Internal and external reference signal automatic switching circuit in measurement and control system

Abstract

The utility model relates to the technical field of microwave radio frequency, in particular to an automatic switching circuit for internal and external reference signals in a measurement and control system. Comprising a power divider, a detector, a comparator, a driver, an internal reference source and a radio frequency switch, the detector is used for outputting detection voltage; the comparator is used for comparing the threshold voltage with the detection voltage, so that a low level is output when the threshold voltage is greater than the detection voltage, or a high level is output when the threshold voltage is smaller than the detection voltage; when the control end of the driver is connected to a low level, the output end of the driver outputs a driving current to the internal reference source; the radio frequency switch is used for connecting the first input end of the radio frequency switch with the output end of the radio frequency switch when the control end of the radio frequency switch is connected to a high level, or connecting the second input end of the radio frequency switch with the output end of the radio frequency switch when the control end of the radio frequency switch is connected to a low level. The method can automatically adapt to the switching of the internal and external reference signals, and improves the flexibility of the whole system.

Description

TECHNICAL FIELD

[0001] The utility model relates to a microwave radio frequency technical field, concretely relates to a kind of internal and external reference signal automatic switching circuit in measurement and control system. BACKGROUND

[0002] With the continuous development of economic globalization and informationization, satellite measurement and control technology has become an important part of the development of modern communication technology, and the frequency source module, as the core component of satellite measurement and control system equipment, provides the local oscillator and clock signal for the entire system, ensuring normal operation of the system. In practical application, the frequency source is provided with an internal reference clock signal, which is used as a system clock.

[0003] When the satellite measurement and control system needs to be externally connected to an external system, the clocks of the two systems need to be synchronized. The existing clock synchronization method is to synchronize the satellite measurement and control system to the clock of the external system. However, if the power of the external reference signal (i.e., the external clock signal) of the external system is relatively weak, it will affect the normal use of the equipment after being externally connected to the external system. INVENTION CONTENTS

[0004] Therefore, the utility model provides a kind of internal and external reference signal automatic switching circuit in measurement and control system to solve the problem that weaker external reference signal in prior art can affect the use of equipment as synchronization clock.

[0005] The utility model provides a kind of internal and external reference signal automatic switching circuit in measurement and control system, comprising: power divider, detector, comparator, driver, internal reference source and radio frequency switch;

[0006] The power divider, detector, comparator, driver and internal reference source are connected in series, the input end of the power divider is connected with the external reference signal, the first output end of the power divider is connected with the first input end of the radio frequency switch, the second output end of the power divider is connected with the input end of the detector, the output end of the detector is connected with the first input end of the comparator, the second output end of the comparator is connected with threshold voltage, the output end of the comparator is connected with the control end of the driver and the control end of the radio frequency switch respectively, the output end of the driver is connected with the internal reference source, and the output end of the internal reference source is connected with the second input end of the radio frequency switch.

[0007] The detector is used to output a detection voltage.

[0008] The comparator is used to compare the threshold voltage and the detection voltage, so that when the threshold voltage is greater than the detection voltage, a low level is output, or when the threshold voltage is less than the detection voltage, a high level is output.

[0009] The driver is used to output a driving current to the internal reference source when the control end is connected with a low level.

[0010] The first input end of the radio frequency switch is connected with the output end of the radio frequency switch when the control end of the radio frequency switch is connected with a high level, or the second input end of the radio frequency switch is connected with the output end of the radio frequency switch when the control end of the radio frequency switch is connected with a low level.

[0011] Further, the input end of the power divider is connected with an attenuation network, and the external reference signal is connected with the input end of the power divider through the attenuation network.

[0012] Further, the radio frequency switch is a matching switch.

[0013] Further, the internal reference source is a crystal oscillator.

[0014] Further, the output of the internal reference source is a 100MHz clock signal. Advantages

[0015] 1. The application can automatically adapt to the switching of the internal and external reference signals, improving the flexibility of the overall system. The detection voltage is positively correlated with the power of the external reference signal. If the power of the external reference signal is less than the power threshold, the detection voltage is less than the threshold voltage, and the comparator outputs a low level to the control end of the driver and the control end of the radio frequency switch, respectively, so that the driver outputs a driving current to the internal reference source, the internal reference source outputs an internal reference signal, and the second input end of the radio frequency switch is connected with the output end of the radio frequency switch, so that the output end of the radio frequency switch outputs the internal reference signal, avoiding the situation that when the power of the external reference signal is relatively small, the quality and stability of the signal may be insufficient to provide sufficient clock synchronization effect, thereby affecting the normal use of the device.

