Low noise amplifier circuit and low noise amplifier

Abstract

The utility model provides a low-noise amplifier circuit and a low-noise amplifier, the low-noise amplifier circuit comprises a low-noise amplification module and an automatic gain adjustment module, the input end of the low-noise amplification module is connected with the input end of the low-noise amplifier circuit; the output end of the low-noise amplifier module is used as the output end of the low-noise amplifier circuit; the input end of the automatic gain adjusting module is connected with the output end of the low-noise amplification module, and the output end of the automatic gain adjusting module is connected with the input end of the low-noise amplification module. According to the low-noise amplifier, the automatic gain adjusting module is arranged, and meanwhile, the gain adjusting signal output by the automatic gain adjusting module is generated based on the difference between the output signal and the preset power, so that the power of the output signal, adjusted by the gain adjusting signal, of the low-noise amplifier module is stable, and the linearity of the low-noise amplifier is enhanced; and signal distortion is avoided.

Description

Technical Field

[0001] The utility model relates to the field of wireless transmission, in particular to a low noise amplifier circuit and a low noise amplifier. Background Art

[0002] Due to energy loss during signal transmission, the signal quality received by the antenna end of the RF receiver is poor, and the receiver's low-noise amplifier is required to amplify the weak signal; when amplifying the lower-power signal received by the antenna, the output power of the low-noise amplifier will increase with the increase of input power. The output power is equal to the sum of the input power of the signal and the amplifier gain. At this time, the low-noise amplifier is in a linear working state; when the power of the input signal exceeds the 1dB compression point of the amplifier, the amplifier is in a nonlinear state, and the output signal passing through the amplifier will be severely distorted. Utility Model Content

[0003] The main purpose of the utility model is to provide a low noise amplifier circuit and a low noise amplifier, aiming to solve the problem of distortion caused by amplification by the low noise amplifier when the input signal power is too large in the prior art.

[0004] To achieve the above object, the utility model provides a low-noise amplifier circuit, which includes a low-noise amplifier module and an automatic gain adjustment module, wherein the input end of the low-noise amplifier module is connected to the input end of the low-noise amplifier circuit, and the output end of the low-noise amplifier module serves as the output end of the low-noise amplifier circuit; the input end of the automatic gain adjustment module is connected to the output end of the low-noise amplifier module, and the output end of the automatic gain adjustment module is connected to the input end of the low-noise amplifier module; wherein:

[0005] The low-noise amplifier module is used to amplify the input signal to obtain an output signal;

[0006] The automatic gain adjustment module is used to generate a gain adjustment signal according to the difference between the parameter information corresponding to the output signal and the preset power parameter, and feed the gain adjustment signal back to the low-noise amplifier module to adjust the amplification gain of the low-noise amplifier module.

[0007] Optionally, the automatic gain adjustment module includes an automatic gain adjustment unit and a sensitivity setting unit; the input end of the automatic gain adjustment unit is connected to the output end of the low-noise amplification module through the sensitivity setting unit, and the output end of the automatic gain adjustment unit is connected to the input end of the low-noise amplification module.

[0008] Optionally, the automatic gain adjustment unit includes an error integration subunit, a reference power supply subunit and a peak detection subunit; wherein the peak detection subunit includes a first peak detection subunit and a second peak detection subunit, the reference power supply subunit is connected to the first input end of the error integration subunit through the first peak detection subunit, the voltage stabilization subunit is connected to the second input end of the error integration subunit through the sensitivity setting unit and the second peak detection subunit in sequence, and the output end of the error integration subunit serves as the output end of the automatic gain adjustment subunit.

[0009] Optionally, the error integrator unit includes a first amplifier, a first resistor, a first capacitor and a first inductor; wherein:

[0010] The inverting input terminal of the first amplifier serves as the first input terminal of the error integrator unit, the non-inverting input terminal of the first amplifier serves as the second input terminal of the error integrator unit, the output terminal of the first amplifier is connected to the inverting input terminal of the first amplifier through the first resistor and the first capacitor respectively, the output terminal of the first amplifier is also connected to the first terminal of the first inductor, and the second terminal of the first inductor serves as the output terminal of the error integrator unit.

