Balanced sideband separation radio frequency receiving device

Abstract

The invention relates to a balanced sideband separation radio frequency receiving device, which comprises a first radio frequency 90-degree coupler, a power divider, a second radio frequency 90-degree coupler, a third radio frequency 90-degree coupler, a frequency mixing module, a first magic T, a second magic T, an intermediate frequency 90-degree coupler and a load, and the 90-degree emitting end outputs a lower sideband signal. Compared with the prior art, the mixer, the magic T, the power divider, the radio frequency 90-degree coupler and the intermediate frequency 90-degree coupler are organically combined, separation of upper and lower sideband signals is achieved, simultaneous detection of the upper and lower sideband signals can be achieved, the upper and lower sideband signals are emitted from fixed ports, and system errors caused by discrete observation are effectively avoided.

Description

Technical Field

[0001] The invention relates to the field of astronomical detection instruments, and in particular to a balanced sideband separation radio frequency receiving device. Background Art

[0002] As a key component of radio telescopes, radio astronomy receiver systems have gone through a process from early performance limitations to gradual improvements. Early receiver systems had deficiencies in noise performance and sensitivity. With the application of technologies such as low-noise amplifiers and cooled mixers, performance has improved, but in the face of higher observation accuracy and efficiency requirements, traditional receiver systems are gradually unable to meet the needs. In the field of modern communications and detection, the accurate reception and analysis of weak signals in complex electromagnetic environments is also a problem that needs to be solved urgently.

[0003] The balanced sideband separation mixer receiver has many significant advantages. First, it has high sensitivity and extremely low noise temperature, and can effectively receive weak signals. For example, in radio astronomy observations, it can detect weak radio signals from more distant celestial bodies, providing more data for astronomical research. Second, the possibility of spectral line overlap is low, and the upper and lower sideband signals can be effectively separated. In addition, the sideband type and port of the output signal are fixed, reducing the probability of spectral line overlap. In spectrum analysis, the signal spectrum can be made clearer to avoid signal confusion and misjudgment caused by spectral line overlap. For example, in the observation of molecular spectral lines in the millimeter wave band, the spectral line characteristics of different molecules can be accurately distinguished, which helps the study of interstellar molecules. Third, it has high-precision amplitude calibration capability, which can maintain amplitude and phase stability during signal transmission and achieve high-precision amplitude calibration. This is crucial in scenarios where accurate measurement of signal strength is required, such as radar systems that can improve target detection and recognition accuracy. Fourth, it has good broadband reception capability and a wide receiving bandwidth, which can adapt to the signal reception needs of different frequency ranges. In modern communication systems, it can be compatible with multiple communication standards and frequency bands, improving the versatility and adaptability of the system.

[0004] The balanced sideband separation mixer receiver has important applications in many fields due to its advantages. In the field of radio astronomy observation, it is the core component of the radio telescope and is widely used in the study of molecular clouds in the Milky Way, observation of star formation and evolution, study of interstellar medium physics, and molecular spectral line surveys. By receiving and analyzing weak radio signals from the universe, it helps astronomers gain a deeper understanding of the physical properties and evolution of astronomical objects. In deep space exploration, its high sensitivity and low noise characteristics enable it to effectively receive and process weak signals from distant spacecraft in deep space environments, providing guarantees for spacecraft communication and control. In electronic reconnaissance and intelligence gathering, it can be used to intercept and analyze enemy communication signals. Its broadband receiving capability and high-precision signal processing capability enable it to quickly and accurately acquire target signals and analyze and decode them in complex electromagnetic environments, providing support for intelligence gathering and decision-making.

