Amplitude-phase adjustable two-way analog predistorter

Abstract

The invention discloses a two-way type analog predistorter with an adjustable amplitude and phase. Comprising a first one-to-two Wilkinson power divider, a second one-to-two Wilkinson power divider in signal connection with the first one-to-two Wilkinson power divider, a first nonlinear generator in signal connection with the second one-to-two Wilkinson power divider, a second nonlinear generator and a phase adjustable control circuit, the three-in-one Wilkinson combiner is in signal connection with the first nonlinear generator, the second nonlinear generator and the phase adjustable control circuit; the two-in-one Wilkinson combiner is in signal connection with the three-in-one Wilkinson combiner; the amplitude adjustable control circuit is in signal connection with the two-in-one Wilkinson combiner; and the amplitude adjustable control circuit is in signal connection with a first one-to-two Wilkinson power divider. According to the power amplifier, the adjustability is improved through the amplitude adjustable control circuit and the phase adjustable control circuit, and good linearization is carried out on power amplifiers of different types and under different conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of computer vision and remote sensing image processing, and in particular to a dual-path analog predistorter with adjustable amplitude and phase. Background Art

[0002] Change detection, as one of the core technologies of remote sensing Earth observation, plays an irreplaceable role in a variety of fields, including disaster monitoring and assessment, urban monitoring, and environmental perception. With the rapid advancement of aerospace information technology, Synthetic Aperture Radar (SAR) imagery data has become increasingly abundant and has become an indispensable data source for change detection. However, due to its unique electromagnetic active imaging mechanism, SAR images are subject to complex coherent speckle noise and pseudo-change problems. These issues significantly reduce the separability between the changed area and the background, severely impacting the accuracy and reliability of change detection.

[0003] Currently, matrix decomposition-based methods are favored due to their strong noise suppression capabilities and high computational efficiency. These methods primarily focus on leveraging the sparse nature of the change region, constructing a low-rank matrix decomposition model to extract the sparse components that represent the change. However, the effectiveness of these methods relies heavily on a prerequisite: the proportion of the change region within the entire observation area must be extremely small, which is often difficult to meet in reality. Furthermore, when faced with complex and changing scenarios, these methods have difficulty accurately separating the sparse components, resulting in large errors in the extraction of the change region.

[0004] Based on this, how to design a more general, robust and adaptable change detection method to overcome the above limitations and improve the accuracy and reliability of change detection is an important issue that needs to be solved urgently. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention aims to provide a dual-path analog predistorter with adjustable amplitude and phase to address the problem that the operating state of existing analog predistortion linearizers is not adjustable and cannot adapt to different models of power amplifiers. To achieve the above-mentioned object and other advantages of the present invention, a dual-path analog predistorter with adjustable amplitude and phase is provided, comprising:

[0006] A first one-to-two Wilkinson power divider, a second one-to-two Wilkinson power divider signal-connected to the first one-to-two Wilkinson power divider, a first nonlinear generator, a second nonlinear generator, and a phase-adjustable control circuit signal-connected to the second one-to-two Wilkinson power divider, a three-in-one Wilkinson combiner signal-connected to the first nonlinear generator, the second nonlinear generator, and the phase-adjustable control circuit, a two-in-one Wilkinson combiner signal-connected to the three-in-one Wilkinson combiner, and an amplitude-adjustable control circuit signal-connected to the two-in-one Wilkinson combiner, wherein the amplitude-adjustable control circuit is signal-connected to the first one-to-two Wilkinson power divider.

[0007] Preferably, the input end of the amplitude-adjustable control circuit is connected to the first output end of the first one-in-two Wilkinson power divider, and the output end of the amplitude-adjustable control circuit is connected to the first input end of the two-in-one Wilkinson combiner;

[0008] The amplitude adjustable control circuit adopts a variable capacitance diode and a voltage source, and realizes the function of independent amplitude adjustment within the frequency band by adjusting the voltage source separately.

[0009] Preferably, the input end of the first nonlinear generator is connected to an output end of the second one-in-two Wilkinson power divider, and the output end of the first nonlinear generator is connected to an input end of the three-in-one Wilkinson combiner;

[0010] The first nonlinear generator uses a Schottky diode and a voltage source to achieve the basic nonlinear requirements of the analog predistorter.

[0011] Preferably, the output end of the second nonlinear generator is connected to an input end of the three-in-one Wilkinson combiner;

[0012] The second nonlinear generator includes a first Schottky diode and a second voltage source, and is configured to cooperate with the first nonlinear generator to achieve basic nonlinear requirements of the analog predistorter.

