Clock signal generation method, related device and storage medium

Abstract

The embodiment of the invention provides a clock signal generation method, a related device and a storage medium. The method comprises the following steps: receiving a carrier signal from a near field communication card reader in a first transmitting gap when near field communication card equipment transmits a subcarrier signal, determining a radio frequency field clock signal according to the received carrier signal, and monitoring the phase influence of antenna residual energy of the subcarrier signal on the radio frequency field clock signal to obtain phase deviation; and in the transmitting gap after the first transmitting gap, phase calibration is performed on the phase-locked loop clock signal according to the radio frequency field clock signal and / or phase compensation is performed on the phase-locked loop clock signal according to the phase deviation, so that the clock signal for active load modulation is obtained, and the phase deviation of the generated clock signal for active load modulation is reduced.

Description

Technical Field

[0001] The present disclosure belongs to the field of communication technologies, and particularly relates to a clock signal generation method, a related device, and a storage medium. Background Art

[0002] Near field communication (NFC) is a short-range wireless communication technology based on radiofrequency identification (RFID). The NFC reader (PCD) sends a carrier signal, and the NFC card device (PICC) modulates a subcarrier signal on the carrier signal through active load modulation (ALM, active load modulation). The subcarrier signal transmitted by the NFC card device needs to be synchronized with the clock of the carrier signal transmitted by the NFC reader (i.e., maintain the same frequency and a fixed phase relationship). Since the NFC card device and the NFC reader use different clock signal sources, the NFC card device needs to implement a clock signal with a very small frequency error from the clock signal of the carrier signal of the NFC reader through a radio frequency field clock extraction circuit and a phase-locked loop. During a frame of active load modulation, even a small frequency error between the clock signal of the carrier signal and the clock signal of the subcarrier signal will accumulate into a large phase deviation. Taking a frame transmission time of 20 ms (about 271,200 clock cycles with a frequency of 13.56 MHz) as an example for a rough estimate, when the frequency error between the clock signal of the subcarrier signal transmitted by the NFC card device and the clock signal of the carrier signal transmitted by the NFC reader is only 1 ppm, the cumulative phase error between the two within a frame transmission time can reach 97°. Therefore, usually, the phase of the clock signal for ALM is calibrated during the transmission gap of the subcarrier signal transmitted by the NFC card device to reduce the cumulative phase error.

[0003] In the process of implementing the present application, the inventors found that usually, the Q value of the antenna network is relatively high, which causes the residual energy of the subcarrier signal in the antenna of the NFC card device not to decay to be much smaller than the energy of the carrier signal obtained from the NFC reader during the transmission gap of the subcarrier signal transmitted by the NFC card device. This results in the clock extracted from the carrier signal by the radio frequency field clock extraction circuit not being able to reflect the phase of the carrier signal transmitted by the NFC reader, thereby causing a large phase deviation in the subsequent phase-calibrated clock signal for ALM, resulting in poor ALM callback quality, and even the NFC reader being unable to correctly demodulate, affecting the communication performance. Summary of the Invention

[0004] In view of the above problems, embodiments of the present disclosure provide a clock signal generation method, a related device, and a storage medium, aiming to reduce the phase deviation of the generated clock signal for active load modulation.

[0005] According to a first aspect of an embodiment of the present disclosure, a clock signal generation method is provided, including:

[0006] During a first transmission gap when the near-field communication card device transmits a subcarrier signal, receive a carrier signal from the near-field communication reader, determine a radio-frequency field clock signal according to the received carrier signal, monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio-frequency field clock signal, and obtain a phase offset.

[0007] During a transmission gap after the first transmission gap, perform phase calibration on the phase-locked loop clock signal according to the radio-frequency field clock signal and / or perform phase compensation on the phase-locked loop clock signal according to the phase offset, to obtain a clock signal for active load modulation.

[0008] Optionally, after performing phase calibration on the phase-locked loop clock signal according to the radio-frequency field clock signal and / or performing phase compensation on the phase-locked loop clock signal according to the phase offset during a transmission gap after the first transmission gap, to obtain a clock signal for active load modulation, the clock signal generation method further includes:

[0009] During a corresponding transmission stage when the near-field communication card device transmits a subcarrier signal, generate a subcarrier signal according to the corresponding clock signal for active load modulation.

