Digital radio frequency transmitter based on optimized mapping modulation

Abstract

The invention discloses a digital radio frequency transmitter based on optimized mapping modulation, and the transmitter comprises an interpolation unit which is used for improving the sampling frequency of a baseband signal, and obtaining an intermediate frequency signal; the rectangular coordinate-to-polar coordinate conversion unit is used for obtaining the amplitude and phase of the intermediate frequency signal; the sector judgment unit is used for judging the sector where the signal is located according to the high order of the phase of the intermediate frequency signal and determining the phase difference between the sector where the signal is located and the mapping table reserved area; the mapping table generation unit is used for generating an intermediate frequency mapping table; the mapping coding unit is used for respectively calculating index addresses according to the low bits of the amplitude and the phase of the intermediate frequency signal, and searching an initial radio frequency digital sequence with the length of N corresponding to an intermediate frequency mapping table; the radio frequency digital sequence shifting unit is used for circularly shifting the initial radio frequency digital sequence by different digits according to the sectors where the signals are located to obtain correct radio frequency digital sequences corresponding to the signals; and the radio frequency digital-to-analog conversion unit is used for converting the radio frequency digital signal into a radio frequency analog signal.

Description

Technical Field

[0001] The present invention relates to the field of radio technology, and in particular to a low-power digital radio frequency transmitter based on optimized mapping modulation. Background Art

[0002] Faced with the increasingly tight radio spectrum resources and the iterative updates of emerging communication standards, communication networks are faced with the dual challenges of optimizing spectrum utilization and adapting to diverse technical needs. Especially with the advancement of 5G and future 6G technologies, higher requirements are placed on efficient spectrum utilization, low-latency communications, and massive device access capabilities. In addition, with the rapid development of the Internet of Things and the Industrial Internet, the demand for customized communication solutions in different application scenarios is increasing. In this context, it is particularly critical to deploy radio transmitters that can support multiple specifications and standards at the same time, have carrier frequency variability, and are highly reconfigurable.

[0003] In order to achieve this new deployment, the physical layer of the transmitter must be able to support the simultaneous transmission of multi-frequency, multi-rate, and multi-standard signals. The design and construction of traditional analog RF transmitters rely on fixed hardware architectures optimized for specific signal types and communication standards. The devices and circuit systems they contain limit the bandwidth and transmission rate of the signal, and can only adapt to new frequency bands or standards by replacing physical hardware. The deployment and maintenance costs are high, and they lack flexibility and adaptability. In this context, the concept of digital RF transmitters was proposed. It uses software-defined radio (SDR) technology to place baseband signal processing, signal coding, and frequency shifting operations in the digital domain. It can adapt to new communication protocols and frequency requirements through software updates without changing hardware. It can achieve high flexibility and reconfigurability, support multi-frequency, multi-rate, and multi-standard signal transmission, reduce update costs, and improve deployment efficiency and performance.

[0004] Bit width modulation technology is the core of digital transmitters. In addition to the common DSM modulation technology and PWM modulation technology, the existing patent application with publication number CN114826291A proposes mapping modulation technology, which realizes the mapping of intermediate frequency complex signals and radio frequency pulses based on the look-up table (LUT). The operation is simple and greatly reduces the resource consumption of the multiplier. At the same time, the digital radio frequency transmitter based on mapping modulation technology has the characteristics of flexible frequency conversion, simple structure, low DSP (Digital Signal Processor) resource consumption, and good output signal performance indicators.

