Local oscillator leakage adjusting circuit and digital transmitter and analog transmitter based on local oscillator leakage adjusting circuit

Abstract

The invention discloses a local oscillator leakage adjusting circuit and a digital transmitter and an analog transmitter based on the local oscillator leakage adjusting circuit, and the local oscillator leakage adjusting circuit comprises a digital pre-modulator which is used for carrying out the power amplification or reduction of a local oscillator signal according to a first-level modulation code, and obtaining a local oscillator signal after first-level modulation, the primary modulation code is used for controlling the gain of the digital pre-modulator; the digital power amplifier is used for carrying out power amplification on the local oscillator signal subjected to primary modulation according to a secondary modulation code to obtain an output signal, and the secondary modulation code is used for controlling the gain of the digital power amplifier. The primary modulation code and the secondary modulation code are used for controlling the total gain of the output signal relative to the local oscillator signal to be a preset gain value all the time. According to the invention, local oscillator leakage is controlled through a digital device, parameter adjustment is not dependent on the device, broadband and good robustness can be realized, and extremely low local oscillator leakage can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of signal transmitters, and in particular relates to a local oscillator leakage adjustment circuit and a digital transmitter and an analog transmitter based thereon. Background Art

[0002] As the data rate of modern wireless communication systems continues to increase, transmitters are required to have high linearity, support high-order modulation, wideband modulation and other performance. In addition, the operating frequency of the transmitter has been increased from sub-6GHz to the millimeter wave band to increase available spectrum resources and bandwidth. However, the local oscillator leakage of the transmitter increases with the increase of frequency, which restricts the increase of the transmitter data rate.

[0003] Ideally, the amplitude of the transmitter's RF output signal RF should change linearly with the baseband signal encoding, while the output phase remains unchanged. However, due to the transistor parasitic capacitance C par existence, see Figure 1 , which will cause part of the signal to leak from the input port to the output port through the parasitic capacitance of the transistor. The local oscillator leakage signal LO leak Generally, the phase of the amplified signal sig output by the amplifier is different; therefore, after the amplified signal and the local oscillator leakage signal are vector-synthesized, the RF output signal will be distorted and no longer have a linear relationship with the baseband signal encoding; the dynamic range of the RF output signal will also decrease as the local oscillator leakage increases, making it difficult to achieve high-order modulation.

[0004] One current method to counteract LO leakage is to introduce a compensation signal LO that is equal in magnitude and opposite in direction to the LO leakage signal. comp , to cancel the local oscillator leakage. Figure 1 The inverted compensation signal is directly connected to the output terminal through an additional parallel capacitor Cp, and the local oscillator leakage is suppressed by inverting the compensation signal. leak and LO comp When the amplitudes are equal and the phases are opposite, the LO leakage can be completely cancelled.

[0005] However, this local oscillator leakage cancellation method relies on device parameter adjustment and is difficult to achieve broadband. Moreover, the local oscillator leakage cancellation effect depends on the parameters of the compensation capacitor and the parasitic capacitor. Both devices are analog devices and are greatly affected by factors such as the environment (such as temperature) and processing deviations, and have poor robustness. Summary of the invention

[0006] The embodiment of the present invention provides a local oscillator leakage adjustment circuit and a digital transmitter and an analog transmitter based thereon, which can solve the problem that the current local oscillator leakage cancellation method relies on device parameter adjustment and is difficult to achieve broadband and has poor robustness.

[0007] In a first aspect, an embodiment of the present invention provides a local oscillator leakage adjustment circuit, including:

[0008] A digital premodulator, the digital premodulator is used to amplify or reduce the power of the local oscillator signal according to the primary modulation code to obtain a primary modulated local oscillator signal, wherein the primary modulation code is used to control the gain of the digital premodulator;

[0009] A digital power amplifier is used to amplify the power of the local oscillator signal after primary modulation according to secondary modulation coding to obtain an output signal, wherein the secondary modulation coding is used to control the gain of the digital power amplifier, and the primary modulation coding and the secondary modulation coding are used to control the total gain of the output signal relative to the local oscillator signal to always be a preset gain value.

