Dab signal processing device, dab receiving system and vehicle

Abstract

The application relates to the technical field of wireless communication, and discloses a DAB signal processing device, a DAB receiving system and a vehicle, wherein the device comprises: an input filtering module configured to perform out-of-band interference filtering processing on an initial DAB radio frequency signal to obtain a filtering preprocessed signal; a low-noise amplification module configured to perform intermodulation interference detection on the filtering preprocessed signal, perform intermodulation suppression processing on the filtering preprocessed signal according to the intermodulation interference detection result to obtain a first intermediate signal, and perform dynamic gain control on the first intermediate signal according to the amplitude-frequency characteristic of the first intermediate signal to obtain an amplified radio frequency signal; and an output filtering module configured to perform sideband shaping processing on the amplified radio frequency signal to obtain a target DAB radio frequency signal. The application not only improves the anti-saturation capability of a front-end circuit, but also effectively realizes in-band intermodulation suppression and sideband slope optimization, and significantly improves the anti-radiation interference performance of a DAB system.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a DAB signal processing device, a DAB receiving system, and a vehicle. Background Technology

[0002] Digital Audio Broadcasting (DAB) is a key component of in-vehicle infotainment systems and is widely used in automobiles to transmit information such as road conditions, weather, and news. However, in real-world applications, DAB receiving systems often operate in complex electromagnetic environments, making them susceptible to strong radiation interference. This can lead to degraded reception performance or malfunctions, severely impacting the user experience. Summary of the Invention

[0003] This application provides a DAB signal processing device, a DAB receiving system, and a vehicle, which solves the technical problem of poor anti-radiation interference performance of current DAB receiving systems. Through the synergistic effect of multi-stage cascaded signal filtering and gain processing, it not only improves the anti-saturation capability of the front-end circuit, but also effectively realizes in-band intermodulation suppression and sideband slope optimization, significantly improving the anti-radiation interference performance of the DAB system.

[0004] To achieve the above objectives, the main technical solutions adopted in this application include:

[0005] In a first aspect, embodiments of this application provide a DAB signal processing apparatus, the apparatus comprising:

[0006] An input filtering module is configured to perform out-of-band interference filtering on the received initial DAB radio frequency signal to obtain a filtered pre-processed signal.

[0007] A low-noise amplification module includes an intermodulation suppression unit and an adaptive amplification unit. The intermodulation suppression unit is configured to perform intermodulation interference detection on the filtered preprocessed signal, and to perform intermodulation suppression processing on the filtered preprocessed signal according to the intermodulation interference detection result to obtain a first intermediate signal. The adaptive amplification unit is configured to perform dynamic gain control on the first intermediate signal according to the amplitude-frequency characteristics of the first intermediate signal to obtain an amplified radio frequency signal.

[0008] An output filtering module is configured to perform sideband shaping on the amplified radio frequency signal to obtain the target DAB radio frequency signal.

[0009] The DAB signal processing device proposed in this application utilizes a multi-stage module synergy approach. It employs an input filtering module for radiated interference filtering, achieving pre-selection filtering at the device's front end. This provides high-quality signal input to the subsequent low-noise amplification module while preventing saturation in the later stages. The low-noise amplification module then implements dynamic intermodulation suppression and adaptive gain. Compared to related technologies, this application's embodiment can flexibly adjust the relevant parameters of intermodulation suppression and gain to adapt to signal processing conditions, effectively suppressing intermodulation and in-band interference, thus improving the signal-to-noise ratio during in-band interference. Finally, the output filtering module performs signal sideband shaping, optimizing the sideband slope and further reducing sideband interference, significantly enhancing the device's anti-radiated interference capability and effectively improving the performance of the DAB receiving system.

[0010] Optionally, in some embodiments of this application, the intermodulation suppression unit includes:

[0011] An intermodulation detection subunit is configured to extract a first frequency component and a second frequency component of the filtered preprocessed signal, and determine a target intermodulation frequency point based on the first frequency component and the second frequency component.

[0012] A notch filter subunit is configured to adjust the notch filter center frequency according to the target cross-modulation point, so that the amplitude of the filtered preprocessed signal is suppressed at the notch filter center frequency and then output as the first intermediate signal.

[0013] This application embodiment utilizes an intermodulation detection subunit to accurately identify intermodulation interference components and determine the target intermodulation frequency, thereby enabling the wave limiting subunit to perform targeted intermodulation suppression according to the actual signal processing conditions, significantly improving the in-band intermodulation suppression capability and optimizing the signal-to-noise ratio of the first intermediate signal.

