A signal processing method and related device

Abstract

Embodiments of the present application disclose a signal processing method and related equipment, which can be applied to a terahertz short-distance communication scenario. The method comprises: a sending end device modulating an original baseband signal to obtain a target modulation signal. The level set of the target baseband signal corresponding to the target modulation signal comprises positive levels and negative levels. The level set comprises positive levels and negative levels. The level set comprises at least one first level, and a second level similar or equal in amplitude to the first level but opposite in polarity is not included in the level set. The level set further comprises at least a third level and a fourth level, the third level and the fourth level being similar or equal in amplitude and opposite in polarity. Further, the sending end device sends the target modulation signal to a receiving end device. The receiving end device can complete demodulation by using a differential demodulation method according to amplitude information and phase information of the signal, without relying on carrier synchronization, thereby reducing the complexity and power consumption of implementation.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a signal processing method and related equipment. Background Technology

[0002] Terahertz short-range interconnects utilize terahertz active cables (TACs) to achieve high-speed, high-bandwidth terahertz signal transmission over short distances. The transmitting device receives the baseband signal from an external port and modulates it onto a terahertz carrier for transmission. The receiving device receives the terahertz modulated signal from the TAC, demodulates it, and finally outputs the recovered baseband signal from the output port to achieve data transmission.

[0003] To enable the receiving device to correctly demodulate terahertz modulated signals, one current approach is carrier synchronization. The transmitting device inserts pilot information into the transmitted signal, and the receiving device uses this pilot information and the demodulation error of the received signal to extract the frequency and phase deviations of the transmitted and received carriers. After compensating for the synchronization error in the received signal, the receiving end can correctly demodulate the transmitted signal. However, both the implementation of pilot information insertion at the transmitting end and carrier synchronization at the receiving end significantly increase system complexity and power consumption. Summary of the Invention

[0004] This application provides a signal processing method and related equipment.

[0005] In a first aspect, this application provides a signal processing method applied to a transmitting device. The method includes the following steps: First, the transmitting device obtains a target modulated signal by modulating an original baseband signal. During the modulation process, in addition to modulating the original baseband signal onto a carrier wave, the level of the original baseband signal also needs to be adjusted to obtain the target baseband signal, thereby constructing a specific level distribution. Specifically, the level set of the target baseband signal includes positive and negative levels. This level set includes at least one first level, and a second level with an amplitude similar to or equal to the first level but opposite polarity is not included in this level set. Furthermore, the level set also includes at least a third level and a fourth level, where the third level has an amplitude similar to or equal to the fourth level but opposite polarity. Then, the transmitting device transmits the target modulated signal to a receiving device.

[0006] In this embodiment, the transmitting device can process the baseband signal to adjust the level of each symbol in the baseband signal, thereby obtaining a specific signal format suitable for differential demodulation. With a coherent reception architecture at the receiving device, for this specific signal format, the receiving device can complete demodulation using differential demodulation based on the signal's own amplitude and phase information, without relying on carrier synchronization. In this way, carrier synchronization and the addition of data pilots are unnecessary, as is differential coding, reducing implementation complexity and power consumption.

[0007] In some possible implementations, minimizing the number of amplitude values ​​in the level set can reduce the power consumption required by the transmitting device to send the modulated signal. For example, the total number of amplitude values ​​in the level set is less than 32.

[0008] In some possible implementations, the number of positive and negative levels in the level set is as close as possible but not equal, which can also reduce the power consumption required by the transmitting device to transmit the modulated signal. For example, the difference between the number of positive and negative levels in the level set is greater than 0 and less than 32.

[0009] In some possible implementations, the transmitting device modulates the original baseband signal to obtain the target modulated signal by: first, the transmitting device performing carrier modulation based on a first carrier signal and the original baseband signal to obtain the original modulated signal; then, the transmitting device generating the target modulated signal based on the original modulated signal and the second carrier signal. The first carrier signal has the same frequency as the second carrier signal, but the amplitude of the first carrier signal is different from the amplitude of the second carrier signal. This method provides a specific implementation for adjusting the level of the original baseband signal, enhancing the feasibility of this solution.

[0010] In some possible implementations, this solution can be applied to terahertz short-range communication scenarios, wherein the first carrier signal and the second carrier signal are terahertz carrier signals, which enhances the practicality of this solution.

[0011] In some possible implementations, the transmitting device performs carrier modulation based on the first carrier signal and the original baseband signal to obtain the original modulated signal, including: the transmitting device modulates the original baseband signal onto the first carrier signal using a radio frequency switch to obtain the original modulated signal. This provides a specific implementation method for carrier modulation of the original baseband signal, further improving the feasibility of this solution.

[0012] In some possible implementations, the transmitting device performs carrier modulation on the first carrier signal and the original baseband signal to obtain the original modulated signal, including: the transmitting device performs carrier modulation on the first carrier signal and the original baseband signal using a mixer to obtain the original modulated signal. This provides another specific implementation for carrier modulation of the original baseband signal, enhancing the flexibility of this solution.

[0013] In some possible implementations, the transmitting device generates the target modulated signal based on the original modulated signal and the second carrier signal by: the transmitting device performing power combining of the original modulated signal and the second carrier signal using a power combiner to obtain the target modulated signal. This provides a specific implementation of carrier injection, further increasing the practicality of this solution.

[0014] In some possible implementations, the transmitting device generates the target modulated signal based on the original modulated signal and the second carrier signal by: determining a bias voltage based on the second carrier signal and applying the bias voltage to the original modulated signal to obtain the target modulated signal. This provides another specific implementation of carrier injection, improving the flexibility of this solution.

[0015] In some possible implementations, the transmitting device modulates the original baseband signal to obtain the target modulated signal by: first, adjusting the level of the original baseband signal to obtain the target baseband signal, wherein the target baseband signal has a set of levels; and then, performing carrier modulation based on a third carrier signal and the target baseband signal to obtain the target modulated signal. This provides another specific implementation for adjusting the level of the original baseband signal, improving the scalability of this solution.

[0016] In some possible implementations, the transmitting device performs carrier modulation based on the third carrier signal and the target baseband signal to obtain the target modulated signal, including: the transmitting device performs carrier modulation on the third carrier signal and the target baseband signal using a mixer to obtain the target modulated signal.

[0017] In some possible implementations, the transmitting device adjusts the level of the original baseband signal to obtain the target baseband signal by: the transmitting device adjusting the voltage output of the DC power supply through a voltage adjustment device, and coupling the adjusted voltage with the original baseband signal to obtain the target baseband signal.

[0018] In some possible implementations, the transmitting device adjusts the level of the original baseband signal to obtain the target baseband signal by: the transmitting device adjusting the bias voltage applied to the original baseband signal by the DC power supply through a bias voltage adjustment device to obtain the target baseband signal.

[0019] Secondly, embodiments of this application provide a transmitting end device, including a modulation module and a transmitting module. The modulation module is used to modulate the original baseband signal to obtain a target modulation signal, wherein the level set of the target baseband signal corresponding to the target modulation signal includes positive and negative levels. This level set includes at least one first level, and a second level with an amplitude similar to or equal to the first level but opposite polarity is not included in this level set. Furthermore, the level set also includes at least a third level and a fourth level, where the third level and the fourth level have similar or equal amplitudes but opposite polarities. The transmitting module is used to transmit the target modulation signal to a receiving end device.