[0013] Preferably, the output end of the phase adjustable control circuit is connected to an input end of the three-in-one Wilkinson combiner;

[0014] The phase adjustable control circuit includes a first varactor diode and a first voltage source, and is used to achieve a phase independent adjustable function within a wide bandwidth by adjusting the first voltage source alone.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention has a 400 MHz operating bandwidth and a relative bandwidth of 5.8%, and can be adapted to power amplifiers of different models or under different conditions without changing the circuit structure.

[0017] The amplitude adjustable circuit of the present invention uses varactor diodes connected in reverse series, and the amplitude can be adjusted by adjusting the voltage source of the amplitude adjustable control circuit separately.

[0018] The phase-adjustable circuit of the present invention uses varactor diodes connected in reverse parallel, and the phase can be adjusted by adjusting the voltage source of the phase-adjustable control circuit separately.

[0019] The present invention can reduce coupling between a phase adjustable control circuit and an amplitude adjustable control circuit and reduce mutual interference by using a one-to-two Wilkinson power divider and a one-to-three Wilkinson power divider.

[0020] In the present invention, both the nonlinear generator 1 and the nonlinear generator 2 generate nonlinear signals through Schottky diodes, and the two nonlinear generators work in coordination to achieve the basic nonlinear characteristics of the analog predistorter. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a principle diagram of a dual-path analog predistorter with adjustable amplitude and phase according to the present invention;

[0022] Figure 2 Schematic diagram of the structure of a dual-path analog predistorter with adjustable amplitude and phase according to the present invention;

[0023] Figure 3 The simulation results of the independent amplitude adjustment of the dual-path analog predistorter with adjustable amplitude and phase at 6.7 GHz according to the present invention are as follows;

[0024] Figure 4 The simulation results of the phase independent adjustment at 6.7 GHz of the dual-path analog predistorter with adjustable amplitude and phase according to the present invention are as follows;

[0025] Figure 5 The simulation results of the independent amplitude adjustment of the dual-path analog predistorter with adjustable amplitude and phase at 7.1 GHz according to the present invention are as follows;

[0026] Figure 6 1 is a simulation result of the phase independent adjustment of the dual-path analog predistorter with adjustable amplitude and phase at 7.1 GHz according to the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] In order to illustrate the structure and working performance of the analog predistorter of the present invention, an example of an analog predistorter with two working frequencies and working at an appropriate input power is given here. The working frequency band, amplitude adjustment range and phase adjustment range of this embodiment do not restrict the working frequency coverage range, amplitude adjustment range and phase adjustment range of the analog predistorter of the present invention. The design structure diagram is as follows: Figure 2 .

[0029] Reference Figure 1 , a dual-path analog predistorter with adjustable amplitude and phase, comprising:

[0030] A first one-to-two Wilkinson power divider 1, a second one-to-two Wilkinson power divider 2 signal-connected to the first one-to-two Wilkinson power divider 1, a first nonlinear generator 4, a second nonlinear generator 5 and a phase-adjustable control circuit 6 signal-connected to the second one-to-two Wilkinson power divider 2, a three-in-one Wilkinson combiner 7 signal-connected to the first nonlinear generator 4, the second nonlinear generator 5 and the phase-adjustable control circuit 6, a two-in-one Wilkinson combiner 8 signal-connected to the three-in-one Wilkinson combiner 7, and an amplitude-adjustable control circuit 3 signal-connected to the two-in-one Wilkinson combiner 8, wherein the amplitude-adjustable control circuit 3 is signal-connected to the first one-to-two Wilkinson power divider 1.

[0031] Furthermore, the first one-to-two Wilkinson power divider 1 and the second one-to-two Wilkinson power divider 2 have the same structure, both including an isolation resistor and a microstrip line structure, wherein the microstrip line structure is input through a first rectangular microstrip line, has a characteristic impedance of Z0, and a length of one quarter of the center frequency wavelength (λ / 4), and the first rectangular microstrip line connects the second rectangular microstrip line and the third rectangular microstrip line to form a T-type power distribution network; the characteristic impedances of the second rectangular microstrip line and the third rectangular microstrip line are both The fourth and fifth rectangular microstrip lines are connected to the ends of the second and third rectangular microstrip lines respectively for signal output, and an isolation resistor with a resistance of Z0 is connected between the two output ports.