[0010] In a second aspect, an embodiment of the present invention provides a digital transmitter based on a local oscillator leakage adjustment circuit, comprising:

[0011] A first local oscillator leakage adjustment circuit, the first local oscillator leakage adjustment circuit includes a first digital premodulator and a first digital power amplifier, the first digital premodulator is used to amplify or reduce the power of the first orthogonal component of the local oscillator signal according to the primary modulation code to obtain the first orthogonal component of the local oscillator signal after the primary modulation, and the first digital power amplifier is used to amplify the power of the first orthogonal component of the local oscillator signal after the primary modulation according to the secondary modulation code to obtain the first orthogonal component of the output signal;

[0012] A second local oscillator leakage adjustment circuit, the second local oscillator leakage adjustment circuit includes a second digital premodulator and a second digital power amplifier, the second digital premodulator is used to amplify or reduce the power of the second orthogonal component of the local oscillator signal according to the primary modulation code to obtain the second orthogonal component of the primary modulated local oscillator signal, and the second digital power amplifier is used to amplify the power of the second orthogonal component of the primary modulated local oscillator signal according to the secondary modulation code to obtain the second orthogonal component of the output signal;

[0013] Among them, the primary modulation code is used to control the gain of the first digital premodulator and the second digital premodulator, the secondary modulation code is used to control the gain of the first digital power amplifier and the second digital power amplifier, and the primary modulation code and the secondary modulation code are used to control the total gain of the output signal relative to the local oscillator signal to always be a preset gain value;

[0014] The signal synthesizer is used to perform signal synthesis processing on the first orthogonal component of the output signal and the second orthogonal component of the output signal to obtain a radio frequency output signal.

[0015] In a third aspect, an embodiment of the present invention provides an analog transmitter based on a local oscillator leakage adjustment circuit, including:

[0016] A digital-to-analog converter, the digital-to-analog converter is used to perform digital-to-analog conversion on the baseband signal encoding to obtain a baseband signal;

[0017] A filter is used to filter the baseband signal to obtain an intermediate frequency signal;

[0018] A digital pre-modulator is used to amplify or reduce the power of the local oscillator signal according to the primary modulation code to obtain a primary modulated local oscillator signal;

[0019] A mixer, the mixer is used to mix the local oscillator signal after the primary modulation with the intermediate frequency signal to obtain a mixed output signal;

[0020] A digital power amplifier, the digital power amplifier is used to amplify the power of the mixed output signal according to the secondary modulation coding to obtain an output signal;

[0021] A power amplifier is used to amplify the output signal to obtain a radio frequency output signal.

[0022] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: the present invention controls the total gain of the output signal relative to the local oscillator signal to remain unchanged at a preset gain value through primary modulation coding and secondary modulation coding, thereby maintaining the linearity of the output signal and reducing the impact of local oscillator leakage; the local oscillator leakage is modulated by digital devices such as digital premodulators and digital power amplifiers, which does not rely on circuit parameter adjustment and is insensitive to factors such as frequency, process, and temperature, thereby avoiding the problem of poor robustness caused by analog devices and achieving broadband local oscillator leakage suppression. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a principle diagram of a local oscillator leakage self-suppression technology;

[0024] Figure 2 It is a structural schematic diagram of a transmitter based on local oscillator leakage self-suppression technology;

[0025] Figure 3 A schematic diagram of the structure of a local oscillator leakage adjustment circuit provided by an embodiment of the present invention;

[0026] Figure 4 A schematic diagram of the relationship between baseband signal coding, primary modulation coding and secondary modulation coding provided in an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of a local oscillator leakage signal provided by an embodiment of the present invention;

[0028] Figure 6 The present invention is a structural schematic diagram of a digital transmitter based on a local oscillator leakage adjustment circuit provided by Strength;

[0029] Figure 7 A schematic diagram of the structure of an analog transmitter based on a local oscillator leakage adjustment circuit provided in an embodiment of the present invention;

[0030] Figure 8 A schematic diagram for comparing radio frequency output signals provided by an embodiment of the present invention;

[0031] Fig. 9 A schematic diagram of a change in a local oscillator leakage signal when the secondary modulation code is 0 provided in an embodiment of the present invention;

[0032] Fig.10 A two-level coded constellation diagram provided by an embodiment of the present invention;

[0033] Fig.11 A high-order modulation test diagram of a transmitter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0035] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0036] It should also be understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0037] As used in the present specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]", depending on the context.