[0005] However, in order to meet the high requirements of actual application scenarios for transmission speed, system dynamic range, and signal-to-noise ratio, the bit width of the input signal may need to be increased. In the solution proposed in the patent application with publication number CN114826291A, the LUT size increases exponentially with the increase of signal bit width, and power consumption also increases with the increase of bit width. This will lead to excessive consumption of storage resources, increase the complexity of system implementation, increase the circuit area and cost of the device, and even exceed the maximum capacity of common RAM (Random Access Memory) in some cases, and cannot be implemented on FPGA (Field Programmable Gate Array). Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a digital radio frequency transmitter based on optimized mapping modulation, which can effectively reduce the storage resource requirements of the digital radio frequency transmitter to at most 1 / 2 of the storage resources required by the existing digital radio frequency transmitter. N , N The pulse length is greatly reduced, which greatly reduces the scale and power consumption of the circuit implementation, improves its applicability and meets the needs of modern wireless transmitters.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A digital radio frequency transmitter based on optimized mapping modulation, comprising: An interpolation unit, used to increase the sampling frequency of the baseband signal to obtain an intermediate frequency signal; A rectangular coordinate conversion polar coordinate unit is used to obtain the amplitude and phase of the intermediate frequency signal; A sector determination unit, used to determine the sector where the signal is located according to the high bit of the phase of the intermediate frequency signal, and determine the phase difference between the sector where the signal is located and the reserved area of ​​the mapping table; A mapping table generating unit, used for generating an intermediate frequency LUT mapping table; The mapping encoding unit is used to calculate the index address according to the low bits of the amplitude and phase of the intermediate frequency signal, and search the corresponding length of the intermediate frequency LUT mapping table. N The initial radio frequency digital sequence; A radio frequency digital sequence shift unit is used to cyclically shift the initial radio frequency digital sequence by different bits according to the sector where the signal is located, so as to obtain the correct radio frequency digital sequence corresponding to each signal; The radio frequency digital-to-analog conversion unit is used to convert the radio frequency digital signal into a radio frequency analog pulse signal.

[0008] Furthermore, the interpolation unit is used to convert the bit width W 1 baseband signal x 0(s ) Interpolation to get the intermediate frequency signal x 1( m ), the intermediate frequency sampling frequency is f IF , f IF satisfy , f c is the carrier frequency, α Not greater than An integer, that is α =1,2,3... .

[0009] Furthermore, the amplitude and phase of the intermediate frequency signal output by the rectangular coordinate conversion polar coordinate unit are quantized to a bit width of W A binary sequence of 2; The radio frequency digital sequence shift unit is used to inversely transform the digital sequence read in the reduced mapping table into the corresponding digital sequence in the complete mapping table.

[0010] Furthermore, sectors are the phase-equal divisions of the entire complex plane. N or area, when α no N When the factor of or is 1, there are N sectors, and the phase range covered by each sector is ;when α yes N When the factor of is not 1, there are sectors, and the phase range covered by each sector is ; for α no N The factor of or 1, according to the phase high bits to determine the sector where the signal is located; for α yes N The factor of is not 1, according to the signal phase high The sector where the bit judgment signal is located, Indicates rounding up.

[0011] Furthermore, the generation method of the mapping table generation unit is specifically as follows: List all the lengths N , the level number is L The digital sequence of ,in , ; Calculate all digital sequences at the carrier frequency f cThe amplitude and phase of the digital sequence constitute the quantized value set of the intermediate frequency signal ; List all amplitudes that satisfy , phase satisfaction or The intermediate frequency signal , , Representing a collection Any value in Representing a collection Any value in ; For all intermediate frequency signals , search for the point with the smallest Euclidean distance in the intermediate frequency signal quantization value set Q ; will with The corresponding number sequence Stored in the addresses corresponding to the amplitude and phase, forming a LUT mapping table.

[0012] Furthermore, Fourier transform is used to obtain the digital sequence at the carrier frequency f c The amplitude and phase of the digital sequence constitute the set of quantized values ​​of the intermediate frequency signal. The calculation formula is: ; In the formula, f RF is the RF sampling frequency; f RF = N · f IF ; is a sequence of numbers, i is an integer, i= 0,1,···, N -1; j is an integer, j= 0,1,···, N -1; when f c = α · f IF ,and α Not greater than When the digital sequence is an integer, it shifts left one bit each time it is cyclically shifted. f c The corresponding phase increase of the intermediate frequency signal quantization value or , thus we get the idea of ​​mapping modulation algorithm.