[0010] Optionally, the monitoring the phase influence of the antenna residual energy of the subcarrier signal on the radio-frequency field clock signal, and obtaining a phase offset includes:

[0011] During the first transmission gap, calculate the phase offset between the radio-frequency field clock signal and the phase-locked loop clock signal.

[0012] Optionally, before the first transmission gap, the clock signal generation method further includes:

[0013] When no active load modulation is performed, receive a carrier signal from the near-field communication reader, determine a radio-frequency field clock signal according to the received carrier signal, and perform phase calibration on the phase-locked loop clock signal according to the radio-frequency field clock signal.

[0014] Optionally, when it is determined that binary phase shift keying is adopted, during a one-frame transmission time of the subcarrier signal, during a first transmission gap when the near-field communication card device transmits the subcarrier signal, monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio-frequency field clock signal, and obtain a phase offset.

[0015] In a subsequent transmission gap when the near - field communication card device transmits a sub - carrier signal, phase calibration of the phase - locked loop clock signal is performed according to the radio - frequency field clock signal, and phase compensation of the phase - locked loop clock signal is performed according to the phase offset to obtain a clock signal for active load modulation.

[0016] Optionally, when it is determined to use on - off keying, during one - bit transmission time of the sub - carrier signal, in the first transmission gap when the near - field communication card device transmits the sub - carrier signal, the phase influence of the antenna residual energy of the sub - carrier signal on the radio - frequency field clock signal is monitored to obtain a phase offset.

[0017] In a subsequent transmission gap when the near - field communication card device transmits a sub - carrier signal, phase calibration of the phase - locked loop clock signal is performed according to the radio - frequency field clock signal, and phase compensation of the phase - locked loop clock signal is performed according to the phase offset to obtain a clock signal for active load modulation.

[0018] During the time when active load modulation is not performed, phase calibration of the phase - locked loop clock signal is performed according to the radio - frequency field clock signal.

[0019] Optionally, the phase - locked loop clock signal is generated by adjusting the frequency of the local clock signal based on the radio - frequency field clock signal when active load modulation is not performed.

[0020] According to a second aspect of the embodiments of the present disclosure, there is provided a clock signal generation device, including:

[0021] A phase - offset monitoring unit, configured to receive a carrier signal from a near - field communication card reader in a first transmission gap when the near - field communication card device transmits a sub - carrier signal, determine the radio - frequency field clock signal according to the received carrier signal, and monitor the phase influence of the antenna residual energy of the sub - carrier signal on the radio - frequency field clock signal to obtain a phase offset.

[0022] An active - load - modulation clock - signal generation unit, configured to perform phase calibration of the phase - locked loop clock signal according to the radio - frequency field clock signal and / or perform phase compensation of the phase - locked loop clock signal according to the phase offset in a transmission gap after the first transmission gap to obtain a clock signal for active load modulation.

[0023] According to a third aspect of the embodiments of the present disclosure, there is provided a near - field communication card device, including:

[0024] The above - mentioned clock signal generation device, configured to generate a clock signal for active load modulation, so as to generate a sub - carrier signal according to the clock signal for active load modulation.

[0025] According to a fourth aspect of the embodiments of the present disclosure, there is provided a near - field communication system, including:

[0026] A near-field communication reader for transmitting a carrier signal;

[0027] The above-mentioned near-field communication card device is used to generate a clock signal for active load modulation, and generate a subcarrier signal according to the clock signal for active load modulation.

[0028] According to a fifth aspect of the embodiments of the present disclosure, there is provided an electronic device, including: a processor, a memory, and a program stored on the memory and executable on the processor. When the program is executed by the processor, the steps of the method described above are implemented.

[0029] According to a sixth aspect of the embodiments of the present disclosure, there is provided a storage medium, on which a computer program or instruction is stored. When the computer program or instruction is executed by a processor, the steps of the method described above are implemented.

