Radio frequency signal stable-phase transmission method

Abstract

The invention discloses a radio-frequency signal stable-phase transmission method, which comprises the following steps: S1, after a signal to be transmitted is transmitted into a power divider, one path of signal enters a phase adjustment unit to obtain a signal, and the other path of signal enters a digital phase comparison unit and is subjected to phase comparison with a signal before transmission; s2, the signal is divided into two paths of signals after being transmitted into a power divider, one path of signal is transmitted to a receiving end through a signal transmission link, and the other path of signal is returned to a transmitting end through an original optical fiber link; s3, inputting the signal returned to the transmitting end into a digital phase comparison unit for phase comparison with the signal to obtain phase fluctuations introduced by the signal through an optical fiber link twice; and S4, calculating the phase delay of the optical fiber link according to the digital phase comparison unit, assigning the phase adjustment quantity by the phase adjustment unit, and carrying out phase offset. Through back-and-forth detection of the noise of the optical fiber link and phase compensation before the signal passes through the optical fiber link, phase delay introduced in the subsequent transmission process is offset, and stable signal transmission is realized.

Description

Technical Field

[0001] This invention relates to the field of radio frequency signal transmission technology, and in particular to a method for stable phase transmission of radio frequency signals. Background Technology

[0002] In practical applications, it is often necessary to transmit radio frequency signals over long distances. However, during long-distance output, the phase of the radio frequency signal often changes due to variations in transmission delay, which affects the phase noise and stability of the signal and reduces the signal quality. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for stable phase transmission of radio frequency signals.

[0004] The objective of this invention is achieved through the following technical solution: a method for stable phase transmission of radio frequency signals, comprising the following steps:

[0005] S1: The signal to be transmitted After being fed into the power divider, one path enters the phase adjustment unit to obtain the signal. Another path enters the digital phase comparison unit and is compared with the signal before transmission. Perform phase comparison;

[0006] S2: Signal After being fed into the power divider, the signal is split into two paths. One path is transmitted to the receiver via the signal transmission link, and the other path is returned to the transmitter via the original fiber optic link.

[0007] S3: Signal returned to the transmitter Input to digital phase comparison unit and signal Phase comparison is performed to obtain the phase fluctuations introduced by the signal twice as it passes through the fiber optic link. ;

[0008] S4: The phase delay of the optical fiber link is calculated based on the digital phase comparison unit, and the microprocessor controls the phase adjustment unit to adjust the phase amount. Perform the assignment and phase cancellation.

[0009] Preferably, in step S1, the signal to be transmitted The expression is:

[0010] ;

[0011] in, The signal amplitude, For signal frequency, The phase of the signal to be transmitted;

[0012] Signal The expression is:

[0013] ;

[0014] in, The variable phase introduced for the phase adjustment unit.

[0015] Preferably, in step S1, the signal entering the digital phase comparison unit is digitally mixed with the signal before transmission. Perform a phase comparison.

[0016] Preferably, step S2 further includes the following step:

[0017] S21: The laser carrier is modulated by internal or external modulation, and the modulated signal enters the optical fiber link through the optical fiber circulator and is transmitted from the transmitter to the receiver.

[0018] S22: The fiber optic circulator at the receiving end splits the optical signal into two paths. One optical signal is demodulated by a photodetector to obtain the receiving signal. ,

[0019] ;

[0020] in, For signal The phase delay of the optical fiber link introduced during a single transmission from the transmitter to the receiver;

[0021] The other optical signal returns to the original fiber optic link through the fiber optic circulator and then returns to the transmitter along the original fiber optic link. The optical signal returning to the transmitter is demodulated by a photodetector to obtain a signal containing two phase delays of the fiber optic link. ,

[0022] .

[0023] Preferably, in step S3, two radio frequency signals are acquired by a high-speed analog-to-digital converter, and the phase fluctuations introduced by the signals through the fiber optic link twice are obtained by digital mixing. ,

[0024] .

[0025] Preferably, in step S4, the phase adjustment amount The value assigned is:

[0026] ;

[0027] At this time, the radio frequency signal demodulated by the receiving end In The phases will cancel each other out. It becomes:

[0028] .

[0029] The present invention has the following advantages: The present invention achieves stable signal transmission by performing round-trip detection of fiber optic link noise and performing phase compensation before the signal passes through the fiber optic link to cancel the phase delay introduced in the subsequent transmission process. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the process for a stable phase transmission method for radio frequency signals. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this embodiment, as Figure 1 As shown, a method for stable phase transmission of radio frequency signals includes the following steps:

[0038] S1: The signal to be transmitted After being fed into the power divider, one path enters the phase adjustment unit to obtain the signal. Another path enters the digital phase comparison unit and is compared with the signal before transmission. Phase comparison is performed; preferably, the signal entering the digital phase comparison unit is digitally or analogly mixed with the signal before transmission. For phase comparison, this embodiment selects digital mixing.

[0039] S2: Signal After being fed into the power divider, the signal is split into two paths. One path is transmitted to the receiver via the signal transmission link, and the other path is returned to the transmitter via the original fiber optic link.

[0040] S3: Signal returned to the transmitter Input to digital phase comparison unit and signal Phase comparison is performed to obtain the phase fluctuations introduced by the signal twice as it passes through the fiber optic link. ;

[0041] S4: The phase delay of the optical fiber link is calculated based on the digital phase comparison unit, and the microprocessor controls the phase adjustment unit to adjust the phase amount. Phase cancellation is performed. By probing the fiber optic link noise round trip and performing phase compensation before the signal passes through the fiber optic link to cancel the phase delay introduced during subsequent transmission, stable signal transmission is achieved.

