Ringing signal modulation circuit for near field communication
By simplifying the ringing signal modulation circuit structure and using components such as damping resistors, field-effect transistors, and capacitors for data modulation, the high cost problem caused by the large number of components in the existing technology is solved, and low-cost and stable and reliable near-field communication signal transmission is achieved.
Patent Information
- Application Number
- CN202422757546.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-11-13
AI Technical Summary
Existing near-field communication modulation circuits are complex in structure and contain a large number of components, resulting in high costs.
A simplified ringing signal modulation circuit structure is adopted, including a processor unit, a modulation and shaping unit, and a resonant transmission unit. Data modulation is performed using components such as damping resistors, field-effect transistors, capacitors, and inductors, and signal transmission is achieved through modulation waveform control.
It achieves near-field communication signal modulation with simple structure, few components, low cost, and stable and reliable operation, thereby reducing equipment costs.
Smart Images
Figure CN223514901U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of near-field communication technology, and more specifically to a ringing signal modulation circuit for near-field communication. Background Technology
[0002] With the widespread adoption of smart devices and the Internet of Things (IoT), the application prospects of near-field communication (NFC) technology are very broad. In the future, we will see the emergence of more NFC-enabled devices, which can achieve fast and convenient data transmission, interoperability between devices, and error correction through NFC technology. As an emerging short-range wireless communication technology, NFC has already been widely used in mobile payment, electronic ticketing, access control, and identity recognition. With the continuous development of the IoT and smart devices, the application prospects of NFC technology will be even broader.
[0003] The existing modulation circuits for near-field communication have a relatively complex structure and many components, which increases the cost of near-field communication. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a ringing signal modulation circuit for near-field communication, which has a simple structure, few components, low cost, and is stable and reliable.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.
[0006] A ringing signal modulation circuit for near-field communication includes a processor unit for serially outputting data to be transmitted and generating a charging pulse signal required by the modulation circuit based on the output data, a modulation shaping unit for controlling the modulation output waveform, and a resonant transmitting unit for transmitting the modulation signal. The output terminal of the processor unit is connected to the input terminal of the modulation shaping unit, and the output terminal of the modulation shaping unit is connected to the input terminal of the resonant transmitting unit. The modulation shaping unit includes a resonant charging unit for charging the harmonic transmitting unit and a modulation waveform control unit for controlling the modulation waveform of the harmonic transmitting unit. The input terminals of the resonant charging unit and the modulation waveform control unit are respectively connected to the input terminal of the processor unit, and the output terminals of the resonant charging unit and the modulation waveform control unit are respectively connected to the harmonic transmitting unit.
[0007] To further optimize the technical solution, the harmonic charging unit includes a damping resistor R2 and a field-effect transistor Q1 connected in series at the charging pulse signal output terminal of the processor unit. A pull-down resistor R1 is provided between the damping resistor R2 and the connection terminal of the processor unit and the ground terminal. The damping resistor R2 is connected to the gate of the field-effect transistor Q1, the source of the field-effect transistor Q1 is grounded, and the drain of the field-effect transistor Q1 is connected to the input terminal of the harmonic emitting unit.
[0008] To further optimize the technical solution, the modulation waveform control unit includes a field-effect transistor Q2 located at the data output terminal of the processor unit and an output resistor R4 located at the drain output terminal of the field-effect transistor Q2. An integrating circuit for controlling the on / off state of the field-effect transistor G2 is provided at the connection terminal between the gate of the field-effect transistor Q2 and the output terminal of the processor unit.
[0009] To further optimize the technical solution, the integrating circuit includes a capacitor C1 connected to the output terminal of the processor unit and a bias resistor R3 set between the gate and source of the field-effect transistor Q2, and the conducting of Q2 is controlled by the integrating circuit.
[0010] To further optimize the technical solution, the harmonic transmitting unit includes a capacitor C2 connected in parallel between the drain and source of the field-effect transistor Q2, an inductor L1 connected on the drain of the field-effect transistor Q2, and an inductor L2 for transmitting signals. The resonant frequency of the modulation circuit can be changed by adjusting the values of capacitor C2 and inductor L1.
[0011] The technological advancements achieved by this utility model are as follows, due to the adoption of the above technical solutions.