[0011] Optionally, the peak detection subunit includes a first diode, a second capacitor, a second resistor and a third resistor; wherein:

[0012] The anode of the first diode is connected to the voltage stabilizing subunit or the sensitivity setting unit, the cathode of the first diode is grounded through the second resistor and the second capacitor respectively, and the cathode of the first diode is also connected to the error integrator subunit through the third resistor.

[0013] Optionally, the sensitivity setting unit includes a third capacitor, a sensitivity adjustment subunit, and a fourth resistor; wherein:

[0014] The first end of the sensitivity adjustment subunit is connected to the output end of the low noise amplifier module, the second end of the sensitivity adjustment subunit is connected to the second peak detection subunit through the third capacitor, and the fourth resistor is connected between the voltage stabilizing subunit and the second peak detection subunit.

[0015] Optionally, the sensitivity adjustment subunit is a variable resistor.

[0016] Optionally, the automatic gain adjustment unit further includes a voltage stabilizing subunit, and the voltage stabilizing subunit is connected between the reference supply subunit and the first peak detection subunit.

[0017] Optionally, the low-noise amplifier circuit further includes a compatible amplification module; the input end of the compatible amplification module is connected to the input end of the low-noise amplification module, and the output end of the compatible amplification module is connected to the output end of the low-noise amplification module; wherein:

[0018] The compatible amplifying module and the low-noise amplifying module have different modulation modes.

[0019] In addition, to achieve the above object, the utility model also provides a low noise amplifier, which includes a housing and the low noise amplifier circuit as described above, and the low noise amplifier circuit is arranged in the housing.

[0020] The utility model proposes a low-noise amplifier circuit and a low-noise amplifier, wherein the low-noise amplifier circuit includes a low-noise amplifier module and an automatic gain adjustment module, wherein the input end of the low-noise amplifier module is connected to the input end of the low-noise amplifier circuit, and the output end of the low-noise amplifier module is used as the output end of the low-noise amplifier circuit; the input end of the automatic gain adjustment module is connected to the output end of the low-noise amplifier module, and the output end of the automatic gain adjustment module is connected to the input end of the low-noise amplifier module; wherein: the low-noise amplifier module is used to amplify the input signal to obtain an output signal; the automatic gain adjustment module is used to generate a gain adjustment signal according to the difference between the parameter information corresponding to the output signal and the preset power parameter, and feed the gain adjustment signal back to the low-noise amplifier module to adjust the amplification gain of the low-noise amplifier module. By setting the automatic gain adjustment module, at the same time, the gain adjustment signal output by the automatic gain adjustment module is generated based on the difference between the output signal and the preset power, so that the power of the output signal of the low-noise amplifier module adjusted by the gain adjustment signal is stable, the linearity of the low-noise amplifier is enhanced, and signal distortion is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0022] Figure 1 It is a functional module diagram of an embodiment of a low noise amplifier circuit of the utility model;

[0023] Figure 2 This is a circuit structure diagram of an embodiment of a low noise amplifier circuit of the utility model;

[0024] Figure 3 This is a circuit diagram of an embodiment of a low noise amplifier circuit of the utility model;

[0025] Figure 4 This is a circuit diagram of an embodiment of a low noise amplifier circuit of the utility model;

[0026] Figure 5 It is a signal waveform diagram when the existing low noise amplifier is used;

[0027] Figure 6 This is a signal waveform diagram when the low noise amplifier of the utility model is used;

[0028] Figure 7 This is a waveform diagram of an FM signal when a low-noise amplifier having a compatible amplification module is used in the utility model;

[0029] Figure 8 The figure is a DAB signal waveform diagram when the low noise amplifier provided with a compatible amplification module in the utility model is used.

[0030] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

[0031] Description of Figure Numbers:

[0032] Label name Label name 100 Automatic gain adjustment module R1~R5 The first resistor to the fifth resistor 110 Automatic gain control unit C1~C3 First capacitor to third capacitor 111 Error Integrator D1 The first diode 1121 The first peak detection subunit L1 First Inductor 1122 The second peak detection subunit Q1 First Amplifier 113 Reference power supply unit S1 The first transistor 114 Voltage regulator unit S2 The second transistor 120 Sensitivity setting unit 300 Compatible amplifier modules 121 Sensitivity adjustment subunit RT Variable resistor 200 Low noise amplifier module DETAILED DESCRIPTION

[0033] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments 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.

