A VHF band high-power power amplifier isolation circuit capable of fast shutdown signal

Abstract

The utility model relates to a VHF band high -power power amplifier isolation circuit of quick shutdown signal belongs to power amplifier circuit technical field. Circuit includes signal input circuit, first drive amplifier circuit, second drive amplifier circuit, forestage amplifier circuit, last stage amplifier circuit and signal transceiver circuit that connect gradually in proper order, wherein, the output of forestage amplifier circuit and the input of last stage amplifier circuit have first signal isolation module in series, for isolating the output signal of forestage amplifier circuit, the output of last stage amplifier circuit and the input of signal transceiver circuit have second signal isolation module in series, for isolating the output signal of last stage amplifier circuit. The utility model discloses through two signal isolation modules and carries out isolation to the output signal of forestage amplifier circuit and last stage amplifier circuit respectively, improves the isolation of power amplifier circuit. Simultaneously, the transmitting signal and the receiving signal are completely isolated, have reduced the interference to the receiving signal, and the overall circuit structure is simple, has reduced the manufacturing cost of power amplifier circuit.

Description

Technical Field

[0001] This utility model relates to the field of power amplifier circuit technology, and more specifically to a VHF band high-power power amplifier isolation circuit that can quickly shut off signals. Background Technology

[0002] High-power amplifier modules are core components in radar, communication, and navigation systems. Their transmit power directly determines the system's operating range, their turn-off speed determines the rapid response of transmission and reception, and their isolation determines anti-interference capability and communication quality. In VHF and lower frequency bands, to transmit higher-power signals but limited by the device's capacity, multiple-channel, multi-stage amplifiers are cascaded. While achieving high power, this results in persistent signal turn-off trailing and further compression of isolation.

[0003] Currently, in VHF band power amplifier circuits, to improve isolation, switches and other devices are typically added to the transmit link. Meanwhile, turn-off speed is improved by modulating the power supply or adding fast discharge circuits. This circuit structure is costly to manufacture and complex, making it difficult to implement in situations with limited module space. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the present invention provides a VHF band high-power amplifier isolation circuit that can quickly shut off the signal, in order to address the technical problems of high manufacturing cost and relatively complex structure of existing VHF band power amplifier circuits.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a VHF band high-power amplifier isolation circuit capable of quickly shutting off signals, comprising a signal input circuit, a first drive amplifier circuit, a second drive amplifier circuit, a pre-amplifier circuit, a final amplifier circuit, and a signal transceiver circuit connected in sequence; wherein...

[0007] A first signal isolation module is connected in series between the output terminal of the preamplifier circuit and the input terminal of the final amplifier circuit.

[0008] A second signal isolation module is connected in series between the output terminal of the final stage amplifier circuit and the input terminal of the signal transceiver circuit.

[0009] Preferably, the first signal isolation module and the second signal isolation module are specifically one or more power diodes connected in parallel.

[0010] Preferably, the signal input circuit includes a signal input switch and a programmable attenuator connected in sequence; the input terminal of the signal input switch is connected to a link signal, and the output terminal of the programmable attenuator is connected to the input terminal of the first drive amplifier circuit.

[0011] Preferably, the first driving amplifier circuit includes a first driving amplifier, a first isolator, and a first power supply modulation circuit; wherein, the output terminal of the first power supply modulation circuit is connected to the control terminal of the first driving amplifier;

[0012] The input terminal of the first driver amplifier is connected to the output terminal of the programmable attenuator, and the output terminal of the first driver amplifier is connected to the input terminal of the second driver amplifier circuit via the first isolator.

[0013] Preferably, the second drive amplifier circuit includes a second drive amplifier, a second isolator, and a second power supply modulation circuit; wherein the output terminal of the second power supply modulation circuit is connected to the control terminal of the second drive amplifier.

[0014] The input terminal of the second driver amplifier is connected to the output terminal of the first isolator, and the output terminal of the second driver amplifier is connected to the input terminal of the preamplifier circuit via the second isolator.

[0015] Preferably, the preamplifier circuit includes a first overvoltage / undervoltage circuit, a third power supply modulation circuit, and a preamplifier; wherein,

[0016] The output of the first overvoltage and undervoltage circuit is connected to the control terminal of the preamplifier via the third power supply modulation circuit.

[0017] The input terminal of the preamplifier is connected to the output terminal of the second isolator, and the output terminal of the preamplifier is connected to the input terminal of the first signal isolation module.

