Receiving antenna circuit based on active sound system

Abstract

The utility model discloses a receiving antenna circuit based on an active sound system, which can perform amplification and low-noise processing on a space signal received by an antenna by introducing a low-noise amplifier U1, thereby effectively enhancing the strength of the received signal and improving the tone quality and performance of the sound system. By designing the power divider / synthesizer U3, the PORT1 port and the PORT2 port, the cascade work of the antennas is realized, so that the number of the antennas is flexibly expanded, the receiving range is expanded, and signal receiving is carried out not only by depending on a single antenna. By using the power distributor / synthesizer U3, the system can flexibly distribute or synthesize signals among different ports, and the flexibility and expandability of the system are improved. Moreover, the design of antenna cascading and a power distributor / synthesizer can be realized, so that other antennas and ports can still work normally when a certain antenna or port breaks down or signals are interrupted, the influence of a single-point fault on the whole system is reduced, and the stability and reliability of the system are greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of antennas, in particular to a receiving antenna circuit based on an active sound system. Background Art

[0002] Active audio systems refer to audio systems with built-in power amplifiers. They are widely used in various audio processing applications due to their high integration and powerful functions. However, when designing the receiving antenna circuit of an active audio system, the compatibility with the built-in power amplifier and signal matching issues must be fully considered to ensure that the system can work stably and efficiently.

[0003] Existing receiving antenna circuits have some significant problems in signal reception. First, due to reasons such as transmission distance and cable loss, the received spatial signal strength may be significantly weakened, which directly affects the sound quality and performance of the audio system. Secondly, traditional receiving antenna circuits can usually only transmit signals to a single device or system, or rely only on a single antenna for signal reception. This design limits the flexibility and scalability of the system, and also increases the risk of single-point failure in the system. Specifically, when a single antenna fails or the signal is interrupted, the entire receiving antenna circuit may stop working, causing the audio system to be unable to be used normally; this not only affects the user experience, but may also have an adverse effect on the operation of the system. In order to solve these problems, users may need to repair or replace the entire antenna circuit, which increases the cost of use and the difficulty of maintenance.

[0004] Therefore, how to redesign the receiving antenna circuit based on the active audio system to improve the strength of the received signal, enhance the flexibility and scalability of the system, and reduce the risk of single point failure is a technical problem that needs to be solved urgently in this technical field. Utility Model Content

[0005] The utility model overcomes the deficiencies of the above-mentioned technologies and provides an offline voice central control system.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A receiving antenna circuit based on an active audio system comprises: an antenna 1, a low noise amplifier U1, a power divider / synthesizer U3, a PORT1 port 3, and a PORT2 port 4. The antenna 1 is used to receive a spatial signal and output the received signal to the low noise amplifier U1 for processing. The PORT1 port and the PORT2 port are respectively connected to the power divider / power synthesizer U3. When the antenna 1 works alone, the power divider / synthesizer U3 is used as a power divider to divide the processed signal from the low noise amplifier U1 into two paths, which are respectively output to the PORT1 port 3 and the PORT2 port 4. When the antenna 1 works in cascade, the PORT2 port 4 is used as an input end to receive a signal from another cascade antenna, and the signal is synthesized into one signal with the processed signal from the low noise amplifier U1 through the power divider / synthesizer U3, and the signal is output to the PORT1 port 3.

[0008] Preferably, the low noise amplifier U1 is a low noise amplifier with a bypass function, and the antenna 1 is a UHF band passive antenna.

[0009] Preferably, it also includes: a power supply circuit 5 for supplying power to the low noise amplifier U1, and the power supply circuit 5 includes a power supply input management circuit 51, the power distributor / synthesizer U3, and a power supply output management circuit 52 connected in sequence.

