A receiver front-end circuit

Abstract

The utility model provides a receiver front-end circuit, comprising: an input end of a filter detection unit as the input end of the receiver front-end circuit; an output end of the filter detection unit is connected to an input end of a first switch unit; a control end of the filter detection unit is connected to a control end of the first switch unit and a control end of a second switch unit; a first output end of the first switch unit is connected to a first input end of a second switch unit through a first attenuation branch; a second output end of the first switch unit is connected to a second input end of the second switch unit through a second attenuation branch; an output end of the second switch unit is used as an output end of the receiver front-end circuit; the noise coefficients of the first attenuation branch and the second attenuation branch are different; therefore, a corresponding attenuation branch can be selected for attenuation according to the power size of an input signal, etc., and each attenuation branch has a different noise coefficient, so that the attenuation branch can be dynamically selected, thereby dynamically changing the sensitivity of the receiver and improving the applicable range of the receiver.

Description

Technical Field

[0001] The utility model belongs to the technical field of transceiver systems, and more specifically, particularly relates to a front-end circuit of a receiver. Background Art

[0002] The existing microwave system includes a receiver and a transmitter. Since the sensitivity of the receiver greatly affects the performance of the receiver, the sensitivity of the receiver needs to be considered in the design process of the receiver. The sensitivity of the receiver defines the minimum signal level that the receiver can receive. The important indicator affecting the sensitivity is the noise factor of the receiver. When other conditions remain unchanged, the lower the noise factor of the receiver, the better the sensitivity of the receiver.

[0003] The receiver includes a receiver front-end circuit, and the noise factor of the receiver is determined by the receiver front-end circuit. In the prior art, the noise factor is reduced by adding a filter to a low-noise amplifier in the front-end circuit of the receiver; however, when configuring the front-end circuit, the selection of the filter and the low-noise amplifier has been determined, that is, the device parameters have been determined, and then the noise factor is determined, and the noise factor is fixed, so the sensitivity of the receiver is also fixed, resulting in low applicability of the receiver. Utility Model Content

[0004] In view of this, an object of the present invention is to provide a receiver front-end circuit for dynamically adjusting the sensitivity of the receiver and improving the application range of the receiver.

[0005] The present application discloses a receiver front-end circuit, comprising: a filter detection unit, a first switch unit, a first attenuation branch, a second attenuation branch and a second switch unit;

[0006] The input end of the filter detection unit serves as the input end of the receiver front-end circuit to receive the input signal;

[0007] The output end of the filter detection unit is connected to the input end of the first switch unit;

[0008] The control end of the filter detection unit is connected to the control end of the first switch unit and the control end of the second switch unit;

[0009] The first output end of the first switch unit is connected to the input end of the first attenuation branch;

[0010] The second output end of the first switch unit is connected to the input end of the second attenuation branch;

[0011] The output end of the first attenuation branch is connected to the first input end of the second switch unit;

[0012] The output end of the second attenuation branch is connected to the second input end of the second switch unit;

[0013] The output end of the second switch unit serves as the output end of the receiver front-end circuit;

[0014] The first attenuation branch and the second attenuation branch have different noise coefficients.

[0015] Optionally, the filter-detection unit comprises: a filter, a detector and a coupler;

[0016] The input end of the filter serves as the input end of the filter detection unit;

[0017] The output end of the filter is connected to the input end of the coupler;

[0018] The first output end of the coupler serves as the output end of the filter-detection unit;

[0019] The second output end of the coupler is connected to the input end of the detector;

[0020] The output end of the detector serves as the control end of the filter-detection unit.

[0021] Optionally, the filter detection unit further includes: a driving circuit;

[0022] The first input terminal of the driving circuit is connected to a reference voltage source;

[0023] The second input terminal of the driving circuit is connected to the output terminal of the detector;

[0024] The output end of the driving circuit serves as the control end of the filter detection unit.