[0038] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0039] References to "one embodiment" or "some embodiments" etc. described in the present specification mean that one or more embodiments of the present invention include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0040] Figure 2 Shown is a schematic diagram of the structure of a transmitter based on local oscillator leakage self-suppression technology.

[0041] See also Figure 2 , the current differential structure transmitter introduces two capacitors to offset the local oscillator leakage of the forward signal and the reverse signal respectively. When the local oscillator leakage self-suppression technology is not used, see Figure 2 There is no LOLSS curve in the RF output signal, and the phase of the RF output signal has large amplitude modulation-amplitude modulation distortion and amplitude modulation-phase modulation distortion. At the same time, when the local oscillator leakage is large, the dynamic range of the transmitter is limited.

[0042] After adopting the local oscillator leakage self-suppression technology, see Figure 2 The LOLSS curve can effectively improve the linearity and dynamic range of the transmitter to support wider bandwidth and higher-order modulation signals.

[0043] However, this local oscillator leakage cancellation method relies on device parameter adjustment and is difficult to achieve broadband. Moreover, the local oscillator leakage cancellation effect depends on the parameters of the compensation capacitor and the parasitic capacitor. Both devices are analog devices and are greatly affected by factors such as the environment (such as temperature) and processing deviations, and have poor robustness.

[0044] In view of this, the present invention controls the total gain of the output signal relative to the local oscillator signal to remain at a preset gain value through primary modulation coding and secondary modulation coding, thereby maintaining the linearity of the output signal and reducing the impact of local oscillator leakage; the local oscillator leakage is modulated by digital devices such as digital premodulators and digital power amplifiers, which does not rely on circuit parameter adjustment and is insensitive to factors such as frequency, process, and temperature. It can avoid the poor robustness problem caused by analog devices and achieve broadband local oscillator leakage suppression.

[0045] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0046] Example 1

[0047] Figure 3 The figure shows a schematic diagram of the structure of a local oscillator leakage adjustment circuit provided by an embodiment of the present invention. As an example but not a limitation, the local oscillator leakage adjustment circuit may include a digital pre-modulator 1 and a digital power amplifier 2 .

[0048] For example, see Figure 1 The first input terminal of the digital premodulator 1 can input the local oscillator signal LO (i.e., the carrier signal), and the second input terminal can input the primary modulation code BB LO The output end can be connected to the first input end of the digital power amplifier 2. The second input end of the digital power amplifier 2 can input the secondary modulation code BB m .

[0049] For details, see Figure 4 , the digital premodulator 1 can be based on the primary modulation code BB LO The local oscillator signal LOI is amplified or reduced to obtain a primary modulated local oscillator signal Mod.LO. The digital power amplifier 2 can amplify the primary modulated local oscillator signal according to the secondary modulation code to obtain an output signal RFout.

[0050] Optionally, the digital power amplifier 2 can simultaneously realize functions such as digital-to-analog conversion, up-mixing and power amplification.

[0051] Exemplarily, the primary modulation coding can be used to control the gain of the digital premodulator 1, and the secondary modulation coding can be used to control the gain of the digital power amplifier 2. Under the joint control of the primary modulation coding and the secondary modulation coding, the total gain of the output signal compared to the local oscillator signal is always a preset gain value.

[0052] Exemplarily, the total gain may be equal to the product of the gain P1 of the digital premodulator 1 and the gain P2 of the digital power amplifier, and the values ​​of P1 and P2 may be equal to the values ​​of the primary modulation code and the secondary modulation code, respectively.

[0053] In some embodiments, when the amplitude of the local oscillator signal is 0, both the primary modulation code and the secondary modulation code are 0; at this time, the digital premodulator 1 is turned off, so that the local oscillator signal after the primary modulation is minimized, and the local oscillator leakage generated by the digital power amplifier 2 is greatly reduced.