[0010] Preferably, the power supply input management circuit 51 includes a DC power supply input circuit, which includes: a positive power supply input terminal T1, a first diode D1, a first capacitor C15, a second capacitor C14, and a first inductor L7. The positive electrode of the first diode D1 is connected to the positive power supply input terminal T1, and the negative electrode of the first diode D1 is respectively connected to one end of the first capacitor C15, one end of the second capacitor C14, and one end of the first inductor L7. The other end of the first capacitor C15 and the other end of the second capacitor C14 are both grounded, and the other end of the first inductor L7 is respectively connected to the PORT2 port 4 and the first end P1 of the power distributor / synthesizer U3.

[0011] Preferably, when the antenna 1 works in cascade, the PORT2 port 4 is used as a power supply input terminal, and the power supply input management circuit 51 also includes: the PORT2 port 4, the PORT2 port 4 is connected to the first end P1 of the power distributor / synthesizer U3, and the PORT2 port 4 is connected to the second end P2 of the power distributor / synthesizer U3.

[0012] Preferably, the power supply output management circuit 52 includes: a second inductor L6, a low voltage difference linear regulator U2, a third inductor L3, and a first resistor R3, one end of the second inductor L6 is connected to the third end P3 of the power distributor / synthesizer U3 through the second resistor R5-1, the other end of the second inductor L6 is connected to the Vin pin of the low voltage difference linear regulator U2, one end of the third inductor L3 is connected to the Vout pin of the low voltage difference linear regulator U2, and the other end serves as the first voltage output terminal V of the power supply output management circuit 52. 1 is connected to the low noise amplifier U1, one end of the first resistor R3 is connected to the Vout pin of the low voltage difference linear regulator U2, and the other end is used as the second voltage output terminal V2 of the power supply output management circuit 52, a third capacitor C11 and a fourth capacitor C12 are connected in parallel between the Vin pin of the low voltage difference linear regulator U2 and the ground terminal, a fifth capacitor C5 and a sixth capacitor C6 are connected in parallel between the Vout pin of the low voltage difference linear regulator U2 and the ground terminal, and a GND pin of the low voltage difference linear regulator U2 is grounded.

[0013] Preferably, the low noise amplifier U1 is connected to a mode switching circuit for controlling it to be in LNA mode or bypass mode, and the mode switching circuit includes: a switching switch 61 connected to the power supply loop 5 and capable of forming a loop when closed, the switching switch 61 is a first single-pole double-throw switch S1, the first end of the first single-pole double-throw switch S1 is connected to the mode control pin of the low noise amplifier U1, the second end is connected to an output end of the power supply loop 5, and the third end is grounded; when the first end of the first single-pole double-throw switch S1 is connected to its second end, the low noise amplifier U1 switches to the LNA mode; when the first end of the first single-pole double-throw switch S1 is connected to its third end, the low noise amplifier U1 switches to the bypass mode.

[0014] Preferably, the first single-pole double-throw switch S1 is also connected in parallel with a second single-pole double-throw switch SW1 to form a double-pole double-throw switch that can act synchronously; the first end of the second single-pole double-throw switch SW1 is connected to the second end of the first single-pole double-throw switch S1, the second end is connected to a first indicator light circuit 71 for indicating that the low-noise amplifier U1 is in the LNA mode, and the third end is connected to a second indicator light circuit 72 for indicating that the low-noise amplifier U1 is in the bypass mode, and the first indicator light circuit 71 is connected in parallel with the second indicator light circuit 72;

[0015] The first indicator light circuit 71 and the second indicator light circuit 72 are connected in parallel to form a first connection point T3. The first connection point T3 is connected to the antenna input pin through the third resistor R7. The fourth inductor L12 and the fifth inductor L13 are connected between the antenna input pin and the ground. The fourth inductor L12 and the fifth inductor L13 are connected in parallel.