[0030] The embodiments of the present disclosure bring the following beneficial effects:

[0031] The clock signal generation method provided by the embodiments of the present disclosure receives a carrier signal from a near-field communication reader during a first transmission gap when the near-field communication card device transmits a subcarrier signal, determines a radio frequency field clock signal according to the received carrier signal, monitors the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal to obtain a phase offset, and during a transmission gap after the first transmission gap, performs phase calibration on the phase-locked loop clock signal according to the radio frequency field clock signal and / or performs phase compensation on the phase-locked loop clock signal according to the phase offset to obtain a clock signal for active load modulation. The phase offset can characterize the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal. During the active load modulation process, the near-field communication card device can perform phase calibration on the phase-locked loop clock signal according to the radio frequency field clock signal, thereby reducing the phase deviation of the generated clock signal for active load modulation. It can also monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal during the transmission gap of transmitting the subcarrier signal, and use the phase offset characterizing this phase influence to compensate the phase-locked loop clock signal on the basis of phase calibration, thereby further reducing the phase deviation of the generated clock signal for active load modulation, and further improving the clock synchronization between the subcarrier signal transmitted by the near-field communication card device and the carrier signal transmitted by the near-field communication reader, improving the callback quality of active load modulation, ensuring that the near-field communication reader can correctly demodulate, and improving communication performance.

[0032] Other features and advantages of the embodiments of the present disclosure will be described in the subsequent specification, and some will be obvious from the specification, or understood by implementing the embodiments of the present disclosure. The objectives and other advantages of the embodiments of the present disclosure are achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0033] To make the above objects, features, and advantages of the embodiments of the present disclosure more apparent and understandable, the following preferred embodiments are specifically described below in conjunction with the accompanying drawings. Description of the Drawings

[0034] Through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, the above and other objects, features, and advantages of the embodiments of the present disclosure will become clearer. In the drawings:

[0035] Figure 1 is a schematic structural diagram of a near - field communication system in the related art;

[0036] Figure 2 is a schematic diagram of the waveform of the sub - carrier signal transmitted by the transmitting circuit of a near - field communication card device in the related art and the antenna residual energy of the sub - carrier signal received by the radio - frequency field clock extraction circuit;

[0037] Figure 3 is a schematic structural diagram of a near - field communication system according to an embodiment of the present disclosure;

[0038] Figure 4 is a schematic diagram of the waveform of the sub - carrier signal transmitted by the transmitting circuit of a near - field communication card device according to an embodiment of the present disclosure and the timing of phase calibration and / or phase compensation;

[0039] Figure 5 is a schematic diagram of the waveform of the sub - carrier signal transmitted by the transmitting circuit of a near - field communication card device according to another embodiment of the present disclosure and the timing of phase calibration and / or phase compensation;

[0040] Figure 6 is a schematic flowchart of a clock signal generation method according to an embodiment of the present disclosure;

[0041] Figure 7 is a schematic structural diagram of a clock signal generation device according to an embodiment of the present disclosure;

[0042] Figure 8 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure. Detailed Embodiments

[0043] The various embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. In each of the drawings, the same elements are denoted by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0044] The following terms are used herein:

[0045] ALM synchronously superimposes the subcarrier signal transmitted by the NFC card device onto the carrier signal transmitted by the NFC reader to generate amplitude modulation. In one embodiment, ALM is an active transmission of a 13.56 MHz signal modulated according to Type A / B / F standards. This can greatly enhance the generated signal strength and allow the use of a smaller antenna by meeting the required standards of similar NFC forums, ISO 14443 (contactless card standards), EMVCo, etc. regarding the load modulation amplitude parameter.