[0020] In some possible implementations, minimizing the number of amplitude values ​​in the level set can reduce the power consumption required by the transmitting device to send the modulated signal. For example, the total number of amplitude values ​​in the level set is less than 32.

[0021] In some possible implementations, the number of positive and negative levels in the level set is as close as possible but not equal, which can also reduce the power consumption required by the transmitting device to transmit the modulated signal. For example, the difference between the number of positive and negative levels in the level set is greater than 0 and less than 32.

[0022] In some possible implementations, the modulation module includes a carrier generation device, a gain adjustment device, a carrier modulation device, and a carrier injection device. The carrier generation device generates a first carrier signal. The carrier modulation device modulates the first carrier signal and the original baseband signal to obtain an original modulated signal. The gain adjustment device adjusts the gain of the first carrier signal to obtain a second carrier signal. The first carrier signal has the same frequency as the second carrier signal, but the amplitudes of the first carrier signal and the second carrier signal are different. The carrier injection device generates a target modulated signal based on the original modulated signal and the second carrier signal.

[0023] In some possible implementations, the first carrier signal and the second carrier signal are terahertz carrier signals.

[0024] In some possible implementations, the carrier modulation device includes a radio frequency (RF) switch. The RF switch is used to modulate the original baseband signal onto a first carrier signal to obtain the original modulated signal.

[0025] In some possible implementations, the carrier modulation apparatus includes a mixer. The mixer is used to perform carrier modulation on the first carrier signal and the original baseband signal to obtain the original modulated signal.

[0026] In some possible implementations, the carrier injection device includes a power combiner. The power combiner is used to power combine the original modulated signal and the second carrier signal to obtain the target modulated signal.

[0027] In some possible implementations, the carrier injection device includes a bias voltage adjustment device. The bias voltage adjustment device is used to determine a bias voltage based on the second carrier signal and apply the bias voltage to the original modulation signal to obtain the target modulation signal.

[0028] In some possible implementations, the modulation module includes a level adjustment device, a carrier generation device, and a carrier modulation device. The level adjustment device adjusts the level of the original baseband signal to obtain a target baseband signal, which has a set of levels. The carrier generation device generates a third carrier signal. The carrier modulation device modulates the third carrier signal and the target baseband signal to obtain a target modulated signal.

[0029] In some possible implementations, the carrier modulation apparatus includes a mixer. The mixer is used to perform carrier modulation on the third carrier signal and the target baseband signal to obtain the target modulated signal.

[0030] In some possible implementations, the level adjustment device includes a DC power supply, a voltage regulator, and a combiner. The DC voltage source is used to output a voltage. The voltage regulator is used to adjust the magnitude of the voltage. The combiner is used to couple the regulated voltage with the original baseband signal to obtain the target baseband signal.

[0031] In some possible implementations, the level adjustment device includes a DC power supply and a bias voltage adjustment device. The DC power supply is used to apply a bias voltage to the original baseband signal. The bias voltage adjustment device is used to adjust the bias voltage to obtain the target baseband signal.

[0032] Thirdly, this application provides a signal processing method applied to a receiving device. The method includes the following steps: The receiving device receives a modulated signal from a transmitting device. The set of levels of the baseband signal corresponding to the modulated signal includes positive and negative levels. This set of levels includes at least one first level, and a second level with an amplitude similar to or equal to the first level but opposite polarity is not included in this set of levels. Furthermore, the set of levels also includes at least a third level and a fourth level, the third level having an amplitude similar to or equal to the fourth level but opposite polarity. The receiving device performs amplitude detection on the modulated signal to obtain the level amplitude of each symbol in the baseband signal. The receiving device performs phase detection on the modulated signal to obtain the phase difference between every two adjacent symbols in the baseband signal. The receiving device demodulates the first symbol to be demodulated based on the level amplitude of the first symbol, the first symbol including symbols in the baseband signal having the first level and symbols with a level of 0. The receiving device demodulates the second symbol to be demodulated based on the phase difference between the reference symbol and the second symbol to be demodulated. The second symbol includes all symbols in the baseband signal except for the first symbol. The reference symbol is the symbol that has been demodulated before the second symbol to be demodulated, and the reference symbol does not include symbols with a level of 0.

[0033] In some possible implementations, minimizing the number of amplitude values ​​in the level set can reduce the power consumption required by the transmitting device to send the modulated signal. For example, the total number of amplitude values ​​in the level set is less than 32.

[0034] In some possible implementations, the number of positive and negative levels in the level set is as close as possible but not equal, which can also reduce the power consumption required by the transmitting device to transmit the modulated signal. For example, the difference between the number of positive and negative levels in the level set is greater than 0 and less than 32.

[0035] In some possible implementations, the method further includes: the receiving device generating a carrier signal; and the receiving device performing quadrature mixing of the modulation signal and the carrier signal to obtain an I / Q signal.

[0036] The receiving device performs amplitude detection on the modulated signal to obtain the level amplitude of each symbol in the baseband signal, including: the receiving device performs amplitude detection on the I / Q signals to obtain the level amplitude of each symbol in the baseband signal.

[0037] The receiving device performs phase detection on the modulated signal to obtain the phase difference between every two adjacent symbols in the baseband signal, including: the receiving device performs phase detection on the I / Q signal to obtain the phase of each symbol in the baseband signal, and calculates the phase difference between every two adjacent symbols in the baseband signal based on the phase of each symbol in the baseband signal.

[0038] In some possible implementations, the receiving device performs amplitude detection on the modulated signal to obtain the level amplitude of each symbol in the baseband signal, which includes: the receiving device performs level detection on the modulated signal using an envelope detector to obtain the level of each symbol in the baseband signal.

[0039] The receiving device performs phase detection on the modulated signal to obtain the phase difference between every two adjacent symbols in the baseband signal. This includes: splitting the modulated signal to obtain a first modulated signal and a second modulated signal; delaying the second modulated signal to obtain a third modulated signal; and mixing the first and third modulated signals to obtain a mixed signal, and performing phase detection on the mixed signal to obtain the phase difference between every two adjacent symbols in the baseband signal.

[0040] Fourthly, embodiments of this application provide a receiving device, including a receiving module, an amplitude detection module, a phase detection module, and a demodulation module. The receiving module receives a modulated signal from a transmitting device. The set of levels of the baseband signal corresponding to the modulated signal includes positive and negative levels. This set of levels includes at least one first level, and a second level with an amplitude similar to or equal to the first level but opposite polarity is not included in this set of levels. Furthermore, the set of levels also includes at least a third level and a fourth level, where the third level and the fourth level have similar or equal amplitudes but opposite polarities. The amplitude detection module performs amplitude detection on the modulated signal to obtain the level amplitude of each symbol in the baseband signal. The phase detection module performs phase detection on the modulated signal to obtain the phase difference between every two adjacent symbols in the baseband signal. The demodulation module demodulates the first symbol to be demodulated based on the level amplitude of the first symbol, where the first symbol includes symbols in the baseband signal having a first level and symbols with a level of 0. The demodulation module is also used to demodulate the second symbol to be demodulated based on the phase difference between the reference symbol and the second symbol to be demodulated. The second symbol includes all symbols in the baseband signal except for the first symbol. The reference symbol is the symbol that has been demodulated before the second symbol to be demodulated, and the reference symbol does not include symbols with a level of 0.