[0016] Preferably, an antenna interface circuit 2 is also connected between the antenna 1, the low-noise amplifier U1 and the ground, and the antenna interface circuit 2 includes: a seventh capacitor C1, an eighth capacitor C2, a ninth capacitor C3, a sixth inductor L1, and a fourth resistor R1. One end of the seventh capacitor C1 is connected to the antenna input pin, and the other end is respectively connected to one end of the ninth capacitor C3 and one end of the sixth inductor L1 through the eighth capacitor C2. The other end of the ninth capacitor C3 is respectively connected to one end of the fourth resistor R1 and the low-noise amplifier U1. The other end of the sixth inductor L1 and the other end of the fourth resistor R1 are both grounded.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] 1. This case introduces a low-noise amplifier U1 to amplify and perform low-noise processing on the spatial signal received by antenna 1, thereby effectively enhancing the strength of the received signal and improving the sound quality and performance of the audio system. By designing the power distributor / synthesizer U3 and PORT1 port 3 and PORT2 port 4, the cascade operation of the antenna is realized, so as to flexibly expand the number of antennas and increase the receiving range, rather than just relying on a single antenna for signal reception. In addition, through the use of the power distributor / synthesizer U3, the system can flexibly distribute or synthesize signals between different ports, thereby improving the flexibility and scalability of the system. Moreover, this case can realize the design of antenna cascade and power distributor / synthesizer, so that if a certain antenna or port fails or the signal is interrupted, other antennas and ports can still work normally, reducing the impact of single-point failures on the entire system and greatly improving the stability and reliability of the system. In this way, the receiving antenna circuit of this case can improve the strength of the received signal, enhance the flexibility and scalability of the system, and reduce the risk of single-point failures. Users can enjoy better sound quality, more stable performance and more convenient use experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a circuit diagram of the first embodiment of the present invention.

[0020] Figure 2 It is a circuit schematic diagram of the power supply input management circuit of the first embodiment of the present case.

[0021] Figure 3 It is a circuit schematic diagram of the power supply output management circuit of the first embodiment of the present case.

[0022] Figure 4 It is the circuit principle diagram of the second embodiment of this case.

[0023] Figure 5 It is the circuit schematic diagram of the third embodiment of this case. DETAILED DESCRIPTION

[0024] The following examples further illustrate the features of the present invention and other related features to facilitate understanding by those skilled in the art:

[0025] Embodiment 1

[0026] like Figure 1 As shown, a receiving antenna circuit based on an active audio system includes: an antenna 1, a low noise amplifier U1, a power divider / synthesizer U3, a PORT1 port 3, and a PORT2 port 4. The antenna 1 is used to receive a spatial signal and output the received signal to the low noise amplifier U1 for processing. The PORT1 port and the PORT2 port are respectively connected to the power divider / power synthesizer U3; when the antenna 1 works alone, the power divider / synthesizer U3 is used as a power divider to divide the processed signal from the low noise amplifier U1 into two paths, which are output to the PORT1 port 3 and the PORT2 port 4 respectively; when the antenna 1 works in cascade, the PORT2 port 4 can also be the PORT1 port as an input end, receive the signal of another cascade antenna, and synthesize the signal with the processed signal from the low noise amplifier U1 through the power divider / synthesizer U3 into one signal, which is output to the PORT1 port (when the PORT1 port is used as the input end, it is output to the PORT2 port).

[0027] As mentioned above, by introducing the low-noise amplifier U1, this case can amplify and low-noise process the spatial signal received by antenna 1, thereby effectively enhancing the strength of the received signal and improving the sound quality and performance of the audio system. By designing the power distributor / synthesizer U3 and PORT1 port 3 and PORT2 port 4, the cascade operation of the antenna is realized, so as to flexibly expand the number of antennas and increase the receiving range, rather than just relying on a single antenna for signal reception. In addition, through the use of the power distributor / synthesizer U3, the system can flexibly distribute or synthesize signals between different ports, thereby improving the flexibility and scalability of the system. Moreover, this case can realize the design of antenna cascade and power distributor / synthesizer, so that when a certain antenna or port fails or the signal is interrupted, other antennas and ports can still work normally, reducing the impact of single-point failures on the entire system and greatly improving the stability and reliability of the system. In this way, the receiving antenna circuit of this case can improve the strength of the received signal, enhance the flexibility and scalability of the system, and reduce the risk of single-point failures. Users can enjoy better sound quality, more stable performance and more convenient use experience.