[0025] Optionally, the driving circuit includes: a comparator and a two-stage inverter;

[0026] The first input terminal of the comparator serves as the first input terminal of the driving circuit;

[0027] The second input terminal of the comparator serves as the second input terminal of the driving circuit;

[0028] The output end of the comparator is connected to the input end of the two-stage inverter;

[0029] The output end of the two-stage inverter serves as the output end of the driving circuit.

[0030] Optionally, the first attenuation branch includes: a first attenuator;

[0031] The input end of the first attenuator serves as the input end of the first attenuation branch;

[0032] The output end of the first attenuator serves as the output end of the first attenuation branch.

[0033] Optionally, the second attenuation branch includes: a low noise amplifier and a second attenuator;

[0034] The input end of the low noise amplifier serves as the input end of the second attenuation branch;

[0035] The output end of the low noise amplifier is connected to the input end of the second attenuator;

[0036] The output end of the second attenuator serves as the output end of the second attenuation branch.

[0037] Optionally, the first attenuator of the first attenuation branch and the second attenuator of the second attenuation branch are both fixed attenuators.

[0038] Optionally, the first attenuator of the first attenuation branch is a digitally controlled attenuator.

[0039] Optionally, the receiver front-end circuit is 50 mm long, 46 mm wide and 12.2 mm high.

[0040] Optionally, the filter, the coupler, the detector, the first switch unit, the second switch unit, the first attenuator, the second attenuator and the low noise amplifier are all arranged in a housing of the receiver front-end circuit;

[0041] The filter and the coupler are integrated together and arranged at the upper left corner of the housing;

[0042] The detector is arranged below the filter and the coupler;

[0043] The first switch unit is arranged at a right adjacent position between the filter and the coupler;

[0044] The first attenuator and the second switch unit are integrated together and arranged at a right adjacent position of the first switch unit;

[0045] The low noise amplifier and the second attenuator are integrated together and arranged at adjacent positions on the right side of the detector.

[0046] It can be seen from the above technical scheme that the utility model provides a receiver front-end circuit, including: the input end of the filter detection unit serves as the input end of the receiver front-end circuit to receive the input signal; the output end of the filter detection unit is connected to the input end of the first switch unit; the control end of the filter detection unit is connected to the control end of the first switch unit and the control end of the second switch unit; the first output end of the first switch unit is connected to the input end of the first attenuation branch; the second output end of the first switch unit is connected to the input end of the second attenuation branch; the output end of the first attenuation branch is connected to the first input end of the second switch unit; the output end of the second attenuation branch is connected to the second input end of the second switch unit; the output end of the second switch unit serves as the output end of the receiver front-end circuit; the noise coefficients of the first attenuation branch and the second attenuation branch are different; therefore, the corresponding attenuation branch can be selected for attenuation according to the power size of the input signal, and the noise coefficient of each attenuation branch is different, and the attenuation branch can be dynamically selected, thereby dynamically changing the sensitivity of the receiver and improving the applicable range of the receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 It is a schematic diagram of a receiver front-end circuit provided by an embodiment of the utility model;

[0049] Figure 2 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model;

[0050] Figure 3 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model;

[0051] Figure 4 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model;

[0052] Figure 5 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model;

[0053] Figure 6 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model;

[0054] Figure 7 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model;

[0055] Figure 8 It is a schematic diagram of another receiver front-end circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0057] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0058] An embodiment of the present application provides a receiver front-end circuit for solving the problem in the prior art that the sensitivity of the receiver is fixed, resulting in low applicability of the receiver.

[0059] The existing microwave system includes a receiver and a transmitter; there are many types of receivers, which can be zero intermediate frequency RF receivers, superheterodyne RF receivers, digital intermediate frequency receivers, etc.; each of the above receivers is used to receive RF signals and down-convert RF signals to intermediate frequency signals, and to adjust the intermediate frequency signals. There are also many types of transmitters, which can be direct modulation transmitters, superheterodyne RF transmitters, digital intermediate frequency transmitters, etc.; each of the above transmitters is used to transmit signals at a certain frequency; the transmission frequency of the transmitter is not specifically limited here, and is within the protection scope of this application.