[0042] Furthermore, in step S1, the signal to be transmitted The expression is:

[0043] ;

[0044] in, The signal amplitude, For signal frequency, The phase of the signal to be transmitted;

[0045] Signal The expression is:

[0046] ;

[0047] in, A variable phase is introduced for the phase adjustment unit. Specifically, it should be noted that this invention mainly considers the perturbation of the signal phase; therefore, the signal amplitude is ignored in subsequent processes. Considering only the frequency and phase components of the signal, the phase adjustment unit can be a phase shifter or an existing device such as a frequency synthesizer based on a phase-locked loop structure.

[0048] Furthermore, step S2 also includes the following steps:

[0049] S21: The laser carrier is modulated by internal or external modulation, and the modulated signal enters the optical fiber link through the optical fiber circulator and is transmitted from the transmitter to the receiver.

[0050] S22: The fiber optic circulator at the receiving end splits the optical signal into two paths. One optical signal is demodulated by a photodetector to obtain the receiving signal. ,

[0051] ;

[0052] in, For signal The phase delay of the optical fiber link introduced during a single transmission from the transmitter to the receiver;

[0053] The other optical signal returns to the original fiber optic link through the fiber optic circulator and then returns to the transmitter along the original fiber optic link. The optical signal returning to the transmitter is demodulated by a photodetector to obtain a signal containing two phase delays of the fiber optic link. ,

[0054] .

[0055] Specifically, during the process of the optical signal returning from the receiver to the transmitter, the delay of the optical fiber link is added to the optical signal again. Therefore, it is related to the signal transmitted from the transmitter before transmission. In comparison, signal Phase delays were introduced in two fiber optic links.

[0056] In this embodiment, in step S3, two radio frequency signals are acquired by a high-speed analog-to-digital converter, and the phase fluctuations introduced by the signals through the fiber optic link twice are obtained by digital mixing. ,

[0057] .

[0058] The fiber optic link phase delay calculated by the digital phase comparison unit is then controlled by a microprocessor-controlled phase adjustment unit, which adjusts the phase by an amount that would otherwise be used to adjust the fiber optic link phase delay. The value assigned is:

[0059] ;

[0060] At this time, the radio frequency signal demodulated by the receiving end In The phases will cancel each other out. It becomes:

[0061] .

[0062] The signal demodulated at this time The signal to be transmitted at the transmitting end The frequency and phase are exactly the same, and no phase delay is introduced during signal transmission in the fiber optic link. In other words, this invention achieves stable signal transmission by detecting link noise round trip and performing phase correction before the signal passes through the optical fiber link, thereby compensating for the link delay introduced during subsequent transmission.

[0063] In real systems, phase adjustment units often have phase control errors (such as phase shifters or phase microsteps), affecting the accuracy of link phase compensation. Therefore, this compensation system can also adjust the signal after passing through the phase control unit. With the signal to be transmitted By measuring the phase difference, the actual phase offset introduced by the phase adjustment unit can be accurately obtained. Then, through closed-loop control, the signal phase control offset is constantly maintained. This eliminates the error introduced by the phase control unit and ensures the phase stability of the receiver signal.

[0064] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for stable phase transmission of radio frequency signals, characterized in that: Includes the following steps: S1: The signal to be transmitted After being fed into the power divider, one path enters the phase adjustment unit to obtain the signal. Another path enters the digital phase comparison unit and is compared with the signal before transmission. Perform phase comparison; S2: Signal After being fed into the power divider, the signal is split into two paths. One path is transmitted to the receiver via the signal transmission link, and the other path is returned to the transmitter via the original fiber optic link. S3: Signal returned to the transmitter Input to digital phase comparison unit and signal Phase comparison is performed to obtain the phase fluctuations introduced by the signal twice as it passes through the fiber optic link. ; S4: The phase delay of the optical fiber link is calculated based on the digital phase comparison unit, and the microprocessor controls the phase adjustment unit to adjust the phase amount. Perform the assignment and phase cancellation.

2. The method for stable phase transmission of radio frequency signals according to claim 1, characterized in that: In step S1, the signal to be transmitted The expression is: ； in, The signal amplitude, For signal frequency, The phase of the signal to be transmitted; Signal The expression is: ； in, The variable phase introduced for the phase adjustment unit.

3. The method for stable phase transmission of radio frequency signals according to claim 2, characterized in that: In step S1, the signal entering the digital phase comparison unit is digitally mixed with the signal before transmission. Perform a phase comparison.

4. The method for stable phase transmission of radio frequency signals according to claim 3, characterized in that: Step S2 further includes the following steps: S21: The laser carrier is modulated by internal or external modulation, and the modulated signal enters the optical fiber link through the optical fiber circulator and is transmitted from the transmitter to the receiver. S22: The fiber optic circulator at the receiving end splits the optical signal into two paths. One optical signal is demodulated by a photodetector to obtain the receiving signal. , ； in, For signal The phase delay of the optical fiber link introduced during a single transmission from the transmitter to the receiver; The other optical signal returns to the original fiber optic link through the fiber optic looper, and then returns to the transmitter along the original fiber optic link. The optical signal returning to the transmitter is demodulated by a photodetector to obtain a signal containing two phase delays of the fiber optic link. , 。 5. The method for stable phase transmission of radio frequency signals according to claim 4, characterized in that: In step S3, two radio frequency signals are acquired by a high-speed analog-to-digital converter, and the phase fluctuations introduced by the signals through the fiber optic link twice are obtained by digital mixing. , 。 6. The method for stable phase transmission of radio frequency signals according to claim 5, characterized in that: In step S4, the phase adjustment amount The value assigned is: ； At this time, the radio frequency signal demodulated by the receiving end In The phases will cancel each other out. It becomes: 。

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