[0035] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0037] The utility model provides a low noise amplifier circuit, which is used in low noise amplifiers. Figure 1 , Figure 1 This is a functional module diagram of an embodiment of the low-noise amplifier circuit of the utility model. In this embodiment, the low-noise amplifier circuit includes a low-noise amplifier module 200 and an automatic gain adjustment module 100, the input end of the low-noise amplifier module 200 is connected to the input end of the low-noise amplifier circuit, and the output end of the low-noise amplifier module 200 serves as the output end of the low-noise amplifier circuit; the input end of the automatic gain adjustment module 100 is connected to the output end of the low-noise amplifier module 200, and the output end of the automatic gain adjustment module 100 is connected to the input end of the low-noise amplifier module 200; wherein:

[0038] The low noise amplifier module 200 is used to amplify the input signal to obtain an output signal;

[0039] The automatic gain adjustment module 100 is used to generate a gain adjustment signal according to the difference between the parameter information corresponding to the output signal and the preset power parameter, and feed the gain adjustment signal back to the low-noise amplifier module 200 to adjust the amplification gain of the low-noise amplifier module 200.

[0040] The low-noise amplifier module 200 amplifies the input signal; the automatic gain adjustment module 100 is used to adjust the amplification gain of the low-noise amplifier module 200; it can be understood that different amplification gains of the low-noise amplifier module 200 have different amplification effects on the input signal, and the output signal of the low-noise amplifier module 200 is also different. Therefore, adjusting the amplification gain of the low-noise amplifier module 200 can achieve the adjustment of the output signal.

[0041] The preset power parameter is the expected power of the output signal; it should be noted that the preset power parameter does not necessarily indicate a specific set power value, but can be a dynamic balance of the output signal power based on device settings and parameter settings. When this dynamic balance is achieved, the low-noise amplifier can be considered to have a stable power output.

[0042] In this embodiment, the gain adjustment signal is generated based on the difference between the parameter information corresponding to the output signal and the preset power parameter; therefore, by adjusting the amplification gain of the low-noise amplifier module 200 through the gain adjustment signal, the difference between the parameter information corresponding to the adjusted output signal and the preset power parameter can be reduced, thereby ensuring the stability of the output signal power. In practical applications, the gain adjustment signal is mainly used to suppress the increase of the output signal power. It can be understood that when the power of the input signal is small, the output power of the low-noise amplifier and the power of the input signal are linearly amplified, and when the power of the input signal exceeds the 1dB point of the low-noise amplifier, the low-noise amplifier presents nonlinear amplification for the input signal. As the power of the input signal increases, the output signal will be severely distorted, and further even cause system saturation and damage; and when the preset power parameter remains stable, when the power of the output signal is too large, the gain adjustment signal will reduce the difference between the output signal and the preset power parameter, that is, suppress the increase of the output signal, thereby ensuring the stability of the power output.

[0043] In this embodiment, an automatic gain adjustment module 100 is provided. At the same time, a gain adjustment signal output by the automatic gain adjustment module 100 is generated based on the difference between parameter information corresponding to the output signal and a preset power parameter, thereby stabilizing the power of the output signal of the low-noise amplifier module 200 adjusted by the gain adjustment signal, enhancing the linearity of the low-noise amplifier, and avoiding signal distortion.

[0044] Further, see Figure 2 The automatic gain adjustment module 100 includes an automatic gain adjustment unit 110 and a sensitivity setting unit 120; the input end of the automatic gain adjustment unit 110 is connected to the output end of the low-noise amplification module 200 through the sensitivity setting unit 120, and the output end of the automatic gain adjustment unit 110 is connected to the input end of the low-noise amplification module 200.

[0045] The sensitivity setting unit 120 is used to set the sensitivity of the automatic gain adjustment unit 110 in responding to the output power. Specifically, when the sensitivity is set to a higher value, the automatic gain adjustment unit 110 is more sensitive to the power change of the output power, the number of adjustments to the output power is more, and the output power is adjusted when the increase of the output power is low. On the contrary, when the sensitivity is set to a lower value, the automatic gain adjustment unit 110 is not sensitive to the power change of the output power, the number of adjustments to the output power is less, and the output power is adjusted when the increase of the output power is high.

