Memristor-based frequency shift keying modulator

Abstract

The present application relates to a kind of memristor base frequency shift keying modulator, the modulator includes modulation unit and carrier generation unit in series, the modulation unit includes multiple different width-length ratios of MOSFET, the source of each MOSFET is connected bias voltage, the drain of each MOSFET is connected series node, set MOSFET has n, wherein the gate of the i-th MOSFET is connected the i-th binary input end b i , series node connects carrier generation unit, the carrier generation unit includes negative differential memristor, one end of negative differential memristor is connected series node, the other end is grounded, the width-length ratio of n MOSFET is different from each other.Compared with prior art, the present application has the advantages of eliminating the conversion interface between digital domain and analog domain and the like.

Description

Technical Field

[0001] This invention relates to the technical field of frequency shift keying modulators, and in particular to a memristor-based frequency shift keying modulator. Background Technology

[0002] With the rise of industries such as industrial automation, healthcare, and smart agriculture, the wireless Internet of Things (IoT) is developing rapidly, creating a demand for data acquisition and transmission. Typically, wireless IoT hardware deployments utilize wireless sensor networks as the data acquisition layer, facilitating real-time data transmission across various scenarios by enabling wireless communication between smart devices and a remote central cloud in low-frequency bands. In this process, sensor data undergoes analog-to-digital conversion, preprocessing, and modulation before being converted into radio signals via an antenna. However, digital binary signals lack equivalent direct physical quantities that can be described by wave propagation equations, resulting in a sharp interface between the digital and analog domains during modulation. Although traditional modulators typically consist of a digital-to-analog converter and a carrier generation unit to convert digital input into a modulated signal carrying information, the physical separation between the digital processing unit and the analog transmission module inherently leads to a trade-off between speed, power, and accuracy during the conversion process.

[0003] The literature Wang, Cong, et al. Nature Electronics 6.5 (2023):381-389. and Liu, Chang, et al. Nature Communications 15.1 (2024):1523. showcase current signal modulation schemes based on memristors. Most current modulation schemes based on memristor arrays rely on external carriers and analog-to-digital converters to achieve the modulation of sensing signals, making it difficult to simultaneously achieve direct digital modulation and carrier generation functions. The conversion interface between the digital and analog domains is sharp, and miniaturization of memristor arrays is difficult. Summary of the Invention

[0004] The purpose of this invention is to provide a memristor baseband shift keying modulator that integrates carrier generation and digital signal modulation functions, thereby eliminating the conversion interface between the digital and analog domains while generating a local carrier signal.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A memristor-based frequency shift keying modulator includes a modulation unit and a carrier generation unit connected in series. The modulation unit includes multiple MOSFETs with different aspect ratios. The source of each MOSFET is connected to a bias voltage, and the drain of each MOSFET is connected to a series node. There are n MOSFETs in total, where the gate of the i-th MOSFET is connected to the i-th binary input terminal b.i The series node connects to the carrier generation unit, which includes a negative differential memristor. One end of the negative differential memristor is connected to the series node, and the other end is grounded. The width-to-length ratios of the n MOSFETs are different.

[0007] Furthermore, the binary input terminal b i The input is either 0 or 1. When the input to the binary input terminal bi is 0, the i-th MOSFET is turned off, and the binary input terminal b... i When the input is 1, the i-th MOSFET is turned on.

[0008] Furthermore, for two different MOSFETs, if the width-to-length ratio of one MOSFET is greater than that of the other MOSFET, then the current when the first MOSFET is turned on is greater than the current when the second MOSFET is turned on.

[0009] Furthermore, for the a-th MOSFET and the b-th MOSFET, if a is greater than b, then the width-to-length ratio of the a-th MOSFET is greater than that of the b-th MOSFET.

[0010] Furthermore, the oscillation signal of the series node is the output of the modulator.

[0011] Furthermore, the negative differential memristor is initially in a high-resistance state. When the voltage applied to the negative differential memristor exceeds the threshold voltage, the negative differential memristor changes from a high-resistance state to a low-resistance state. As the voltage applied to the negative differential memristor decreases below the holding voltage, the negative differential memristor changes from a low-resistance state to a high-resistance state.

[0012] Furthermore, the negative differential memristor includes a parasitic capacitance and a memristor body, which are connected in parallel.

[0013] Furthermore, the carrier generation unit also includes a parallel capacitor.

[0014] Furthermore, the parallel capacitor and the negative differential memristor are connected in parallel.