[0054] In a possible implementation, the primary modulation code may be positively correlated with the size of the local oscillator signal, and the secondary modulation code may be negatively correlated with the size of the local oscillator signal. When the local oscillator signal becomes smaller, the primary modulated local oscillator signal will also decrease significantly as the local oscillator signal decreases, generating a scalable primary modulated local oscillator signal. Compared with the primary modulated local oscillator signal with constant gain, see Figure 5 When the local oscillator signal decreases, the local oscillator leakage in the circuit will also scale with the size of the local oscillator signal after the first-level modulation, reducing the impact of the local oscillator leakage.

[0055] In one example, if the local oscillator leakage adjustment circuit is applied to a 2×8-bit transmitter, the baseband signal code BB, the primary modulation code BB LO , Secondary Modulation Code BB m The product of the primary modulation code and the secondary modulation code can be equal to the baseband signal code BB and 2 N1 The product of

[0056]

[0057] Exemplarily, the baseband signal coding may include multiple value intervals. When the value of the baseband signal coding is in the nth value interval, the value of the primary modulation coding may be 2. n ; n is a non-negative integer less than or equal to N1.

[0058] For example, when n is greater than 0, the nth value interval of the baseband signal coding can be [2 n+3 ,2 n+4 -1]; the 0th value interval of the baseband signal coding can be [1,2 4 -1].

[0059] For example, the 0th value interval of the baseband signal coding is [1,2 3 -1], the first value interval is [8,2 5 -1], starting from the second value interval, the nth value interval is [2 n+3 ,2 n+4 -1].

[0060] It should be understood that the present invention does not limit the specific range of the value interval of the baseband signal coding, as long as the total number of the value intervals of the baseband signal coding is equal to N1.

[0061] Exemplarily, N1 is the number of bits of the digital premodulator.

[0062] For example, when the digital premodulator 1 bit is 2 3 When , the values ​​of the primary modulation code, the secondary modulation code, and the value range of the baseband signal coding can be referred to the following Table 1.

[0063] Table 1

[0064]

[0065] In another example, if the local oscillator leakage adjustment circuit is applied to a 2×11-bit transmitter, the baseband signal code BB, the primary modulation code BB LO , Secondary Modulation Code BB m They work together, but the primary modulation code and the secondary modulation code are independent of each other; their values ​​are related to the interval in which the baseband signal coding value lies.

[0066] Similarly, the baseband signal encoding may include multiple value intervals.

[0067] It should be understood that the present invention does not limit the specific range of the value interval of the baseband signal coding, as long as the total number of the value interval of the baseband signal coding is equal to N1, where N1 is the number of bits of the digital premodulator.

[0068] For example, when the value of the baseband signal code is in the nth value interval of the baseband signal, the value of the primary modulation code may be 2 n , the value of the secondary modulation code can be 2 N1-n Although the two satisfy the product equals 2 N1 , but they are actually independent of each other.

[0069] For example, when the digital premodulator 1 bit is 2 3 When , the values ​​of the primary modulation code, the secondary modulation code, and the value range of the baseband signal coding can be referred to the following Table 2.

[0070] Table 2

[0071]

[0072] In another possible implementation, the primary modulation code may be negatively correlated with the size of the local oscillator signal, while the secondary modulation code may be positively correlated with the size of the local oscillator signal.

[0073] The present invention controls the total gain of the output signal relative to the local oscillator signal to remain unchanged at a preset gain value through primary modulation coding and secondary modulation coding, which can maintain the linearity of the output signal and reduce the influence of local oscillator leakage; modulates the local oscillator leakage through digital devices such as digital premodulators and digital power amplifiers, which does not rely on circuit parameter adjustment, is insensitive to factors such as frequency, process, and temperature, and can avoid the problem of poor robustness caused by analog devices, and realize broadband local oscillator leakage suppression and high-order modulation. Furthermore, the two different settings of primary modulation coding and secondary modulation coding enable the local oscillator leakage adjustment circuit provided by the present invention to be applied in a transmitter with reconfigurable bits, thereby expanding the scope of application.

[0074] Example 2

[0075] Based on Example 1, Figure 6 The structure diagram of a digital transmitter based on a local oscillator leakage adjustment circuit provided by the present invention is shown. As an example but not a limitation, the digital transmitter may include a first local oscillator leakage adjustment circuit 61, a second local oscillator leakage adjustment circuit 62 and a signal synthesizer 63.