[0046] Figure 1 It is a schematic structural diagram of a near-field communication system in the related art. As Figure 1 shown, the near-field communication system includes an NFC reader 200 and an NFC card device 100. For convenience of description, Figure 1 only the antenna and matching circuit 110, radio frequency field clock extraction circuit 120, and transmission circuit 130 in the NFC card device 100 are shown. The NFC reader 200 and the NFC card device 100 achieve carrier and data transmission through inductive coupling. As the antenna size of the NFC card device 100 becomes smaller and smaller, the coupling effect with the antenna of the NFC reader 200 becomes weaker, resulting in only a very small part of the large transmission energy at the antenna end of the NFC reader 200 reaching the antenna end of the NFC card device 100. In addition, in order to ensure that the NFC reader 200 can receive sufficient modulation energy from the NFC card device 100, it is required that the NFC card device 100 also performs active load modulation with a strong transmission energy. However, since both the transmission circuit 130 and the radio frequency field clock extraction circuit 120 of the NFC card device 100 are connected to the antenna and matching circuit 110, the energy obtained by the receiving end of the NFC card device 100 from its transmission circuit 130 will be much greater than the energy received from the NFC reader 200. That is, the waveform of the subcarrier signal transmitted by the transmission circuit 130 of the NFC card device 100 returning to the radio frequency field clock extraction circuit 120 through the matching circuit will completely cover the waveform of the carrier signal received from the NFC reader 200.

[0047] Generally, the Q value of the antenna network is relatively high, which will cause the residual energy of the subcarrier signal in the antenna of the NFC card device 100 not to decay to be much smaller than the energy of the carrier signal obtained from the NFC reader 200 during the transmission gap of the subcarrier signal transmitted by the NFC card device 100. Figure 2 It is a schematic diagram of the waveform of the subcarrier signal transmitted by the transmission circuit of the NFC card device in the related art and a schematic diagram of the antenna residual energy of the subcarrier signal received by the radio frequency field clock extraction circuit. As Figure 2As shown in the figure, taking the subcarrier signal with a frequency of 848 KHz transmitted by the transmitting circuit 130 as an example. When binary phase shift keying is used for active load modulation (BPSKALM), during the transmission stage when the NFC card device 100 transmits the subcarrier signal, the radio frequency field clock extraction circuit 120 receives the subcarrier signal. During the transmission gap when the NFC card device 100 transmits the subcarrier signal, the radio frequency field clock extraction circuit 120 can still receive the antenna residual energy of the subcarrier signal. Even at the phase switching point of BPSK, the radio frequency field clock extraction circuit 120 can still receive a large amount of antenna residual energy. This causes the clock extracted by the radio frequency field clock extraction circuit 120 from the carrier signal not to reflect the phase of the carrier signal transmitted by the NFC reader 200, resulting in a large phase deviation of the subsequent clock signal generated by phase calibration for ALM, poor ALM callback quality, and the NFC reader 200 being unable to correctly demodulate, affecting the communication performance.

[0048] Based on this, the embodiments of the present disclosure provide a clock signal generation method, related device, and storage medium to improve the above problems.

[0049] Figure 3 It is a schematic structural diagram of a near-field communication system provided according to an embodiment of the present disclosure. As Figure 3 shown, the near-field communication system provided by the embodiments of the present disclosure includes an NFC reader 200 and an NFC card device 300. The NFC card device 300 includes an antenna and matching circuit 310, a radio frequency field clock extraction circuit 320, a phase-locked loop 330, an antenna residual measurement circuit 340, a phase calibration circuit 350, and a transmitting circuit 360.

[0050] In some embodiments, the NFC reader 200 refers to an NFC-enabled device that initiates an NFC connection. The NFC card device 300 refers to an NFC-enabled device that responds to requests from the NFC reader 200. The NFC reader 200 or the NFC card device 300 can be different types of electronic devices such as mobile phones, tablets, personal computers (PCs), personal digital assistants (PDAs), smart watches, netbooks, wearable electronic devices, augmented reality (AR) devices, virtual reality (VR) devices, in-vehicle devices, smart cars, smart speakers, robots, smart glasses, and so on. In some embodiments, the NFC card device 300 is inductively coupled to the NFC reader 200 through the antenna and matching circuit 310 to achieve carrier and data transmission.