[0041] In some possible implementations, minimizing the number of amplitude values ​​in the level set can reduce the power consumption required by the transmitting device to send the modulated signal. For example, the total number of amplitude values ​​in the level set is less than 32.

[0042] In some possible implementations, the number of positive and negative levels in the level set is as close as possible but not equal, which can also reduce the power consumption required by the transmitting device to transmit the modulated signal. For example, the difference between the number of positive and negative levels in the level set is greater than 0 and less than 32.

[0043] In some possible implementations, the receiving device further includes an I / Q mixer and a carrier generation device. The carrier generation device is used to generate a carrier signal. The I / Q mixer is used to orthogonally mix the modulation signal and the carrier signal to obtain the I / Q signal. The amplitude detection module is specifically used to perform amplitude detection on the I / Q signal to obtain the level amplitude of each symbol in the baseband signal. The phase detection module is specifically used to perform phase detection on the I / Q signal to obtain the phase of each symbol in the baseband signal, and calculate the phase difference between every two adjacent symbols in the baseband signal based on the phase of each symbol in the baseband signal.

[0044] In some possible implementations, the amplitude detection module includes an envelope detector, and the phase detection unit module includes a splitter, a delay adjustment device, a mixer, and a phase detector. The envelope detector performs level detection on the modulated signal to obtain the amplitude of each symbol in the baseband signal. The splitter splits the modulated signal to obtain a first modulated signal and a second modulated signal. The delay adjustment device delays the second modulated signal to obtain a third modulated signal. The mixer mixes the first and third modulated signals to obtain a mixed signal. The phase detector performs phase detection on the mixed signal to obtain the phase difference between every two adjacent symbols in the baseband signal.

[0045] Fifthly, embodiments of this application provide a communication system, including a transmitting device as described in any embodiment of the second aspect and a receiving device as described in any embodiment of the fourth aspect.

[0046] In this embodiment, the transmitting device can process the baseband signal to adjust the level of each symbol in the baseband signal, thereby obtaining a specific signal format suitable for differential demodulation. With a coherent receiving architecture, the receiving device can demodulate this specific signal format using differential demodulation based on the signal's amplitude and phase information, without relying on carrier synchronization. This approach eliminates the need for carrier synchronization, data pilots, and differential coding, reducing implementation complexity and power consumption. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of a communication system according to an embodiment of this application;

[0048] Figure 2 This is a schematic diagram of an embodiment of a signal processing method applied to a transmitting device in this application;

[0049] Figure 3 This is a schematic diagram of the level distribution of the original baseband signal in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of the level distribution of the target baseband signal in an embodiment of this application;

[0051] Figure 5 This is a constellation diagram of the baseband I / Q signals in an embodiment of this application;

[0052] Figure 6 This is a schematic diagram of an embodiment of a signal processing method applied to a receiving device in this application;

[0053] Figure 7 This is another constellation diagram of the baseband I / Q signals in the embodiments of this application;

[0054] Figure 8 This is another constellation diagram of the baseband I / Q signals in the embodiments of this application;

[0055] Figure 9 This is a schematic diagram of the first structure of the transmitting device in this application embodiment;

[0056] Figure 10 This is a schematic diagram of a second structure of the transmitting device in this application embodiment;

[0057] Figure 11 This is a schematic diagram of carrier modulation via a radio frequency switch in an embodiment of this application;

[0058] Figure 12 This is a schematic diagram of an example of inverse power combining in this application.

[0059] Figure 13 This is a schematic diagram of a third structure of the transmitting device in this application embodiment;

[0060] Figure 14 This is a schematic diagram of the first structure of the receiving device in the embodiments of this application;

[0061] Figure 15 This is a schematic diagram of a second structure of the receiving device in an embodiment of this application;

[0062] Figure 16 This is a schematic diagram of a third structure of the receiving device in the embodiments of this application;

[0063] Figure 17 This is a schematic diagram of the structure of a communication system according to an embodiment of this application. Detailed Implementation

[0064] This application provides a signal processing method and related apparatus. The transmitting device can process the baseband signal to adjust the level of each symbol in the baseband signal, thereby obtaining a baseband signal with a specific level distribution. The receiving device can demodulate the baseband signal using differential demodulation based on its amplitude and phase information, reducing implementation complexity and power consumption. It should be noted that the terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0065] Figure 1 This is a schematic diagram of the structure of a communication system according to an embodiment of this application. Figure 1 As shown, this application is mainly applied to the scenario of terahertz short-range communication. The transmitting device 1 and the receiving device 2 realize the short-range transmission of high-speed, high-bandwidth terahertz signals through a terahertz active cable (TAC) 3. In order to increase the transmission distance of the terahertz signal in the TAC (3) and provide a larger signal bandwidth and data transmission rate, the transmitting device 1 and the receiving device 2 need to use coherent modulation and demodulation to improve the receiving sensitivity. Specifically, the transmitting device 1 receives the baseband signal input from the external port, the carrier generation module 12 outputs the terahertz carrier, and the modulation module 11 modulates the baseband signal onto the terahertz carrier for transmission. The receiving device 2 receives the terahertz modulated signal from the TAC (3), the carrier generation module 22 outputs the terahertz carrier, and the demodulation module 21 demodulates the terahertz modulated signal according to the terahertz carrier to recover the baseband signal.

[0066] It should be understood that the aforementioned transmitting device 1 and receiving device 2 are defined based on the data flow direction. The transmitting device 1 may also include the aforementioned demodulation module 21 and carrier generation module 22 to implement the functions of the receiving device 2. Similarly, the receiving device 2 may also include the aforementioned modulation module 11 and carrier generation module 12 to implement the functions of the transmitting device 1.

[0067] Currently, coherent demodulation typically employs carrier synchronization or differential phase shifting (DPS). However, these methods involve high complexity in signal processing and significant power consumption in both the transmitting and receiving devices. Therefore, this application provides a signal processing method and related equipment that reduces implementation complexity and power consumption, which will be described in detail below.

[0068] Figure 2 This is a schematic diagram of an embodiment of a signal processing method applied to a transmitting device according to this application. In this example, the signal processing method includes the following steps.

[0069] 201. The transmitting device modulates the original baseband signal to obtain the target modulated signal.