[0015] Furthermore, the negative differential device is a memristor with threshold switching behavior.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The modulation module of this invention is composed of MOSFETs with different aspect ratios connected in parallel. A binary input signal is given to the gate of the MOSFETs to control their switching. The modulation module and the carrier generation unit are connected in series to form the complete modulator module, and the oscillation signal at the series node is the output of the modulator. As the potential at the series node rises, the negative differential memristor switches to a low-resistance state when the potential reaches its transition threshold, causing the potential to drop; subsequently, when the potential reaches its holding voltage, the device switches back to a high-resistance state, the capacitor is recharged, and an oscillation signal with frequency characteristics is output at the series node. Under the action of the digital signal, the MOSFETs in the modulation module selectively turn on, which results in charging currents of different magnitudes, thereby modulating the frequency of the oscillation signal. After completing the sequential correspondence between the digital input bit weights and the width-to-length ratio of the MOSFET units, the modulator can realize the frequency output modulated by the digital input, thereby achieving frequency shift keying (FSK) function. When all input signals are low level, the current flowing through the modulation module is minimal; as the low bit and high bit are high level inputs, the current increases sequentially, reaching its maximum when all input levels are high. With the increase of digital input, the frequency of the oscillation output increases accordingly, exhibiting a distinguishable frequency range, realizing the control of analog frequency signals by digital signals, achieving the modulation of continuous signals, and eliminating the conversion interface between the digital and analog domains while realizing the generation of local carrier signals, thus promoting the miniaturization of integrated modulators. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the memristor-based modulator of the present invention;

[0019] Figure 2 This is an integrated solution for negative differential memristors and MOSFETs;

[0020] Figure 3 This refers to the response of the modulation module under binary input.

[0021] Figure 4 The threshold behavior of a negative differential memristor device;

[0022] Figure 5 These are the basic characteristics of a modulator;

[0023] Figure 6 This is a modulation output based on consecutive letters. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0025] This invention proposes a memristor baseband shift keying modulator, comprising a modulation unit and a carrier generation unit connected in series. The modulation unit includes multiple MOSFETs with different aspect ratios. The source of each MOSFET is connected to a bias voltage, and the drain of each MOSFET is connected to a series node. There are n MOSFETs in total, where the gate of the i-th MOSFET is connected to the i-th binary input terminal b. i The series node connects to the carrier generation unit, which includes a negative differential memristor. One end of the negative differential memristor is connected to the series node, and the other end is grounded. The width-to-length ratios of the n MOSFETs are different.

[0026] This invention proposes a frequency shift keying (FSK) implementation by integrating a negative differential memristor and a MOSFET unit. This modulator combines carrier generation and digital-to-analog conversion functions, enabling continuous modulation of the oscillation frequency based on direct parallel digital input. Continuous FSK modulation can be achieved by assigning MOSFET units with different aspect ratios based on bit weights. Memristor-based FSK provides an effective solution for direct digital signal modulation, promoting the development of miniaturized, energy-efficient, and integrable modulators for IoT applications.

[0027] Figure 1 The negative differential memristor baseband shift keying modulator consists of a modulation module and a carrier generation unit. The carrier generation module is implemented using a self-sustaining oscillator constructed from a negative differential memristor; the modulation module uses MOSFETs with different aspect ratios to adjust the charging current based on parallel digital input, thereby outputting oscillation signals of different frequencies.

[0028] Device Structure: The carrier generation unit consists of a negative differential memristor connected in parallel with a capacitor. The parallel capacitor can be implemented using the device's own parasitic capacitance. The modulation module consists of MOSFETs with different aspect ratios connected in parallel. A binary input signal is given to the gate of the MOSFETs to control their switching. The modulation module and the carrier generation unit are connected in series to form the complete modulator module. The oscillation signal at the series node is the output of the modulator.

[0029] Working Principle: For the carrier generation unit, a charging current caused by the bias voltage charges the carrier generation unit. As the potential at the series node rises, the negative differential memristor switches to a low-resistance state when the potential reaches its transition threshold, causing the potential to drop; subsequently, when the potential reaches its holding voltage, the device switches back to a high-resistance state, the capacitor recharges, and an oscillating signal with frequency characteristics is output at the series node. Under the action of the digital signal, the MOSFETs in the modulation module selectively turn on, resulting in charging currents of different magnitudes, thereby modulating the frequency of the oscillation signal. After completing the sequential correspondence between the digital input bit weights and the width-to-length ratio of the MOSFET units, the modulator can realize the frequency output modulated by the digital input, thus achieving the frequency shift keying function.