[0051] In some embodiments, during the first transmission gap when the RF field clock extraction circuit 320 transmits a subcarrier signal in the NFC card device 300, the carrier signal is received from the NFC reader 200 through the antenna and the matching circuit 310, and the RF field clock signal FILED_CLK is determined according to the received carrier signal. The RF field clock signal FILED_CLK reflects the clock frequency and phase of the carrier signal. It should be noted that the RF field clock extraction circuit 320 can use related technologies to recover the RF field clock signal FILED_CLK from the carrier signal, and the embodiments of the present disclosure do not limit this. In some embodiments, during the first transmission gap when the NFC card device 300 transmits a subcarrier signal, the antenna residue measurement circuit 340 can monitor the phase influence of the antenna residue energy of the subcarrier signal on the RF field clock signal FILED_CLK to obtain the phase offset ΔPH. In some embodiments, during the first transmission gap when the NFC card device 300 transmits a subcarrier signal, the antenna residue measurement circuit 340 calculates the phase offset ΔPH between the RF field clock signal FILED_CLK and the phase-locked loop clock signal PLL_CLK. It should be noted that the phase-locked loop clock signals mentioned in the embodiments of the present disclosure are all generated by the phase-locked loop 330 based on the RF field clock signal FILED_CLK to adjust the frequency of the local clock signal without active load modulation. It should be noted that the local clock signal can be the clock signal provided by the clock source (such as a crystal oscillator) of the NFC card device 300. The phase-locked loop 330 can use related technologies to generate the phase-locked loop clock signal PLL_CLK, and the embodiments of the present disclosure do not limit this.

[0052] It is easy to understand that generally the Q value of the antenna network is relatively high. During the first transmission gap when the NFC card device 300 transmits a subcarrier signal, the antenna residue energy of the subcarrier signal in the NFC card device 300 has not decayed to be much smaller than the energy of the carrier signal obtained from the NFC reader 200. That is to say, during the first transmission gap when the NFC card device 300 transmits a subcarrier signal, the carrier signal received by the RF field clock extraction circuit 320 from the NFC reader 200 through the antenna and the matching circuit 310 contains to a certain extent the antenna residue energy of the subcarrier signal in the NFC card device 300. The RF field clock signal FILED_CLK determined by the RF field clock extraction circuit 320 according to the received carrier signal can represent the antenna residue energy of the subcarrier signal in the NFC card device 300. The phase offset ΔPH between the RF field clock signal FILED_CLK and the phase-locked loop clock signal PLL_CLK can represent the phase influence of the antenna residue energy of the subcarrier signal on the RF field clock signal FILED_CLK.

[0053] In some embodiments, during the transmission gap after the first transmission gap of the subcarrier signal transmitted by the NFC card device 300, the phase calibration circuit 350 performs phase calibration on the phase-locked loop clock signal PLL_CLK according to the radio frequency field clock signal FILED_CLK and / or performs phase compensation on the phase-locked loop clock signal PLL_CLK according to the phase offset ΔPH, to obtain the clock signal ALM_CLK for active load modulation. It can be understood that during the active load modulation process, the NFC card device 300 can perform phase calibration on the phase-locked loop clock signal PLL_CLK according to the radio frequency field clock signal FILED_CLK, so as to reduce the phase deviation of the generated clock signal for ALM. The NFC card device 300 can also monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal FILED_CLK during the transmission gap of the subcarrier signal, and compensate the phase-locked loop clock signal PLL_CLK by using the phase offset ΔPH characterizing the phase influence on the basis of phase calibration, so as to further reduce the phase deviation of the generated clock signal for ALM.

[0054] In some embodiments, before the first transmission gap of the subcarrier signal transmitted by the NFC card device 300, when active load modulation has not been performed yet, the radio frequency field clock extraction circuit 320 receives a carrier signal from the NFC reader 200, determines the radio frequency field clock signal FILED_CLK according to the received carrier signal, and the phase calibration circuit 350 performs phase calibration on the phase-locked loop clock signal PLL_CLK according to the radio frequency field clock signal FILED_CLK. It can be understood that performing pre-phase calibration on the phase-locked loop clock signal PLL_CLK according to the radio frequency field clock signal FILED_CLK before active load modulation can reduce the phase deviation of the generated clock signal for ALM during subsequent active load modulation.