[0016] If the power of the external reference signal is greater than the power threshold, it means that the strength of the external reference signal is high and may have good quality and stability, so the detection voltage is greater than the threshold voltage, and the comparator outputs a high level to the control end of the driver and the control end of the radio frequency switch, respectively, so that the driver stops outputting the driving current to the internal reference source, and the first input end of the radio frequency switch is connected with the output end of the radio frequency switch, so that the output end of the radio frequency switch outputs the external reference signal.

[0017] 2. The attenuation network can effectively reduce the strength of the external reference signal, thereby avoiding the influence of the over-strength external reference signal on the entire system. It ensures that the circuit will not fail when receiving the external signal due to signal overload, and improves the bearing capacity and stability of the system.

[0018] 3. The matching switch can select the corresponding path according to the low level or high level connected to the control end. BRIEF DESCRIPTION OF DRAWINGS

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in 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 utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Power divider; 2. Detector; 3. Comparator; 4. Driver; 5. Internal reference source; 6. RF switch; 7. Attenuation network. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] A reference clock provides a stable reference for the frequency source and even the entire system. An internal, stable reference clock signal is set up and used as the system clock. When the system needs to synchronize with an external system clock, an external clock signal is required. However, the internal reference signal and the external reference signal often have inconsistent frequencies and stability, causing the devices to fail to synchronize and affecting their operation. Traditional reference switching methods utilize phase-locked loops (PLLs), which use the phase error between internal and external reference signals to lock and track the signal, thus achieving clock synchronization. However, this approach has complex circuitry and poor flexibility.

[0025] The following is combined Figure 1 The following describes embodiments of the present invention.

[0026] According to an embodiment of the present invention, an automatic switching circuit for internal and external reference signals in a measurement and control system is provided, comprising: a power divider, a detector, a comparator, a driver, an internal reference source, and a radio frequency switch;

[0027] The power divider, the detector, the comparator, the driver and the internal reference source are connected in series, an external reference signal is connected with an input end of the power divider, a first output end of the power divider is connected with a first input end of the radio frequency switch, a second output end of the power divider is connected with an input end of the detector, an output end of the detector is connected with a first input end of the comparator, a second output end of the comparator is connected with a threshold voltage, an output end of the comparator is connected with a control end of the driver and a control end of the radio frequency switch respectively, an output end of the driver is connected with the internal reference source, and an output end of the internal reference source is connected with a second input end of the radio frequency switch.

[0028] The internal reference source is used for outputting an internal reference signal, the power divider divides the external reference signal into two paths, the detector realizes linear conversion of the input external reference signal into an analog detection voltage signal, and the detection voltage is greater with the increase of the power of the input external reference signal. The driver is a high-power driving device, when the control level is low, the internal MOS is opened, and a driving current of 2A at most can be provided; similarly, when the control level is high, the internal MOS is closed, and the current is turned off.

[0029] The detector is used for outputting a detection voltage.

[0030] The comparator is used for comparing the threshold voltage and the detection voltage, so that a low level is output when the threshold voltage is greater than the detection voltage, or a high level is output when the threshold voltage is less than the detection voltage.

[0031] The driver is used for outputting a driving current to the internal reference source when the control end of the driver is connected with a low level.

[0032] The radio frequency switch is used for connecting the first input end of the radio frequency switch with the output end of the radio frequency switch when the control end of the radio frequency switch is connected with a high level, or connecting the second input end of the radio frequency switch with the output end of the radio frequency switch when the control end of the radio frequency switch is connected with a low level.

[0033] The application can automatically adapt to the switching of the internal and external reference signals, and improve the flexibility of the overall system. The detection voltage is positively correlated with the power of the external reference signal, if the power of the external reference signal is less than a power threshold, the detection voltage is less than the threshold voltage, the comparator outputs a low level to the control end of the driver and the control end of the radio frequency switch respectively, the driver outputs a driving current to the internal reference source, the internal reference source outputs an internal reference signal, and the second input end of the radio frequency switch is connected with the output end of the radio frequency switch, so that the output end of the radio frequency switch outputs the internal reference signal, thereby avoiding that when the power of the external reference signal is relatively small, the quality and stability of the signal are insufficient to provide sufficient clock synchronization effect, and the normal use of the equipment is affected.

[0034] If the power of the external reference signal is greater than the power threshold, it indicates that the strength of the external reference signal is high and may have good quality and stability, then the detection voltage is greater than the threshold voltage, the comparator outputs high level to the control end of the driver and the control end of the radio frequency switch, so that the driver closes the output driving current to the internal reference source, and the first input end of the radio frequency switch is connected with the output end of the radio frequency switch, so that the output end of the radio frequency switch outputs the external reference signal.