[0014] Optionally, in some embodiments of this application, the intermodulation detection subunit determines the target intermodulation frequency point in the following manner:

[0015] Determine the first frequency of the first frequency component and the second frequency of the second frequency component;

[0016] Multiply the first frequency by two to obtain twice the first frequency, and use the absolute value of the difference between twice the first frequency and the second frequency to determine the first cross-modulation point;

[0017] Multiply the second frequency by two to obtain twice the second frequency, and use the absolute value of the difference between the twice the second frequency and the first frequency to determine the second cross-modulation point;

[0018] The first and second cross-modulation points are used as the target cross-modulation points.

[0019] Optionally, in some embodiments of this application, the adaptive amplification unit further includes:

[0020] A signal amplification subunit is configured to amplify the first intermediate signal according to a preset gain;

[0021] A detection subunit is configured to perform amplitude-frequency detection on the first intermediate signal to obtain the amplitude-frequency characteristics of the first intermediate signal;

[0022] A control subunit is configured to determine a noise signal based on the amplitude-frequency characteristics and adjust the preset gain when the noise signal meets preset conditions.

[0023] This application embodiment obtains the amplitude-frequency characteristics of the first intermediate signal through detection processing, thereby enabling the low-noise amplification module to determine the noise situation based on the amplitude-frequency characteristics and adaptively adjust the signal gain according to the noise situation. This avoids degrading the signal-to-noise ratio by amplifying with a fixed gain when the noise is too high, effectively improving the adaptability and gain flexibility of the low-noise amplification module to different noise environments, and further enhancing the anti-interference capability of the DAB signal processing device.

[0024] Optionally, in some embodiments of this application, the control subunit adjusts the preset gain in the following manner:

[0025] The preset gain is reduced when the noise signal meets the preset conditions, wherein the preset conditions are that the noise signal is within a preset passband and the amplitude of the noise signal exceeds a preset threshold.

[0026] The embodiments of this application can achieve adaptive adjustment of signal gain when the in-band noise interference intensity is large. By timely reducing the preset gain, the degree of noise amplification is effectively reduced, avoiding excessive noise interference to the signal, and significantly improving the signal processing flexibility of the low noise amplification module under noise interference conditions.

[0027] Optionally, in some embodiments of this application, the input filtering module includes a first filtering unit, a second filtering unit, and a third filtering unit cascaded in sequence;

[0028] The first filtering unit is configured to perform pre-selection filtering on the initial DAB radio frequency signal to filter out out-of-band interference of the initial DAB radio frequency signal and obtain a first filtered signal.

[0029] The second filtering unit is configured to provide interference overload protection for the first filtered signal to prevent the third filtering unit from being in a saturated state, thereby obtaining the second filtered signal.

[0030] A third filtering unit is configured to perform in-band attenuation compensation on the second filtered signal to obtain the filtered preprocessed signal; wherein the in-band attenuation compensation is caused by the first filtering unit and the second filtering unit.

[0031] This application embodiment utilizes a first filtering unit to pre-filter the initial DAB RF signal, significantly reducing radiated interference from the electromagnetic environment. A second filtering unit suppresses strong interference within the passband, providing overload protection for the subsequent third filtering unit and preventing it from saturating. The third filtering unit then compensates for the in-band attenuation caused by the first two filtering units, preventing excessive suppression of useful signals in the initial DAB RF signal, thereby ensuring the signal quality of the pre-processed filtered signal.

[0032] Optionally, in some embodiments of this application, the first filtering unit includes a passive filter, the second filtering unit includes a limiter, and the third filtering unit includes an active filter;

[0033] The passive filter has an input terminal adapted to receive the initial DAB radio frequency signal, an output terminal adapted to connect to the input terminal of the limiter, an output terminal adapted to connect to the input terminal of the active filter, and an output terminal adapted to output the filtered preprocessed signal.

[0034] The first filtering unit, as a passive filter, effectively handles high-intensity interference signals that may exist in the initial DAB RF signal due to its strong anti-saturation capability, preventing saturation caused by excessive signal strength and ensuring continuous and stable operation of the filter. The second filtering unit, as a limiter, limits the amplitude of in-band interference, thus preventing the active filter from entering a saturation state and generating nonlinear distortion. The third filtering unit, as an active filter, effectively compensates for in-band attenuation, thereby improving the signal-to-noise ratio of the channel.

[0035] Optionally, in some embodiments of this application, the output filtering module includes:

[0036] A fourth filtering unit is configured to perform band-selective filtering on the amplified radio frequency signal to obtain a second intermediate signal;

[0037] The fifth filtering unit is configured to perform shaping processing on the second intermediate signal to obtain the target DAB radio frequency signal, such that the sideband slope of the target DAB radio frequency signal is greater than a preset slope value.