[0055] In some embodiments, the phase calibration circuit 350 performs phase calibration and / or phase compensation on the phase-locked loop clock signal PLL_CLK during the transmission gap after the first transmission gap of the subcarrier signal transmitted by the NFC card device 300. After the phase calibration and / or phase compensation, the transmission circuit 360 generates a subcarrier signal according to the corresponding clock signal for active load modulation during the corresponding transmission stage of the subcarrier signal transmitted by the NFC card device 300. It can be understood that by performing phase calibration and / or phase compensation on the phase-locked loop clock signal PLL_CLK, the phase deviation of the generated clock signal for ALM is reduced, the clock synchronization between the subcarrier signal transmitted by the NFC card device 300 and the carrier signal transmitted by the NFC reader 200 is improved, and thus the ALM callback quality is improved, ensuring that the NFC reader 200 can correctly demodulate and improving the communication performance.

[0056] Figure 4Schematic diagram of the waveform of the subcarrier signal transmitted by the transmitting circuit of the NFC card device according to an embodiment of the present disclosure and schematic diagram of the timing of phase calibration and / or phase compensation. As Figure 4 shown, taking the subcarrier signal with a transmission frequency of 848 KHz transmitted by the transmitting circuit 360 as an example. When it is determined to adopt binary phase shift keying for active load modulation (BPSK ALM), before active load modulation is performed, the phase calibration circuit 350 calibrates the phase of the phase-locked loop clock signal PLL_CLK according to the radio frequency field clock signal FILED_CLK. During one frame transmission time of the subcarrier signal, during the first transmission gap when the NFC card device 300 transmits the subcarrier signal, the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal is monitored to obtain the phase offset ΔPH. During subsequent transmission gaps when the NFC card device 300 transmits the subcarrier signal, the phase of the phase-locked loop clock signal PLL_CLK is calibrated according to the radio frequency field clock signal FILED_CLK, and the phase of the phase-locked loop clock signal PLL_CLK is compensated according to the phase offset ΔPH to obtain the clock signal ALM_CLK for active load modulation. After phase calibration and / or phase compensation, the transmitting circuit 360 generates a subcarrier signal according to the corresponding clock signal ALM_CLK for active load modulation during the corresponding transmission stage when the NFC card device 300 transmits the subcarrier signal.

[0057] Figure 5 Schematic diagram of the waveform of the subcarrier signal transmitted by the transmitting circuit of the NFC card device according to another embodiment of the present disclosure and schematic diagram of the timing of phase calibration and / or phase compensation. As Figure 5As shown, taking the subcarrier signal with a frequency of 848 KHz transmitted by the transmitting circuit 360 as an example. When it is determined to perform active load modulation (OOK ALM) using on-off keying, before the active load modulation is carried out, the phase calibration circuit 350 calibrates the phase of the phase-locked loop clock signal PLL_CLK according to the radio frequency field clock signal FILED_CLK. During the transmission time of one bit of the subcarrier signal, in the first transmission gap when the NFC card device 300 transmits the subcarrier signal, the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal is monitored to obtain the phase offset ΔPH. In the subsequent transmission gaps when the NFC card device 300 transmits the subcarrier signal, the phase of the phase-locked loop clock signal PLL_CLK is calibrated according to the radio frequency field clock signal FILED_CLK, and the phase of the phase-locked loop clock signal PLL_CLK is compensated according to the phase offset ΔPH to obtain the clock signal ALM_CLK for active load modulation. During the time when no active load modulation is performed, the phase of the phase-locked loop clock signal PLL_CLK is calibrated according to the radio frequency field clock signal FILED_CLK. After phase calibration and / or phase compensation, the transmitting circuit 360 generates a subcarrier signal according to the corresponding clock signal ALM_CLK for active load modulation during the corresponding transmission stage when the NFC card device 300 transmits the subcarrier signal.

[0058] Figure 6 FIG. is a schematic flowchart of a clock signal generation method according to an embodiment of the present disclosure. The clock signal generation method in the embodiment of the present disclosure is applied to the NFC card device 300. As Figure 6 shown, the clock signal generation method includes:

[0059] In step S610, in the first transmission gap when the near-field communication card device transmits the subcarrier signal, a carrier signal is received from the near-field communication reader, the radio frequency field clock signal is determined according to the received carrier signal, and the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal is monitored to obtain the phase offset.