[0035] Therefore, when the external reference signal meets certain conditions (such as power higher than the set threshold), the circuit automatically switches to the external reference signal, ensuring that the signal source with better stability is used preferentially. This adaptive switching greatly facilitates the operation of the system and reduces the need for manual intervention. In addition, the present application discards the traditional complex phase-locked loop scheme and uses series-connected power divider, detector and comparator elements, making the circuit structure more simple. The simplified circuit design not only reduces the manufacturing and maintenance costs, but also greatly improves the reliability of the system, avoiding faults caused by the complexity of the circuit. By applying the detector and comparator, the stability between the internal reference signal and the external reference signal is ensured. The comparator is responsible for real-time monitoring of the detection voltage and comparison with the threshold voltage, thereby providing adaptive control. For example, when the power of the external signal is sufficient, the system automatically switches to the external reference signal, effectively reducing system errors caused by signal mismatch. The close cooperation between the detector and the comparator enables the circuit to provide real-time feedback on the current signal state, thereby quickly responding to changes in the external environment. Efficient signal processing and feedback mechanisms can improve the system's adaptability to external signals, shorten switching delays, and improve the response speed of the measurement and control system.

[0036] Further, the input end of the power divider is connected with an attenuation network, and the external reference signal is connected with the input end of the power divider through the attenuation network. The attenuation network can effectively reduce the strength of the external reference signal, thereby avoiding the impact of the external reference signal on the entire system caused by the external reference signal being too strong. This ensures that the circuit will not fail due to signal overload when receiving external signals, improving the system's bearing capacity and stability. The attenuation network can improve the port matching characteristics of the signal, reducing the reflection loss between the signal source and the receiving end. By optimizing the signal flow, the attenuation network enables the power divider to better process the input signal, improving the transmission efficiency and the integrity of the signal.

[0037] Further, the radio frequency switch is a matching switch. The matching switch can select the corresponding path according to the low level or high level input to the control end.

[0038] Further, the internal reference source is a high-stability crystal oscillator.

[0039] Further, the output of the internal reference source is a 100MHz clock signal.

[0040] Working principle:

[0041] When the attenuation network has an external reference signal input, the detector outputs a corresponding detection voltage, which linearly increases with the continuous increase of the input signal.

[0042] When the input reference signal power is greater than the power threshold, the comparator outputs a high level, the driver has no current output, the internal reference source power supply is turned off, and the output end of the radio frequency switch is connected with the power divider.

[0043] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. An automatic switching circuit for internal and external reference signals in a telemetry system, characterized by, The application relates to a radio frequency switch control circuit. The radio frequency switch control circuit comprises a power divider (1), a detector (2), a comparator (3), a driver (4), an internal reference source (5) and a radio frequency switch (6). The power divider (1), the detector (2), the comparator (3), the driver (4) and the internal reference source (5) are connected in series, an external reference signal is connected with an input end of the power divider (1), a first output end of the power divider (1) is connected with a first input end of the radio frequency switch (6), a second output end of the power divider (1) is connected with an input end of the detector (2), an output end of the detector (2) is connected with a first input end of the comparator (3), a second output end of the comparator (3) is connected with a threshold voltage, an output end of the comparator (3) is connected with a control end of the driver (4) and a control end of the radio frequency switch (6) respectively, an output end of the driver (4) is connected with the internal reference source (5), and an output end of the internal reference source (5) is connected with a second input end of the radio frequency switch (6). The detector (2) is used for outputting a detection voltage. The comparator (3) is used for comparing the threshold voltage and the detection voltage, so that a low level is outputted when the threshold voltage is greater than the detection voltage, or a high level is outputted when the threshold voltage is smaller than the detection voltage. The driver (4) is used for outputting a driving current to the internal reference source (5) when the control end is connected with a low level. The radio frequency switch (6) is used for connecting the first input end with the output end of the radio frequency switch (6) when the control end is connected with a high level, or connecting the second input end with the output end of the radio frequency switch (6) when the control end is connected with a low level.

2. The automatic switching circuit according to claim 1, wherein An attenuation network (7) is connected with the input end of the power divider (1), and the external reference signal is connected with the input end of the power divider (1) through the attenuation network (7).

3. The automatic switching circuit according to claim 1, wherein The radio frequency switch (6) is a matching switch.

4. The automatic switching circuit according to claim 1, wherein The internal reference source (5) is a crystal oscillator.

5. The automatic switching circuit according to claim 1, wherein The output of the internal reference source (5) is a 100MHz clock signal.

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