[0046] By setting the sensitivity setting unit 120 , the gain adjustment degree of the automatic gain adjustment unit 110 for the low noise amplification module 200 can be set, so as to adapt to more application scenarios.

[0047] Further, the automatic gain adjustment unit 110 includes an error integration subunit 111, a reference power supply subunit 113 and a peak detection subunit; wherein the peak detection subunit includes a first peak detection subunit 1121 and a second peak detection subunit 1122, the reference power supply subunit 113 is connected to the first input end of the error integration subunit 111 through the first peak detection subunit 1121, the reference power supply subunit 113 is connected to the second input end of the error integration subunit 111 through the sensitivity setting unit 120 and the second peak detection subunit 1122 in sequence, and the output end of the error integration subunit 111 serves as the output end of the automatic gain adjustment subunit.

[0048] The reference supply subunit 113 is used to provide a stable reference voltage;

[0049] The peak detection subunit is used to obtain a modulation signal corresponding to the signal, and output the modulation signal to the error integration subunit 111;

[0050] The first peak detection subunit 1121 obtains a modulation signal corresponding to the reference voltage; the second peak detection subunit 1122 obtains a modulation signal corresponding to the output signal.

[0051] The error integrator unit 111 is used to compare the reference voltage with the modulation signal corresponding to the output signal, and continuously integrate the difference between the reference voltage and the modulation signal corresponding to the output signal, and obtain the gain adjustment signal after the error integrator unit 111 is stable.

[0052] Furthermore, the error integrator unit 111 includes a first amplifier Q1, a first resistor R1, a first capacitor C1 and a first inductor L1; wherein:

[0053] The inverting input terminal of the first amplifier Q1 serves as the first input terminal of the error integrator unit 111, the non-inverting input terminal of the first amplifier Q1 serves as the second input terminal of the error integrator unit 111, the output terminal of the first amplifier Q1 is connected to the inverting input terminal of the first amplifier Q1 through the first resistor R1 and the first capacitor C1 respectively, the output terminal of the first amplifier Q1 is also connected to the first terminal of the first inductor L1, and the second terminal of the first inductor L1 serves as the output terminal of the error integrator unit 111.

[0054] The first amplifier Q1, the first resistor R1, and the first capacitor C1 form an integrator. The first amplifier Q1 obtains a difference by comparing the modulated signals input at the two input terminals, and integrates the difference. At the same time, the signal output by the first amplifier Q1 based on the difference returns to the inverting input terminal of the first amplifier Q1 through the first resistor R1 and the first capacitor C1, and the cycle repeats until the difference disappears and the integrator is stable. The first amplifier Q1 outputs a gain adjustment signal to the low-noise amplifier module 200 through the first inductor L1.

[0055] Furthermore, the peak detection subunit includes a first diode D1, a second capacitor C2, a second resistor R2 and a third resistor R3; wherein:

[0056] The anode of the first diode D1 is connected to the reference power supply subunit 113 or the sensitivity setting unit 120, the cathode of the first diode D1 is grounded through the second resistor R2 and the second capacitor C2 respectively, and the cathode of the first diode D1 is also connected to the error integrator unit 111 through the third resistor R3.

[0057] When the first diode D1 is turned on, the signal charges the second capacitor C2, and the voltage across the capacitor gradually increases. When the signal peak is reached, the voltage begins to decrease, and the voltage on the second resistor R2 cannot be maintained. The second capacitor C2 begins to discharge to the second resistor R2, thereby realizing the detection of the signal peak and obtaining the corresponding modulation signal.

[0058] Further, the sensitivity setting unit 120 includes a third capacitor C3, a sensitivity adjustment subunit 121 and a fourth resistor R4; wherein:

[0059] The first end of the sensitivity adjustment subunit 121 is connected to the output end of the low noise amplification module 200, the second end of the sensitivity adjustment subunit 121 is connected to the second peak detection subunit 1122 through the third capacitor C3, and the fourth resistor R4 is connected between the reference power supply subunit 113 and the second peak detection subunit 1122.