[0018] Preferably, the final stage amplifier circuit includes a third isolator, a second overvoltage / undervoltage circuit, a fourth power supply modulation circuit, and a final stage amplifier; wherein,

[0019] The output of the second overvoltage and undervoltage circuit is connected to the control terminal of the final stage amplifier via the fourth power supply modulation circuit;

[0020] The input terminal of the third isolator is connected to the output terminal of the first signal isolation module, the output terminal of the third isolator is connected to the input terminal of the final stage amplifier, and the output terminal of the final stage amplifier is connected to the input terminal of the second isolation module.

[0021] Preferably, the signal transceiver circuit includes a fourth isolator, a filter, a circulator, a coupler, a receiving module, and a signal transceiver antenna; wherein,

[0022] The input terminal of the fourth isolator is connected to the output terminal of the second signal isolation module, and the output terminal of the fourth isolator is connected to the first terminal of the circulator via a filter.

[0023] The signal transceiver antenna is connected to the second end of the circulator via a coupler, and the third end of the circulator is connected to the receiving module.

[0024] In summary, this utility model has the following beneficial effects:

[0025] This invention establishes a first signal isolation module and a second signal isolation module after the preamplifier circuit and the final amplifier circuit of a VHF band high-power power amplifier isolation circuit capable of rapid signal shutdown. These modules isolate the output signals of the preamplifier circuit and the final amplifier circuit, respectively, effectively intercepting residual transmitted signals in the link after the transmit shutdown command is issued. This achieves rapid shutdown of high-power transmitted signals and improves the isolation of the power amplifier circuit. Simultaneously, the two signal isolation modules completely isolate the transmitted and received signals, reducing interference to the received signal. The overall circuit structure is simple, reducing the manufacturing cost of the power amplifier circuit. Attached Figure Description

[0026] Figure 1 This is a circuit diagram of the isolation circuit for a high-power VHF band amplifier that can quickly shut off signals, according to this utility model.

[0027] Figure 2 This is a conventional link design diagram for a high-power VHF band amplifier;

[0028] Figure 3 This is a diagram showing the actual output delay of a conventional high-power amplifier signal in the VHF band.

[0029] Figure 4 This is a schematic diagram illustrating the mutual interference between transmitted and received signals caused by signal delay in conventional high-power power amplifiers in the VHF band.

[0030] Figure 5 This is a circuit diagram of the isolation circuit for a VHF band high-power amplifier with a newly added diode gate valve that can quickly shut off the signal.

[0031] Figure 6 This is a schematic diagram illustrating the principle of the isolation circuit for a high-power VHF amplifier capable of quickly shutting off residual transmission signals according to this utility model.

[0032] Figure 7 This utility model presents a diagram showing the state of a VHF band high-power amplifier isolation circuit with a fast signal shutdown capability and no delay during signal shutdown.

[0033] Figure 8This is a structural diagram of the isolation circuit of a VHF band high-power amplifier with a parallel multi-stage diode gate valve that can quickly shut off signals.

[0034] Figure 9 This is an improved circuit diagram of the isolation circuit for a high-power VHF amplifier that can quickly shut off signals, based on the present invention. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings.

[0036] To make the objectives, solutions, and advantages of this utility model clearer, the following detailed description of this utility model is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0037] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the present invention. In other embodiments, well-known structures, circuits, materials, or methods are not specifically described in order to avoid obscuring the present invention.

[0038] With the rapid development of wireless communication, the demands on communication systems are increasing, requiring high power density, high power output, fast transmit / receive response, high isolation, radiation resistance, and long lifespan. Transmitters are indispensable for wireless communication, and the core component of a transmitter is a high-power amplifier. Therefore, with changing demands, the design requirements for VHF band high-power amplifiers are also increasing, especially for indicators such as high output power, high isolation, and fast transmit / receive response. These indicators are often mutually exclusive; for example, high output power and high isolation often interfere with each other. Designing for isolation and interference immunity significantly improves amplifier efficiency while largely unaffected by other indicators. Currently, the industry, whether using domestic or imported high-power amplifier tubes, only performs simulation verification on the devices themselves to obtain parameters and specifications; some domestic manufacturers haven't even tested the relevant parameters at high power. Whenever a device operates within a component or system, errors will occur in the specifications and data. Therefore, we must improve the design accordingly to ensure the overall system meets the requirements.