[0060] Receivers and transmitters have a wide range of applications. For example, they can be used in various civilian or military equipment such as radar, radio, and television. In addition, since the centimeter wave frequency band of receivers and transmitters can combine good coverage with sufficiently large bandwidth, microwave systems with receivers and transmitters occupy a pivotal position in the above-mentioned fields.

[0061] See also Figure 1The receiver front-end circuit includes: a filter detection unit, a first switch unit, a first attenuation branch, a second attenuation branch and a second switch unit.

[0062] The input end of the filter detection unit serves as the input end of the receiver front-end circuit to receive the input signal.

[0063] The input signal may be a radio frequency signal transmitted by a transmitter at a preset frequency, and other signals are certainly not excluded. No specific limitation is made here and all are within the protection scope of this application.

[0064] Specifically, the receiver front-end circuit can receive the input signal through a receiving antenna. Of course, other methods can also be used to receive the input signal. These methods will not be described in detail here. It depends on the actual situation and are all within the protection scope of this application.

[0065] The output end of the filter-detection unit is connected to the input end of the first switch unit.

[0066] That is to say, after the filter-detection unit processes the input signal accordingly, the processed signal is output to the input end of the first switch unit.

[0067] The first output end of the first switch unit is connected to the input end of the first attenuation branch. The second output end of the first switch unit is connected to the input end of the second attenuation branch.

[0068] The output end of the first attenuation branch is connected to the first input end of the second switch unit.

[0069] The output end of the second attenuation branch is connected to the second input end of the second switch unit.

[0070] The output end of the second switch unit serves as the output end of the receiver front-end circuit.

[0071] That is, the first output end of the first switch unit is connected to the first input end of the second switch unit through the first attenuation branch; the second output end of the first switch unit is connected to the second input end of the second switch unit through the second attenuation branch.

[0072] The control end of the filter-detection unit is connected to the control end of the first switch unit and the control end of the second switch unit. The filter-detection unit is used to control the closing position of the first switch unit and the second switch unit, for example, the input end of the first switch unit can be controlled to be connected to its first output end; or, the input end of the first switch unit can be controlled to be connected to its output end; the first input end of the second switch unit can be controlled to be connected to its first output end; or, the second input end of the second switch unit can be controlled to be connected to its output end.

[0073] Specifically, the first switch unit and the second switch unit may each include at least one switch; the switch may be a single-pole double-throw switch, that is, the first switch unit and the second switch unit may each include a single-pole double-throw switch.

[0074] A single-pole double-throw switch consists of a moving end and a fixed end. The moving end is the so-called "pole", which should be connected to the incoming power line, that is, the end of the incoming power, which is generally the end connected to the switch handle; the other two ends are the two ends of the power output, that is, the so-called fixed ends, which are connected to the electrical equipment. Its function is to control the power output in two different directions, that is, it can be used to control two devices, or it can also control the same device to switch the operating direction. Of course, it can also control one of the two power supplies to output in the same direction.

[0075] For example, the fixed end of the single-pole double-throw switch in the first switch unit directly or indirectly serves as the input end of the first switch unit, and the moving end of the single-pole double-throw switch in the first switch unit is connected to the two output ends of the first switch unit; by controlling the throwing state of the single-pole double-throw switch, the output direction of the first switch unit can be determined; by controlling the moving end of the single-pole double-throw switch to be connected to the first output end of the first switch unit, the output direction of the first switch unit is the first attenuation branch; by controlling the moving end of the single-pole double-throw switch to be connected to the second output end of the first switch unit, the output direction of the first switch unit is the second attenuation branch.

[0076] The fixed end of the single-pole double-throw switch in the second switch unit directly or indirectly serves as the output end of the second switch unit, and the moving end of the single-pole double-throw switch in the second switch unit is connected as the two input ends of the second switch unit; by controlling the throwing state of the single-pole double-throw switch, the input direction of the second switch unit can be determined; by controlling the moving end of the single-pole double-throw switch to be connected to the first input end of the second switch unit, the input direction of the second switch unit is the first attenuation branch; by controlling the moving end of the single-pole double-throw switch to be connected to the second input end of the second switch unit, the input direction of the second switch unit is the second attenuation branch.

