Anti-interference method and system for broadband P-band receiving link

Abstract

The invention discloses an anti-interference method and system for a broadband P-band receiving link, and the method comprises the steps: a variable broadband anti-interference filter adjusts a received working frequency band according to a needed frequency, filters out other signals except the corresponding working frequency band, obtains a primary filtering signal, and transmits the primary filtering signal to a second receiving circuit; the signal is sent to the narrowband anti-interference filter bank through the second receiving circuit; and the narrowband anti-interference filter bank filters other signals outside the specified narrowband region to obtain a target signal and sends the target signal to the third receiving circuit. By using the variable broadband anti-interference filter, the working frequency band can be increased, the influence of an interference signal on a post-stage circuit is reduced, and the anti-interference capability is enhanced. In the inter-pulse frequency hopping process, a narrow-band anti-interference filter bank is used for enhancing the anti-interference capability and reducing the influence of an interference signal on a post-stage circuit. By using devices such as a high-linearity amplifier and a high-linearity mixer, the range of a target signal in a linear region is expanded, and nonlinear distortion is reduced.

Description

Technical Field

[0001] The present application belongs to the field of airborne radio frequency, and in particular, relates to an anti-interference method and system for a broadband P-band receiving link. Background Art

[0002] When the P-band RF receiving link is in the receiving state, due to the low signal operating frequency and relatively wide bandwidth, civil communications and various clutters have a greater interference on the P-band signal. In order to reduce the interference of civil communications and various clutters on the P-band receiving link, it is of great significance and engineering value to study the anti-interference method of the broadband P-band receiving link.

[0003] Conventional P-band RF receiving link anti-interference design first amplifies the received signal power and then suppresses out-of-band spurious signals through a switch filter group. This design method has the following disadvantages: First, the bandwidth is relatively narrow. Due to space size and cost factors, it is not possible to place enough switch filter groups that can cover a large bandwidth, resulting in insufficient system anti-interference bandwidth. Second, given the previous chip process level, the chip selection of existing products did not pay attention to the nonlinear characteristics of devices such as amplifiers and mixers, resulting in serious deterioration of intermodulation spurious signals in complex electromagnetic environments, which can easily cause significant distortion or distortion.

[0004] Therefore, how to improve the anti-interference capability of the broadband P-band receiving link is a problem that needs to be solved. Summary of the invention

[0005] The purpose of this application is to provide an anti-interference method and system for a broadband P-band receiving link to solve the problem that the chip selection of existing chips and existing products does not pay attention to the nonlinear characteristics of devices such as amplifiers and mixers, which can easily cause significant distortion or distortion.

[0006] The technical solution of the present application is: an anti-interference method for a broadband P-band receiving link, comprising: a first receiving circuit receives an antenna signal on an antenna, and sends it to an LNA after limiting and switching filtering;

[0007] The LNA amplifies the signal power of the antenna transmission signal in the linear region, forms an amplified signal and sends it to the variable broadband anti-interference filter;

[0008] The variable broadband anti-interference filter adjusts the received working frequency band according to the required frequency, filters out other signals outside the corresponding working frequency band, obtains a primary filtered signal, sends it to the second receiving circuit, and sends it to the narrowband anti-interference filter group through the second receiving circuit;

[0009] The narrowband anti-interference filter group filters out other signals outside the specified narrowband area, obtains the target signal and sends it to the third receiving circuit.

[0010] Preferably, two groups of LNAs are arranged in series, the two groups of LNAs have the same amplification factor and the same working frequency band, and an automatic switch is arranged in parallel on the LNA located at the rear; the signal after passing through the LNA is a primary amplified signal.

[0011] Preferably, a data processing module is arranged in parallel between the two groups of LNAs, and the data processing module can receive the data of the primary amplified signal and determine whether the power of the primary amplified signal meets the requirements of the target signal. If not, the automatic switch is controlled to be turned on, and the primary amplified signal is amplified twice through the rear LNA.