[0012] This invention provides a ringing signal modulation circuit for near-field communication. The baseband signal to be transmitted is modulated by the modulation circuit to output a ringing signal, which is then transmitted through a transmitting antenna. The modulation circuit of this invention has a simple structure, few components, low cost, and is stable and reliable. Attached Figure Description
[0013] Figure 1 This is a structural block diagram of the present invention;
[0014] Figure 2 This is the circuit diagram for Example 1;
[0015] Figure 3 This is a schematic diagram of the waveform generated in Example 1;
[0016] Figure 4 This is a timing diagram for data transmission in Example 1;
[0017] Figure 5 This is the circuit diagram for Example 2. Detailed Implementation
[0018] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.
[0019] A ringing signal modulation circuit for near-field communication, combined with Figure 1As shown, it includes a processor unit, a modulation and shaping unit, and a harmonic transmitting unit. The processor unit is used to serially output the data to be transmitted and generate the charging pulse signal required by the modulation circuit based on the output data. The modulation and shaping unit is used to control the modulation output waveform, and the harmonic transmitting unit is used to realize the transmission of the modulation signal. The output terminal of the processor unit is connected to the input terminal of the modulation and shaping unit, and the output terminal of the modulation and shaping unit is connected to the input terminal of the resonant transmitting unit.
[0020] The modulation and shaping unit includes a resonant charging unit and a modulation waveform control unit. The resonant charging unit is used to charge the resonant transmitting unit, and the modulation waveform control unit is used to control the modulation waveform of the resonant transmitting unit. The input terminals of the resonant charging unit and the modulation waveform control unit are respectively connected to the input terminals of the processor unit, and the output terminals of the resonant charging unit and the modulation waveform control unit are respectively connected to the resonant transmitting unit.
[0021] Example 1
[0022] The circuit diagram of this embodiment is as follows: Figure 2 As shown, the processor unit is U1, an FPGA chip that outputs the charging pulse signal of the resonant transmitting unit and the serial data signal. The timing diagrams for the charging pulse signal and the transmitted data are as follows: Figure 4 As shown.
[0023] The harmonic charging unit includes a pull-down resistor R1, a damping resistor R2, and a field-effect transistor Q1. The damping resistor R2 and the field-effect transistor Q1 are connected in series at the charging pulse signal output terminal of the processor unit. The pull-down resistor R1 is positioned between the connection terminal of the damping resistor R2 and the processor unit and the ground terminal. The damping resistor R2 is connected to the gate of the field-effect transistor Q1, the source of the field-effect transistor Q1 is grounded, and the drain of the field-effect transistor Q1 is connected to the input terminal of the harmonic emitting unit. When the charging pulse signal is high, the field-effect transistor Q1 is turned on, and the harmonic emitting unit completes charging through VCC.
[0024] The modulation waveform unit includes an integrator circuit, a field-effect transistor (FET) Q2, and an output resistor R4. FET Q2 is located at the data transmission output terminal of the processor unit, and output resistor R4 is located at the drain output terminal of FET Q2. The integrator circuit is located at the connection point between the gate of FET Q2 and the processor unit output terminal, used to control the on / off state of FET Q2. The integrator circuit includes a capacitor C1 and a bias resistor R3. Capacitor C1 is connected to the processor unit output terminal, and bias resistor R3 is located between the gate and source of FET Q2. When the transmitted data is logic "1", FET Q2 is turned off, and the resonant transmitting unit completes charging under the coordination of a charging pulse signal.
[0025] The harmonic transmitting unit includes a capacitor C2, an inductor L1, and a transmitting inductor L2. Capacitor C2 is connected in parallel between the drain and source of the field-effect transistor Q2. Inductor L1 is connected to the drain of the field-effect transistor Q2. The transmitting inductor L2 is connected in series with inductor L1 and is used to transmit the signal. Capacitor C2, inductor L1, and transmitting inductor L2 form a resonant circuit. When fully charged, it performs modulation and transmission under the control of the modulation waveform control unit. The modulation signal waveform is as follows: Figure 3 As shown.
[0026] Example 2
[0027] The circuit diagram of this embodiment is as follows: Figure 5 As shown, the difference from Embodiment 1 lies in the different harmonic transmitting unit.