[0013] Furthermore, the mapping modulation algorithm is specifically: exist α no N When the factor is 1, any phase range in the mapping table is retained. The interval of exist α yes N When the factor is not 1, any phase range in the mapping table is retained. The interval of If the input signal phase is within the reserved range, the corresponding digital RF sequence is obtained directly by looking up the table; If the input signal phase is not within the retention range, the signal is rotated clockwise. or of i Enter the coverage range of the mapping table, get the corresponding digital sequence, and then move left again. i to obtain the correct RF digital sequence.

[0014] Furthermore, the point with the smallest Euclidean distance is searched in the intermediate frequency signal quantization value set Q. , the calculation method is: ; In the formula, ; is the amplitude factor of the intermediate frequency signal; is the amplitude resolution; is the phase resolution; = .

[0015] Furthermore, the digital sequence The calculation formula for the storage address is: ; In the formula, ; round Indicates the result after rounding.

[0016] Further, the mapping coding unit is specifically: the bit width of the amplitude and phase are W 2 The intermediate frequency signal, according to the amplitude and phase of the intermediate frequency signal or bits, calculate the index address, and map the intermediate frequency signal to a bit width of W 3 、 Length is N The digital sequence P ( n ).

[0017] Compared with the prior art, the present invention is based on an optimized mapping-modulated digital radio frequency transmitter, which can reduce the storage space occupied by the mapping table to 1 / 2 of that of the existing mapping-modulated digital radio frequency transmitter. N or α / N Not only has the storage efficiency been significantly improved, but the power consumed by the mapping part has also been greatly reduced. In typical application scenarios, the power can be reduced to less than half of that of the existing mapped modulated digital RF transmitter, making mapped modulation more flexible and compatible in various application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic structural diagram of a digital radio frequency transmitter based on optimized mapping modulation.

[0019] Figure 2 This is a schematic diagram of sector division when the mapping ratio is 16 and the ratio of the carrier frequency to the intermediate frequency sampling frequency is 1.

[0020] Figure 3 a) is the mapping table generated by mapping modulation before optimization, and b) is the mapping table generated by mapping modulation after optimization.

[0021] Figure 4 FIG. 4 is a structural diagram of a digital radio frequency transmitter in a specific embodiment.

[0022] Figure 5 Flowchart of the optimized mapping table generation method.

[0023] Figure 6 This is the specific circuit structure of the sector judgment unit.

[0024] Figure 7 The invention is a specific circuit structure of a radio frequency digital sequence shift unit. DETAILED DESCRIPTION

[0025] The digital radio frequency transmitter based on optimized mapping modulation of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0026] See also Figure 1 The present invention discloses a digital radio frequency transmitter based on optimized mapping modulation, including an interpolation unit, a rectangular coordinate conversion polar coordinate unit, a sector judgment unit, a mapping table generation unit, a mapping encoding unit, a radio frequency digital sequence shift unit and a radio frequency digital-to-analog conversion unit. After the baseband signal passes through the interpolation unit, it becomes an intermediate frequency signal, and the intermediate frequency sampling frequency is f IF , and then through the mapping encoding unit, it becomes a radio frequency signal, and the radio frequency sampling frequency is f RF The intermediate frequency sampling frequency and the radio frequency sampling frequency meet fRF = N · f IF , N is the pulse length.

[0027] Define carrier frequency f c The IF sampling frequency f IF The ratio is α ,Right now , the mapping modulation algorithm can be α When taking integers, the size of the mapping table is significantly reduced, which can greatly reduce the power consumption of the mapping part in the digital RF transmitter. α no N The factor of or is 1, that is, when When the storage resources occupied by the mapping table are reduced to 1 / 2 of the existing digital RF transmitter based on optimized mapping modulation, N ; and α yes N and is not 1, that is, when When the storage resources occupied by the mapping table are reduced to the existing digital RF transmitter based on optimized mapping modulation, α / N .

[0028] Specifically, the interpolation unit is used to increase the sampling frequency of the baseband signal to obtain an intermediate frequency signal. W 1 baseband signal x 0( s ) Interpolation to get the intermediate frequency signal x 1( m ), intermediate frequency sampling frequency f IF satisfy , f c is the carrier frequency, α Not greater than An integer, that is α =1,2,3... In this embodiment, Figure 4 As shown, the up-sampling filter is used to realize the function of the interpolation unit and increase the sampling frequency of the baseband signal to f IF , the baseband signal x 0 ( s ) Interpolation to get the intermediate frequency signal x 1 ( m ).