[0038] This application embodiment utilizes a fourth filtering unit to perform frequency band selection on the amplified radio frequency signal, removing unnecessary frequency components. Then, the signal is shaped by a fifth filtering unit, which can effectively improve the sideband roll-off slope, making the transition band between the signal passband and stopband narrower, thereby suppressing sideband interference and further improving the anti-radiation interference capability of the DAB signal processing device.

[0039] Secondly, embodiments of this application provide a DAB receiving system, the system comprising:

[0040] DAB receiver;

[0041] And the DAB signal processing apparatus as described in the above embodiments, wherein the DAB receiver is connected to the DAB signal processing apparatus.

[0042] The DAB receiving system proposed in this application improves its anti-radiation interference capability through a DAB signal processing device. Compared with related technologies, this application embodiment can flexibly adjust the relevant parameters of intermodulation suppression and gain to adapt to signal processing conditions, thereby effectively suppressing intermodulation and in-band interference and improving the signal-to-noise ratio under in-band interference. Finally, the output filtering module is used to achieve signal sideband shaping, realizing sideband slope optimization, further reducing sideband interference, and greatly improving the device's anti-radiation interference capability, thus effectively improving the performance of the DAB receiving system.

[0043] Thirdly, embodiments of this application provide a vehicle that includes the DAB receiving system as described in the above embodiments. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of a DAB receiving system in related technologies;

[0046] Figure 2 This is a schematic diagram of the structure of a DAB signal processing device according to an embodiment of this application;

[0047] Figure 3 This is a schematic diagram of the structure of an input filtering module proposed in an embodiment of this application;

[0048] Figure 4 This is one of the structural schematic diagrams of a low-noise amplification module proposed in an embodiment of this application;

[0049] Figure 5 This is a second schematic diagram of the structure of a low-noise amplification module proposed in one embodiment of this application;

[0050] Figure 6 This is a schematic diagram of the structure of an output filtering module proposed in an embodiment of this application;

[0051] Figure 7 This is a schematic diagram of the structure of a DAB receiving system proposed in an embodiment of this application. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0053] As a third-generation broadcasting technology, DAB employs digital coding and COFDM modulation, offering significant advantages over traditional FM broadcasting, including purer sound quality, stronger resistance to multipath interference, and the ability to transmit multimedia information. This technology is widely used in automobiles and has become a key component of in-vehicle infotainment systems, capable of transmitting real-time traffic conditions, weather forecasts, and news information.

[0054] However, in real-world applications, DAB receiving systems are often in complex electromagnetic environments, making them susceptible to strong radiation interference, which can lead to decreased receiving performance or malfunctions, severely impacting the user experience.

[0055] In related technologies, such as Figure 1 As shown, in the front-end circuit design of the DAB receiver 150, an input filter 120 is typically placed between the passive antenna 110 and the low-noise amplifier (LNA) 130. The signal output from the LNA 130 is then transmitted to the DAB receiver 150 via an output filter 140. However, related technologies have insufficient out-of-band rejection capabilities. For example, the input filter 120 is a passive filter with a low sideband roll-off slope, which easily leads to DAB malfunctions during Radiated Immunity (RI) tests. Furthermore, when two high-amplitude single-tone interferences are present, due to insufficient filtering performance, the resulting third-order intermodulation components easily fall into the receiver passband, severely degrading the signal-to-noise ratio and making it impossible to properly resolve the signal.

[0056] Furthermore, LNAs in related technologies typically employ fixed gain, which causes them to amplify both interference and useful signals indiscriminately under special operating conditions such as sudden strong interference. This can easily lead to saturation of subsequent circuits or nonlinear distortion, thereby deteriorating the system's signal-to-noise ratio.

[0057] Therefore, there is an urgent need for a DAB receiver front-end filtering scheme with high resistance to radiation interference.

[0058] To address the aforementioned technical problems, this application provides an embodiment of a DAB signal processing device. The DAB signal processing device provided in this specification can be applied to DAB receiving systems, including but not limited to the filtering design of radio frequency functions in vehicle-mounted DAB radios, industrial-grade DAB data receiving terminals, etc.

[0059] This application provides a DAB signal processing device. Figure 2 This is a schematic diagram of the structure of a DAB signal processing device according to an embodiment of this application, as shown below. Figure 2 As shown, the device includes an input filtering module 210, a low-noise amplification module 220, and an output filtering module 230.

[0060] The input filtering module 210 is configured to perform out-of-band interference filtering on the received initial DAB radio frequency signal to obtain a filtered preprocessed signal.