[0076] For example, see Figure 6 The first local oscillator leakage adjustment circuit 61 may include a first digital premodulator 611 and a first digital power amplifier 612, and the second local oscillator leakage adjustment circuit 62 may include a second digital premodulator 621 and a second digital power amplifier 622. The first input end of the first digital premodulator 611 may input the first orthogonal component of the local oscillator signal, the second input end may input the primary modulation code, and the output end may be connected to the first input end of the first digital power amplifier 612. The second input end of the first digital power amplifier may input the secondary modulation code, and the output end may be connected to the first input end of the signal synthesizer 63.

[0077] Similarly, the second orthogonal component of the local oscillator signal can be input to the first input terminal of the second digital premodulator 621, the primary modulation code can be input to the second input terminal, and the output terminal is connected to the first input terminal of the second digital power amplifier 622. The secondary modulation code can be input to the second input terminal of the second digital power amplifier 622, and the output terminal is connected to the second input terminal of the signal synthesizer 63.

[0078] Specifically, the first digital premodulator 611 is used to code the first-level modulation BB LO The first orthogonal component LOI of the local oscillator signal is power-amplified or reduced to obtain the first orthogonal component Mod.LOI of the local oscillator signal after primary modulation. The first digital power amplifier 612 is used to generate a first orthogonal component Mod.LOI according to the secondary modulation code BB. m The first orthogonal component Mod.LOI of the local oscillator signal after primary modulation is power amplified to obtain the first orthogonal component RF of the output signalI The second digital pre-modulator 621 is used to code the first-level modulation BB LO The second quadrature component LOQ of the local oscillator signal is power-amplified or reduced to obtain the second quadrature component Mod.LOQ of the local oscillator signal after primary modulation. The second digital power amplifier 622 is used to amplify the second quadrature component Mod.LOQ of the local oscillator signal after primary modulation according to the secondary modulation coding to obtain the second quadrature component RF of the output signal. Q The signal synthesizer 63 is used to synthesize the first quadrature component RF of the output signal. I , the second orthogonal component RF Q Perform signal synthesis processing to obtain a radio frequency output signal.

[0079] The present invention controls the total gain of the output signal relative to the local oscillator signal to remain unchanged at a preset gain value through primary modulation coding and secondary modulation coding, thereby maintaining the linearity of the output signal and reducing the influence of local oscillator leakage; the local oscillator leakage is modulated by digital devices such as digital premodulators and digital power amplifiers, which does not rely on circuit parameter adjustment and is insensitive to factors such as frequency, process, and temperature. The problem of poor robustness caused by analog devices can be avoided, broadband local oscillator leakage suppression and high-order modulation can be achieved, and extremely low local oscillator leakage can be achieved.

[0080] Example 3

[0081] Based on Example 1, Figure 7 The structure diagram of an analog transmitter based on a local oscillator leakage adjustment circuit provided by an embodiment of the present invention is shown. As an example but not limitation, the analog transmitter may include a digital-to-analog converter 71, a filter 72, a mixer 73, a digital premodulator 74, a digital power amplifier 75 and a power amplifier 76.

[0082] Exemplarily, the input end of the digital-to-analog converter 71 may input the baseband signal code, and the output end may be connected to the input end of the filter 72, and the output end of the filter 72 may be connected to the first input end of the mixer 73. The first input end of the digital premodulator 74 inputs the local oscillator signal, the second input end inputs the primary modulation code, and the output end is connected to the second input end of the mixer 73. The output end of the mixer 73 may be connected to the first input end of the digital power amplifier 75. The second input end of the digital power amplifier 75 may input the secondary modulation code, and the output end is connected to the input end of the power amplifier 76.

[0083] Specifically, the digital-to-analog converter 71 can be used to perform digital-to-analog conversion on the baseband signal encoding to obtain the baseband signal, and the filter 72 filters the baseband signal to obtain the intermediate frequency signal. The digital premodulator 74 amplifies or reduces the power of the local oscillator signal according to the primary modulation code to obtain the primary modulated local oscillator signal. The mixer 73 mixes the intermediate frequency signal and the primary modulated local oscillator signal to obtain a mixed output signal. The digital power amplifier 75 amplifies the power of the mixed output signal according to the secondary modulation code to obtain the output signal. The power amplifier 76 amplifies the output signal again to obtain the RF output signal.