[0060] In step S620, in the transmission gaps after the first transmission gap, the phase of the phase-locked loop clock signal is calibrated according to the radio frequency field clock signal and / or the phase of the phase-locked loop clock signal is compensated according to the phase offset to obtain the clock signal for active load modulation.

[0061] Since the specific process of generating the clock signal for active load modulation has been described in detail above, it will not be repeated here.

[0062] Figure 7 FIG. shows a schematic structural diagram of a clock signal generation device according to an embodiment of the present disclosure. The clock signal generation device 700 is applied to the NFC card device 300. As Figure 7The clock signal generating device 700 shown includes a phase offset monitoring unit 710 and an active load modulation clock signal generating unit 720.

[0063] The phase offset monitoring unit 710 is configured to receive a carrier signal from a near - field communication reader during a first transmission gap when the near - field communication card device transmits a sub - carrier signal, determine a radio - frequency field clock signal according to the received carrier signal, monitor the phase influence of the antenna residual energy of the sub - carrier signal on the radio - frequency field clock signal, and obtain a phase offset.

[0064] The active load modulation clock signal generating unit 720 is configured to, during a transmission gap after the first transmission gap, perform phase calibration on a phase - locked loop clock signal according to the radio - frequency field clock signal and / or perform phase compensation on the phase - locked loop clock signal according to the phase offset, so as to obtain a clock signal for active load modulation.

[0065] Since the specific process of generating the clock signal for active load modulation has been described in detail above, it will not be elaborated here.

[0066] An embodiment of the present disclosure also provides an electronic device, as Figure 8 shown, including a memory 820, a processor 810, and a program stored on the memory 820 and executable on the processor 810. When the program is executed by the processor 810, it can implement each process of the above - mentioned method embodiments and can achieve the same technical effects. To avoid repetition, it will not be elaborated here.

[0067] Those of ordinary skill in the art can understand that all or part of the steps in the above - mentioned various methods can be completed by instructions or by controlling relevant hardware through instructions. The instructions can be stored in a computer - readable storage medium and loaded and executed by a processor. For this reason, an embodiment of the present disclosure also provides a storage medium on which a computer program or instructions are stored. When the computer program or instructions are executed by a processor, each process of the above - mentioned method embodiments can be implemented.

[0068] Since the instructions stored in the storage medium can execute the steps in the method provided by the embodiments of the present disclosure, the beneficial effects that can be achieved by the method provided by the embodiments of the present disclosure can be realized. See the previous embodiments for details and will not be elaborated here. The specific implementation of each of the above operations can be seen in the previous embodiments and will not be elaborated here.

[0069] In summary, according to the embodiments of the present disclosure, during a first transmission gap when the near - field communication card device transmits a sub - carrier signal, a carrier signal is received from a near - field communication reader, and a radio - frequency field clock signal is determined according to the received carrier signal.

[0070] Monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal to obtain a phase offset. During the transmission gap after the first transmission gap, phase calibrate the phase-locked loop clock signal according to the radio frequency field clock signal and / or perform phase compensation on the phase-locked loop clock signal according to the phase offset to obtain a clock signal for active load modulation. The phase offset can characterize the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal. During the active load modulation process, the near field communication card device can phase calibrate the phase-locked loop clock signal according to the radio frequency field clock signal, thereby reducing the phase deviation of the generated clock signal for active load modulation. It can also monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal during the transmission gap for transmitting the subcarrier signal, and use the phase offset characterizing this phase influence to compensate the phase-locked loop clock signal on the basis of phase calibration, thereby further reducing the phase deviation of the generated clock signal for active load modulation, and further improving the clock synchronization between the subcarrier signal transmitted by the near field communication card device and the carrier signal transmitted by the near field communication reader, improving the callback quality of active load modulation, ensuring that the near field communication reader can correctly demodulate, and improving the communication performance.

[0071] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly illustrating the present disclosure, and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation manners here. The obvious changes or modifications derived therefrom are still within the protection scope of the present disclosure.