[0061] Specifically, the input filtering module 210 performs initial frequency band selection on the broadband initial signal received by the antenna. Its main purpose is to suppress high-power interference signals outside the operating frequency band and prevent these out-of-band interferences from causing circuit saturation in subsequent amplification stages. After the radiated interference filtering process of the input filtering module 210, the out-of-band interference components in the initial DAB RF signal are significantly attenuated, thus obtaining the filtered preprocessed signal.

[0062] The low-noise amplification module 220 includes an intermodulation suppression unit 221 and an adaptive amplification unit 222. The intermodulation suppression unit 221 is configured to perform intermodulation interference detection on the filtered preprocessed signal and obtain a first intermediate signal after performing intermodulation suppression processing on the filtered preprocessed signal based on the intermodulation interference detection result.

[0063] Specifically, in a communication system, when multiple signals of different frequencies are simultaneously input to the low-noise amplifier module 220, new frequency components will be generated due to nonlinear characteristics. If these new frequency components fall within the useful signal frequency band, they will cause in-band intermodulation interference to the useful signal. In this embodiment, the intermodulation suppression unit 221 uses digital signal processing (DSP) technology to perform intermodulation detection on the frequency, amplitude, and other characteristics of the filtered preprocessed signal, thereby identifying intermodulation interference components. Then, it calculates in real time the target intermodulation frequency points that may be generated by the interaction of these intermodulation interference components.

[0064] The adaptive amplification unit 222 is configured to perform dynamic gain control on the first intermediate signal based on the amplitude-frequency characteristics of the first intermediate signal to obtain an amplified radio frequency signal.

[0065] Specifically, the adaptive amplification unit 222 is used to amplify the first intermediate signal after intermodulation suppression processing. Compared with related technologies, the embodiments of this application can adaptively adjust the amplification gain based on the amplitude-frequency characteristics of the first intermediate signal. When interference and intermodulation noise with large amplitude within the passband are detected in the first intermediate signal, which may lead to a deterioration of the signal-to-noise ratio, the adaptive amplification unit 222 will automatically reduce the gain to avoid over-amplification of these interference signals, thereby effectively suppressing in-band interference and providing input information with a higher signal-to-noise ratio for subsequent signal processing.

[0066] The output filtering module 230 is configured to perform sideband shaping on the amplified RF signal to obtain the target DAB RF signal.

[0067] Specifically, after two stages of signal processing by the input filtering module 210 and the low-noise amplification module 220, some interference components may still exist near the sidebands of the amplified RF signal. For example, weak interference near the target frequency may not be completely filtered out, resulting in insufficient sideband slope. In this embodiment, the output filtering module 230 first determines the useful signal frequency band and performs sideband shaping on the amplified RF signal. The sideband region exceeding the useful signal frequency band is rapidly attenuated, so that the waveform of the shaped target DAB RF signal can match the useful signal frequency band, thereby improving the sideband slope of the target DAB RF signal.

[0068] Therefore, the DAB signal processing device provided in this embodiment, through the coordinated action of multiple modules, utilizes the input filtering module 210 to perform radiated interference filtering, thereby achieving pre-selection filtering at the front end of the device. This provides high-quality signal input to the subsequent low-noise amplification module 220 while preventing the subsequent circuit from reaching saturation. The low-noise amplification module 220 then implements dynamic intermodulation suppression and adaptive gain. Compared with related technologies, this embodiment can flexibly adjust the relevant parameters of intermodulation suppression and gain to adapt to signal processing conditions, effectively suppressing intermodulation and in-band interference, and improving the signal-to-noise ratio during in-band interference. Finally, the output filtering module 230 performs signal sideband shaping, optimizing the sideband slope and further reducing sideband interference, greatly improving the device's anti-radiated interference capability, and thus effectively enhancing the performance of the DAB receiving system.

[0069] Figure 3 This paper shows a schematic diagram of the structure of the input filtering module 210 according to an embodiment of this application. In some embodiments of this application, such as... Figure 3 As shown, the input filtering module 210 may include a first filtering unit 211, a second filtering unit 212 and a third filtering unit 213 connected in sequence.

[0070] The first filtering unit 211 is configured to perform pre-selection filtering on the initial DAB radio frequency signal to filter out interference from the initial DAB radio frequency signal and obtain the first filtered signal.

[0071] Specifically, the first filtering unit 211 includes a passive filter, which includes, but is not limited to, an elliptic filter, an LC filter, a surface acoustic wave (SAW) filter, and a cavity resonant filter. Because passive filters have strong anti-saturation capabilities, using a passive filter as the primary pre-selection filter in the first stage of the input filtering module 210 can withstand sudden strong radiated interference that may exist in the initial DAB RF signal without easily causing performance abnormalities. This significantly attenuates strong radiated interference (such as equipment radiation, electromagnetic clutter signals, etc.) far from the target frequency band in the initial DAB RF signal, while allowing the first filtered signal within the useful signal band to pass through with low loss.