[0032] Furthermore, the amplitude-adjustable control circuit 3 includes: a first capacitor, a second capacitor, a first resistor R, a second varactor diode, a first inductor, and a fourth voltage source. The input signal enters the amplitude-adjustable control circuit 3 through the first capacitor, and the first capacitor is used to isolate the DC signal. The signal enters the cathode of the second varactor diode, and the second varactor diode is connected in reverse series to adjust the signal amplitude. One end of the first inductor is connected to the anode of the second varactor diode, and the other end is grounded to control the direction and magnitude of the current flow. The signal is output after passing through the second capacitor, and the second capacitor is used to isolate the DC signal. The fourth voltage source and the first resistor are placed before the cathode of the second varactor diode, and the fourth voltage source is cascaded with the first resistor to ensure circuit safety. By adjusting the voltage value of the fourth voltage source, the capacitance of the second varactor diode can be changed, thereby achieving signal amplitude adjustment.

[0033] Furthermore, the first nonlinear generator 4 includes: a third capacitor, a fourth capacitor, a second resistor, a second inductor, a second Schottky diode, and a third voltage source. The input signal enters the first nonlinear generator 4 through the third capacitor, and the third capacitor is used to isolate the DC signal. The signal enters the anode of the second Schottky diode, and the second Schottky diode is connected in a forward series connection to generate nonlinear distortion. One end of the second inductor is connected to the cathode of the second Schottky diode and the other end is grounded to control the direction and magnitude of current flow. The signal is output after passing through the fourth capacitor, and the fourth capacitor is used to isolate the DC signal. The third voltage source and the second resistor are placed before the anode of the second Schottky diode, and the third voltage source is cascaded with the second resistor to ensure circuit safety. By pre-setting the voltage value of the third voltage source, the desired nonlinear distortion signal is generated.

[0034] Furthermore, the second nonlinear generator 5 includes: a fifth capacitor, a sixth capacitor, a third resistor, a third inductor, a first Schottky diode, and a second voltage source. The input signal enters the second nonlinear generator 5 through the fifth capacitor, and the fifth capacitor is used to isolate the DC signal. The signal enters the anode of the first Schottky diode, which is connected in a forward series connection to generate nonlinear distortion. One end of the third inductor is connected to the cathode of the first Schottky diode and the other end is grounded to control the direction and magnitude of current flow. The signal is output after passing through the sixth capacitor, and the sixth capacitor is used to isolate the DC signal. The second voltage source and the third resistor are placed before the anode of the second Schottky diode. The second voltage source is cascaded with the third resistor to ensure circuit safety. By pre-designing the voltage value of the second voltage source, the second nonlinear generator 5 can be assisted in generating a nonlinear distortion signal.

[0035] Furthermore, the phase-adjustable control circuit 6 includes: a seventh capacitor, an eighth capacitor, a fourth resistor, a first varactor diode, and a first voltage source. The input signal enters the phase-adjustable control circuit 6 through the seventh capacitor, and the seventh capacitor is used to isolate the DC signal. The signal enters the cathode of the first varactor diode, which is connected in reverse parallel, and the positive electrode of the first varactor diode is grounded, which is used to adjust the signal phase. The signal is output after passing through the eighth capacitor, and the eighth capacitor is used to isolate the DC signal. The first voltage source and the fourth resistor are located before the cathode of the second varactor diode, and the first voltage source is cascaded with the fourth resistor to ensure circuit safety. By adjusting the voltage value of the first voltage source, the capacitance value of the first varactor diode can be changed, thereby achieving signal amplitude adjustment.

[0036] The present invention has a dual-path analog predistorter with adjustable amplitude and phase, and has been simulated and tested at 6.7 GHz. Figure 2 , the amplitude adjustable simulation results at 6.7GHz are as follows Figure 3 The horizontal axis is the input power and the vertical axis is the gain. When the input power is -10 to 10dBm, the gain changes by about 2.55dB (0.44dB to 3dB) within the voltage range of the amplitude adjustable control circuit's voltage source from 0 to 20V, indicating that the amplitude adjustable control circuit 3 can effectively adjust the signal amplitude. The simulation results of phase adjustment at 6.7GHz are shown in Figure 2. Figure 4 The horizontal axis is the input power, and the vertical axis is the phase. When the voltage source of the phase adjustable control circuit is in the voltage range of 0 to 20V, the phase variation range is about 8.3° (-16.6° to -8.3°). The design structure diagram of the embodiment of the dual-path analog predistorter with adjustable amplitude and phase is shown in FIG. Figure 2 , the amplitude adjustable simulation results at 7.1GHz are as follows Figure 5 , in the voltage range of the voltage source of the amplitude adjustable control circuit from 0 to 20V, the gain variation range is about 1.5dB (-1.1dB to 0.4dB), indicating that the amplitude adjustable control circuit 3 can effectively adjust the amplitude of the signal. The simulation results of phase adjustment at 7.1GHz are as follows Figure 6 When the voltage source of the phase adjustable control circuit is within the voltage range of 0 to 20V, the phase variation range is 17.2° (-23.5° to -6.3°). The dual-path analog predistorter of the present invention can effectively compensate for the nonlinear distortion of the power amplifier through independent adjustment of the amplitude adjustable control circuit and the phase adjustable control circuit, and has excellent adaptability in a wide frequency band.