Claims

1. A clock signal generation method, comprising: Receiving a carrier signal from a near-field communication reader during a first transmission gap when the near-field communication card device transmits a subcarrier signal, determining a radio frequency field clock signal according to the received carrier signal, monitoring the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal, and obtaining a phase offset; During a transmission gap after the first transmission gap, performing phase calibration on a phase-locked loop clock signal according to the radio frequency field clock signal and / or performing phase compensation on the phase-locked loop clock signal according to the phase offset to obtain a clock signal for active load modulation.

2. The clock signal generation method according to claim 1, wherein After performing phase calibration on a phase-locked loop clock signal according to the radio frequency field clock signal and / or performing phase compensation on the phase-locked loop clock signal according to the phase offset to obtain a clock signal for active load modulation during a transmission gap after the first transmission gap, the clock signal generation method further comprises: Generating a subcarrier signal according to the corresponding clock signal for active load modulation during a corresponding transmission stage when the near-field communication card device transmits a subcarrier signal.

3. The clock signal generation method according to claim 1 or 2, wherein, The monitoring the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal and obtaining a phase offset comprises: Calculating the phase offset between the radio frequency field clock signal and the phase-locked loop clock signal during the first transmission gap.

4. The clock signal generation method according to claim 1 or 2, wherein Before the first transmission gap, the clock signal generation method further comprises: Receiving a carrier signal from the near-field communication reader when no active load modulation is performed, determining a radio frequency field clock signal according to the received carrier signal, and performing phase calibration on the phase-locked loop clock signal according to the radio frequency field clock signal.

5. The clock signal generation method according to claim 4, wherein, When binary phase shift keying is determined to be used, during a frame transmission time of the subcarrier signal, during a first transmission gap when the near-field communication card device transmits a subcarrier signal, monitoring the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal, and obtaining a phase offset; During subsequent transmission gaps when the near-field communication card device transmits a subcarrier signal, performing phase calibration on the phase-locked loop clock signal according to the radio frequency field clock signal and performing phase compensation on the phase-locked loop clock signal according to the phase offset to obtain a clock signal for active load modulation.

6. The clock signal generation method according to claim 4, wherein, When on-off keying is determined to be used, during a bit transmission time of the subcarrier signal, during a first transmission gap when the near-field communication card device transmits a subcarrier signal, monitoring the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal, and obtaining a phase offset; During subsequent transmission gaps when the near-field communication card device transmits a subcarrier signal, performing phase calibration on the phase-locked loop clock signal according to the radio frequency field clock signal and performing phase compensation on the phase-locked loop clock signal according to the phase offset to obtain a clock signal for active load modulation; Performing phase calibration on the phase-locked loop clock signal according to the radio frequency field clock signal during a time when no active load modulation is performed.

7. The clock signal generation method according to claim 1 or 2, wherein, The phase-locked loop clock signal is generated by adjusting the frequency of a local clock signal based on the radio frequency field clock signal when no active load modulation is performed.

8. A clock signal generation device, comprising: A phase offset monitoring unit, configured to receive a carrier signal from a near field communication reader during a first transmission gap when the near field communication card device transmits a subcarrier signal, determine a radio frequency field clock signal according to the received carrier signal, monitor the phase influence of the antenna residual energy of the subcarrier signal on the radio frequency field clock signal, and obtain a phase offset; An active load modulation clock signal generating unit, configured to perform phase calibration on a phase locked loop clock signal according to the radio frequency field clock signal and / or perform phase compensation on the phase locked loop clock signal according to the phase offset during a transmission gap after the first transmission gap, so as to obtain a clock signal for active load modulation.

9. A near field communication card device, comprising: The clock signal generating device according to claim 8, configured to generate a clock signal for active load modulation, so as to generate a subcarrier signal according to the clock signal for active load modulation.

10. A near field communication system, comprising: A near field communication reader, configured to transmit a carrier signal; The near field communication card device according to claim 9, configured to generate a clock signal for active load modulation and generate a subcarrier signal according to the clock signal for active load modulation.

11. An electronic device, comprising: A processor, a memory, and a program stored on the memory and executable on the processor, wherein when the program is executed by the processor, the steps of the method according to any one of claims 1 to 7 are implemented.

12. A storage medium, on which a computer program or instruction is stored, wherein when the computer program or instruction is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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