirelessly transmits the electrical signals converted by the signal conversion unit; and the receiving device comprises: at least one receiving antenna that wirelessly receives the electrical signals transmitted from the at least one transmitting antenna; and a sensing information acquisition unit that acquires information about an object to be sensed based on the multiple electrical signals received by the at least one receiving antenna.

2. The sensing system according to claim 1, further comprising a signal branching unit that branches the electrical signal converted by the signal conversion unit into a plurality of electrical signals, wherein the at least one transmitting antenna is a plurality of transmitting antennas, and the plurality of transmitting antennas wirelessly transmit the plurality of electrical signals branched by the signal branching unit.

3. The sensing system according to claim 1, further comprising a weighting unit for assigning weights to the plurality of optical signals generated by the optical signal generation unit, wherein the signal conversion unit converts the plurality of optical signals to which the weighting unit has assigned weights into electrical signals.

4. The sensing system according to claim 1, wherein the plurality of transmitting antennas are a plurality of transmitting antennas arranged in a matrix.

5. A transmitting device comprising: an optical signal generation unit that generates optical signals of multiple frequencies; a signal conversion unit that converts the multiple optical signals generated by the optical signal generation unit into electrical signals having multiple frequency components; and at least one transmitting antenna that wirelessly transmits the electrical signals converted by the signal conversion unit.

6. A program that causes the computer of a transmitting device to execute: an optical signal generation process that generates optical signals of multiple frequencies; a signal conversion process that converts the multiple optical signals generated in the optical signal generation process into electrical signals having multiple frequency components; and a wireless transmission process that wirelessly transmits the electrical signals converted in the signal conversion process from at least one transmitting antenna.

7. A sensing method using a transmitting device and a receiving device, comprising: an optical signal generation process in which the transmitting device generates optical signals of multiple frequencies; a signal conversion process in which the transmitting device converts the multiple optical signals generated in the optical signal generation process into electrical signals having multiple frequency components; a wireless transmission process in which the transmitting device wirelessly transmits the electrical signals converted in the signal conversion process from at least one transmitting antenna; a wireless reception process in which the receiving device wirelessly receives the electrical signals transmitted from the at least one transmitting antenna with at least one receiving antenna; and a sensing information acquisition process in which the receiving device acquires information about an object to be sensed based on the electrical signals received in the wireless reception process.

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