[0030] Figure 2 An integrated solution for negative differential memristors and MOSFETs:

[0031] Step 1: Deposit a negative differential memristor material on the source electrode of the MOSFET parallel power supply as the bottom electrode. The negative differential memristor material can be NbO2 (niobium dioxide), VO2 (vanadium dioxide), SiTe (silicon telluride), SiO2:Ag (silver-doped silicon oxide), α-Si:Cu (copper-doped amorphous silicon), α-Si:Ag (silver-doped amorphous silicon), or a mixture of AM4Q8 (chalcogenide Mott insulator, A=Ga,Ge; M=V,Nb,Ta,Mo; Q=S,Se). Materials with volatile threshold switching characteristics can be used.

[0032] Step 2: Deposit the top electrode on the capacitor film. The electrode material is not limited and can be conductive materials such as TiN, Poly-Si, Pd, Pt, W, Cu, Ag, or Au.

[0033] The modulation module's response to binary input: Figure 3 The diagram illustrates that a modulation module composed of parallel MOSFETs should exhibit the current response shown in the figure above. The current flowing through the modulation module is minimal when all input signals are low; the current increases sequentially with the low-bit and high-bit inputs reaching high levels, maximizing when all input levels are high.

[0034] Threshold behavior of negative differential memristor devices: Figure 4 The paper demonstrates that the fabricated negative differential memristor device should exhibit the following characteristics under voltage scanning: Figure 4 The volatile memristor exhibits bidirectional threshold transition characteristics. When the voltage applied to the top electrode exceeds the threshold voltage, the volatile memristor transitions from a high-resistivity state to a low-resistivity state. During voltage retracement, when the voltage falls below the holding voltage, the device returns to a high-resistivity state because the voltage at the top electrode is insufficient to maintain its low-resistivity state.

[0035] Basic characteristics of modulators: Figure 5 This paper demonstrates a modulator based on a negative differential memristor device that achieves the conversion of binary signals to frequency outputs with direct parallel digital inputs. As the digital input increases, the frequency of the oscillation output increases accordingly, exhibiting a distinguishable frequency range that meets signal modulation requirements.

[0036] Continuous modulation output: Figure 6 The paper demonstrates that, after inputting a continuous binary signal containing information, a memristor-based modulator can convert the signal into an oscillating sequence containing frequency characteristics, proving the modulator's ability to modulate continuous signals.

[0037] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A memristor fundamental frequency shift keying modulator, characterized in that, The modulator includes a modulation unit and a carrier generation unit connected in series. The modulation unit includes multiple MOSFETs with different aspect ratios. The source of each MOSFET is connected to a bias voltage, and the drain of each MOSFET is connected to a series node. There are n MOSFETs in total, where the gate of the i-th MOSFET is connected to the i-th binary input terminal b. i The series node connects to the carrier generation unit, which includes a negative differential memristor. One end of the negative differential memristor is connected to the series node, and the other end is grounded. The width-to-length ratios of the n MOSFETs are different. The negative differential memristor is initially in a high-resistance state. When the voltage applied to the negative differential memristor exceeds the threshold voltage, the negative differential memristor changes from a high-resistance state to a low-resistance state. As the voltage applied to the negative differential memristor decreases below the holding voltage, the negative differential memristor changes from a low-resistance state to a high-resistance state. A negative differential memristor is a memristor with threshold switching behavior.

2. A memristor fundamental frequency shift keying modulator according to claim 1, characterized in that, The binary input terminal b i The input is either 0 or 1. When the input to the binary input terminal bi is 0, the i-th MOSFET is turned off, and the binary input terminal b... i When the input is 1, the i-th MOSFET is turned on.

3. A memristor fundamental frequency shift keying modulator according to claim 1, characterized in that, For two different MOSFETs, if the width-to-length ratio of one MOSFET is greater than that of the other MOSFET, then the current when the first MOSFET is turned on will be greater than the current when the second MOSFET is turned on.

4. A memristor fundamental frequency shift keying modulator according to claim 3, characterized in that, For the a-th MOSFET and the b-th MOSFET, if a is greater than b, then the width-to-length ratio of the a-th MOSFET is greater than that of the b-th MOSFET.

5. A memristor fundamental frequency shift keying modulator according to claim 1, characterized in that, The oscillation signal of the series node is the output of the modulator.

6. A memristor fundamental frequency shift keying modulator according to claim 1, characterized in that, The negative differential memristor includes a parasitic capacitance and a memristor body, which are connected in parallel.

7. A memristor fundamental frequency shift keying modulator according to claim 1, characterized in that, The carrier generation unit also includes a parallel capacitor.

8. A memristor fundamental frequency shift keying modulator according to claim 7, characterized in that, A parallel capacitor and a negative differential memristor are connected in parallel.

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