[0060] The input signal is transmitted to the second peak detection subunit 1122 through the sensitivity adjustment subunit 121, and the voltage signal output by the reference power supply subunit 113 is transmitted to the second peak detection subunit 1122 through the fourth resistor R4;

[0061] Furthermore, the sensitivity adjustment subunit 121 is a variable resistor RT.

[0062] In order to facilitate the adjustment of the sensitivity of the sensitivity setting unit 120, in this embodiment, the sensitivity adjustment subunit 121 is set as a variable resistor RT, so that when the sensitivity needs to be adjusted, it can be achieved by directly adjusting the resistance value of the sensitivity adjustment subunit 121 without replacing the sensitivity adjustment subunit 121 with a different resistance value.

[0063] It can be understood that, the larger the resistance value of the variable resistor RT is, the more voltage the variable resistor RT obtains, and the smaller the voltage of the input signal output to the second peak detection subunit 1122 is, and therefore, the sensitivity of the automatic gain adjustment unit 110 to the input signal is lower; conversely, the smaller the resistance value of the variable resistor RT is, the smaller the voltage the variable resistor RT obtains, and the larger the voltage of the input signal output to the second peak detection subunit 1122 is, and therefore, the sensitivity of the automatic gain adjustment unit 110 to the input signal is higher.

[0064] Furthermore, the automatic gain adjustment unit 110 further includes a voltage stabilizing subunit 114 , and the voltage stabilizing subunit 114 is connected between the reference supply subunit 113 and the first peak detection subunit 1121 .

[0065] The preset power parameter in this embodiment is a preset voltage; the reference power supply subunit 113 provides a voltage output for the error integrator subunit 111, and the preset voltage output to the error integrator subunit 111 is set by the voltage stabilizing subunit 114, so that the error integrator subunit 111 compares the preset voltage with the output signal, and continuously integrates the difference between the two to obtain a gain adjustment signal.

[0066] The specific structure of the low noise amplifier module 200 can be set based on the actual application scenario. Figure 3 , the configurable structure of the low noise amplifier module 200 in one case is described:

[0067] The low-noise amplifier module 200 amplifies the input signal through the amplification effect of the first transistor S1. According to the transistor principle, the larger the transistor base current, the larger the collector output current; in the amplified state, the transistor base current and the collector current are linearly amplified, and in the saturated state, the transistor base current and the collector current are nonlinearly amplified.

[0068] The base of the first transistor S1 is connected to the input terminal TI of the low noise amplifier, and the collector of the first transistor S1 is connected to the output terminal TO of the low noise amplifier to amplify the input signal; specifically, in one embodiment, the specific structure of the low noise amplification module can be:

[0069] The output terminal of the automatic gain adjustment module 100 is connected to the input terminal TI of the low noise amplifier;

[0070] The input terminal TI of the low noise amplifier is connected to the base of the first transistor S1 through the fourth capacitor C4, and the input terminal TI of the low noise amplifier is also forward grounded through the second diode D2;

[0071] The input terminal TI of the low noise amplifier is also grounded via a third diode D3 and an RC circuit in sequence, wherein the third diode is forwardly grounded, and the RC circuit is composed of a fifth resistor R5 and a fourth capacitor C4 connected in parallel;

[0072] The base of the first transistor S1 is connected to the collector of the first transistor S1 through the sixth capacitor C6 and the sixth resistor R6 in sequence;

[0073] The base of the first transistor S1 is connected to the first end of the seventh resistor R7, and the second end of the seventh resistor R7 is connected to the collector of the first transistor S1 through an LC circuit, and the LC circuit is composed of a second inductor L2 and a seventh capacitor C7 connected in parallel; the second end of the seventh resistor R7 is also grounded through an eighth capacitor C8; the second end of the seventh resistor R7 is also connected to the positive electrode of the power supply through the eighth resistor R8, and the positive electrode of the power supply is also grounded through a ninth resistor R9;

[0074] The collector of the first transistor S1 is connected to the first end of the tenth capacitor C10, the second end of the tenth capacitor C10 is grounded through the ninth resistor R9, the second end of the tenth capacitor C10 is also grounded through the eleventh resistor R11 and the twelfth resistor R12, the end of the eleventh resistor R11 away from the tenth resistor R10 is connected to the output end TO of the low noise amplifier, and the output end TO of the low noise amplifier is also forward grounded through the fourth diode D4;

[0075] The emitter of the first transistor S1 is grounded through the twelfth resistor R12.