[0029] Specifically, the rectangular coordinate conversion polar coordinate unit is used to obtain the amplitude and phase of the intermediate frequency signal. The amplitude and phase of the intermediate frequency signal output by the rectangular coordinate conversion polar coordinate unit are quantized with a bit width of W 2. In this embodiment, Figure 4 As shown in the figure, CORDIC (Coordinate Rotation Digital Computer) is used to realize the function of converting rectangular coordinates to polar coordinates, converting rectangular coordinates to polar coordinates to obtain the amplitude and phase of the intermediate frequency signal to calculate the index of the lookup mapping table, where the signal x 1 ( m ) is and , which are bit-width W 2 binary sequence.

[0030] Specifically, the sector determination unit is used to determine the sector where the signal is located according to the high bit of the phase of the intermediate frequency signal, and determine the phase difference between the sector where the signal is located and the reserved area of ​​the mapping table. Figure 4 As shown, N The path selector 1 is used to implement the function of the sector judgment unit. The specific circuit structure of the sector judgment unit is as follows: Figure 6 shown.

[0031] Sectors are the phase-equal divisions of the entire complex plane. N or Different sectors use different flag The value indicates that the sector where the mapping table is located corresponds to flag The value is 0, and the corresponding flag The values ​​increase in a counterclockwise direction, with adjacent flag The sector phase interval represented by the value is .for α no N Factor or 1, according to the higher phase Bit, Indicates rounding up to determine the sector where the signal is located.

[0032] for α yes N The factor is not 1, according to the higher signal phase The bit determines the sector where the signal is located. Figure 2 for N =16, the sector division situation, the blue area is the sector where the mapping table is located. N The input terminals of the selector 1 are different flag value, the strobe signal is a higher phase or bit The present invention splits a multi-way selector into multiple selectors with fewer ways to improve the fault tolerance and maintainability of the system.

[0033] Specifically, the mapping table generation unit is used to generate the intermediate frequency LUT mapping table. The mapping table generation unit is the optimization part of the present invention for the mapping modulation technology. The mapping table generated before optimization is as follows: Figure 3 As shown in a), the mapping table generated after optimization is as follows Figure 3 In this embodiment, as shown in b). Figure 4 As shown, the embedded CPU is used to implement the function of the mapping table generation unit, which is used to generate an optimized LUT mapping table.

[0034] like Figure 5 As shown, the generation method of the mapping table generation unit is as follows: S1: List all the lengths of N , the level number is L The digital sequence of ,in , . Use Fourier transform to obtain all digital sequences At the carrier frequency f c The amplitude and phase of the digital sequence constitute the quantized value set of the intermediate frequency signal .

[0035] The calculation formula is: ; In the formula, f RF is the RF sampling frequency; f RF = N · f IF ; is a sequence of numbers, i is an integer, i= 0,1,···, N -1; j is an integer, j= 0,1,···, N -1.

[0036] when f c = α · f IF ,and α Not greater than When the digital sequence is an integer, it shifts left one bit each time it is cyclically shifted. f cThe corresponding phase increase of the intermediate frequency signal quantization value or , thus we get the idea of ​​mapping modulation algorithm.

[0037] Specifically, in α no N When the factor is 1, any phase range in the mapping table is retained. in the interval α yes N When the factor is not 1, any phase range in the mapping table is retained. If the input signal phase is within the reserved range, the corresponding digital RF sequence is obtained directly by looking up the table. If the input signal phase is not within the reserved range, the signal is rotated clockwise. or of i Enter the coverage range of the mapping table, get the corresponding digital sequence, and then move left again. i to obtain the correct RF digital sequence.

[0038] S2: List all amplitudes that meet , phase satisfaction or The intermediate frequency signal.