[0037] The number of devices and processing scales described herein are intended to simplify the description of the present invention, and the application, modification, and variation of the present invention will be apparent to those skilled in the art. Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiment. They can be applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily implemented. Therefore, the present invention is not limited to the specific details and illustrations shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims

1. A dual-path analog predistorter with adjustable amplitude and phase, characterized in that: include: A first one-to-two Wilkinson power divider (1), a second one-to-two Wilkinson power divider (2) signal-connected to the first one-to-two Wilkinson power divider (1), a first nonlinear generator (4) signal-connected to the second one-to-two Wilkinson power divider (2), a second nonlinear generator (5) and a phase-adjustable control circuit (6), a three-in-one Wilkinson combiner (7) signal-connected to the first nonlinear generator (4), the second nonlinear generator (5) and the phase-adjustable control circuit (6), a two-in-one Wilkinson combiner (8) signal-connected to the three-in-one Wilkinson combiner (7), and an amplitude-adjustable control circuit (3) signal-connected to the two-in-one Wilkinson combiner (8), wherein the amplitude-adjustable control circuit (3) is signal-connected to the first one-to-two Wilkinson power divider (1).

2. The dual-path analog predistorter with adjustable amplitude and phase according to claim 1, characterized in that: The input end of the amplitude-adjustable control circuit (3) is connected to the first output end of the first one-to-two Wilkinson power divider (1), and the output end of the amplitude-adjustable control circuit (3) is connected to the first input end of the two-in-one Wilkinson combiner (8); The amplitude adjustable control circuit (3) adopts a variable capacitance diode and a voltage source, and realizes the function of independently adjustable amplitude within a frequency band by adjusting the voltage source separately.

3. The dual-path analog predistorter with adjustable amplitude and phase as claimed in claim 1, characterized in that: The input end of the first nonlinear generator (4) is connected to an output end of the second one-to-two Wilkinson power divider (2), and the output end of the first nonlinear generator (4) is connected to an input end of the three-in-one Wilkinson combiner (7); The first nonlinear generator (4) adopts a Schottky diode and a voltage source to realize the basic nonlinear requirement of the analog predistorter.

4. The dual-path analog predistorter with adjustable amplitude and phase according to claim 1, wherein: The output end of the second nonlinear generator (5) is connected to an input end of the three-in-one Wilkinson combiner (7); The second nonlinear generator (5) comprises a first Schottky diode and a second voltage source, and is used to cooperate with the first nonlinear generator (4) to achieve basic nonlinear requirements of the analog predistorter.

5. The dual-path analog predistorter with adjustable amplitude and phase as claimed in claim 1, characterized in that: The output end of the phase adjustable control circuit (6) is connected to an input end of the three-in-one Wilkinson combiner (7); The phase adjustable control circuit (6) comprises a first variable capacitance diode and a first voltage source, and is used to realize the phase independent adjustable function within a wide band by adjusting the first voltage source alone.

6. The dual-path analog predistorter with adjustable amplitude and phase as claimed in claim 1, characterized in that: The first one-to-two Wilkinson power divider (1) is used to divide the input signal into two paths; The second one-to-two Wilkinson power divider (2) is used to further divide one signal into three paths; The amplitude adjustable control circuit (3) is used to adjust the amplitude of the signal; The first nonlinear generator (4) is used to generate a first nonlinear signal; The second nonlinear generator (5) is used to generate a second nonlinear signal; The phase adjustable control circuit (6) is used to adjust the phase of the signal; The three-in-one Wilkinson combiner (7) is used to combine three signals into one signal; The two-in-one Wilkinson combiner (8) is used to combine two signals into one output.

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