[0039] In the design and subsequent debugging of high-power amplifiers, designers and debugging personnel follow the peripheral circuit layout of the demo board provided by the component manufacturer. After the product is assembled and powered on for testing, the performance indicators often fail to meet the requirements. Therefore, different methods are needed to make adjustments. However, the performance indicators of isolation and transmit signal turn-off time are often difficult to match and debug, so other approaches are needed to make adjustments to meet the performance requirements.

[0040] Traditional VHF band power amplifier circuit designs focus on high-power devices, such as power amplifiers. Their specifications, such as output power, conversion efficiency, and linearity, are relatively singular and balanced. Control timing, power control, and temperature / environmental change control are then added to the circuit to achieve coordinated operation of the entire system. However, due to multi-stage connections and simultaneous operation of multiple channels, the isolation and transmit signal turn-off time of the assembled product vary significantly and cannot be adjusted. Therefore, further improvements are needed to the existing VHF band power amplifier circuits to optimize the circuit structure and reduce costs. The following section, in conjunction with the appendix of this utility model... Figures 1-7 The embodiments of this utility model will be described in detail below.

[0041] Example 1:

[0042] Reference Figure 1 As shown, this embodiment of a VHF band high-power amplifier isolation circuit capable of quickly shutting off signals includes a signal input circuit, a first drive amplifier circuit, a second drive amplifier circuit, a preamplifier circuit, a final amplifier circuit, and a signal transceiver circuit connected in sequence. Among them,

[0043] A first signal isolation module is connected in series between the output terminal of the preamplifier circuit and the input terminal of the final amplifier circuit. The first signal isolation module is used to isolate the output signal of the preamplifier circuit.

[0044] A second signal isolation module is connected in series between the output terminal of the final stage amplifier circuit and the input terminal of the signal transceiver circuit. The second signal isolation module is used to isolate the output signal of the final stage amplifier circuit.

[0045] In this embodiment, the first signal isolation module and the second signal isolation module can isolate the signals in the link, thereby increasing the signal isolation. At the same time, when the transmission link is turned off, the residual transmission signal in the link can be isolated from the signal received by the antenna, reducing interference to the received signal.

[0046] Reference Figure 2As shown, in a typical VHF high-power amplifier link, the input signal passes through a switch and a programmable attenuator to the first driver amplifier, is amplified, then passes through the second driver amplifier, and after two stages of amplification, enters the preamplifier and final amplifier. The signal is then amplified to the required power before passing through a filter, circulator, and coupler for final output. In the entire transmission link, when the transmit signal is turned off, the input signal and the first, second, third, and fourth power supply modulation circuits respond quickly. However, because the third and fourth power supply modulation circuits operate at high voltages (e.g., +28V, +48V), the preamplifier and final amplifier continue to operate during the time it takes for the voltage to drop from +48V to 0V. If this time is relatively long, even after the transmit signal is turned off, issues such as… Figure 3 The 1-second delay tail shown, if left uncontrolled, will interfere with the received signal coming from the antenna. Furthermore, due to the large transmitted signal, it may even damage the receiving module. The mutual interference process between transmitted and received signals is as follows: Figure 4 As shown.

[0047] Currently, existing technologies address the aforementioned defects by debugging the circuit. While other parameters can be adjusted using external matching circuits to find the optimal matching point and ensure all parameters meet requirements, isolation cannot be adjusted in a similar way. The only way to improve isolation is to add devices such as switches to the transmission link; simultaneously, modulation of the power supply or the addition of fast discharge circuits can forcibly and completely shut down the signal in the link. Such circuit design modifications are significant, difficult to implement in space-constrained environments, and the purchase of new components increases manufacturing and time costs.

[0048] Therefore, this embodiment adds a first signal isolation module and a second signal isolation module in series to the isolation circuit of a high-power power amplifier in the VHF band that can quickly shut down the signal, thereby intercepting and isolating the signal in the link and achieving a fast response to shutting down the transmission signal.

[0049] Specifically, in this embodiment, the first signal isolation module and the second signal isolation module are one or more power diodes (i.e., PIN diodes) connected in parallel. The power diodes intercept signals smaller than the diode conduction threshold, and at the same time, the reverse conduction characteristic of the diodes isolates the received signals, so that the output signal does not affect the received signal, thereby improving the signal isolation of the link.