[0072] The second filtering unit 212 is configured to provide interference overload protection for the first filtered signal to prevent the third filtering unit 213 from being in a saturated state and to obtain the second filtered signal.

[0073] Specifically, the second filtering unit 212 includes a limiter, which includes, but is not limited to, a PIN limiter. The PIN limiter is a passive limiting device composed of a PIN diode. It limits the amplitude of strong interference components in the initial DAB RF signal by utilizing the impedance characteristics of the PIN diode under different power signals. Specifically, when the signal power is low, the PIN diode is in a low-impedance conducting state, allowing the signal to pass normally; when the signal power is high, the PIN diode is in a high-impedance cutoff state, attenuating the signal.

[0074] Therefore, in this embodiment, when a PIN limiter is used to quickly clamp the amplitude of the first filtered signal to a safe range and output the second filtered signal when there is a high-power radiated interference signal in the in-band, the strong interference signal is prevented from entering the third filtering unit 213 in the subsequent stage, and the third filtering unit 213 is prevented from entering a saturated state due to excessive input power, so as to ensure that the third filtering unit 213 can perform stable filtering compensation processing on the second filtered signal.

[0075] In related technologies, passive filters are typically used in the pre-stage filtering circuit. During RI testing, the interference frequency falls near the sideband, resulting in insufficient sideband attenuation capability due to significant interference noise. Compared to related technologies, this embodiment employs a high-order filter in the input filtering module 210 to improve the sideband slope and adds a limiter to suppress high-amplitude interference within the band, thereby improving its anti-radiation interference performance.

[0076] The third filtering unit 213 is configured to perform in-band attenuation compensation on the initial DAB RF signal to obtain the filtered preprocessed signal. The in-band attenuation compensation is caused by the first filtering unit 211 and the second filtering unit 212.

[0077] Specifically, the first filtering unit 211, when attenuating out-of-band interference, will inherently attenuate the useful signal within the target frequency band to a certain extent. The second filtering unit 212, during overload protection, may also cause some attenuation of the in-band signal amplitude. The third filtering unit 213 in this embodiment includes an active filter, thereby utilizing the gain characteristics of the active filter to compensate for the signal loss caused by the filtering processing of the first filtering unit 211 and the second filtering unit 212, so that the output filtered preprocessed signal meets the amplitude requirements of the subsequent low-noise amplification module for the input signal.

[0078] Furthermore, in some embodiments of this application, the input terminal of the passive filter is adapted to receive the initial DAB radio frequency signal, the output terminal of the passive filter is adapted to connect to the input terminal of the limiter, the output terminal of the limiter is adapted to connect to the input terminal of the active filter, and the output terminal of the active filter is adapted to output the filtered preprocessed signal.

[0079] Therefore, in this embodiment, the first filtering unit 211, as a passive filter, effectively addresses the high-intensity interference signals that may exist in the initial DAB RF signal due to its strong anti-saturation capability, preventing saturation caused by excessive signal strength and ensuring the filter's continuous and stable operation. The second filtering unit 212, as a limiter, limits the in-band interference amplitude, thereby preventing the active filter from entering a saturation state and generating nonlinear distortion. The third filtering unit 213, as an active filter, effectively compensates for in-band attenuation, thereby improving the channel's signal-to-noise ratio.

[0080] Figure 4 This paper shows a schematic diagram of the structure of the intermodulation suppression unit 221 according to an embodiment of this application. In some embodiments of this application, such as... Figure 4 As shown, the intermodulation suppression unit 221 may include an intermodulation detection subunit 2211 and a wave limiting subunit 2212.

[0081] The intermodulation detection subunit 2211 is configured to extract the first frequency component and the second frequency component of the filtered preprocessed signal, and determine the target intermodulation frequency point based on the first frequency component and the second frequency component.

[0082] Specifically, in this embodiment, the intermodulation detection subunit 2211 performs high-speed continuous sampling of the filtered preprocessed signal using an analog-to-digital converter (ADC) and converts it into a discrete digital signal. Subsequently, spectral analysis of the filtered preprocessed signal is performed based on the discrete digital signal to obtain each frequency component and its amplitude, thereby determining the first and second frequency components with the strongest power among multiple frequency components.

[0083] Furthermore, the intermodulation detection subunit 2211 determines the target intermodulation frequency point in the following manner:

[0084] Determine the first frequency of the first frequency component and the second frequency of the second frequency component. Multiply the first frequency by two to obtain twice the first frequency, and use the absolute value of the difference between twice the first frequency and the second frequency to determine the first cross-modulation point.