[0077] Specifically, the filter-detection unit may switch the first attenuation branch and the second attenuation branch by controlling the states of the first switch unit and the second switch unit, thereby realizing a signal transmission channel for the receiver front-end circuit, thereby improving the performance of the microwave system.

[0078] The first attenuation branch and the second attenuation branch have different noise figures.

[0079] Specifically, the first attenuation branch and the second attenuation branch can be provided with different attenuators to achieve different noise coefficients, or different numbers of devices can be cascaded to achieve different noise systems. Of course, other methods are also possible as long as different noise coefficients of different attenuation branches can be achieved.

[0080] The specific values ​​of the noise coefficient of the first attenuation branch and the noise coefficient of the second attenuation branch are not specifically limited here and can be determined according to actual conditions, all of which are within the protection scope of this application.

[0081] It should be noted that there may be one or more first attenuation branches, and in the case of multiple first attenuation branches, the noise coefficients of the various first attenuation branches may be the same or different, and the same applies to the second attenuation branches.

[0082] The receiver front-end circuit provided in this application can be applied to the design of microwave modules capable of realizing power adaptive control in the centimeter wave frequency band, and of course can also be applied to other designs, which will not be described in detail here. The receiver front-end circuit provided in this application is of great significance for the application of microwave systems in the centimeter wave frequency band and with a large power dynamic range.

[0083] In this embodiment, the input end of the filter-detection unit serves as the input end of the receiver front-end circuit and receives the input signal; the output end of the filter-detection unit is connected to the input end of the first switch unit; the control end of the filter-detection unit is connected to the control end of the first switch unit and the control end of the second switch unit; the first output end of the first switch unit is connected to the input end of the first attenuation branch; the second output end of the first switch unit is connected to the input end of the second attenuation branch; the output end of the first attenuation branch is connected to the first input end of the second switch unit; the output end of the second attenuation branch is connected to the second input end of the second switch unit; the output end of the second switch unit serves as the output end of the receiver front-end circuit; the noise coefficients of the first attenuation branch and the second attenuation branch are different; therefore, the corresponding attenuation branch can be selected for attenuation according to the power size of the input signal, and the noise coefficient of each attenuation branch is different, so the attenuation branch can be dynamically selected, thereby dynamically changing the sensitivity of the receiver and improving the applicable range of the receiver.

[0084] It should be noted that, since in most cases the receiver's receiving dynamics are relatively large and this type of link has only one path, it cannot be flexibly adjusted according to the input signal power, and the receiver's receiving dynamic range is usually limited, resulting in poor design versatility of existing receiver front-end circuits.

[0085] In this embodiment, multiple paths are used, and the required paths can be flexibly adjusted according to the power of the input signal, thereby dynamically adjusting the acceptable range of the receiver, thereby improving the versatility of the receiver front-end circuit.

[0086] Optional, see Figure 2 , filter-detection unit, including: filter, detector and coupler.

[0087] The input end of the filter is used as the input end of the filter detection unit; the input end of the filter is connected to the input end of the receiver front-end circuit to receive the input signal. The filter can effectively filter out the frequency point of a specific frequency in the input signal or the frequency outside the frequency point to obtain a power supply signal of a specific frequency, or eliminate a power supply signal after a specific frequency.

[0088] The output of the filter is connected to the input of the coupler.

[0089] The first output end of the coupler is used as the output end of the filter detection unit and is connected to the input end of the first switch unit.

[0090] The second output terminal of the coupler is connected to the input terminal of the detector;

[0091] The coupler can divide an input signal into two signals, one of which is transmitted normally as the main signal, that is, the signal is transmitted to the input end of the first switch unit through its first output end, and the other signal is transmitted to the input end of the detector through its second output end.

[0092] The output end of the detector is used as the control end of the filter detection unit and is connected to the control end of the first switch unit and the control end of the second switch unit respectively.