[0039] The bit widths for both amplitude and phase are W 2 For the normalized amplitude, the amplitude resolution is specified as , then all possible values ​​of the amplitude are ,in Representing a collection Any value in ; For the normalized phase, the phase resolution is specified as ,exist α no N When the phase is a factor of or equal to 1, the phase range is limited to Then all possible values ​​of the phase are ; exist α yes N When the phase is not equal to 1, the phase range is limited to Then all possible values ​​of the phase are ,in Representing a collection Any value in .

[0040] S3: Values ​​for all intermediate frequency signals , search for the point with the smallest Euclidean distance in the intermediate frequency signal quantization value set Q , the calculation method is: ; In the formula, ; is the amplitude factor of the intermediate frequency signal. Different carrier frequencies correspond to different Q sets. r The selection is also different; is the amplitude resolution; is the phase resolution; = .

[0041] S4: Based on amplitude and phase , will be The corresponding number sequence Stored in the addresses corresponding to the amplitude and phase, forming a LUT mapping table.

[0042] Number sequence The calculation formula for the storage address is: ; In the formula, ; round Indicates the result after rounding.

[0043] Specifically, the mapping encoding unit is used to calculate the index address according to the low bits of the amplitude and phase of the intermediate frequency signal, and search the intermediate frequency LUT mapping table corresponding to the length of N In this embodiment, if Figure 4 As shown, the RAM is used to implement the function of the mapping encoding unit and complete the mapping of the intermediate frequency signal within the phase range of the mapping table to the radio frequency pulse sequence.

[0044] The mapping table is stored in RAM, and the lower or bits, calculate the index address, and then map the intermediate frequency signal to a bit width of W 3 、 Length is N The RF digital sequence P ( n ), a sequence of numbers P ( n ) has a sampling frequency of f RF ,in f RF = N · f IF , NThe reason for taking the low bit of the phase is that all phases that can be represented by the low bit are within the phase range reserved by the mapping table. Using the low bit of the phase and the amplitude to calculate the index address is equivalent to rotating all signals to the mapping table with a reduced size for mapping.

[0045] Specifically, the RF digital sequence shift unit is used to cyclically shift the initial RF digital sequence by different bits according to the sector where the signal is located, so as to obtain the correct RF digital sequence corresponding to each signal. The RF digital sequence shift unit is used to inversely transform the digital sequence read from the reduced mapping table into the corresponding digital sequence in the complete mapping table. In this embodiment, Figure 4 As shown, N registers and N The path selector 2 is used to implement the function of the radio frequency digital sequence shift unit. The specific circuit structure of the radio frequency digital sequence shift unit is as follows: Figure 7 shown.

[0046] The RF digital sequence obtained by mapping the signal in the mapping encoding unit is an integer multiple of the phase difference of the signal. or , the RF digital sequence corresponding to the frequency point within the phase coverage range of the mapping table after the size reduction, and the sequence after cyclic shift is the RF digital sequence corresponding to the signal in the complete mapping table. The unit first reads P ( n ) Circularly shift left by 0 to N -1 will get the digital sequence after the register, and then pass this N Register connection N The input end of the path selector is based on the output of the sector judgment unit. flag The value is used as a selection control signal to obtain the corresponding shifted digital sequence.

[0047] The RF digital-to-analog conversion unit is used to convert the RF digital signal into a RF analog pulse signal. In this embodiment, the MGT (Multi-Gigabit Transceiver, high-speed serial transceiver) is used to implement the function of the RF digital-to-analog conversion unit. Convert to analog pulse signal y ( t ).

[0048] See also Figure 1 , Figure 4 and Figure 5 , each unit of the digital radio frequency transmitter based on optimized mapping modulation of the present invention can be implemented in the following manner.

[0049] Set the RF sampling frequency f RF=15.7GHz, mapping ratio N =16, intermediate frequency sampling frequency f IF =983.04MHz. The input baseband signal sampling frequency is 245.76MHz, that is f BB =245.76MHz, bit width is 8 bits.

[0050] The interpolation unit interpolates the sampling frequency of the baseband signal to the intermediate frequency sampling frequency of 983.04 MHz, and the interpolation multiple is 4. At this time, the clock frequency is 245.76 MHz, and 4 times interpolation is achieved through parallel 4-way interpolation.