[0070] The transmitting device obtains the target modulated signal by modulating the original baseband signal. During modulation, in addition to modulating the original baseband signal onto the carrier wave, the level of the original baseband signal also needs to be adjusted to construct a specific level distribution. That is, the set of levels of the target baseband signal corresponding to the target modulated signal has this specific level distribution. The target baseband signal can be understood as the baseband signal after level adjustment of the original baseband signal. The following uses… Figure 11 and Figure 12 This section uses an example to introduce the original baseband signal, the target modulation signal, and the target baseband signal. Figure 11 As shown, modulating the original baseband signal onto the first carrier signal yields the original modulated signal, which is a high-frequency sine wave signal. The dashed line above the original modulated signal can be considered its envelope, which represents the level distribution of the original baseband signal corresponding to the original modulated signal. Figure 12 As shown, carrier injection of the original modulated signal yields the target modulated signal. Similarly, the dashed line above the target modulated signal can be considered its envelope, which represents the level distribution of the target baseband signal corresponding to the target modulated signal. This carrier injection method allows adjustment of the level of the original baseband signal to obtain the level distribution of the target baseband signal.

[0071] Specifically, the level set includes positive and negative levels. The level set includes at least one first level, and a second level with an amplitude similar to or equal to the first level but opposite polarity is not included in this level set. Furthermore, the level set also includes at least a third and a fourth level, where the third level has an amplitude similar to or equal to the fourth level but opposite polarity. A specific example is provided below to illustrate the level distribution provided in this application.

[0072] Figure 3This is a schematic diagram illustrating the level distribution of the original baseband signal in an embodiment of this application. It should be understood that the level of the original baseband signal is typically composed of positive levels. For example... Figure 3 As shown, taking the raw baseband signal in PAM4 format as an example, this raw baseband signal has four different voltage levels (1, 2, 3, 4). Alternatively, the voltage levels of the raw baseband signal can also be symmetrically distributed with 0 as the reference level. For example, this raw baseband signal has four different voltage levels (-1.5, -0.5, 0.5, 1.5). Furthermore, regardless of the voltage level distribution method, the voltage levels are evenly spaced. This application does not limit the specific size of a voltage level interval. For example, if voltage "1" represents 50mV and voltage "2" represents 100mV, then a voltage level interval is 50mV.

[0073] Figure 4 This is a schematic diagram illustrating a level distribution of the target baseband signal in an embodiment of this application. This embodiment constructs a non-symmetrical level distribution based on a 0 level, which differs from the level distribution of the original baseband signal, and existing modulation methods do not construct this specific level distribution. Specifically, this specific level distribution can be obtained by adjusting the overall level of the original baseband signal upwards or downwards. Figure 4 As shown, it can be Figure 3The original baseband signal levels are adjusted downwards to obtain target baseband signals with four different levels (-1, 0, 1, 2). It can be seen that level "2" corresponds to the first level mentioned above, level "1" and level "-1" correspond to the third and fourth levels mentioned above, while level "-2", which is symmetrical to level "2", is not in the level set of the target baseband signal. It should be understood that the amplitudes of the first and second levels are not necessarily completely equal, nor are the amplitudes of the third and fourth levels. As long as the amplitude difference between the first and second levels is less than or equal to a preset value, and the amplitude difference between the third and fourth levels is less than or equal to a preset value, it also meets the design requirements of this application. This application does not limit the size of this preset value; for example, the preset value can be 10% of a level interval. That is, the maximum acceptable level error in this application is 10% of a level interval. For example, a level distribution of (-0.9, 0, 1, 2) also meets the design requirements of this application, while (-1.5, -0, 1, 2) does not. It should be understood that the third and fourth levels mentioned above can be considered to be of the same amplitude as long as the level error is within the acceptable range. The first level mentioned above can be a level with a unique amplitude in the target baseband signal, rather than referring to a specific level. That is to say, the first level includes at least one level with a unique amplitude. For example, if the target baseband signal has four different levels (-0.5, 0.5, 1.5, 2.5), then the first level includes level "1.5" and level "2.5".

[0074] In some possible implementations, to reduce the power consumption required by the transmitting device to transmit the modulated signal, the number of positive and negative levels in the target baseband signal level set should be as close as possible but not equal, and the number of amplitude values ​​in the level set should be as small as possible. For example, similarly, Figure 3 The original baseband signal levels shown are adjusted downwards overall. Transmitting a signal with a level distribution of (-1, 0, 1, 2) requires less power than transmitting a signal with a level distribution of (-0.5, 0.5, 1.5, 2.5). It should be understood that the number of amplitude values ​​in this level set should satisfy: 1 ​​< M < 32, where M represents the number of amplitude values ​​in the level set. The difference between the number of positive and negative levels in this level set should satisfy: 0 < N < 32. It should be understood that the upper limits for M and N can be 32, 64, etc., but are not limited here.

[0075] 202. The transmitting device sends the target modulation signal to the receiving device.

[0076] The target modulated signal transmitted by the transmitting device is transmitted to the receiving device via a line. The receiving device uses a locally generated carrier to perform coherent demodulation to obtain the baseband I / Q signal. Because the carriers generated by the transmitting and receiving devices may vary in frequency and phase over time, this carrier asynchrony can cause unknown dynamic rotation in the demodulated baseband I / Q signal. Figure 5 This is a constellation diagram of the baseband I / Q signals in an embodiment of this application. Based on the above... Figure 4 The level distribution of the target baseband signal is shown below, as follows: Figure 5 As shown, the four voltage levels (-1, 0, 1, 2) are named A, B, C, and D, respectively. Due to the uncertain rotation of the I / Q phase, the four voltage levels of the target baseband signal will form a central origin and two circular trajectories with different radii on the I / Q plane. Specifically, B is located at the central origin, A and C are located on the circular trajectory with a radius of 1, and D is located on the circular trajectory with a radius of 2. Because the transmitting device constructs the above voltage level distribution of the target baseband signal, the receiving device can still demodulate the received baseband signal to recover the target baseband signal transmitted by the transmitting device even under carrier asynchrony. The signal processing method of the receiving device is described below.

[0077] Figure 6 This is a schematic diagram of an embodiment of a signal processing method applied to a receiving device according to this application. In this example, the signal processing method includes the following steps.

[0078] 601. The receiving device receives the target modulated signal from the transmitting device.

[0079] 602. The receiving equipment performs amplitude detection on the target modulation signal to obtain the level amplitude of each symbol in the target baseband signal.

[0080] It should be understood that the target baseband signal can be divided into symbols, with each symbol containing the same number of bits. The receiving device can sequentially perform amplitude detection on each symbol to obtain the level amplitude of each symbol.

[0081] 603. The receiving equipment performs phase detection on the target modulated signal to obtain the phase difference between every two adjacent symbols in the baseband signal.

[0082] It should be understood that the receiving equipment needs to use differential decision-making for symbols with the same level amplitude. Therefore, the receiving equipment needs to perform phase detection on the target modulated signal to obtain the phase difference between every two adjacent symbols.

[0083] 604. The receiving device demodulates the first symbol to be demodulated based on the level amplitude of the first symbol.

[0084] In this embodiment, the first symbol is a symbol in the target baseband signal that has a first level or a symbol with a level of 0. It should be understood that if the level amplitude of a certain symbol is unique among all symbol levels, then the receiving device can perform demodulation based on the level amplitude of that symbol. Since there is no second level in the target baseband signal that is close to or equal to the first level amplitude but has the opposite polarity, the first level is unique among all symbol levels, and the 0 level is also unique among all symbol levels. Figure 5 For example, if the current level amplitude of the symbol to be demodulated is 2, it can be directly determined as level D. If the current level amplitude of the symbol to be demodulated is 0, it can be directly determined as level B.