[0028] As a preferred embodiment, the antenna 1 adopts a UHF band passive antenna. In this way, the UHF band passive antenna does not require an external power supply, which is more convenient in the active audio system, reduces the connection of power cords and the need for power supply equipment, and reduces the complexity and cost of the system. In addition, UHF passive antennas usually have higher signal reception stability and anti-interference ability.

[0029] like Figure 1 As shown, the low noise amplifier U1 is a low noise amplifier with a bypass function. In this way, the present case adopts a low noise amplifier with a bypass function, which allows the signal to bypass the amplifier for transmission when necessary, so that the signal can pass directly, so as to increase the flexibility of the system. For example, in some cases, such as when the signal is strong enough or in order to simplify the signal path, the bypass function can ensure that the signal is directly transmitted in its original state to avoid unnecessary noise introduction or distortion. Specifically, the low noise amplifier U1 adopts a low noise amplifier with model number NJG1152KA1. The low noise amplifier U1 with model number NJG1152KA1 is used as an amplifier with a bypass function. The noise amplifier has the characteristics of high gain and low noise, so that it can effectively amplify the weak signal received by the antenna and minimize the introduction of noise, thereby improving the signal-to-noise ratio of the signal and the overall performance of the system.

[0030] like Figure 1 As shown, the receiving antenna circuit of the present case also includes: a power supply input management circuit 51 and a power supply output management circuit 52. The power supply input management circuit 51, the power distributor / synthesizer U3, and the power supply output management circuit 52 are connected in sequence to form a power supply loop 5, and the power supply loop 5 is used to power the low noise amplifier U1.

[0031] like Figure 2 As shown, as a preferred embodiment, the power supply input management circuit 51 includes a DC power supply input circuit, and the DC power supply input circuit includes: a positive power supply input terminal T1, a first diode D1, a first capacitor C15, a second capacitor C14, and a first inductor L7. The positive electrode of the first diode D1 is connected to the positive power supply input terminal T1, and the negative electrode of the first diode D1 is respectively connected to one end of the first capacitor C15, one end of the second capacitor C14, and one end of the first inductor L7. The other end of the first capacitor C15 and the other end of the second capacitor C14 are both grounded, and the other end of the first inductor L7 is respectively connected to the PORT2 port 4 and the first end P1 of the power distributor / synthesizer U3.

[0032] As described above, the receiving antenna circuit of the present case includes a power supply loop 5 for powering the low noise amplifier U1. By setting a power supply positive input terminal T1 in the DC power supply input circuit, it is convenient to receive the positive voltage from the power supply and provide energy for the entire power supply system. By setting the first diode D1, it can be used as a reverse protection diode to ensure that the current can only flow from T1 to the subsequent circuit to prevent the reverse voltage from damaging other components in the circuit. By setting the first capacitor C15 and the second capacitor C14 in parallel and the other end of the capacitor being grounded, it is convenient to form a basic filtering circuit to filter out high-frequency noise and ripple in the input power supply and provide a stable DC voltage. The first inductor L7: The inductor and the capacitor together form a low-pass filter to further filter out high-frequency noise. One end of the L7 is connected to the negative pole of D1, and the other end is connected to the PORT2 port 4 and the first end P1 of the power distributor / synthesizer U3 to provide them with a filtered stable power supply.