[0005] In summary, the balanced sideband separation mixer receiver has important application value, but the currently commonly used balanced sideband separation mixer receiver requires the use of many RF couplers, power dividers, mixers, filters and other components. The system complexity and design difficulty are high, and the cost is also high. The complex circuit structure may lead to increased loss and interference in the signal processing process, requiring more sophisticated debugging and optimization. In the balanced sideband separation mixer receiver, it is necessary to ensure the phase balance of components such as RF couplers and mixers to avoid signal distortion and interference. However, due to errors in the manufacturing and assembly process, phase balance may be difficult to achieve completely. When the frequencies of the RF signal and the local oscillator signal are very close, the image suppression effect may be limited, and the separation observation will bring about system errors. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a balanced sideband separation radio frequency receiving device for realizing the separation of upper and lower sideband signals.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A balanced sideband separation radio frequency receiving device comprises a first radio frequency 90 degree coupler, a power divider, a second radio frequency 90 degree coupler, a third radio frequency 90 degree coupler, a mixing module, a first magic T, a second magic T, an intermediate frequency 90 degree coupler and a load, wherein the incident end of the first radio frequency 90 degree coupler is connected to a radio frequency feed source and a load, the incident end of the power divider is connected to a local oscillator signal source, the output ends of the first radio frequency 90 degree coupler and the power divider are respectively connected to the input ends of the second radio frequency 90 degree coupler and the third radio frequency 90 degree coupler, four output ends of the second radio frequency 90 degree coupler and the third radio frequency 90 degree coupler are connected to the input ends of the first magic T and the second magic T in pairs through the mixing module, the output ends of the two magic Ts are connected to the intermediate frequency 90 degree coupler, and the output end of the intermediate frequency 90 degree coupler comprises a 0 degree output end for outputting an upper sideband signal and a 90 degree output end for outputting a lower sideband signal.

[0009] Further, the mixing module includes a first mixer, a second mixer, a third mixer and a fourth mixer;

[0010] The incident ends of the first mixer and the second mixer are respectively connected to the two output ends of the second RF 90-degree coupler, and the output ends of the first mixer and the second mixer are connected to the incident end of the first magic T;

[0011] The incident ends of the third mixer and the fourth mixer are respectively connected to the two output ends of the third radio frequency 90-degree coupler, and the output ends of the third mixer and the fourth mixer are connected to the incident end of the second magic-T.

[0012] Furthermore, the first RF 90-degree coupler includes two output ends that output signals with the same intensity and a phase difference of 90 degrees, and the output ends are respectively connected to the input ends of the second RF 90-degree coupler and the third RF 90-degree coupler.

[0013] Furthermore, the output end of the first RF 90-degree coupler is connected to the second RF 90-degree coupler and the third RF 90-degree coupler in a Y-type connection.

[0014] Furthermore, the power divider includes two output ends that output signals with the same intensity and phase, and the output ends are respectively connected to the input ends of the second RF 90-degree coupler and the third RF 90-degree coupler.

[0015] Furthermore, the output end of the power divider is connected to the second RF 90-degree coupler and the third RF 90-degree coupler in a Y-type connection.

[0016] Furthermore, the first RF 90-degree coupler includes a 0-degree incident end and a 90-degree incident end, the 0-degree incident end is connected to a RF feed source, and the 90-degree incident end is connected to a load.

[0017] Furthermore, the load is a resistor.

[0018] Furthermore, the receiving device is also connected to a digital signal display.

[0019] Furthermore, the digital signal display includes a display screen that outputs a sideband analog signal graph.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention organically combines a mixer, a magic T, a power divider, a radio frequency 90-degree coupler and an intermediate frequency 90-degree coupler. The mixer realizes the functions of frequency conversion and phase conversion. The power divider, the radio frequency 90-degree coupler and the intermediate frequency 90-degree coupler realize the functions of power distribution and phase delay. Finally, the upper and lower sideband signals are separated, and the upper and lower sideband signals can be detected simultaneously. The upper and lower sideband signals are emitted from fixed ports, which effectively avoids the system error caused by discrete observation.

[0022] 2. The present invention has the characteristics of simple structure, high sensitivity and low equivalent noise temperature. The debugging and optimization are relatively simple while also ensuring economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 FIG. 4 is a schematic diagram of an application of an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work should fall within the scope of protection of the present invention.

[0026] A balanced sideband separation radio frequency receiving device, such as Figure 1 As shown, the device includes a first RF 90-degree coupler 1, a power divider 2, a second RF 90-degree coupler 3, a third RF 90-degree coupler 4, a mixing module 5, a first magic T6, a second magic T7, an intermediate frequency 90-degree coupler 8 and a load 9. Ideally, the image suppression ratio of the balanced sideband separation RF receiving device is ∞.