[0085] 605. The receiving device demodulates the second symbol to be demodulated based on the phase difference between the reference symbol and the second symbol to be demodulated.

[0086] In this embodiment, the second symbol is any symbol in the target baseband signal other than the first symbol mentioned above. That is, the amplitude of the first symbol is unique among all the symbol amplitudes, while the amplitude of the second symbol is not unique among all the symbol amplitudes. The target baseband signal contains at least one set of second symbols with similar or equal amplitudes but opposite polarities. For example, the second symbols include the symbols with the third and fourth amplitudes mentioned above. Demodulation cannot be completed solely based on the amplitude of the second symbol; therefore, a reference symbol is needed to demodulate the second symbol. The reference symbol is the symbol that has been demodulated before the second symbol to be demodulated. The following uses… Figure 5 The demodulation method for the second symbol will be introduced using an example. If the amplitude of the second symbol to be demodulated is 1, then the phase difference between the second symbol to be demodulated and the reference symbol is further compared. like And if the reference symbol is D or C, then the second symbol to be demodulated is determined to be level C. If And if the reference symbol is A, then the second symbol to be demodulated is determined to be level A. If or And if the reference symbol is D or C, then the second symbol to be demodulated is determined to be level A. If or If the reference symbol is A, then the second symbol to be demodulated is determined to be at level C. After the determination, the second symbol that has been demodulated is set as the reference symbol.

[0087] It should be noted that since symbols with an amplitude of 0 do not possess phase information, symbols with a level of 0 cannot be used as reference signals. Therefore, if the symbol preceding the currently demodulated second symbol is a symbol with an amplitude of 0, the symbol preceding it that was demodulated and has a non-zero amplitude can be used as a reference symbol to complete demodulation. In other words, in this embodiment, except for symbols with an amplitude of 0, all other demodulated symbols can be used as reference symbols to participate in the demodulation of the next symbol to be demodulated. It should be understood that if the first symbol to be demodulated after the demodulation process begins is the second symbol, there is no reference symbol yet, so the formal demodulation should begin with the first symbol with a first level that has completed demodulation based on amplitude. Figure 5 For example, it should start from the demodulated level D, and a symbol with level D can be used as a reference symbol.

[0088] Figure 7 This is another constellation diagram of the baseband I / Q signals in an embodiment of this application. In some possible implementations, the original baseband signal input to the transmitting device may contain level nonlinear distortion, with unequal spacing between adjacent levels. For example, the level distribution of an undistorted PAM4 signal is (1, 2, 3, 4), while the level distribution of a distorted PAM4 signal is (0.5, 1.4, 2.5, 3.6). According to the above... Figure 2 The level adjustment method described in the illustrated embodiment results in a PAM4 signal level distribution of (-1, -0.1, 1, 2.1). The constellation diagram of the baseband I / Q signals after coherent demodulation at the receiving end device is as follows: Figure 7 As shown. Due to the asynchrony of the transmit and receive carriers, the trajectory of the baseband I / Q signal will exhibit three circles with different radii. Levels A and C lie on the circle with the same radius, while level D lies on the circle with the largest radius. The demodulation rules for levels A, C, and D are the same as those described above. Figure 5 The differential demodulation method described above is the same. The ring formed by level B near the origin also carries I / Q phase information and can be used as a reference symbol in some scenarios. For example, when the radius of the ring containing B is much larger than the signal noise, i.e., the signal-to-noise ratio is high, the demodulation method of level B is the same as described above. Figure 5 In the example, the demodulation method for level D is the same, and the symbol with level B after demodulation can be used as a reference symbol. However, when the radius of the ring containing B is not significantly different from the noise in the signal, the phase of the symbol with level B is easily affected by additive noise, leading to a large phase error that interferes with the demodulation of subsequent symbols. In this case, the demodulation method for level B is the same as described above. Figure 5 In the example, the demodulation method for level B is the same, and the symbol of level B after demodulation is not used as a reference symbol.

[0089] Figure 8This is another constellation diagram of the baseband I / Q signals in an embodiment of this application. In some possible implementations, the original baseband signal input to the transmitting device may also be a PAM8 signal. In the presence of level nonlinear distortion, the level distribution of the PAM8 signal is (0.52, 1.41, 2.52, 3.63, 4.5, 5.45, 6.52, 7.48), named A, B, C, D, E, F, G, and H respectively. According to the above... Figure 2 The level adjustment method described in the illustrated embodiment results in a PAM8 signal level distribution of (-2.91, -2.02, -0.91, 0.2, 1.07, 2.02, 3.09, 4.05). The constellation diagram of the baseband I / Q signals after coherent demodulation at the receiving end device is as follows: Figure 8 As shown. Due to the nonlinear distortion of the original baseband signal levels, under the influence of carrier asynchrony, the I / Q signals corresponding to levels B and F will form an overlapping circular trajectory. The I / Q signals corresponding to levels C and E will form two very close-knit rings, and a similar situation occurs between levels A and G. The demodulation method for the signal corresponding to level H is the same as described above. Figure 5 The demodulation method for level D in the example is the same. The demodulation methods for levels B and F are the same as those described above. Figure 5 In the example, the demodulation methods for levels A and C are the same. The demodulation method for level D is the same as described above. Figure 7 The demodulation method for level B in the example is the same. Under the influence of signal noise, the rings formed by levels C and E become difficult to distinguish due to widening, and their corresponding signs cannot be accurately distinguished using amplitude information. Therefore, levels C and E will still use the same demodulation method as described above. Figure 5 Take, for example, the demodulation method for levels A and C being the same. The difference lies in that, when determining whether a symbol is level C or level E based on its amplitude, an amplitude range encompassing both levels C and E is used for judgment. As long as the symbol's amplitude falls within this range, the symbol is determined to correspond to either level C or level E. Similarly, the demodulation methods for levels A and G are similar.

[0090] The signal processing methods applied to the transmitting and receiving devices have been introduced above. The specific implementation methods will now be described in conjunction with the structures of the transmitting and receiving devices.

[0091] Figure 9 This is a schematic diagram of a first structural embodiment of the transmitting device in this application. Figure 9 As shown, the transmitting device includes a modulation module 901 and a transmitting module 902. The modulation module 901 is used to perform the above-described... Figure 2 The operation of step 201 in the illustrated embodiment. The sending module 902 is used to perform the above. Figure 2The operation of step 202 in the illustrated embodiment. The modulation module 901 modulates the original baseband signal, altering its level distribution to construct a specific level distribution. For details on this specific level distribution, please refer to the description of step 201 above; it will not be repeated here. It should be noted that the modulation module 901 can be implemented in various ways, which will be described below.

[0092] Implementation method 1: Adjust the level of the original baseband signal by carrier modulation and then carrier injection.