[0033] like Figure 1 and Figure 3 As shown, the power supply output management circuit 52 includes: a second inductor L6, a low voltage difference linear regulator U2, a third inductor L3, and a first resistor R3. One end of the second inductor L6 is connected to the third end P3 of the power distributor / synthesizer U3 through the second resistor R5-1, and the other end of the second inductor L6 is connected to the Vin pin of the low voltage difference linear regulator U2. One end of the third inductor L3 is connected to the Vout pin of the low voltage difference linear regulator U2, and the other end serves as the first voltage output end V1 of the power supply output management circuit 52. Connected to the low noise amplifier U1, one end of the first resistor R3 is connected to the Vout pin of the low voltage difference linear regulator U2, and the other end is used as the second voltage output terminal V2 of the power supply output management circuit 52, the third capacitor C11 and the fourth capacitor C12 are connected in parallel between the Vin pin of the low voltage difference linear regulator U2 and the ground terminal, the fifth capacitor C5 and the sixth capacitor C6 are connected in parallel between the Vout pin of the low voltage difference linear regulator U2 and the ground terminal, and the GND pin of the low voltage difference linear regulator U2 is grounded. In specific implementation, the low voltage difference linear regulator U2 can adopt the model ME6201A33PG low voltage difference linear regulator, which has high efficiency and low power consumption characteristics, can minimize energy loss, and improve the efficiency of power supply use. In battery-powered devices, this helps to extend battery life and reduce operating costs.

[0034] As described above, the power supply output management circuit 52 of this case is provided with a low voltage difference linear regulator U2 to facilitate accurate voltage regulation, which is beneficial to the subsequent output voltage to the low noise amplifier U1. Through the provision of the third capacitor C11, the fourth capacitor C12, the fifth capacitor C5, and the sixth capacitor C6, a filter circuit can be formed, so that the power supply output management circuit 52 can provide a more stable and reliable voltage output. The combination of the second inductor L6, the third inductor L3, the third capacitor C11, the fourth capacitor C12, the fifth capacitor C5, and the sixth capacitor C6 constitutes an effective low-pass filter circuit, which can filter out high-frequency noise and ripples in the power supply, reduce interference to the back-end equipment, and is beneficial to improving the overall performance and stability of the circuit.

[0035] like Figure 1 As shown, the low noise amplifier U1 is connected to a mode switching circuit for controlling it to be in LNA mode or bypass mode, and the mode switching circuit includes: a switch 61 connected to the power supply circuit 5 and capable of forming a loop when closed, the switch 61 is a first single-pole double-throw switch S1, the first end of the first single-pole double-throw switch S1 is connected to the mode control pin of the low noise amplifier U1, the second section is connected to an output end of the power supply circuit 5, and the third end is grounded; when the first end of the first single-pole double-throw switch S1 is connected to its second end, the low noise amplifier U1 switches to LNA mode; when the first end of the first single-pole double-throw switch S1 is connected to its third end, the low noise amplifier U1 switches to bypass mode. In specific implementation, the LNA mode can be selected in scenarios where high sensitivity and low noise signal amplification are required; and in some special cases, such as when the received signal is too strong, the LNA circuit power will be overloaded, resulting in a deterioration of the signal-to-noise ratio. At this time, the LNA amplification circuit can be disconnected by switching the switch 61, so that the signal received by the passive antenna is bypassed without amplification and directly transmitted to the output port.

[0036] As described above, the mode switching circuit design of the low noise amplifier U1 adopts a switch 61 connected to the power supply circuit 5 to realize the switching between the LNA mode and the bypass mode. The user or the system can flexibly select the working mode of the low noise amplifier U1 according to actual needs to improve the system performance and signal quality: and the first single-pole double-throw switch S1 is used as the switching switch 61, which has a relatively simple structure and is easy to implement and integrate. At the same time, by controlling the state of the switch, the switching between the LNA mode and the bypass mode can be conveniently realized, and the operation is simple and fast.