[0093] The detector can output different level values ​​by detecting the power of the input signal, thereby outputting different level values ​​to the control end of the first switch unit and the control end of the second switch unit, thereby controlling the switching of the first switch unit and the second switch unit, that is, the first switch unit and the second switch unit switch the signal transmission channel when receiving different level values, realizing adaptive control function, thereby improving system performance.

[0094] In this embodiment, through the combination of the filter, the detector and the coupler, the signal transmission channel of the front-end circuit of the receiver can be dynamically switched, and the sensitivity of the receiver can be dynamically changed, thereby improving the application range of the receiver.

[0095] Optionally, the filter-detection unit also includes: a driving circuit.

[0096] The first input terminal of the driving circuit is connected to a reference voltage source; the reference voltage source can provide a V0 voltage. The specific value of the V0 voltage is not specifically limited here and can be determined according to actual conditions, all of which are within the protection scope of this application.

[0097] The second input terminal of the driving circuit is connected to the output terminal of the detector and receives the voltage value output by the detector.

[0098] The output end of the driving circuit serves as the control end of the filter-detection unit and is connected to the control end of the first switch unit and the control end of the second switch unit respectively.

[0099] After receiving the signal distributed by the coupler, the detector detects the power of the signal and outputs different level values ​​to the second input terminal of the driving circuit according to the power. The driving circuit compares the reference voltage V0 with the output voltage V1 of the detector, and outputs corresponding voltage signals to the control terminal of the first switch unit and the control terminal of the second switch unit, thereby controlling the working state of the first switch unit and the second switch unit.

[0100] Optional, see Figure 3 The above-mentioned driving circuit includes: a comparator and a two-stage inverter.

[0101] The first input terminal of the comparator serves as the first input terminal of the driving circuit, is connected to a reference voltage source, and receives a reference voltage.

[0102] The second input terminal of the comparator serves as the second input terminal of the driving circuit, is connected to the output terminal of the detector, and receives the output voltage of the detector.

[0103] The output terminal of the comparator is connected to the input terminal of the two-stage inverter.

[0104] The output end of the two-stage inverter serves as the output end of the driving circuit.

[0105] The two-stage inverter includes a front-stage inverter and a rear-stage inverter, the input end of the front-stage inverter serves as the input end of the two-stage inverter, the output end of the front-stage inverter is connected to the input end of the rear-stage inverter, and the connection point serves as the first end; the output end of the rear-stage inverter serves as the second end, and the first end and the second end serve together as the output end of the two-stage inverter, connecting the control end of the first switch unit and the control end of the second switch unit.

[0106] Specifically, the output signal of the two-stage inverter is jointly determined by the signal at the first end and the signal at the second end. For example, when the signal at the first end is 1 and the signal at the second end is 0, the output signal of the two-stage inverter, that is, the output signal of the driving circuit, is 10; for example, when the signal at the first end is 0 and the signal at the second end is 1, the output signal of the two-stage inverter, that is, the output signal of the driving circuit, is 01.

[0107] When the output signal of the driving circuit is 10, the first switch unit and the second switch unit can be controlled to switch to the signal transmission channel corresponding to the first attenuation branch; when the output signal of the driving circuit is 01, the first switch unit and the second switch unit can be controlled to switch to the signal transmission channel corresponding to the second attenuation branch. Of course, the corresponding relationship between the output signal and the attenuation branch can also be reversed, such as using the second attenuation branch when it is 10; using the first attenuation branch when it is 01; I will not repeat them one by one here, all of which are within the protection scope of this application.

[0108] That is to say, a circuit of a comparator plus a two-stage inverter is used to control the switching operating voltage of the first switch unit and the second switch unit, that is, the operating voltage of the power adaptive control function. For example, the reference voltage of the comparator is V0, and the output voltage of the detector is V1. If V1 is greater than V0, the comparator outputs the voltage V2, and then transmits the output voltage V2 to the two-stage inverter. At this time, two voltage values ​​A and B are output in a cascade manner through the two-stage inverter. The two voltage values ​​A and B are used together as the output signal of the drive circuit. The output signal of the drive circuit acts on the first switch unit and the second switch unit, and then the output signal of the drive circuit controls the first attenuation branch to be turned on and the second attenuation branch to be turned off; or, the second attenuation branch is turned on and the first attenuation branch is turned off.