[0085] Specifically, the first frequency of the first frequency component is f1, and the second frequency of the second frequency component is f2. The first intermodulation frequency point can be obtained based on third-order intermodulation distortion (IMD3). As shown in the following formula (1):

[0086] Formula (1)

[0087] In addition, the second frequency is multiplied by two to obtain twice the second frequency, and the absolute value of the difference between twice the second frequency and the first frequency is used to determine the second cross-modulation point.

[0088] Specifically, the second cross-modulation point can be obtained based on IMD3. As shown in the following formula (2):

[0089] Formula (2)

[0090] Finally, the first intermodulation frequency point Second frequency modulation point As the aforementioned target intermodulation frequency point.

[0091] It can be seen that the target intermodulation frequency point is very close to the frequency of the useful signal. In order to avoid interference, the limiting subunit 2212 is configured to adjust the notch center frequency according to the target intermodulation frequency point, so that the amplitude of the filtered preprocessed signal is suppressed at the notch center frequency and then output as the first intermediate signal.

[0092] Specifically, in this embodiment, the limiting subunit 2212 is an LC limiter. The LC limiter is used to dynamically adjust the notch center frequency of the LC limiter based on the target intermodulation frequency point output by the intermodulation detection subunit 2211, i.e., the third-order intermodulation component frequencies 2f1-f2 and 2f2-f1 that may fall into the DAB receiving passband, so that the notch characteristics are accurately aligned with the target intermodulation frequency point. When the filtered preprocessed signal passes through the LC limiter, the LC limiter attenuates the signal at the notch center frequency, while having almost no impact on the useful signal in the target frequency band, thereby specifically suppressing the intermodulation interference component and ensuring that the intermodulation interference in the output first intermediate signal is effectively filtered out, preventing it from entering the subsequent circuits and causing a deterioration in the signal-to-noise ratio.

[0093] Therefore, in this embodiment of the application, the intermodulation detection subunit 2211 is used to accurately identify intermodulation interference components and determine the target intermodulation frequency point, thereby enabling the wave limiting subunit 2212 to perform targeted intermodulation suppression according to the actual signal processing conditions, which significantly improves the in-band intermodulation suppression capability and optimizes the signal-to-noise ratio of the first intermediate signal.

[0094] like Figure 5 As shown, the adaptive amplification unit may include a signal amplification subunit 2221, a detection subunit 2222, and a control subunit 2223.

[0095] The signal amplification subunit 2221 is configured to amplify the first intermediate signal according to a preset gain.

[0096] Specifically, in some embodiments of this application, the signal amplification subunit 2221 may include an operational amplifier and a regulator that works in conjunction with the operational amplifier to adjust its gain. The operational amplifier is capable of linearly amplifying the first intermediate signal and introduces low noise, thereby ensuring that the signal-to-noise ratio does not deteriorate significantly during amplification. The regulator is located in the negative feedback loop of the operational amplifier to adjust the amplification factor of the operational amplifier to achieve adaptive gain low-noise signal amplification.

[0097] The detector subunit 2222 is configured to perform amplitude-frequency detection on the first intermediate signal to obtain the amplitude-frequency characteristics of the first intermediate signal.

[0098] Specifically, in some embodiments of this application, the detector subunit 2222 may employ devices such as a logarithmic detector. The logarithmic detector is used to convert the amplitude characteristics of the first intermediate signal into a corresponding DC voltage signal. By analyzing the DC voltage signal, the amplitude information of the first intermediate signal at different frequency points, i.e., the amplitude-frequency characteristics, can be obtained.

[0099] The control subunit 2223 is configured to determine the noise signal based on the amplitude-frequency characteristics and adjust the preset gain when the noise signal meets preset conditions.

[0100] Furthermore, the control subunit 2223 adjusts the preset gain in the following manner:

[0101] The preset gain is reduced when the noise signal meets preset conditions, wherein the preset conditions are that the noise signal is within a preset passband and the amplitude of the noise signal exceeds a preset threshold.

[0102] Specifically, the control subunit 2223 may include devices such as a microcontroller or dedicated digital logic circuits. In some embodiments of this application, frequency signals other than the designated receiving frequency of the DAB receiver are determined to be noise signals. The control subunit 2223 determines whether the amplitude of these noise signals exceeds a preset threshold based on the spectral characteristics of the first intermediate signal, and then determines whether the frequency of these noise signals exceeding the preset threshold is within a preset passband.