[0037] like Figure 1As shown, in a specific implementation, the first single-pole double-throw switch S1 is also connected in parallel with a second single-pole double-throw switch SW1 to form a double-pole double-throw switch that can act synchronously; the first end of the second single-pole double-throw switch SW1 is connected to the second end of the first single-pole double-throw switch S1, the second end is connected to a first indicator light circuit 71 for indicating that the low-noise amplifier U1 is in the LNA mode, and the third end is connected to a second indicator light circuit 72 for indicating that the low-noise amplifier U1 is in the bypass mode, and the first indicator light circuit 71 is connected in parallel with the second indicator light circuit 72;

[0038] The first indicator light circuit 71 and the second indicator light circuit 72 are connected in parallel to form a first connection point T3, and the first connection point T3 is connected to the antenna input pin through the third resistor R7. The fourth inductor L12 and the fifth inductor L13 are connected between the antenna input pin and the ground terminal, and the fourth inductor L12 and the fifth inductor L13 are connected in parallel. In specific implementation, when the impedance of the antenna does not match that of the subsequent circuit such as the RF receiver, signal reflection and energy loss will increase. By connecting two 1μH inductors in parallel, the impedance of the circuit can be adjusted to better match the antenna, thereby reducing signal reflection and energy loss and improving system performance.

[0039] As described above, in this case, by setting the second single-pole double-throw switch SW1 and connecting it in parallel with the first single-pole double-throw switch S1, the second single-pole double-throw switch SW1 can be synchronized with the first single-pole double-throw switch S1, and the first indicator circuit 71 and the second indicator circuit 72 can be connected together, so that when the first single-pole double-throw switch S1 is switched to the LNA mode, the green light-emitting diode of the first indicator circuit 71 can be turned on to synchronously display that it is in the LNA mode state; when the first single-pole double-throw switch S1 is switched to the bypass mode, the red light-emitting diode of the second indicator circuit 72 can be turned on to synchronously display that it is in the bypass mode state; in this way, it is helpful for users to intuitively understand the current working state, which is convenient for troubleshooting and monitoring. In addition, the first connection point T3 is connected to the antenna input pin through the third resistor R7, and combined with the parallel connection of the fourth inductor L12 and the fifth inductor L13, it can play the role of impedance matching in the circuit, which helps to reduce signal loss, improve signal quality, and enhance the anti-interference ability of the system.

[0040] like Figure 1As shown, in a specific implementation, an antenna interface circuit 2 is also connected between the antenna 1, the low-noise amplifier U1, and the ground terminal, and the antenna interface circuit 2 includes: a seventh capacitor C1, an eighth capacitor C2, a ninth capacitor C3, a sixth inductor L1, and a fourth resistor R1. One end of the seventh capacitor C1 is connected to the antenna input pin, and the other end is respectively connected to one end of the ninth capacitor C3 and one end of the sixth inductor L1 through the eighth capacitor C2. The other end of the ninth capacitor C3 is respectively connected to one end of the fourth resistor R1 and the low-noise amplifier U1. The other end of the sixth inductor L1 and the other end of the fourth resistor R1 are both grounded.

[0041] As described above, the seventh capacitor C1, the eighth capacitor C2 and the ninth capacitor C3 of the antenna interface circuit 2 of this case are configured to form a capacitor network, so as to filter out high-frequency noise and clutter in the antenna input signal, thereby improving the purity and signal-to-noise ratio of the signal. At the same time, the addition of these capacitors can also improve the impedance matching between the antenna and the low-noise amplifier, reduce signal reflection and loss, and improve the transmission efficiency of the signal. The setting of the sixth inductor L1, together with the capacitor network, forms a low-pass filter to further filter out high-frequency interference signals and ensure that the low-noise amplifier U1 receives a stable and pure radio frequency signal. This is of great significance for improving the anti-interference ability and reliability of the system. The fourth resistor R1, as a protective resistor, can limit the current passing through the low-noise amplifier U1, prevent the amplifier from being damaged due to excessive antenna input signals, and can also absorb and disperse electrostatic pulses and voltage fluctuations in the circuit to a certain extent, protecting the amplifier from the impact of instantaneous overvoltage.