[0109] Optional, see Figure 4 , the first attenuation branch includes: a first attenuator.

[0110] The input end of the first attenuator serves as the input end of the first attenuation branch and is connected to the first output end of the first switch unit.

[0111] The output end of the first attenuator serves as the output end of the first attenuation branch and is connected to the first input end of the second switch unit.

[0112] Optionally, the second attenuation branch includes: a low noise amplifier and a second attenuator.

[0113] The input end of the low noise amplifier serves as the input end of the second attenuation branch and is connected to the second output end of the first switch unit.

[0114] The output terminal of the low noise amplifier is connected to the input terminal of the second attenuator.

[0115] The output end of the second attenuator serves as the output end of the second attenuation branch and is connected to the second input end of the second switch unit.

[0116] The role of the attenuator is to ensure that the entire receiver is in a linear change state by selecting chips with different attenuation values; the role of the low-noise amplifier is to increase the power of the signal and reduce the noise factor of the system, thereby improving the sensitivity of the entire receiver system.

[0117] The receiver sensitivity formula is Pin, min = -174 (dBm / Hz) + NF (dB) + 10logB (Hz) + SNR, where -174 (dBm / Hz) refers to the thermal noise at room temperature of 25 degrees Celsius; NF (dB) is the noise factor of the receiver; B (Hz) is the channel bandwidth of the receiver; and SNR is the demodulation threshold of the receiver.

[0118] From the above formula, we can see that when the receiver application environment, channel bandwidth and demodulation performance are determined, the only factor that affects the sensitivity is the receiver's noise factor, which is defined as a measure between the receiver's input signal-to-noise ratio and the receiver's output signal-to-noise ratio.

[0119] The formula used for input signal-to-noise ratio and receiver output signal-to-noise ratio is:

[0120] F = (Sin / Nin) / (Sout / Nout).

[0121] Where S is the signal power, N is the noise power, and F is the noise factor.

[0122] In the case of cascade, F=F1+(F2-1) / G1+(F2-1) / G1G2+...+(Fn-1) / G1G2...Gn-1, and NF (dB)=10log(F).

[0123] It can be seen that the noise coefficient of the receiver is mainly affected by the type of devices selected at each stage. When the signal transmission channel is the first attenuation branch, it can ensure that the high-power signal changes linearly; and when the signal transmission channel is the second attenuation branch, it can ensure that the low-power signal has a better noise coefficient, thereby improving the performance of the system and realizing power adaptive control according to the changes of the input signal.

[0124] In this embodiment, a coupler, a detector, a switch unit, an attenuator, etc. are added to the front-end circuit of the receiver, and the linearity parameters of the high-power signal input of the receiver are optimized, which helps to improve the power range received by the system; at the same time, the noise coefficient of the low-power signal input is optimized, thereby improving the signal-to-noise ratio when the low-power model is input, and optimizing the sensitivity index of the receiver system; and power adaptive control is implemented to make the circuit more flexible; that is, while optimizing the sensitivity of the receiver, the versatility, flexibility and adjustability of the receiver are enhanced.

[0125] It should be noted that the design of the receiver front-end circuit in the prior art fixes the sensitivity of the entire receiver, making its versatility poor. For example, when a relatively high-power signal is input, it may cause power saturation in the entire receiver, thereby affecting power detection accuracy and waveform distortion. The input of a relatively low-power signal may cause the signal-to-noise ratio of the signal to deteriorate or the entire receiver may be unable to receive available signal data, thereby causing abnormal demodulation processing or the equipment to fail to work properly.

[0126] In this embodiment, two attenuation branches are used, and an attenuator is set on one attenuation branch to ensure that the high-power signal changes linearly, and an attenuator and a low-noise amplifier are configured on the other branch to ensure that the low-power signal has a good noise coefficient. Because the receiver front-end circuit provided by this application can be applied to high-power signals as well as low-power signals, it can work normally in various situations, improve the power detection accuracy and avoid waveform distortion.