[0103] If the noise signal is within the preset passband, it indicates that the noise signal may significantly interfere with subsequent signal processing, or even cause saturation of the subsequent circuitry. In this case, the control subunit 2223 sends a control signal to the signal amplification subunit 2221. The regulator in the signal amplification subunit 2221 responds to the control signal by adjusting the resistance value in the feedback loop, thereby reducing the preset gain of the operational amplifier to reduce the amplification factor of the noise signal. If the noise signal is not within the preset passband, or the amplitude of the noise signal does not exceed the preset threshold, the control subunit 2223 maintains the preset gain unchanged.

[0104] Therefore, compared with the fixed gain method used in related technologies, the embodiments of this application, through this dynamic adaptive gain adjustment, can not only ensure the effective amplification of useful signals under normal conditions, but also reduce the gain in time under strong noise interference, improve the signal-to-noise ratio under in-band interference, and thus significantly improve the in-band anti-radiation interference capability of the DAB signal processing device.

[0105] Therefore, the embodiments of this application obtain the amplitude-frequency characteristics of the first intermediate signal through detection processing, thereby enabling the low-noise amplification module to determine the noise situation based on the amplitude-frequency characteristics and adaptively adjust the signal gain according to the noise situation. This avoids degrading the signal-to-noise ratio by amplifying with a fixed gain when the noise is too high, effectively improving the adaptability and gain flexibility of the low-noise amplification module to different noise environments, and further enhancing the anti-interference capability of the DAB signal processing device.

[0106] Figure 6 This paper shows a schematic diagram of the structure of the output filtering module 230 according to an embodiment of this application. In some embodiments of this application, such as... Figure 6 As shown, the output filtering module 230 may include a fourth filtering unit 231 and a fifth filtering unit 232.

[0107] The fourth filtering unit 231 is configured to perform band-selective filtering on the amplified radio frequency signal to obtain the second intermediate signal.

[0108] Specifically, in some embodiments of this application, the fourth filtering unit 231 may employ a spiral resonator. A spiral resonator is a type of coupled resonator filter that uses a spiral resonator to replace a traditional parallel resonant circuit, and it features small size and high unloaded Q value (approximately 200-300). In this embodiment, the high Q value of the spiral resonator is used to pre-select the amplified radio frequency signal, preventing interference signals outside the preset passband from being input to the subsequent fifth filtering unit 232.

[0109] The fifth filtering unit 232 is configured to shape the second intermediate signal to obtain the target DAB RF signal, such that the sideband slope of the target DAB RF signal is greater than a preset slope value.

[0110] Specifically, in some embodiments of this application, the fifth filtering unit 232 may employ an LC Chebyshev filter, which utilizes the mathematical properties of Chebyshev polynomials to achieve extremely steep transition band attenuation characteristics while allowing small-amplitude ripple within the passband. When the second intermediate signal is input, the filter sharpens the signal at the edge of the preset passband, that is, it maintains stable transmission of useful signals within the preset passband and rapidly attenuates sideband regions beyond the preset passband, ultimately causing the sideband slope of the output target DAB RF signal to exceed a preset threshold, thereby improving the out-of-band rejection capability of the DAB signal processing device.

[0111] Therefore, in this embodiment, the fourth filtering unit 231 is used to select the frequency band of the amplified radio frequency signal to remove unnecessary frequency components, and then the fifth filtering unit 232 is used to shape the signal, which can effectively improve the sideband slope, making the transition band between the signal passband and stopband narrower, thereby suppressing sideband interference and further improving the anti-radiation interference capability of the DAB signal processing device.

[0112] Accordingly, please refer to Figure 7 This application provides a DAB receiving system, which includes a receiving antenna 10, a DAB receiver 30, and a DAB signal processing device 20 as described in the above embodiment. The input terminal of the DAB signal processing device 20 is connected to the receiving antenna 10, and the output terminal of the DAB signal processing device 20 is connected to the DAB receiver 30.

[0113] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0114] The DAB receiving system proposed in this application improves the anti-radiation interference capability of the DAB receiving system through the DAB signal processing device 20. Compared with related technologies, this application embodiment can flexibly adjust the relevant parameters of intermodulation suppression and gain to adapt to the signal processing conditions, thereby effectively suppressing intermodulation and in-band interference, which is beneficial to improving the signal-to-noise ratio under in-band interference. Finally, the output filtering module is used to achieve signal sideband shaping, realizing sideband slope optimization, further reducing sideband interference, greatly improving the anti-radiation interference capability of the device, and thus effectively improving the performance of the DAB receiving system.

[0115] Accordingly, this application provides a vehicle that includes the DAB receiving system as described in the above embodiments.