[0051] The rectangular coordinate conversion polar coordinate unit converts the rectangular coordinates into polar coordinates, calculates the amplitude and phase of the intermediate frequency signal, and the bit width of the output amplitude and phase are both 10 bits.

[0052] The sector judgment unit is composed of 5 four-way selectors to realize the function of a 16-way selector. The sector in which the signal is located is judged according to the high 4 bits of the phase after frequency shifting. The second highest two bits are used as the channel selection signal of the first-level multiplexer, and the highest two bits are used as the channel selection signal of the second-level multiplexer. flag Add 1 in the direction of increasing phase.

[0053] The mapping table generation unit is based on f RF =15.7GHz, L =2, N =16, f c =983.04MHz, through Figure 5 The steps shown generate a corresponding mapping table for mapping the encoding.

[0054] The mapping table encoding unit calculates the index address through the lower 6 bits of the amplitude and phase of the intermediate frequency signal, and searches for the 1-bit RF digital sequence with a length of 16 corresponding to the LUT.

[0055] The RF digital sequence shift unit is composed of five four-way selectors to realize the function of a sixteen-way selector. flag To determine the number of bits that the sequence needs to be circularly shifted left, flag The lower 2 bits are used as the channel selection signal of the first-stage multiplexer, and the upper 2 bits are used as the channel selection signal of the second-stage multiplexer. The input terminals are P ( n ) is the sequence obtained by circularly shifting left by 0 to 15 bits.

[0056] The RF digital-to-analog conversion unit converts a 1-bit digital sequence into an analog pulse signal output.

[0057] Based on the above parameters, Xilinx XCVU095 FPGA chip was selected for simulation verification. The output results show that the adjacent channel leakage ratio (ACLR) is lower than -40dBc, the error vector magnitude (EVM) is less than 5%, and compared with the relevant indicators of the RF transmitter output signal based on the complete mapping table, the relative error is less than 2%, and the consumed block random access memory (Block RAM, BRAM) is reduced. , the dynamic power consumption of the RF transmitter dropped from 7.718W to 4.575W.

[0058] In summary, the present invention is based on the digital radio frequency transmitter of optimized mapping modulation, which can reduce the storage space occupied by the mapping table to 1 / 2 of the existing digital radio frequency transmitter of mapping modulation. N or α / N Not only has the storage efficiency been significantly improved, but the power consumed by the mapping part has also been greatly reduced. In typical application scenarios, the power can be reduced to less than half of that of the existing mapped modulated digital RF transmitter, making mapped modulation more flexible and compatible in various application scenarios.

[0059] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit disclosed by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A digital radio frequency transmitter based on optimized mapping modulation, characterized in that: include: An interpolation unit, used to increase the sampling frequency of the baseband signal to obtain an intermediate frequency signal; A rectangular coordinate conversion polar coordinate unit is used to obtain the amplitude and phase of the intermediate frequency signal; A sector determination unit, used to determine the sector where the signal is located according to the high bit of the phase of the intermediate frequency signal, and determine the phase difference between the sector where the signal is located and the reserved area of ​​the mapping table; A mapping table generating unit, used for generating an intermediate frequency LUT mapping table; The mapping encoding unit is used to calculate the index address according to the low bits of the amplitude and phase of the intermediate frequency signal, and search the corresponding length of the intermediate frequency LUT mapping table. N The initial radio frequency digital sequence; A radio frequency digital sequence shift unit is used to cyclically shift the initial radio frequency digital sequence by different bits according to the sector where the signal is located, so as to obtain the correct radio frequency digital sequence corresponding to each signal; The radio frequency digital-to-analog conversion unit is used to convert the radio frequency digital signal into a radio frequency analog pulse signal.

2. The digital radio frequency transmitter based on optimized mapping modulation according to claim 1, characterized in that: The interpolation unit is used to convert the bit width W 1 baseband signal x 0( s ) Interpolation to get the intermediate frequency signal x 1( m ), the intermediate frequency sampling frequency is f IF , f IF satisfy , f c is the carrier frequency, α Not greater than An integer, that is α =1,2,3... .