[0084] In order to better illustrate the beneficial effects of the present invention, the following simulation experiments were carried out:

[0085] Figure 8 A comparative schematic diagram of a radio frequency output signal provided by an embodiment of the present invention is shown.

[0086] For example, Figure 8 (a) is the signal generated by the transmitter based on the current local oscillator leakage self-suppression technology. Figure 8 (b) is a signal generated by the digital transmitter provided in Embodiment 2 of the present invention, wherein the red one is the RF output signal, the black one is the local oscillator signal, and the purple one is the local oscillator leakage signal.

[0087] See also Figure 8 , it can be seen that the phase of the local oscillator leakage signal in the traditional technology The sum of the amplitude ΔA will increase with the increase of the local oscillator signal, thereby increasing the nonlinearity of the RF output signal and generating distortion. In the present invention, since the total gain of the RF output signal is unchanged compared with the local oscillator signal, the amplitude and phase of the local oscillator leakage signal are maintained within a stable range. In particular, when the local oscillator signal is small or the local oscillator signal is 0, the gain of the local oscillator signal after the primary modulation generated in the present invention is reduced, or the digital premodulator is directly turned off, which can greatly reduce the amplitude and phase deviation of the local oscillator leakage signal.

[0088] Fig. 9 The diagram shows a schematic diagram of changes in a local oscillator leakage signal when the secondary modulation code is 0 provided by an embodiment of the present invention.

[0089] For example, the secondary modulation code is set to 0, and the magnitude of the local oscillator leakage signal is measured at a frequency of 28 GHz to obtain Fig. 9 The curve in .

[0090] See also Fig. 9Compared with the size of the local oscillator leakage signal when the primary modulation code is 8 (equivalent to when the premodulator is not working), when the primary modulation code is 1, the size of the local oscillator leakage signal is reduced by 18dB. When the primary modulation code is 0, the size of the local oscillator leakage signal is reduced by 48dB. It can be seen that the present invention can greatly reduce the amplitude and phase deviation of the local oscillator leakage signal when the local oscillator signal is small, especially when the local oscillator signal is 0.

[0091] Fig.10 Shown is a two-level coding constellation diagram provided by an embodiment of the present invention.

[0092] For example, when the transmitter operates in 2×8 bit mode, the primary modulation coding and the secondary modulation coding in the local oscillator leakage adjustment circuit should strictly comply with the corresponding relationship shown in Table 1 above, and the two-level coding is related to each other. When the transmitter operates in 2×11 bit mode, the two-level coding can be selected independently, resulting in Fig.10 The constellation diagram shown provides more optional code points. Therefore, the local oscillator leakage adjustment circuit provided by the present invention can improve the bit position of the transmitter.

[0093] Fig.11 Shown is a high-order modulation test diagram of the millimeter wave digital transmitter provided by an embodiment of the present invention.

[0094] For example, see Fig.11 It can be seen that the transmitter provided by the present invention can be modulated under the conditions of 4096QAM and 1024QAM. Compared with the local oscillator leakage self-suppression technology of the current millimeter wave transmitter modulating under the condition of 256QAM, the modulation order of the present invention is higher.

[0095] Therefore, the present invention controls the total gain of the output signal relative to the local oscillator signal to remain unchanged at a preset gain value through primary modulation coding and secondary modulation coding, thereby maintaining the linearity of the output signal and reducing the impact of local oscillator leakage; the local oscillator leakage is modulated by digital devices such as digital premodulators and digital power amplifiers, which does not rely on circuit parameter adjustment and is insensitive to factors such as frequency, process, and temperature. It can avoid the poor robustness problem caused by analog devices, realize broadband local oscillator leakage suppression and high-order modulation, and achieve extremely low local oscillator leakage.

[0096] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0097] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0098] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0099] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, any modifications made without departing from the concept of the present invention should be deemed to belong to the protection scope of the present invention.