[0042] Embodiment 2

[0043] like Figure 4 As shown, the difference between the second embodiment and the first embodiment is that the second embodiment is used for antenna cascade work in the receiving antenna circuit, and its PORT2 port 4 is used as the power supply input terminal for power supply, and the PORT1 port 3 is used as the signal output terminal, and the power supply input management circuit 51 also includes: the PORT2 port 4, the PORT2 port 4 is connected to the first end P1 of the power distributor / synthesizer U3, and the PORT2 port 4 is connected to the second end P2 of the power distributor / synthesizer U3. In this way, a complex DC power supply input circuit can be used without setting a complex DC power supply input circuit, and the power supply voltage can be directly input through the PORT port and directly connected to the power distributor / synthesizer, which simplifies the system design and wiring process, not only reduces the complexity and cost of the system, but also improves the reliability and maintainability of the system.

[0044] Embodiment 3

[0045] like Figure 5As shown, the difference between Example 3 and Example 2 is that, in the receiving antenna circuit for antenna cascade operation, PORT1 port 3 is used as the power supply input terminal, PORT2 port 4 is used as the signal output terminal, and the power supply input management circuit 51 also includes: the PORT1 port 3.

[0046] This case protects a receiving antenna circuit based on an active audio system. All technical solutions that are the same or similar to this case should be deemed to fall within the scope of protection of this case.

Claims

1. A receiving antenna circuit based on an active audio system, characterized in that include: An antenna (1), a low noise amplifier (U1), a power distributor / synthesizer (U3), a PORT1 port (3), and a PORT2 port (4). The antenna (1) is used to receive a spatial signal and output the received signal to the low noise amplifier (U1) for processing. The PORT1 port and the PORT2 port are respectively connected to the power distributor / synthesizer (U3). When the antenna (1) works alone, the power distributor / synthesizer (U3) is used as a power distributor to divide the processed signal from the low noise amplifier (U1) into two paths, which are respectively output to the PORT1 port (3) and the PORT2 port (4). When the antenna (1) works in cascade, the PORT2 port (4) is used as an input end to receive a signal from another cascade antenna, and the signal is synthesized into one signal with the processed signal from the low noise amplifier (U1) through the power distributor / synthesizer (U3), and the signal is output to the PORT1 port (3).

2. A receiving antenna circuit based on an active sound system according to claim 1, characterized in that The low noise amplifier (U1) is a low noise amplifier with a bypass function, and the antenna (1) is a UHF frequency band passive antenna.

3. A receiving antenna circuit based on an active sound system according to claim 2, characterized in that It also includes: a power supply circuit (5) for supplying power to the low noise amplifier (U1), the power supply circuit (5) including a power supply input management circuit (51), the power distributor / synthesizer (U3), and a power supply output management circuit (52) connected in sequence.

4. A receiving antenna circuit based on an active sound system according to claim 3, characterized in that The power supply input management circuit (51) comprises a direct current power supply input circuit, and the direct current power supply input circuit comprises: a positive power supply input terminal (T1), a first diode D1, a first capacitor C15, a second capacitor C14, and a first inductor L7, wherein the positive electrode of the first diode D1 is connected to the positive power supply input terminal (T1), the negative electrode of the first diode D1 is respectively connected to one end of the first capacitor C15, one end of the second capacitor C14, and one end of the first inductor L7, the other end of the first capacitor C15 and the other end of the second capacitor C14 are both grounded, and the other end of the first inductor L7 is respectively connected to the PORT2 port (4) and the first end (P1) of the power distributor / synthesizer (U3).

5. A receiving antenna circuit based on an active sound system according to claim 4, characterized in that When the antenna (1) works in cascade, the PORT2 port (4) is used as a power supply input terminal for power supply, and the power supply input management circuit (51) further comprises: the PORT2 port (4), the PORT2 port (4) is connected to the first end (P1) of the power distributor / synthesizer (U3), and the PORT2 port (4) is connected to the second end (P2) of the power distributor / synthesizer (U3).