3. The digital radio frequency transmitter based on optimized mapping modulation according to claim 2, characterized in that: The amplitude and phase of the intermediate frequency signal output by the rectangular coordinate conversion polar coordinate unit are quantized to a bit width of W Binary sequence of 2; The radio frequency digital sequence shift unit is used to inversely transform the digital sequence read in the reduced mapping table into the corresponding digital sequence in the complete mapping table.

4. The digital radio frequency transmitter based on optimized mapping modulation according to claim 2, characterized in that: Sectors are the phase-equal divisions of the entire complex plane. N or area, when α no N When the factor of or is 1, there are N sectors, and the phase range covered by each sector is ;when α yes N When the factor of is not 1, there are sectors, and the phase range covered by each sector is ; for α no N The factor of or 1, according to the phase high bits to determine the sector where the signal is located; for α yes N The factor of is not 1, according to the signal phase high The sector where the bit judgment signal is located, Indicates rounding up.

5. The digital radio frequency transmitter based on optimized mapping modulation according to claim 4, characterized in that: The generation method of the mapping table generation unit is specifically as follows: List all the lengths N , the level number is L The digital sequence of ,in , ; Calculate all digital sequences at the carrier frequency f c The amplitude and phase of the digital sequence constitute the quantized value set of the intermediate frequency signal ; List all amplitudes that satisfy , phase satisfaction or The intermediate frequency signal is , , Representing a collection Any value in Representing a collection Any value in ; For all intermediate frequency signals , search for the point with the smallest Euclidean distance in the intermediate frequency signal quantization value set Q ; will with The corresponding number sequence Stored in the addresses corresponding to the amplitude and phase, forming a LUT mapping table.

6. The digital radio frequency transmitter based on optimized mapping modulation according to claim 5, characterized in that: Fourier transform is used to obtain the digital sequence at the carrier frequency f c The amplitude and phase of the digital sequence constitute the set of quantized values ​​of the intermediate frequency signal. The calculation formula is: ； In the formula, f RF is the RF sampling frequency; f RF = N · f IF ; is a sequence of numbers, i is an integer, i= 0,1,···, N -1; j is an integer, j= 0,1,···, N -1; when f c = α · f IF ,and α Not greater than When the digital sequence is an integer, it shifts left one bit each time it is cyclically shifted. f c The corresponding phase increase of the intermediate frequency signal quantization value or , thus we get the idea of ​​mapping modulation algorithm.

7. The digital radio frequency transmitter based on optimized mapping modulation according to claim 6, characterized in that: Mapping modulation algorithm, specifically: exist α no N When the factor is 1, any phase range in the mapping table is retained. The interval of exist α yes N When the factor is not 1, any phase range in the mapping table is retained. The interval of If the input signal phase is within the reserved range, the corresponding digital RF sequence is obtained directly by looking up the table; If the input signal phase is not within the preservation range, the signal is rotated clockwise. or of i Enter the coverage range of the mapping table, get the corresponding digital sequence, and then move left again. i to obtain the correct RF digital sequence.

8. The digital radio frequency transmitter based on optimized mapping modulation according to claim 5, characterized in that: Search for the point with the smallest Euclidean distance from the intermediate frequency signal quantization value set Q , the calculation method is: ； In the formula, ; is the amplitude factor of the intermediate frequency signal; is the amplitude resolution; is the phase resolution; = .

9. The digital radio frequency transmitter based on optimized mapping modulation according to claim 5, characterized in that: The calculation formula for the storage address of a digital sequence is: ； In the formula, ; round Indicates the result after rounding.

10. The digital radio frequency transmitter based on optimized mapping modulation according to claim 2, characterized in that: Mapping coding units, specifically: The bit widths for both amplitude and phase are W 2 The intermediate frequency signal, according to the amplitude and phase of the intermediate frequency signal or bits, calculate the index address, and map the intermediate frequency signal to a bit width of W 3 、 Length is N The digital sequence P ( n ).

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