[0050] This embodiment uses a single power diode as a signal isolation module to further explain the circuit principle of this embodiment.

[0051] To improve the isolation and turn-off time of the VHF band high-power amplifier under multi-channel operation, power diodes were added in series after the outputs of both the preamplifier and the final amplifier, without changing other aspects of the link. The specific circuit structure after the improvement is as follows: Figure 5 As shown. The two newly added diodes can be specifically referred to as the first diode and the second diode.

[0052] As is well known, the special properties of PIN diodes have long allowed them to function as switches in the microwave field, acting as a kind of threshold. For example... Figure 6 The diagram shown illustrates the removal of residual signals by the newly added diode gate valve. This embodiment also utilizes the special properties of PIN diodes. When the signal amplitude passing through it reaches a certain threshold, the PIN diode is a circuit, and the signal passes smoothly. When the signal is less than or equal to its threshold, the PIN diode is an open circuit, and the signal does not pass through.

[0053] When the transmit shutdown command is issued, during the period when the supply voltage drops from +48V to 0V, although the residual transmit signal still exists in the link, the newly added first and second diodes act like two thresholds, intercepting the remaining signal below the diode conduction threshold in the link. This signal is then slowly released through the power amplifier load without affecting the newly received signal. For example... Figure 7 As shown, the improved VHF band high-power amplifier isolation circuit, capable of rapidly shutting down signals, achieves rapid shutdown of high-power signals, completely separating the high-power signal from the received signal so that they do not affect each other. Simultaneously, because the residual transmitted signal is intercepted, the leaked transmitted signal is very small, increasing the signal isolation in the link and minimizing the impact on adjacent channels.

[0054] Furthermore, the model parameters of diodes 1 and 2 can be adjusted according to the requirements of each project to achieve the signal threshold, thereby adjusting the turn-off time and isolation. For greater isolation and a shorter transmit signal turn-off time, PIN diodes with higher turn-on voltages are needed, such as those in the MASW-011040, MA4P506-255, and GC4400 series. When the signal is turned off, a larger residual transmit signal will be intercepted before the PIN diode, thus ensuring higher isolation and a shorter turn-off time.

[0055] In this embodiment, as Figure 8As shown, the PIN diodes connected in series in the link do not affect the normal operation of the transmission signal. When transmitting high-power signals, the power tolerance of the PIN diodes must be calculated. If the power tolerance is insufficient, this embodiment uses multiple PIN diodes connected in parallel in the transmission link to distribute the power across the link. The higher the power of the circuit design, the higher the power tolerance requirement of the PIN diodes used; therefore, more PIN diodes are used for signal isolation. Thus, the circuit structure of this embodiment can indirectly improve the output power of the circuit.

[0056] In this embodiment, a first signal isolation module and a second signal isolation module are respectively set after the pre-amplifier circuit and the final amplifier circuit of the VHF band high-power power amplifier isolation circuit that can quickly shut down the signal. These modules isolate the output signals of the pre-amplifier circuit and the final amplifier circuit, respectively, effectively intercepting residual transmitted signals in the link after the transmit shutdown signal command is issued. This achieves rapid shutdown of the high-power transmitted signal and improves the isolation of the power amplifier circuit. Simultaneously, the two signal isolation modules completely isolate the transmitted signal from the received signal, reducing interference to the received signal. The overall circuit structure is simple, reducing the manufacturing cost of the power amplifier circuit.

[0057] Example 2:

[0058] In this embodiment, refer to Figure 5 As shown, the signal input circuit includes a signal input switch and a programmable attenuator connected in sequence. The input terminal of the signal input switch is connected to the link signal, and the output terminal of the programmable attenuator is connected to the input terminal of the first drive amplifier circuit. Through the coordinated operation of the signal input switch and the programmable attenuator, the signal input circuit achieves flexible selection, precise control, and front-end protection of the input signal, providing a stable, controllable, and compatible input signal for subsequent circuits (such as high-power amplifiers), while simultaneously improving the system's automation and intelligence level (eliminating the need for manual adjustment).

[0059] Furthermore, in the high-power amplifier circuit, this embodiment uses a "fuse-type high-power limiter" connected in series between the signal input switch and the programmable attenuator. When the reverse power is too high, the limiter quickly conducts to absorb the power, preventing damage to the front-end circuit. Simultaneously, to enhance the power tolerance of the front-end devices, an RC absorption circuit is installed at both ends of the signal input switch to suppress transient voltages and ensure that the switch is not damaged by instantaneous power surges during switching.