Claims

1. A local oscillator leakage adjustment circuit, characterized in that: include: A digital premodulator, the digital premodulator is used to amplify or reduce the power of the local oscillator signal according to the primary modulation code to obtain a primary modulated local oscillator signal, wherein the primary modulation code is used to control the gain of the digital premodulator; A digital power amplifier, wherein the digital power amplifier is used to power amplify the local oscillator signal after the primary modulation according to the secondary modulation code to obtain an output signal, wherein the secondary modulation code is used to control the gain of the digital power amplifier, and the primary modulation code and the secondary modulation code are used to control the total gain of the output signal relative to the local oscillator signal to always be a preset gain value.

2. The local oscillator leakage adjustment circuit according to claim 1, characterized in that: When the amplitude of the local oscillator signal is 0, both the primary modulation code and the secondary modulation code are 0.

3. The local oscillator leakage adjustment circuit according to claim 2, characterized in that: The primary modulation code is positively correlated with the size of the local oscillator signal, and the secondary modulation code is negatively correlated with the size of the local oscillator signal.

4. The local oscillator leakage adjustment circuit according to claim 3, characterized in that: The first level modulation code BB LO With the secondary modulation code BB m The product of the baseband signal code BB and 2 N1 The product of , N1 is the number of bits of the digital premodulator; The primary modulation coding, the secondary modulation coding and the baseband signal coding satisfy the following formula:

5. The local oscillator leakage adjustment circuit according to claim 4, characterized in that: The baseband signal modulation code includes multiple value intervals. If the value of the baseband signal code is in the nth value interval, the value of the primary modulation code is 2. n , n is a non-negative integer less than or equal to N1.

6. The local oscillator leakage adjustment circuit according to claim 3, characterized in that: The product of the primary modulation code and the secondary modulation code is equal to 2 N1 , N1 is the number of bits of the digital premodulator.

7. The local oscillator leakage adjustment circuit according to claim 6, characterized in that: The baseband signal modulation code includes multiple value intervals. If the value of the baseband signal code is in the nth value interval, the value of the primary modulation code is 2. n , n is a non-negative integer less than or equal to N1.

8. A digital transmitter based on a local oscillator leakage adjustment circuit, characterized in that: include: A first local oscillator leakage adjustment circuit, the first local oscillator leakage adjustment circuit comprising a first digital premodulator and a first digital power amplifier, the first digital premodulator is used to amplify or reduce the power of the first orthogonal component of the local oscillator signal according to the primary modulation code to obtain the first orthogonal component of the local oscillator signal after the primary modulation, and the first digital power amplifier is used to amplify the power of the first orthogonal component of the local oscillator signal after the primary modulation according to the secondary modulation code to obtain the first orthogonal component of the output signal; A second local oscillator leakage adjustment circuit, the second local oscillator leakage adjustment circuit comprising a second digital premodulator and a second digital power amplifier, the second digital premodulator is used to amplify or reduce the power of the second orthogonal component of the local oscillator signal according to the primary modulation code to obtain the second orthogonal component of the primary modulated local oscillator signal, and the second digital power amplifier is used to amplify the power of the second orthogonal component of the primary modulated local oscillator signal according to the secondary modulation code to obtain the second orthogonal component of the output signal; The primary modulation code is used to control the gain of the first digital premodulator and the second digital premodulator, the secondary modulation code is used to control the gain of the first digital power amplifier and the second digital power amplifier, and the primary modulation code and the secondary modulation code are used to control the total gain of the output signal relative to the local oscillator signal to always be a preset gain value; A signal synthesizer is used to perform signal synthesis processing on the first orthogonal component of the output signal and the second orthogonal component of the output signal to obtain a radio frequency output signal.

9. An analog transmitter based on a local oscillator leakage adjustment circuit, characterized in that: include: A digital-to-analog converter, the digital-to-analog converter is used to perform digital-to-analog conversion on the baseband signal encoding to obtain a baseband signal; A filter, wherein the filter is used to filter the baseband signal to obtain an intermediate frequency signal; A digital premodulator, the digital premodulator is used to amplify or reduce the power of the local oscillator signal according to the primary modulation code to obtain a primary modulated local oscillator signal; A mixer, the mixer is used to mix the local oscillator signal after the primary modulation with the intermediate frequency signal to obtain a mixed output signal; A digital power amplifier, the digital power amplifier is used to power amplify the mixed output signal according to secondary modulation coding to obtain an output signal; A power amplifier is used to amplify the output signal to obtain a radio frequency output signal.

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