[0012] Preferably, a blocking switch and a digitally controlled attenuator are provided in the second receiving circuit; the blocking switch is opened after receiving a blocking instruction issued by the RF module system; and the digitally controlled attenuator adjusts the attenuation amount after receiving a digitally controlled instruction issued by the RF module system.

[0013] Preferably, the operating frequency band of the variable wideband anti-interference filter is larger than the operating frequency band of the narrowband anti-interference filter.

[0014] As a specific implementation, an anti-interference system for a broadband P-band receiving link includes an antenna, a first receiving circuit, an LNA, a variable broadband anti-interference filter, a second receiving circuit, a narrowband anti-interference filter group and a third receiving circuit; the antenna, the first receiving circuit, the LNA, the variable broadband anti-interference filter, the second receiving circuit, the narrowband anti-interference filter group and the third receiving circuit are connected in series in sequence.

[0015] Preferably, the first receiving circuit comprises a transceiver switch, a limiter and a switch filter group; the transceiver switch, the limiter and the switch filter group are connected in series with each other, and the transceiver switch can receive antenna signals.

[0016] Preferably, the second receiving circuit comprises a blocking switch and a digitally controlled attenuator arranged in series; the blocking switch is capable of receiving a primary filtered signal.

[0017] The anti-interference method and system for broadband P-band receiving link of the present application have the following advantages:

[0018] 1. Generally speaking, civil communications and various clutters have a greater impact on P-band signals, and the available signal frequency band is narrow. By using a variable broadband anti-interference filter, the working frequency band can be increased. By switching the corresponding working frequency band through the control signal, the impact of the interference signal on the subsequent circuit is reduced, and the anti-interference ability is enhanced.

[0019] 2. By using a narrowband anti-interference filter group, for certain specific and complex frequencies, the interference signal can be suppressed specifically and the anti-interference ability can be enhanced. It can also be reflected in the process of pulse frequency hopping, using a narrowband anti-interference filter group to enhance the anti-interference ability and reduce the impact of interference signals on the subsequent circuits.

[0020] 3. By using high-linearity amplifiers and high-linearity mixers and other devices, the linear region of the target signal is expanded, nonlinear distortion is reduced, and the anti-interference capability of the RF receiving link is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0022] Figure 1 This is a schematic diagram of the overall process of this application;

[0023] Figure 2 Design a flow chart for this application details. DETAILED DESCRIPTION

[0024] 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 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 creative work are within the scope of protection of the present invention.

[0025] An anti-interference system for broadband P-band receiving links, the operating frequency band is suitable for VHF, UHF, and L-band. Figure 1 As shown, it includes an antenna, a first receiving circuit, an LNA, a variable broadband anti-interference filter, a second receiving circuit, a narrowband anti-interference filter group and a third receiving circuit; the antenna, the first receiving circuit, the LNA, the variable broadband anti-interference filter, the second receiving circuit, the narrowband anti-interference filter group and the third receiving circuit are connected in series in sequence.

[0026] Combination Figure 2 The first receiving circuit includes a transceiver switch, a limiter and a switch filter group; the transceiver switch, the limiter and the switch filter group are connected in series with each other, and the transceiver switch can receive antenna signals.

[0027] The second receiving circuit includes a blocking switch and a digitally controlled attenuator arranged in series; the blocking switch can receive a primary filtered signal.

[0028] By respectively setting the first receiving circuit, the second receiving circuit and the third receiving circuit to perform triple signal board adjustment, the entire working frequency band can be stably covered and out-of-band spurious can be suppressed.