[0060] In this embodiment, the first driving amplifier circuit includes a first driving amplifier, a first isolator, and a first power supply modulation circuit; wherein, the output terminal of the first power supply modulation circuit is connected to the control terminal of the first driving amplifier.

[0061] The input terminal of the first driver amplifier is connected to the output terminal of the programmable attenuator, and the output terminal of the first driver amplifier is connected to the input terminal of the second driver amplifier circuit via the first isolator.

[0062] In this embodiment, the second driving amplifier circuit includes a second driving amplifier, a second isolator, and a second power supply modulation circuit; wherein, the output terminal of the second power supply modulation circuit is connected to the control terminal of the second driving amplifier.

[0063] The input terminal of the second driver amplifier is connected to the output terminal of the first isolator, and the output terminal of the second driver amplifier is connected to the input terminal of the preamplifier circuit via the second isolator.

[0064] In this embodiment, both the first and second drive amplifier circuits are used to provide stable, adaptable, and controllable drive signals for the high-power amplifier and to ensure the safety and coordinated operation of the preceding and following stage circuits.

[0065] In some other embodiments of this utility model, a directional coupler is connected in series at the output terminals of the first isolator and the second isolator to detect the drive power of the drive amplifier so that the preceding power supply modulation circuit or the pre-stage programmable attenuator can adjust the gain of the drive amplifier (e.g., increase the power supply voltage if the gain is insufficient) to ensure stable drive power.

[0066] In this embodiment, the preamplifier circuit includes a first overvoltage / undervoltage circuit, a third power supply modulation circuit, and a preamplifier; wherein...

[0067] The output of the first overvoltage and undervoltage circuit is connected to the control terminal of the preamplifier via the third power supply modulation circuit.

[0068] The input of the preamplifier is connected to the output of the second isolator, and the output of the preamplifier is connected to the input of the first signal isolation module.

[0069] In this embodiment, the preamplifier circuit mainly amplifies the signal from the driver stage, making the signal amplitude sufficient to drive the final power amplifier circuit (the core output stage of a high-power amplifier). The final power amplifier typically requires a large drive power to operate at its rated output state. The amplification factor of the preamplifier stage must match the drive requirements of the final stage to ensure that the final stage can fully utilize its power output capability.

[0070] In some other embodiments of this utility model, linearization technology is introduced: a digital predistortion (DPD) module is added to the output of the preamplifier in the preamplifier circuit. The digital predistortion (DPD) module compensates for the nonlinear characteristics of the preamplifier and the final stage in advance through an algorithm, thereby reducing the overall distortion. It is especially suitable for scenarios with strict linearity requirements, such as communication base stations and radar.

[0071] In this embodiment, the final stage amplifier circuit includes a third isolator, a second overvoltage / undervoltage circuit, a fourth power supply modulation circuit, and a final stage amplifier; wherein...

[0072] The output of the second overvoltage and undervoltage circuit is connected to the control terminal of the final stage amplifier via the fourth power supply modulation circuit.

[0073] The input of the third isolator is connected to the output of the first signal isolation module, the output of the third isolator is connected to the input of the final stage amplifier, and the output of the final stage amplifier is connected to the input of the second isolation module.

[0074] In this embodiment, the final stage amplifier circuit is used to amplify the low-power signal (such as radio frequency signal or audio signal) input from the pre-amplifier circuit so that the output power meets the requirements for driving the load.

[0075] In some other embodiments of this invention, a deep negative feedback circuit, such as voltage feedback or current feedback, is set in the final stage amplifier to monitor the deviation between the output signal and the input signal in real time, and the amplification factor is adjusted through feedback to suppress nonlinear distortion.

[0076] In this embodiment, the signal transceiver circuit includes a fourth isolator, a filter, a circulator, a coupler, a receiving module, and a signal transceiver antenna; wherein,

[0077] The input of the fourth isolator is connected to the output of the second signal isolation module, and the output of the fourth isolator is connected to the first end of the circulator via a filter.

[0078] The signal transceiver antenna is connected to the second end of the circulator via a coupler, and the third end of the circulator is connected to the receiving module.