6. A receiving antenna circuit based on an active sound system according to claim 3, characterized in that The power supply output management circuit (52) comprises: a second inductor L6, a low voltage difference linear regulator (U2), a third inductor L3, and a first resistor R3; one end of the second inductor L6 is connected to a third end (P3) of a power distributor / synthesizer (U3) via a second resistor R5-1; the other end of the second inductor L6 is connected to a Vin pin of the low voltage difference linear regulator (U2); one end of the third inductor L3 is connected to a Vout pin of the low voltage difference linear regulator (U2), and the other end serves as a first voltage output end (V1) of the power supply output management circuit (52) The invention is connected to a low noise amplifier (U1); one end of the first resistor R3 is connected to a Vout pin of a low voltage difference linear regulator (U2), and the other end serves as a second voltage output terminal (V2) of a power supply output management circuit (52); a third capacitor C11 and a fourth capacitor C12 are connected in parallel between the Vin pin of the low voltage difference linear regulator (U2) and a ground terminal; a fifth capacitor C5 and a sixth capacitor C6 are connected in parallel between the Vout pin of the low voltage difference linear regulator (U2) and a ground terminal; and a GND pin of the low voltage difference linear regulator (U2) is grounded.

7. A receiving antenna circuit based on an active sound system according to claim 3, characterized in that The low noise amplifier (U1) is connected to a mode switching circuit for controlling the low noise amplifier (U1) to be in an LNA mode or a bypass mode, the mode switching circuit comprising: a switching switch (61) connected to a power supply circuit (5) and capable of forming a loop when closed, the switching switch (61) being a first single-pole double-throw switch S1, the first end of the first single-pole double-throw switch S1 being connected to a mode control pin of the low noise amplifier (U1), the second end being connected to an output end of the power supply circuit (5), and the third end being grounded; when the first end of the first single-pole double-throw switch S1 is connected to its second end, the low noise amplifier (U1) is switched to the LNA mode; when the first end of the first single-pole double-throw switch S1 is connected to its third end, the low noise amplifier (U1) is switched to the bypass mode.

8. A receiving antenna circuit based on an active sound system according to claim 7, characterized in that The first single-pole double-throw switch S1 is also connected in parallel with a second single-pole double-throw switch SW1 to form a double-pole double-throw switch that can act synchronously; a first end of the second single-pole double-throw switch SW1 is connected to a second end of the first single-pole double-throw switch S1, a second end is connected to a first indicator light circuit (71) for indicating that the low-noise amplifier (U1) is in an LNA mode, and a third end is connected to a second indicator light circuit (72) for indicating that the low-noise amplifier (U1) is in a bypass mode, and the first indicator light circuit (71) and the second indicator light circuit (72) are connected in parallel; The first indicator light circuit (71) and the second indicator light circuit (72) are connected in parallel to form a first connection point (T3); the first connection point (T3) is connected to an antenna input pin via a third resistor R7; a fourth inductor L12 and a fifth inductor L13 are connected between the antenna input pin and the ground; the fourth inductor L12 and the fifth inductor L13 are connected in parallel.

9. A receiving antenna circuit based on an active sound system according to claim 1, characterized in that An antenna interface circuit (2) is also connected between the antenna (1), the low-noise amplifier (U1) and the ground terminal. The antenna interface circuit (2) comprises: a seventh capacitor C1, an eighth capacitor C2, a ninth capacitor C3, a sixth inductor L1 and a fourth resistor R1. One end of the seventh capacitor C1 is connected to the antenna input pin, and the other end is respectively connected to one end of the ninth capacitor C3 and one end of the sixth inductor L1 through the eighth capacitor C2. The other end of the ninth capacitor C3 is respectively connected to one end of the fourth resistor R1 and the low-noise amplifier (U1). The other end of the sixth inductor L1 and the other end of the fourth resistor R1 are both grounded.

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