[0127] Optional, see Figure 5 The first attenuator of the first attenuation branch and the second attenuator of the second attenuation branch are both fixed attenuators.

[0128] Optional, see Figure 6 The first attenuator of the first attenuation branch is a digitally controlled attenuator; the second attenuator of the second attenuation branch can be a fixed attenuator or other attenuators, which will not be described here one by one, depending on the actual situation, and are all within the protection scope of this application.

[0129] Fixed attenuators and digitally controlled attenuators essentially have the same function. In comparison, the receiver front-end circuit using a digitally controlled attenuator has a larger adjustable power range, but it requires more control bits, so in actual applications, the optimal form should be selected based on the use environment, system requirements, and control bit margin; that is, the receiver front-end circuit using a digitally controlled attenuator can increase the adjustable dynamics of the receiver, making it more adjustable for actual applications.

[0130] Optional, such as Figure 7 As shown, the length of the receiver front-end circuit is 50mm, the width is 46mm, and the height is 12.2mm.

[0131] Of course, the receiver front-end circuit may also adopt other sizes, which will not be described here one by one. It depends on the actual situation and is within the protection scope of this application.

[0132] Optionally, the filter, the coupler, the detector, the first switch unit, the second switch unit, the first attenuator, the second attenuator and the low noise amplifier are all arranged in a housing of the receiver front-end circuit;

[0133] The filter and coupler are integrated together and set in the upper left corner of the housing.

[0134] like Figure 8 As shown, the filter plus coupler is set at position 1, and the filter is set before the coupler to filter out useless signals before transmitting them to the coupler.

[0135] The detector is arranged below the filter and the coupler.

[0136] The detector is set at position 4.

[0137] The first switch unit is arranged at a right adjacent position of the filter and the coupler.

[0138] The first switch unit is disposed at position 2.

[0139] The first attenuator and the second switch unit are integrated together and arranged at a right adjacent position of the first switch unit.

[0140] The first attenuator and the second switch unit are arranged at position 3. Placing the two devices together can reduce excessive openings on the microstrip line and reduce power loss.

[0141] The low noise amplifier and the second attenuator are integrated together and arranged adjacent to the right side of the detector.

[0142] The low noise amplifier and the second attenuator are set at position 5. On the one hand, they can reduce the opening of the microstrip line, and on the other hand, they can improve the standing wave ratio of the circuit. The standing wave ratio is called voltage standing wave ratio, also known as VSWR and SWR, which is the abbreviation of Voltage Standing Wave Ratio in English. It refers to the ratio of the standing wave antinode voltage to the trough voltage amplitude, also known as standing wave coefficient or standing wave ratio. When the standing wave ratio is equal to 1, it means that the impedance of the feed line and the antenna is completely matched. At this time, all the high-frequency energy is radiated by the antenna, and there is no energy reflection loss; when the standing wave ratio is infinite, it means total reflection, and no energy is radiated at all.

[0143] Specifically, as the design specification of the receiver front-end circuit shows, position 1 must be a filter plus a coupler; as the circuit structure of the coupler shows, position 4 must be at the bottom; as the function of the circuit shows, positions 2 and 3 must be the placement of the first switch unit, the first attenuator, and the second switch unit, and position 5 must be a low-noise amplifier plus a second attenuator. It can be seen that the placement relationship of the receiver front-end circuit presents a symmetrical relationship between the upper and lower paths, thereby reducing the horizontal length and the volume of the receiver front-end circuit.

[0144] Since the receiver front-end circuit presents an asymmetric structure as a whole, the local part of the receiver front-end circuit may present a symmetrical structure, that is, the two switch units are symmetrical about the midpoint of the first attenuation branch and the second attenuation branch. Therefore, in terms of position placement, the overall receiver front-end circuit may adopt an asymmetric structure, and the local part of the receiver front-end circuit (two switch units and attenuation branches) may adopt a symmetrical structure. The overall asymmetric structure of the receiver front-end circuit can reduce the lateral length of the receiver front-end circuit, so that the lateral occupancy ratio can be reduced in specific application scenarios; the symmetrical structure of the local part of the receiver front-end circuit can optimize the balance stability of the local circuit and have better overall aesthetics.