[0029] As a specific implementation, an anti-interference method for a broadband P-band receiving link is also included, using the above system, including the following steps:

[0030] Step S100, the first receiving circuit receives the antenna signal on the antenna, and sends it to the LNA after limiting and switching filtering;

[0031] Preferably, two groups of LNA are connected in series, and the two groups of LNA have the same amplification factor and the same working frequency band, and an automatic switch is set in parallel on the LNA located at the rear; the signal after passing through the LNA is a primary amplified signal. The function of the two groups of LNA is to perform secondary amplification through the series-connected LNA when the amplification factor of one group of LNA cannot meet the requirements; when the amplification factor of one group of LNA meets the requirements, the switch is manually turned on to skip the second group of LNA (low noise amplifier); the automatic switch is turned on when the RF module system does not need to receive signals;

[0032] Specifically, a data processing module is arranged in parallel between the two groups of LNAs. The data processing module can receive the data of the primary amplified signal and determine whether the power of the primary amplified signal meets the requirements of the target signal. If not, the automatic switch is controlled to be turned on, and the primary amplified signal is amplified twice through the rear LNA to ensure the power stability of the amplified signal.

[0033] Step S200, the LNA amplifies the signal power of the antenna transmission signal in the linear region to form an amplified signal and sends it to the variable broadband anti-interference filter; the signal works in the linear region to reduce the influence of nonlinear distortion.

[0034] Step S300, the variable broadband anti-interference filter adjusts the received working frequency band according to the required frequency, filters out other signals outside the corresponding working frequency band, obtains a primary filtered signal, sends it to the second receiving circuit, and sends it to the narrowband anti-interference filter group through the second receiving circuit;

[0035] Preferably, a blocking switch and a digitally controlled attenuator are provided in the second receiving circuit; the blocking switch is opened after receiving a blocking instruction from the radio frequency module system; the digitally controlled attenuator adjusts the attenuation after receiving a digital control instruction from the radio frequency module system, thereby correcting the attenuation. The digitally controlled attenuator adjusts the attenuation according to the required power gain.

[0036] The operating frequency band of the variable broadband anti-interference filter is larger than that of the narrowband anti-interference filter. It is implemented by combining multiple SAW filters. By controlling the switching to different passband frequencies, this design can further filter out the spurious signals that are not filtered out by the narrowband anti-interference filter.

[0037] The variable broadband anti-interference filter adopts voltage control or current control, and changes the internal voltage or current through the control line, so as to switch to different passband frequencies and filter the communication signal. The feature is that it can cover the entire working frequency band and suppress out-of-band spurious.

[0038] Step S400: The narrowband anti-interference filter group filters out other signals outside the designated narrowband area, obtains the target signal and sends it to the third receiving circuit.

[0039] It has the following advantages:

[0040] 1. Generally speaking, civil communications and various clutters have a greater impact on P-band signals, and the available signal frequency band is narrow. By using a variable broadband anti-interference filter 3, the operating frequency band can be increased. By switching the corresponding operating frequency band through the control signal, the impact of the interference signal on the subsequent circuit is reduced, and the anti-interference ability is enhanced.

[0041] 2. By using a narrowband anti-interference filter group, for certain specific and complex frequencies, the interference signal can be suppressed specifically and the anti-interference ability can be enhanced. It can also be reflected in the process of pulse frequency hopping, using a narrowband anti-interference filter group to enhance the anti-interference ability and reduce the impact of interference signals on the subsequent circuits.

[0042] 3. By using high-linearity amplifiers and high-linearity mixers and other devices, the linear region of the target signal is expanded, nonlinear distortion is reduced, and the anti-interference capability of the RF receiving link is enhanced.

[0043] The following is a specific example for explanation, setting the system working center frequency to 451.5MHz and the bandwidth to 453MHz. The low noise amplifier uses the low noise amplifier chip GRF2070, the narrowband anti-interference filter group uses the SAW filter chips TA1472A, TA2050A, and TA1744A from Taiwan Jiashuo, China, and the variable broadband anti-interference filter uses the adjustable filter chip JTMD2268-E5 from Shanghai Hongye Electronic Technology Co., Ltd.