[0028] The harmonic transmitting unit in this embodiment includes an adjusting capacitor C2, a capacitor C3, an inductor L1, an inductor L2, and a transmitting inductor L3. Capacitors C2 and C3 are connected in parallel between the drain and source of the field-effect transistor Q2. Inductor L1 is connected to the drain of the field-effect transistor Q2. The transmitting inductor L3 is connected in series with inductor L1. Inductor L2 is connected to the source of the field-effect transistor Q2. The transmitting inductor L3 is connected in series with inductor L2 and used to transmit signals. The values of adjusting capacitor C2 and inductor L1 are used to change the resonant frequency of the modulation circuit. The adjusting capacitor C2, capacitor C3, inductor L1, inductor L2, and transmitting inductor L3 form a resonant circuit. When fully charged, it performs modulation and transmission under the control of the modulation waveform control unit. The modulation signal waveform is as follows: Figure 3 As shown, the resonant circuit consists of adjusting capacitor C2, capacitor C3, inductor L1, inductor L2, and emitting inductor L3, with a resonant frequency of 4.5MHz.
[0029] The working principle of this invention is as follows: When the processor sends the data "1", the processor outputs a charging pulse signal. At this time, the field-effect transistor Q1 is turned on, and the field-effect transistor Q2 is turned off. VCC charges the resonant transmitting unit and begins to oscillate and transmit signals. When the charging pulse is low, the charging ends. As the capacitor C1 and the bias resistor R3 integrator circuit charge, the field-effect transistor Q2 gradually changes from off to on. At this time, the resonant transmitting circuit completes the discharge through the output resistor R4 and the field-effect transistor Q2, and gradually stops the resonant transmitting signal.
[0030] When processing and transmitting data "0", the processor does not output a pulse signal. At this time, MOSFET Q1 is cut off, MOSFET Q2 is turned on, the resonant transmitting circuit is not charged, the resonant transmitting circuit does not resonate, and the signal transmission stops.
[0031] Through the above circuit control, the final output logic signal will be modulated as follows: Figure 4 The modulated output waveform is shown.
[0032] The above modulation method and modulation circuit are used to complete the modulation and transmission of data.
Claims
1. A ringing signal modulation circuit for near-field communication, characterized in that: The system includes a processor unit for serially outputting data to be transmitted and generating charging pulse signals required by the modulation circuit based on the output data, a modulation and shaping unit for controlling the modulation output waveform, and a resonant transmitting unit for transmitting the modulation signal. The output terminal of the processor unit is connected to the input terminal of the modulation and shaping unit, and the output terminal of the modulation and shaping unit is connected to the input terminal of the resonant transmitting unit. The modulation and shaping unit includes a resonant charging unit for charging the harmonic transmitting unit and a modulation waveform control unit for controlling the modulation waveform of the harmonic transmitting unit. The input terminals of the resonant charging unit and the modulation waveform control unit are respectively connected to the input terminal of the processor unit, and the output terminals of the resonant charging unit and the modulation waveform control unit are respectively connected to the harmonic transmitting unit.
2. The ringing signal modulation circuit for near-field communication according to claim 1, characterized in that: The harmonic charging unit includes a damping resistor R2 and a field-effect transistor Q1 connected in series at the charging pulse signal output terminal of the processor unit. A pull-down resistor R1 is provided between the damping resistor R2 and the processor unit connection terminal and the ground terminal. The damping resistor R2 is connected to the gate of the field-effect transistor Q1. The source of the field-effect transistor Q1 is grounded. The drain of the field-effect transistor Q1 is connected to the input terminal of the harmonic emitting unit.
3. The ringing signal modulation circuit for near-field communication according to claim 1, characterized in that: The modulation waveform control unit includes a field-effect transistor Q2 disposed at the data output terminal of the processor unit and an output resistor R4 disposed at the drain output terminal of the field-effect transistor Q2. An integrating circuit for controlling the on / off state of the field-effect transistor Q2 is disposed at the connection terminal between the gate of the field-effect transistor Q2 and the output terminal of the processor unit.
4. A ringing signal modulation circuit for near-field communication according to claim 3, characterized in that: The integrator circuit includes a capacitor C1 connected to the output of the processor unit and a bias resistor R3 disposed between the gate and source of the field-effect transistor Q2.
5. A ringing signal modulation circuit for near-field communication according to claim 3, characterized in that: The harmonic transmitting unit includes a capacitor C2 connected in parallel between the drain and source of the field-effect transistor Q2, an inductor L1 connected on the drain of the field-effect transistor Q2, and an inductor L2 for transmitting signals. The resonant frequency of the modulation circuit can be changed by adjusting the values of capacitor C2 and inductor L1.