[0093] Figure 10 This is a schematic diagram of a second structure of the transmitting device in an embodiment of this application. For example... Figure 10 As shown, the modulation module 901 includes a carrier generation device 1001, a carrier modulation device 1002, a gain adjustment device 1003, and a carrier injection device 1004. Specifically, the carrier generation device 1001 generates a first carrier signal of a specified frequency locally. The first carrier signal can be split into two paths and output to the carrier modulation device 1002 and the gain adjustment device 1003 respectively. The first carrier signal can be a terahertz carrier signal. The carrier generation device 1001 can be composed of a crystal oscillator, a frequency multiplier, and a phase-locked loop circuit, and may further include an amplifier circuit to generate a high-power carrier. The carrier modulation device 1002 modulates the input original baseband signal onto the first carrier signal to obtain an original modulated signal. The gain adjustment device 1003 adjusts the gain of the first carrier signal to obtain a second carrier signal, wherein the first carrier signal and the second carrier signal have the same frequency but different amplitudes. The gain adjustment device 1003 can specifically be an adjustable gain amplifier or an attenuator. The carrier injection device 1004 generates a target modulated signal based on the original modulated signal and the second carrier signal. It should be understood that carrier injection allows for specific adjustment of the carrier energy in the original modulated signal to obtain the target modulated signal, which is equivalent to adjusting the level of the original baseband signal to obtain the target baseband signal. The carrier injection device 1004 can generate the target modulated signal based on the original modulated signal and the second carrier signal.

[0094] In one possible implementation, the carrier modulation device 1002 may specifically be a radio frequency switch. Figure 11 This is a schematic diagram illustrating carrier modulation via a radio frequency switch in an embodiment of this application. Figure 11 As shown, the on and off states of the RF switch correspond to the level of the original baseband signal, thereby adjusting the amplitude of the first carrier signal. It should be understood that in practical applications, the RF switch is not limited to... Figure 11The diagram shows two states: on and off. For example, if the original baseband signal is a PAM4 signal, the on / off state of the RF switch can correspond to four different levels of the PAM4 signal. In another possible implementation, the carrier modulation device 1002 can also be a mixer, where the original baseband signal and the first carrier signal are multiplied together to achieve carrier modulation.

[0095] In one possible implementation, the carrier injection device 1004 can be a power combiner, which combines the original modulation signal and the second carrier signal to obtain the target modulation signal. In another possible implementation, the carrier injection device 1004 can also be a bias voltage adjustment device, which determines a bias voltage based on the second carrier signal and applies this bias voltage to the original modulation signal to obtain the target modulation signal. It should be noted that the specific implementation of the carrier injection device 1004 can be selected based on the implementation of the carrier modulation device 1002 described above, and this application does not impose any specific limitations. For example, if the carrier modulation device 1002 uses an RF switch, then the carrier injection device 1004 can use a power combiner. As another example, if the carrier modulation device 1002 uses a mixer, and the original modulation signal after mixing is a pair of differential signals, then the carrier injection device 1004 can use a bias voltage adjustment device, which injects the second carrier into the original modulation signal to obtain the target modulation signal by applying different bias voltages to the differential signals of the original modulation signal.

[0096] Optionally, the modulation module 901 may further include a phase adjustment device 1005. The phase of the carrier frequency in the original modulation signal may change significantly due to group delay. Therefore, in order to construct the level distribution of the target baseband signal described in the above embodiment, it is also necessary to adjust the phase of the second carrier signal through the phase adjustment device 1005. It should be understood that the phase adjustment device 1005 may specifically be a phase shifter or an adjustable phase shifter, or a delay line of a specific length or an adjustable delay line; no specific limitation is made here. It should be noted that the above implementation using an RF switch does not adjust the phase of the carrier. The baseband signal corresponding to the original modulation signal may all be at a positive level. The phase of the second carrier signal can be adjusted by the phase adjustment device 1005 so that the phase of the second carrier signal differs from that of the carrier frequency in the original modulation signal by 180°. The carrier injection device 1004 performs inverse power synthesis on the second carrier signal and the original modulation signal to obtain the target modulation signal. Figure 12 This is a schematic diagram of an example of inverse power combining in this application. Figure 12As shown, the level of the baseband signal can be changed by inverted power combining. The implementation using a mixer allows for carrier phase adjustment. The phase adjustment device 1005 can adjust the phase of the second carrier signal so that the phase difference between the second carrier signal and the carrier frequency point in the original modulation signal is 0°. The carrier injection device 1004 performs coherent power combining of the second carrier signal and the original modulation signal to obtain the target modulation signal.

[0097] Method 2: First adjust the original baseband signal level and then perform carrier modulation.

[0098] Figure 13 This is a schematic diagram of a third structure of the transmitting device in an embodiment of this application. For example... Figure 13 As shown, the modulation module 901 includes a level adjustment device 1301, a carrier generation device 1302, and a carrier modulation device 1303. Specifically, the level adjustment device 1301 is used to adjust the level of the original baseband signal to obtain the target baseband signal. The carrier generation device 1302 is used to generate a carrier signal. The carrier modulation device 1303 is used to modulate the target baseband signal onto the carrier signal to obtain the target modulated signal. The level adjustment device 1301 includes a DC power supply 13a, a voltage adjustment device 13b, and a combiner 13c. The voltage adjustment device 13b is used to adjust the voltage output by the DC power supply 13a. The combiner 13c is used to couple the adjusted voltage with the original baseband signal to obtain the target baseband signal. In another possible implementation, a bias voltage adjustment device can be used instead of the voltage adjustment device 13b and the combiner 13c. For example, when the original baseband signal is a pair of differential signals, the bias voltage adjustment device can adjust the bias voltage applied by the DC power supply 13a to the original baseband signal to obtain the target baseband signal.

[0099] In this way, the level of the original baseband signal can be directly adjusted to construct the level distribution of the target baseband signal described in the above embodiment, and then the target baseband signal can be carrier modulated to obtain the target modulated signal. Specifically, the carrier modulation device 1303 can be a mixer, where the target baseband signal and the carrier signal are multiplied to achieve carrier modulation. Due to the multiplication characteristic of the mixer, the sign polarity of the target baseband signal is mapped to the phase information of the carrier signal; that is, the phase information of the carrier signal can reflect the level polarity of the target baseband signal.

[0100] Figure 14 This is a schematic diagram of a first structural embodiment of the receiving device in this application. Figure 14As shown, the receiving device includes a receiving module 1401, a carrier generation device 1402, an I / Q mixer 1403, an amplitude detection module 1404, a phase detection module 1405, and a demodulation module 1406. Specifically, the receiving module 1401 receives the target modulation signal from the transmitting device. The carrier generation device 1402 generates a carrier signal at a specified frequency. The I / Q mixer 1403 uses the carrier signal to perform quadrature mixing on the target modulation signal to obtain the I / Q signal. The amplitude detection module 1404 performs amplitude detection on the I / Q signal to obtain the level amplitude of each symbol in the target baseband signal. The phase detection module 1405 performs phase detection on the I / Q signal to obtain the phase of each symbol in the target baseband signal, and then calculates the phase difference between each two adjacent symbols. The demodulation module 1406 demodulates the signal based on the information output by the amplitude detection module 1404 and the phase detection module 1405 to recover the original baseband signal. The demodulation module 1406 specifically performs the above-described... Figure 6 The operations of steps 604 and 605 in the illustrated embodiment will not be described again here. It should be noted that this application does not limit the specific implementation of the amplitude detection module 1404, phase detection module 1405, and demodulation module 1406. For example, the amplitude detection module 1404 and phase detection module 1405 can be implemented using digital operational amplifier circuits or in a digital signal processor. For example, the amplitude detection module 1404 can be an envelope detector or a power detector, and the phase detection module 1405 can be a phase detector. The demodulation module 1406 can be implemented using a digital state machine circuit or in a digital signal processor.