[0145] The features recorded in the various embodiments in this specification can be replaced or combined with each other, and the same and similar parts between the various embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative work.

[0146] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present utility model.

[0147] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A receiver front-end circuit, characterized in that: include: A filter detection unit, a first switch unit, a first attenuation branch, a second attenuation branch and a second switch unit; The input end of the filter detection unit serves as the input end of the receiver front-end circuit to receive the input signal; The output end of the filter detection unit is connected to the input end of the first switch unit; The control end of the filter detection unit is connected to the control end of the first switch unit and the control end of the second switch unit; The first output end of the first switch unit is connected to the input end of the first attenuation branch; The second output end of the first switch unit is connected to the input end of the second attenuation branch; The output end of the first attenuation branch is connected to the first input end of the second switch unit; The output end of the second attenuation branch is connected to the second input end of the second switch unit; The output end of the second switch unit serves as the output end of the receiver front-end circuit; The first attenuation branch and the second attenuation branch have different noise coefficients.

2. The receiver front-end circuit according to claim 1, characterized in that: The filter-detection unit comprises: a filter, a detector and a coupler; The input end of the filter serves as the input end of the filter detection unit; The output end of the filter is connected to the input end of the coupler; The first output end of the coupler serves as the output end of the filter-detection unit; The second output end of the coupler is connected to the input end of the detector; The output end of the detector serves as the control end of the filter-detection unit.

3. The receiver front-end circuit according to claim 2, characterized in that: The filter detection unit further includes: a driving circuit; The first input terminal of the driving circuit is connected to a reference voltage source; The second input terminal of the driving circuit is connected to the output terminal of the detector; The output end of the driving circuit serves as the control end of the filter detection unit.

4. The receiver front-end circuit according to claim 3, characterized in that: The driving circuit comprises: a comparator and a two-stage inverter; The first input terminal of the comparator serves as the first input terminal of the driving circuit; The second input terminal of the comparator serves as the second input terminal of the driving circuit; The output end of the comparator is connected to the input end of the two-stage inverter; The output end of the two-stage inverter serves as the output end of the driving circuit.

5. The receiver front-end circuit according to claim 1, characterized in that: The first attenuation branch comprises: a first attenuator; The input end of the first attenuator serves as the input end of the first attenuation branch; The output end of the first attenuator serves as the output end of the first attenuation branch.

6. The receiver front-end circuit according to claim 1, characterized in that: The second attenuation branch includes: a low noise amplifier and a second attenuator; The input end of the low noise amplifier serves as the input end of the second attenuation branch; The output end of the low noise amplifier is connected to the input end of the second attenuator; The output end of the second attenuator serves as the output end of the second attenuation branch.

7. The receiver front-end circuit according to claim 1, characterized in that: The first attenuator of the first attenuation branch and the second attenuator of the second attenuation branch are both fixed attenuators.

8. The receiver front-end circuit according to claim 1, characterized in that: The first attenuator of the first attenuation branch is a digitally controlled attenuator.

9. The receiver front-end circuit according to claim 4, characterized in that: The receiver front-end circuit has a length of 50 mm, a width of 46 mm, and a height of 12.2 mm.

10. The receiver front-end circuit according to claim 9, characterized in that: The filter, the coupler, the detector, the first switch unit, the second switch unit, the first attenuator, the second attenuator and the low noise amplifier are all arranged in the housing of the receiver front-end circuit; The filter and the coupler are integrated together and arranged at the upper left corner of the housing; The detector is arranged below the filter and the coupler; The first switch unit is arranged at a right adjacent position between the filter and the coupler; The first attenuator and the second switch unit are integrated together and arranged at a right adjacent position of the first switch unit; The low noise amplifier and the second attenuator are integrated together and arranged at adjacent positions on the right side of the detector.

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