[0079] In this embodiment, the circulator is the core device for transmit / receive switching. Its function is to achieve physical isolation between the transmitted and received signals by utilizing the "unidirectional transmission characteristic". During transmission, the high-power signal output from the final stage power amplifier is directionally transmitted to the antenna through the circulator to prevent signal leakage to the receiving module (otherwise, the high-power transmitted signal would directly burn out the low-noise amplifier at the receiving end).

[0080] During reception, the weak signal received by the antenna is directionally transmitted to the receiving module through a circulator to avoid noise interference from the transmission link.

[0081] The fourth isolator further enhances the isolation effect: when there is reflected power in the antenna (such as load mismatch), the isolator can block the reflected signal from flowing back to the transmission link, and at the same time prevent noise from the transmission link from entering the receiving module, ensuring that the transmitted and received signals do not interfere with each other.

[0082] The core function of a filter is "frequency selection," which means retaining the target frequency signal and filtering out noise and interference.

[0083] When transmitting signals, the filter removes harmonics generated by the final stage power amplifier (such as the second and third harmonics that may appear after high-power amplification) and out-of-band spurious signals to avoid interfering with communication in other frequency bands.

[0084] When receiving signals, the filter only allows weak signals from the target frequency band to enter the receiving module, filtering out interference signals from the external environment (such as radiation and electromagnetic noise from other devices) and reducing the processing load on the receiving module. This function is fundamental to ensuring the "purity" of transmitted and received signals, and is especially crucial in scenarios where multiple frequency bands coexist (such as communication base stations and radar).

[0085] The coupler's function is to "extract a portion of the signal proportionally" for monitoring and feedback. During transmission, the coupler extracts a small amount of signal (typically 1% to 10% of the total power) from the transmission link and transmits it to the power detection circuit to monitor in real time whether the transmission power meets the design requirements (such as whether it is overpowered or stable).

[0086] If abnormal power is detected (such as excessive power or fluctuations), it can be fed back to the front-end circuit (such as the power supply modulation circuit of the final stage power amplifier) ​​to dynamically adjust the output power and avoid damage to the antenna or the final stage power amplifier due to power runaway.

[0087] The receiver module is the core of the receiver link. Its function is to process the weak signals (usually in the microwatt or even nanowatt range) received by the antenna: First, the weak signals are amplified by a low-noise amplifier (LNA) (to prevent noise from drowning out the signal); then, through demodulation, filtering and other processing, the original information (such as the baseband data of communication signals, the echo characteristics of radar signals) is restored; combined with the preprocessing of the filter, the receiver module can accurately extract the target signal in a strong interference environment and ensure the receiving sensitivity (such as the "minimum identifiable signal power" in communication).

[0088] In this embodiment, referring to Table 1 below and combining the circuit structures of Embodiments 1 and 2, the circuit's frequency, power, in-band ripple, turn-off time, harmonic suppression, out-of-band suppression, transmit isolation, and transmit / receive isolation are analyzed. The VHF band high-power amplifier isolation circuit designed in this invention, capable of quickly turning off signals, has the following technical advantages:

[0089] (1) By adding a power diode as a signal isolation module to the circuit, the output power, isolation, and signal fast turn-off speed of the circuit are improved. This allows the VHF band high-power amplifier isolation circuit with fast signal turn-off to switch between transmission and reception quickly through timing in a matrix transceiver system, without worrying about high-power signal leakage to the receiver, thus meeting the usage requirements. In a matrix multi-channel transceiver system, the isolation is high, and the operation of the transmitting channel will not affect adjacent channels, resulting in strong anti-interference capability.

[0090] (2) The isolation circuit of the VHF band high-power amplifier with fast signal turn-off has a simple circuit structure, low manufacturing cost, and a simple and reliable diode installation method. Even if it is not fully considered in the design, it can still be operated in a limited space in the subsequent improvement process because the PIN diode itself is small in size and easy to install. At the same time, the use of multiple PIN diodes in parallel increases the power withstand capability, improves the isolation and the turn-off time of the transmitted signal, and fully meets the design specifications of the whole machine.

[0091] Table 1. Performance Analysis of Isolation Circuits for High-Power VHF Amplifiers with Fast Signal Shutdown

[0092]

[0093] Example 3:

[0094] In this embodiment, when the VHF band high-power amplifier isolation circuit capable of quickly shutting off signals from Embodiments 1 and 2 is applied to a practical scenario, its circuit structure has been improved according to the working scenario. For example... Figure 9 As shown, the transceiver of the VHF band high-power amplifier isolation circuit that can quickly shut off signals is designed based on the characteristics of the power amplifier tube, such as wide operating bandwidth, high output linear power, high dual-channel isolation, and fast signal shutdown.