[0101] Figure 15 This is a schematic diagram of a second structure of the receiving device in an embodiment of this application. For example... Figure 15As shown, the receiving device includes a receiving module 1501, an envelope detector 1502, a delay adjustment device 1503, a mixer 1504, a phase detector 1505, and a demodulation module 1506. Specifically, the receiving module 1501 is used to receive the target modulation signal from the transmitting device. The target modulation signal output by the receiving module 1501 can be divided into two paths: the first path is used for amplitude detection, and the second path is used for phase detection. The envelope detector 1502 can perform level detection on the first path of the target modulation signal to obtain the level amplitude of each symbol in the target baseband signal. It should be understood that devices such as power detectors, Schottky barrier diodes (SBDs), and Gilber cell mixers can also be used to achieve similar functions to the envelope detector 1502. The second target modulation signal can be further divided into two paths. One path is processed by the delay adjustment device 1503 and then output to the mixer 1504. The other path is output directly to the mixer 1504 without any delay processing. It should be understood that this embodiment can use a fixed delay or an adjustable delay, and the specific method is not limited here.

[0102] After the delayed signal R1 and the undelayed signal R2 are mixed by mixer 1504, a baseband signal with differential phase can be output. Signal R1 is represented as R1(t) = S(t+D)cos(wt+φ). Signal R2 is represented as R2(t) = S(t+D)cos(wt(t+D)+φ). Here, S(t) is the baseband signal, D is the delay, wt is the carrier signal, and φ is an unknown carrier phase. The mixed baseband signal is B(t) = R1(t)R2(t) = S(t)S(t+D)cos(wtD). Since the frequency of the carrier signal wt is much greater than the symbol rate F of data transmission, the delay D can be set to the value closest to 1 / F that satisfies wtD = 2Nπ, at which point B(t) = S(t)S(t+D). Phase detector 1505 is used to extract the phase from signal B. At the correct sampling time of the symbol, S(t) and S(t+D) have only two voltage polarities: positive and negative. Therefore, the output of phase detector 1505 also has only two phase values: 0 and π. When the voltage polarities of S(t) and S(t+D) are the same, the output of phase detector 1505 is 0. When the voltage polarities of S(t) and S(t+D) are opposite, the output of phase detector 1505 is π. Demodulation module 1406 is used to demodulate the signal based on the information output by envelope detector 1502 and phase detector 1505 to recover the original baseband signal. Specifically, demodulation module 1406 performs the above... Figure 6 The operations of steps 604 and 605 in the illustrated embodiment will not be described again here.

[0103] Figure 16This is a schematic diagram of a third structure of the receiving device in an embodiment of this application. In some possible implementations, the signal received by the receiving device may be affected by inter-symbol interference (ISI), which can severely degrade the signal's bit error rate. To improve the demodulation performance of the baseband signal, in the above... Figure 14 Based on the structure shown, such as Figure 16 As shown, the receiving device may also include an equalizer 1407. The equalizer 1407 can perform channel equalization on the I / Q signals to compensate for inter-symbol interference generated during transmission. The equalization function can be implemented using methods such as feed-forward equalization (FFE) or continuous-time linear equalization (Continuous-Time Linear Equalization). The equalized signal can be demodulated normally by the demodulation module 1406. Furthermore, in the case of asynchronous clocks between the transmitting and receiving ends, the receiving device can also perform clock recovery using the clock recovery module 1408 after extracting the amplitude of the I / Q signals. It should be understood that the equalizer 1407 and clock recovery module 1408 described above can also be implemented in a digital signal processor. It should be noted that the receiving device in this embodiment can implement the function of a coherent receiver. In addition to the devices listed above, the receiving device may also include other devices such as a dispersion compensator and a phase recovery module; specific details are not limited here.

[0104] Figure 17 This is a schematic diagram of a communication system according to an embodiment of this application. The communication system includes a transmitting end device 1701 and a receiving end device 1702. The transmitting end device 1701 is used to perform the above-described... Figure 2 The illustrated embodiment describes the operation of some or all of the steps. The receiving device 1702 is used to perform the above-described steps. Figure 6 The operation of some or all of the steps in the illustrated embodiment. Specifically, the transmitting device 1701 can be as described above. Figure 9 , Figure 10 or Figure 13 The transmitting end device described in any of the embodiments. The receiving end device 1702 can be the one described above. Figure 14 , Figure 15 or Figure 16 The receiving device described in any of the embodiments.

[0105] In this embodiment, the transmitting device can process the baseband signal to adjust the level of each symbol in the baseband signal, thereby obtaining a specific signal format suitable for differential demodulation. With a coherent receiving architecture, the receiving device can demodulate this specific signal format using differential demodulation based on the signal's amplitude and phase information, without relying on carrier synchronization. This approach eliminates the need for carrier synchronization, data pilots, and differential coding, reducing implementation complexity and power consumption.

[0106] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A signal processing method, characterized in that, include: The transmitting device modulates the original baseband signal to obtain a target modulated signal. The modulation is used to adjust the overall level of the original baseband signal upwards or downwards to obtain a set of levels for the target baseband signal corresponding to the target modulated signal. This set of levels includes positive and negative levels. The set of levels includes at least one first level and excludes a second level. The first level and the second level have opposite polarities. The difference between the amplitude of the first level and the amplitude of the second level is less than or equal to a preset value. The set of levels includes at least a third level and a fourth level. The third level and the fourth level have opposite polarities. The difference between the amplitude of the third level and the amplitude of the fourth level is less than or equal to the preset value. The transmitting device sends the target modulation signal to the receiving device.

2. The method according to claim 1, characterized in that, The total amplitude of the levels in the level set is less than 32.

3. The method according to claim 1 or 2, characterized in that, The difference between the number of positive levels and the number of negative levels in the level set is greater than 0 and less than 32.

4. The method according to claim 1 or 2, characterized in that, The transmitting device modulates the original baseband signal to obtain the target modulated signal, including: The transmitting device performs carrier modulation based on the first carrier signal and the original baseband signal to obtain the original modulated signal; The transmitting device generates the target modulation signal based on the original modulation signal and the second carrier signal, wherein the frequency of the first carrier signal is the same as the frequency of the second carrier signal, and the amplitude of the first carrier signal is different from the amplitude of the second carrier signal.

5. The method according to claim 4, characterized in that, The first carrier signal and the second carrier signal are terahertz carrier signals.