[0044] The first receiving circuit transmits a signal through an antenna, and the antenna receives a communication signal and outputs it to the first receiving circuit, and the two are bidirectional. When in the receiving state, the signal passing through the first receiving circuit is output to the variable broadband anti-interference filter, and the signal power is amplified in its linear region. The LNA outputs the signal to the variable broadband anti-interference filter, switches the passband according to the system requirements, and the signal filtered by the variable broadband anti-interference filter is output to the second receiving circuit. The second receiving circuit outputs the signal to the narrowband anti-interference filter group. According to the signal operating frequency required by the system, the passband frequency of the narrowband anti-interference filter group is adjusted to suppress out-of-band spurious, and the signal is output to the third receiving circuit through the variable broadband anti-interference filter. The first receiving circuit, the second receiving circuit, and the third receiving circuit contain attenuators and bandpass filters to adjust the communication signal power and enhance the anti-interference ability of the receiving link. When the system has high requirements for certain operating frequency communication signals or the signal situation is complex, a narrowband anti-interference filter group and a variable broadband anti-interference filter combination are used to suppress the interference signal. When the system has no special requirements, only the variable broadband anti-interference filter is used to suppress the interference signal, which can meet the requirements.

[0045] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0046] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An anti-interference method for a broadband P-band receiving link, characterized in that: include: The first receiving circuit receives the antenna signal on the antenna and sends it to the LNA after limiting and switching filtering; The LNA amplifies the signal power of the antenna transmission signal in the linear region, forms an amplified signal and sends it to the variable broadband anti-interference filter; The variable broadband anti-interference filter adjusts the received working frequency band according to the required frequency, filters out other signals outside the corresponding working frequency band, obtains a primary filtered signal, sends it to the second receiving circuit, and sends it to the narrowband anti-interference filter group through the second receiving circuit; The narrowband anti-interference filter group filters out other signals outside the specified narrowband area, obtains the target signal and sends it to the third receiving circuit.

2. The anti-interference method for a broadband P-band receiving link as claimed in claim 1, characterized in that: The LNA is arranged in series with two groups, the two groups of LNA have the same amplification factor and the same working frequency band, and an automatic switch is arranged in parallel on the LNA located at the rear; the signal after passing through the LNA is a primary amplified signal.

3. The anti-interference method for a broadband P-band receiving link as claimed in claim 2, characterized in that: A data processing module is arranged in parallel between the two groups of LNAs, and the data processing module can receive the data of the primary amplified signal and determine whether the power of the primary amplified signal meets the requirements of the target signal. If not, the automatic switch is controlled to be turned on, and the primary amplified signal is amplified twice through the rear LNA.

4. The anti-interference method for a broadband P-band receiving link as claimed in claim 1, characterized in that: The second receiving circuit is provided with a blocking switch and a digitally controlled attenuator; the blocking switch is opened after receiving a blocking instruction issued by the radio frequency module system; the digitally controlled attenuator adjusts the attenuation amount after receiving a digitally controlled instruction issued by the radio frequency module system.

5. The anti-interference method for a broadband P-band receiving link as claimed in claim 1, characterized in that: The operating frequency band of the variable wideband anti-interference filter is greater than the operating frequency band of the narrowband anti-interference filter.

6. An anti-interference system for a broadband P-band receiving link, using the method according to any one of claims 1 to 5, characterized in that: The invention comprises an antenna, a first receiving circuit, an LNA, a variable broadband anti-interference filter, a second receiving circuit, a narrowband anti-interference filter group and a third receiving circuit; the antenna, the first receiving circuit, the LNA, the variable broadband anti-interference filter, the second receiving circuit, the narrowband anti-interference filter group and the third receiving circuit are connected in series in sequence.

7. The anti-interference system for a broadband P-band receiving link as claimed in claim 6, characterized in that: The first receiving circuit includes a transceiver switch, a limiter and a switch filter group; the transceiver switch, the limiter and the switch filter group are connected in series with each other, and the transceiver switch can receive antenna signals.

8. The anti-interference system for a broadband P-band receiving link as claimed in claim 6, characterized in that: The second receiving circuit includes a blocking switch and a digitally controlled attenuator arranged in series; the blocking switch is capable of receiving a primary filtered signal.

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