[0027] In the device, the 0-degree incident end of the first RF 90-degree coupler 1 is connected to the RF feed source, the 90-degree incident end is connected to the load 9, and the output end outputs two signals with an intensity of 1:1 and a phase difference of 90 degrees. The two output ends are respectively connected to the input ends of the second RF 90-degree coupler 3 and the third RF 90-degree coupler 4.

[0028] The incident end of the power divider 2 is connected to the local oscillator signal source, and the output end outputs two signals with 1:1 strength and the same phase. The two output ends are respectively connected to the input ends of the second RF 90 degree coupler 3 and the third RF 90 degree coupler 4.

[0029] The first RF 90-degree coupler 1 and the power divider 2 are both connected to the device using a Y-type structure.

[0030] When the output ends of the first RF 90-degree coupler 1 and the power divider 2 are connected to the second RF 90-degree coupler 3 and the third RF 90-degree coupler 4 respectively, they are also connected using a Y-type structure.

[0031] The four output ends of the second RF 90-degree coupler 3 and the third RF 90-degree coupler 4 are connected in pairs to the input ends of the first magic T6 and the second magic T7 through the mixing module 5 .

[0032] The mixing module 5 includes a first mixer 51, a second mixer 52, a third mixer 53 and a fourth mixer 54. The four mixers are biased independently and output sum frequencies and difference frequencies.

[0033] The incident ends of the first mixer 51 and the second mixer 52 are connected to the two output ends of the second RF 90-degree coupler 3 respectively, and the output ends of the first mixer 51 and the second mixer 52 are connected to the incident end of the first magic T6.

[0034] The incident ends of the third mixer 53 and the fourth mixer 54 are connected to the two output ends of the third RF 90-degree coupler 4 respectively, and the output ends of the third mixer 53 and the fourth mixer 54 are connected to the incident end of the second magic T7.

[0035] The output ends of the two magic Ts are connected to the intermediate frequency 90-degree coupler 8. Among the two output ends of the intermediate frequency 90-degree coupler 8, the 0-degree output end outputs an upper sideband signal, and the 90-degree output end outputs a lower sideband signal.

[0036] In another embodiment, the receiving device is further connected to a digital signal display, and the display screen of the digital signal display outputs a sideband analog signal graph.

[0037] Next, the actual application of the balanced sideband separation radio frequency receiving device in this embodiment is described by taking examples.

[0038] like Figure 2 As shown, quadrature hybrid is an orthogonal mixer, the first RF 90 degree coupler 1, the second RF 90 degree coupler 3, the third RF 90 degree coupler 4 and the intermediate frequency 90 degree coupler 8 are all orthogonal mixers, In-phase powerdivider is an in-phase power divider, that is, power divider 2, Mixer bias+ is each mixer in the mixing module 5, the external Load simulates the mixing process of the magic T, represents the first magic T6 and the second magic T7, and 4K load is the load 9.

[0039] Although the power divider 2 and the first RF 90-degree coupler 1 are both connected to the device using a Y-type structure to separate the input signal, this will cause a phase difference of π. Therefore, in order to solve this problem, the wires in the figure also use a Y-type structure at the junction of CE and the junction of DF, which will also produce a reverse phase difference of π. That is, when the output ends of the first RF 90-degree coupler 1 and the power divider 2 are respectively connected to the second RF 90-degree coupler 3 and the third RF 90-degree coupler 4, they are also connected using a Y-type structure to produce a phase difference of π. The π phase difference caused by the two times just cancels out, so the phase difference can be ignored in the calculation.