[0116] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0117] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

[0118] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0119] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0120] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the device embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0121] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

[0122] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A DAB signal processing device, characterized in that, The device includes: An input filtering module is configured to perform out-of-band interference filtering on the received initial DAB radio frequency signal to obtain a filtered pre-processed signal. A low-noise amplification module includes an intermodulation suppression unit and an adaptive amplification unit. The intermodulation suppression unit is configured to perform intermodulation interference detection on the filtered preprocessed signal, and to perform intermodulation suppression processing on the filtered preprocessed signal according to the intermodulation interference detection result to obtain a first intermediate signal. The adaptive amplification unit is configured to perform dynamic gain control on the first intermediate signal according to the amplitude-frequency characteristics of the first intermediate signal to obtain an amplified radio frequency signal. An output filtering module is configured to perform sideband shaping on the amplified radio frequency signal to obtain the target DAB radio frequency signal; The cross-modulation suppression unit includes: An intermodulation detection subunit is configured to extract a first frequency component and a second frequency component of the filtered preprocessed signal, and determine a target intermodulation frequency point based on the first frequency component and the second frequency component. A limiting subunit is configured to adjust the notch center frequency according to the target cross-modulation point, and to attenuate the signal at the notch center frequency so that the amplitude of the filtered preprocessed signal is suppressed at the notch center frequency and output as the first intermediate signal. The limiting subunit is an LC limiter.

2. The DAB signal processing apparatus according to claim 1, characterized in that, The intermodulation detection subunit determines the target intermodulation frequency point in the following manner: Determine the first frequency of the first frequency component and the second frequency of the second frequency component; Multiply the first frequency by two to obtain twice the first frequency, and use the absolute value of the difference between twice the first frequency and the second frequency to determine the first cross-modulation point; Multiply the second frequency by two to obtain twice the second frequency, and use the absolute value of the difference between the twice the second frequency and the first frequency to determine the second cross-modulation point; The first and second cross-modulation points are used as the target cross-modulation points.

3. The DAB signal processing apparatus according to claim 1, characterized in that, The adaptive amplification unit includes: A signal amplification subunit is configured to amplify the first intermediate signal according to a preset gain; A detection subunit is configured to perform amplitude-frequency detection on the first intermediate signal to obtain the amplitude-frequency characteristics of the first intermediate signal; A control subunit is configured to determine a noise signal based on the amplitude-frequency characteristics and adjust the preset gain when the noise signal meets preset conditions.

4. The DAB signal processing apparatus according to claim 3, characterized in that, The control subunit adjusts the preset gain in the following manner: The preset gain is reduced when the noise signal meets the preset conditions, wherein the preset conditions are that the noise signal is within a preset passband and the amplitude of the noise signal exceeds a preset threshold.

5. The DAB signal processing apparatus according to claim 1, characterized in that, The input filtering module includes a first filtering unit, a second filtering unit, and a third filtering unit cascaded in sequence. The first filtering unit is configured to perform pre-selection filtering on the initial DAB radio frequency signal to filter out out-of-band interference of the initial DAB radio frequency signal and obtain a first filtered signal. The second filtering unit is configured to provide interference overload protection for the first filtered signal to prevent the third filtering unit from being in a saturated state, thereby obtaining the second filtered signal. A third filtering unit is configured to perform in-band attenuation compensation on the second filtered signal to obtain the filtered preprocessed signal; wherein the in-band attenuation compensation is caused by the first filtering unit and the second filtering unit.

6. The DAB signal processing apparatus according to claim 5, characterized in that, The first filtering unit includes a passive filter, the second filtering unit includes a limiter, and the third filtering unit includes an active filter; The passive filter has an input terminal adapted to receive the initial DAB radio frequency signal, an output terminal adapted to connect to the input terminal of the limiter, an output terminal adapted to connect to the input terminal of the active filter, and an output terminal adapted to output the filtered preprocessed signal.

7. The DAB signal processing apparatus according to claim 1, characterized in that, The output filtering module includes: A fourth filtering unit is configured to perform band-selective filtering on the amplified radio frequency signal to obtain a second intermediate signal; The fifth filtering unit is configured to perform shaping processing on the second intermediate signal to obtain the target DAB radio frequency signal, such that the sideband slope of the target DAB radio frequency signal is greater than a preset slope value.

8. A DAB receiving system, characterized in that, The system includes: Receiving antenna; DAB receiver; And the DAB signal processing apparatus as described in any one of claims 1 to 7, wherein the input terminal of the DAB signal processing apparatus is connected to the receiving antenna, and the output terminal of the DAB signal processing apparatus is connected to the DAB receiver.

9. A vehicle, characterized in that, The vehicle includes the DAB receiving system as described in claim 8.

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