6. The method according to claim 4, characterized in that, The transmitting device performs carrier modulation based on the first carrier signal and the original baseband signal to obtain the original modulated signal, including: The transmitting device modulates the original baseband signal onto the first carrier signal using a radio frequency switch to obtain the original modulated signal.

7. The method according to claim 4, characterized in that, The transmitting device performs carrier modulation based on the first carrier signal and the original baseband signal to obtain the original modulated signal, including: The transmitting device uses a mixer to perform carrier modulation on the first carrier signal and the original baseband signal to obtain the original modulated signal.

8. The method according to claim 4, characterized in that, The transmitting device generates the target modulation signal based on the original modulation signal and the second carrier signal, including: The transmitting device uses a power combiner to combine the original modulation signal and the second carrier signal to obtain the target modulation signal.

9. The method according to claim 4, characterized in that, The transmitting device generates the target modulation signal based on the original modulation signal and the second carrier signal, including: The transmitting device determines the bias voltage based on the second carrier signal and applies the bias voltage to the original modulation signal to obtain the target modulation signal.

10. The method according to claim 1 or 2, characterized in that, The transmitting device modulates the original baseband signal to obtain the target modulated signal, including: The transmitting device adjusts the level of the original baseband signal to obtain the target baseband signal; The transmitting device performs carrier modulation based on the third carrier signal and the target baseband signal to obtain the target modulated signal.

11. The method according to claim 10, characterized in that, The transmitting device performs carrier modulation based on the third carrier signal and the target baseband signal to obtain the target modulated signal, including: The transmitting device uses a mixer to perform carrier modulation on the third carrier signal and the target baseband signal to obtain the target modulated signal.

12. The method according to claim 10, characterized in that, The transmitting device adjusts the level of the original baseband signal to obtain the target baseband signal, including: The transmitting device adjusts the voltage output of the DC power supply through a voltage adjustment device, and couples the adjusted voltage with the original baseband signal to obtain the target baseband signal.

13. The method according to claim 10, characterized in that, The transmitting device adjusts the level of the original baseband signal to obtain the target baseband signal, including: The transmitting device adjusts the bias voltage applied to the original baseband signal by the DC power supply through a bias voltage adjustment device to obtain the target baseband signal.

14. A transmitting device, characterized in that, Includes a modulation module and a transmission module; The modulation module is used to modulate the original baseband signal to obtain a target modulation signal. The modulation is used to adjust the overall level of the original baseband signal upwards or downwards to obtain a set of levels for the target baseband signal corresponding to the target modulation signal. The set of levels for the target baseband signal includes positive and negative levels. The set of levels includes at least one first level and does not include a second level. The first level and the second level have opposite polarities. The difference between the amplitude of the first level and the amplitude of the second level is less than or equal to a preset value. The set of levels includes at least a third level and a fourth level. The third level and the fourth level have opposite polarities. The difference between the amplitude of the third level and the amplitude of the fourth level is less than or equal to the preset value. The transmitting module is used to transmit the target modulation signal to the receiving device.

15. The transmitting device according to claim 14, characterized in that, The total amplitude of the levels in the level set is less than 32.

16. The transmitting device according to claim 14 or 15, characterized in that, The difference between the number of positive levels and the number of negative levels in the level set is greater than 0 and less than 32.

17. The transmitting device according to claim 14 or 15, characterized in that, The modulation module includes a carrier generation device, a gain adjustment device, a carrier modulation device, and a carrier injection device; The carrier generation device is used to generate a first carrier signal; The carrier modulation device is used to perform carrier modulation based on the first carrier signal and the original baseband signal to obtain the original modulated signal; The gain adjustment device is used to adjust the gain of the first carrier signal to obtain a second carrier signal, wherein the frequency of the first carrier signal is the same as the frequency of the second carrier signal, and the amplitude of the first carrier signal is different from the amplitude of the second carrier signal. The carrier injection device is used to generate the target modulation signal based on the original modulation signal and the second carrier signal.

18. The transmitting device according to claim 17, characterized in that, The first carrier signal and the second carrier signal are terahertz carrier signals.

19. The transmitting device according to claim 17, characterized in that, The carrier modulation device includes a radio frequency switch; The radio frequency switch is used to modulate the original baseband signal onto the first carrier signal to obtain the original modulated signal.

20. The transmitting device according to claim 17, characterized in that, The carrier modulation device includes a mixer; The mixer is used to perform carrier modulation on the first carrier signal and the original baseband signal to obtain the original modulated signal.

21. The transmitting device according to claim 17, characterized in that, The carrier injection device includes a power combiner; The power combiner is used to perform power combining on the original modulation signal and the second carrier signal to obtain the target modulation signal.

22. The transmitting device according to claim 17, characterized in that, The carrier injection device includes a bias voltage adjustment device; The bias voltage adjustment device is used to determine the bias voltage based on the second carrier signal and apply the bias voltage to the original modulation signal to obtain the target modulation signal.

23. The transmitting device according to claim 14 or 15, characterized in that, The modulation module includes a level adjustment device, a carrier generation device, and a carrier modulation device; The level adjustment device is used to adjust the level of the original baseband signal to obtain the target baseband signal. The carrier generation device is used to generate a third carrier signal; The carrier modulation device is used to perform carrier modulation based on the third carrier signal and the target baseband signal to obtain the target modulation signal.

24. The transmitting device according to claim 23, characterized in that, The carrier modulation device includes a mixer; The mixer is used to perform carrier modulation on the third carrier signal and the target baseband signal to obtain the target modulated signal.

25. The transmitting device according to claim 23, characterized in that, The level adjustment device includes a DC power supply, a voltage regulator, and a combiner; The DC power supply is used to output voltage; The voltage regulating device is used to regulate the magnitude of the voltage. The combiner is used to couple the regulated voltage with the original baseband signal to obtain the target baseband signal.

26. The transmitting device according to claim 23, characterized in that, The level adjustment device includes a DC power supply and a bias voltage adjustment device; The DC power supply is used to apply a bias voltage to the original baseband signal. The bias voltage adjustment device is used to adjust the bias voltage to obtain the target baseband signal.

27. A communication system, characterized in that, The device includes a transmitting end device and a receiving end device as described in any one of claims 14 to 26, wherein the receiving end device includes a receiving module, an amplitude detection module, a phase detection module, and a demodulation module; The receiving module is used to receive modulated signals from the transmitting device. The amplitude detection module is used to perform amplitude detection on the modulation signal to obtain the level amplitude of each symbol in the baseband signal corresponding to the modulation signal; The phase detection module is used to perform phase detection on the modulation signal to obtain the phase difference between every two adjacent symbols in the baseband signal; The demodulation module is used to demodulate the first symbol according to the level amplitude of the first symbol, wherein the first symbol includes symbols in the baseband signal that have the first level and symbols with a level of 0; The second symbol to be demodulated is demodulated based on the phase difference between the reference symbol and the second symbol to be demodulated. The second symbol includes all symbols in the baseband signal except for the first symbol. The reference symbol is the symbol that has been demodulated before the second symbol to be demodulated, and the reference symbol does not include symbols with a level of 0.

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