[0040] In an ideal situation, an RF signal is input to the 90-degree incident end point A of the first RF 90-degree coupler 1, and an LO signal is input to the input end point B of the power divider 2;

[0041] The input signal size is as follows:

[0042] A-RF:

[0043] B-LO:

[0044] After being processed by the first RF 90-degree coupler 1, signal C and signal D are output respectively;

[0045] The magnitudes of signal C and signal D are as follows:

[0046] C:

[0047] D:

[0048] After the B-LO signal is processed by the power divider 2, the signal E and the signal F are output respectively;

[0049] The magnitudes of signal E and signal F are as follows:

[0050] E:

[0051] F:

[0052] First, the upper half is analyzed. Signal C and signal E are input into the second RF 90-degree coupler 3. After being processed by the second RF 90-degree coupler 3, signal G and signal H are obtained.

[0053] The magnitudes of signal G and signal H are as follows:

[0054] G:

[0055] H:

[0056] The signal G is then input to the first mixer 51 and processed to obtain the signal K, while the signal H is input to the second mixer 52 and processed to obtain the signal L;

[0057] The signal size of signal K is as follows:

[0058] K:

[0059]

[0060] Among them, after signal G is processed, an IF signal, that is, a difference frequency signal, will be obtained. The specific size is the second half of the above expression of the size of signal K. IF stands for intermediate frequency, which represents the intermediate frequency. Depending on the difference of ω, the IF signal will be different. Here, the sum frequency signal is not considered, and only the difference frequency signal is analyzed. The analysis is as follows:

[0061]

[0062] Similarly, according to the analysis steps of signal K, the analysis results of the difference frequency signal of signal L can be obtained as follows:

[0063] L:

[0064]

[0065] Next, the KL signals are combined and mixed with the external Load in a magic-T-like manner to obtain signal O.

[0066] When RF >ω LO , that is, when the input signal is the upper sideband:

[0067] The sum signal output by the magic T is:

[0068]

[0069] The difference signal output by the magic T is:

[0070]

[0071] When RF <ω LO , that is, when the input signal is the lower sideband:

[0072] The sum signal output by the magic T is:

[0073]

[0074] The difference signal output by the magic T is:

[0075]

[0076]

[0077] Next, the lower half is analyzed. Signal D and signal F are input into the third RF 90-degree coupler 4. After being processed by the third RF 90-degree coupler 4, signal I and signal J are obtained.

[0078] The magnitudes of signal I and signal J are as follows:

[0079] I:

[0080] J:

[0081] The signal I is then input to the third mixer 53 and processed to obtain the signal M, while the signal H is input to the fourth mixer 54 and processed to obtain the signal N;

[0082] After processing, signal M will also get an IF signal, that is, a difference frequency signal. Here, the sum frequency signal is not considered, and only the difference frequency signal is analyzed. However, it can be found that the upper and lower sidebands of the difference frequency signal of signal M are the same, and the size is as follows:

[0083] M:

[0084] Similarly, the upper and lower sidebands of the signal N difference frequency signal are also the same, and the sizes are as follows:

[0085] N:

[0086] Next, the MN signals are combined and mixed with the external Load in a magic-T-like manner to obtain signal P.

[0087] When RF >ω LO , that is, when the input signal is the upper sideband:

[0088] The sum signal output by the magic T is:

[0089]

[0090] The difference signal output by the magic T is:

[0091]

[0092] When RF <ω LO , that is, when the input signal is the lower sideband:

[0093] The sum signal output by the magic T is:

[0094]

[0095] The difference signal output by the magic T is:

[0096]

[0097] Finally, the signal O and the signal P are input into the intermediate frequency 90 degree coupler 8 to obtain the following signal:

[0098] When RF >ω LO , that is, when the input signal is the upper sideband:

[0099] The upper port output of the intermediate frequency 90 degree coupler 8:

[0100] The lower port output of the intermediate frequency 90 degree coupler 8 is: 0.

[0101] That is, the upper sideband signal is emitted from the upper port, and the emitted signal strength is Phase delay 90°.

[0102] When RF <ω LO , that is, when the input signal is the lower sideband:

[0103] Upper port output of IF 90 degree coupler 8: 0

[0104] The lower port output of the intermediate frequency 90 degree coupler 8:

[0105] That is, the lower sideband signal is emitted from the lower port, and the emitted signal strength is The phase sign changes and leads by 180°.

[0106] If the input signal input ports are swapped, the device can still maintain that the upper port outputs the upper sideband signal and the lower port outputs the lower sideband signal.