[0095] The VHF band high-power amplifier isolation circuit with rapid signal shutdown employs a four-stage amplification. The first and second driver amplifiers use a dual-branch balanced structure for broadband matching. Both the preamplifier and the final amplifier are discrete component amplifiers. The preamplifier amplifies the signal power to approximately 30W. After passing through the first signal isolation module, it is split into two paths by a high-power switch. The two final amplifiers amplify the signal to 1300W and transmit it through two antennas. The final amplifier focuses on ensuring output power, while the preamplifier, first driver amplifier circuit, and second driver amplifier circuit focus on gain enhancement while ensuring gain flatness and input / output VSWR. The two-stage power diodes and high-power switches in the link significantly improve channel isolation and signal shutdown speed. Finally, it operated normally according to design values ​​in various environmental tests.

[0096] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A VHF band high-power power amplifier isolation circuit capable of rapidly shutting off signals, characterized in that, It includes a signal input circuit, a first driver amplifier circuit, a second driver amplifier circuit, a preamplifier circuit, a final amplifier circuit, and a signal transceiver circuit connected in sequence; wherein, A first signal isolation module is connected in series between the output terminal of the preamplifier circuit and the input terminal of the final amplifier circuit. A second signal isolation module is connected in series between the output terminal of the final stage amplifier circuit and the input terminal of the signal transceiver circuit.

2. The VHF band high-power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The first signal isolation module and the second signal isolation module are specifically one or more power diodes connected in parallel.

3. The VHF band high-power power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The signal input circuit includes a signal input switch and a programmable attenuator connected in sequence; the input terminal of the signal input switch is connected to the link signal, and the output terminal of the programmable attenuator is connected to the input terminal of the first drive amplifier circuit.

4. The VHF band high-power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The first driving amplifier circuit includes a first driving amplifier, a first isolator, and a first power supply modulation circuit; wherein, the output terminal of the first power supply modulation circuit is connected to the control terminal of the first driving amplifier; The input terminal of the first driver amplifier is connected to the output terminal of the programmable attenuator, and the output terminal of the first driver amplifier is connected to the input terminal of the second driver amplifier circuit via the first isolator.

5. The VHF band high-power power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The second drive amplifier circuit includes a second drive amplifier, a second isolator, and a second power supply modulation circuit; wherein, the output terminal of the second power supply modulation circuit is connected to the control terminal of the second drive amplifier. The input terminal of the second driver amplifier is connected to the output terminal of the first isolator, and the output terminal of the second driver amplifier is connected to the input terminal of the preamplifier circuit via the second isolator.

6. The VHF band high-power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The preamplifier circuit includes a first overvoltage / undervoltage circuit, a third power supply modulation circuit, and a preamplifier; wherein... The output of the first overvoltage and undervoltage circuit is connected to the control terminal of the preamplifier via the third power supply modulation circuit. The input terminal of the preamplifier is connected to the output terminal of the second isolator, and the output terminal of the preamplifier is connected to the input terminal of the first signal isolation module.

7. The VHF band high-power power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The final stage amplifier circuit includes a third isolator, a second overvoltage / undervoltage circuit, a fourth power supply modulation circuit, and a final stage amplifier; wherein... The output of the second overvoltage and undervoltage circuit is connected to the control terminal of the final stage amplifier via the fourth power supply modulation circuit; The input terminal of the third isolator is connected to the output terminal of the first signal isolation module, the output terminal of the third isolator is connected to the input terminal of the final stage amplifier, and the output terminal of the final stage amplifier is connected to the input terminal of the second isolation module.

8. The VHF band high-power amplifier isolation circuit capable of rapidly shutting off signals according to claim 1, characterized in that: The signal transceiver circuit includes a fourth isolator, a filter, a circulator, a coupler, a receiving module, and a signal transceiver antenna; wherein, The input terminal of the fourth isolator is connected to the output terminal of the second signal isolation module, and the output terminal of the fourth isolator is connected to the first terminal of the circulator via a filter. The signal transceiver antenna is connected to the second end of the circulator via a coupler, and the third end of the circulator is connected to the receiving module.

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