[0107] By using this device, the input RF signal and the local oscillator signal can be separated with only a simple structure, and the upper sideband signal is always output at the upper port of the intermediate frequency 90-degree coupler 8, and the lower sideband signal is always output at the lower port of the intermediate frequency 90-degree coupler 8, and the separated signals are observed.

[0108] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A balanced sideband separation radio frequency receiving device, comprising a first radio frequency 90 degree coupler (1), a power divider (2), a second radio frequency 90 degree coupler (3), a third radio frequency 90 degree coupler (4), a mixing module (5), a first magic T (6), a second magic T (7), an intermediate frequency 90 degree coupler (8) and a load (9), characterized in that: The incident end of the first radio frequency 90 degree coupler (1) is connected to a radio frequency feed source and a load (9), the incident end of the power divider (2) is connected to a local oscillator signal source, the output ends of the first radio frequency 90 degree coupler (1) and the power divider (2) are respectively connected to the input ends of the second radio frequency 90 degree coupler (3) and the third radio frequency 90 degree coupler (4), the four output ends of the second radio frequency 90 degree coupler (3) and the third radio frequency 90 degree coupler (4) are connected in pairs to the input ends of the first magic T (6) and the second magic T (7) through a mixing module (5), the output ends of the two magic Ts are connected to an intermediate frequency 90 degree coupler (8), and the output end of the intermediate frequency 90 degree coupler (8) includes a 0 degree output end for outputting an upper sideband signal and a 90 degree output end for outputting a lower sideband signal.

2. A balanced sideband separation radio frequency receiving device according to claim 1, characterized in that: The mixing module (5) comprises a first mixer (51), a second mixer (52), a third mixer (53) and a fourth mixer (54); The incident ends of the first mixer (51) and the second mixer (52) are respectively connected to the two output ends of the second radio frequency 90-degree coupler (3), and the output ends of the first mixer (51) and the second mixer (52) are connected to the incident end of the first magic T (6); The incident ends of the third mixer (53) and the fourth mixer (54) are respectively connected to the two output ends of the third radio frequency 90-degree coupler (4), and the output ends of the third mixer (53) and the fourth mixer (54) are connected to the incident end of the second magic T (7).

3. A balanced sideband separation radio frequency receiving device according to claim 1, characterized in that: The first radio frequency 90 degree coupler (1) comprises two output ends for outputting signals with the same intensity and a phase difference of 90 degrees, and the output ends are respectively connected to the input ends of the second radio frequency 90 degree coupler (3) and the third radio frequency 90 degree coupler (4).

4. A balanced sideband separation radio frequency receiving device according to claim 3, characterized in that: The output end of the first radio frequency 90-degree coupler (1) is connected to the second radio frequency 90-degree coupler (3) and the third radio frequency 90-degree coupler (4) in a Y-type connection.

5. The balanced sideband separation radio frequency receiving device according to claim 1, characterized in that: The power divider (2) comprises two output ends for outputting signals with the same intensity and phase, and the output ends are respectively connected to the input ends of the second radio frequency 90 degree coupler (3) and the third radio frequency 90 degree coupler (4).

6. A balanced sideband separation radio frequency receiving device according to claim 5, characterized in that: The connection mode between the output end of the power divider (2) and the second radio frequency 90-degree coupler (3) and the third radio frequency 90-degree coupler (4) is a Y-type connection.

7. The balanced sideband separation radio frequency receiving device according to claim 1, characterized in that: The first radio frequency 90-degree coupler (1) comprises a 0-degree incident end and a 90-degree incident end, the 0-degree incident end is connected to a radio frequency feed source, and the 90-degree incident end is connected to a load (9).

8. The balanced sideband separation radio frequency receiving device according to claim 1, characterized in that: The load (9) is a resistor.

9. The balanced sideband separation radio frequency receiving device according to claim 1, characterized in that: The receiving device is also connected to a digital signal display.

10. A balanced sideband separation radio frequency receiving device according to claim 9, characterized in that: The digital signal display includes a display screen that outputs a sideband analog signal graph.

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