[0076] The peripheral devices of the first transistor S1 can be configured based on actual application requirements, which will not be described in detail here.

[0077] Further, see Figure 4 , the low noise amplifier circuit further includes a compatible amplification module 300; the input end of the compatible amplification module 300 is connected to the input end of the low noise amplification module 200, and the output end of the compatible amplification module 300 is connected to the output end of the low noise amplification module 200; wherein:

[0078] The compatible amplifying module 300 and the low noise amplifying module 200 have different modulation modes.

[0079] In practical applications, a receiver using a low noise amplifier may need to support different modulation modes, such as AM (Amplitude Modulation), FM (Frequency Modulation), and DAB (Digital Audio Broadcasting). This embodiment sets a compatible amplification module 300 to enable amplification of input signals of different modulation modes.

[0080] The low noise amplifying module 200 and the compatible amplifying module 300 respectively amplify the received input signals and then output them; the specific structure of the compatible amplifying module 300 can be set based on the actual corresponding modulation mode.

[0081] Furthermore, the modulation mode of the low noise amplifying module 200 is FM, and the modulation mode of the compatible amplifying module 300 is DAB.

[0082] In this embodiment, the low noise amplifying module 200 is used to amplify the FM input signal, and the compatible amplifying module 300 is used to amplify the DAB input signal.

[0083] The compatible amplification module 300 can also amplify the input signal through the amplification effect of the second transistor S2; the base of the second transistor S2 is connected to the input terminal TI of the low-noise amplifier, and the collector of the second transistor S2 is connected to the output terminal TO of the low-noise amplifier to amplify the input signal; specifically, in one embodiment, the specific structure of the compatible amplification module can be:

[0084] The input terminal TI of the low noise amplifier is connected to the base of the second transistor S2 through the third inductor L3, the fourth inductor L4, and the twelfth capacitor C12 in sequence, and the input terminal TI of the low noise amplifier is also forward grounded through the fifth diode D5;

[0085] A connection point between the third inductor L3 and the fourth inductor L4 is grounded via an eleventh capacitor;

[0086] The base of the second transistor S2 is connected to the collector of the second transistor S2 via a thirteenth capacitor C13 and a thirteenth resistor R13 in sequence;

[0087] The base of the second transistor S2 is connected to the first end of the fourteenth resistor R14, and the second end of the fourteenth resistor R14 is connected to the collector of the second transistor S2 through an LC circuit, and the LC circuit is composed of a fifth inductor L5 and a fourteenth capacitor C14 connected in parallel; the second end of the fourteenth resistor R14 is also grounded through a fifteenth capacitor C15; the fourteenth resistor R14 is also connected to the positive electrode of the power supply through the fifteenth resistor R15, and the positive electrode of the power supply is also grounded through a sixteenth resistor R16;

[0088] The collector of the second transistor S2 is connected to the first end of the seventeenth capacitor C17, the second end of the seventeenth capacitor C17 is grounded through the eighteenth capacitor C18, and the second end of the seventeenth capacitor C17 is connected to the output terminal TO of the low noise amplifier through the sixth inductor L6;

[0089] The emitter of the second transistor S2 is grounded through the sixteenth resistor R16.

[0090] The peripheral devices of the second transistor S2 can be configured based on actual application requirements, which will not be described in detail here.

[0091] The utility model also protects a low noise amplifier, which includes a housing and a low noise amplifier circuit, and the low noise amplifier circuit is arranged in the housing. The structure of the low noise amplifier circuit can refer to the above embodiment, and will not be repeated here. As a matter of course, since the low noise amplifier of this embodiment adopts the technical solution of the above low noise amplifier circuit, the low noise amplifier has all the beneficial effects of the above low noise amplifier circuit.

[0092] See also Figure 5 , Figure 5 It is a signal waveform diagram when the existing low noise amplifier is used; Figure 5 It can be seen that the IM3 value of the existing low noise amplifier is 50dBM;

[0093] See also Figure 6 , Figure 6 is a signal waveform diagram when the low noise amplifier of the utility model is used; Figure 6 It can be seen that the IM3 value of the low noise amplifier of the utility model is 61dBM; the low noise amplifier of the utility model has a very high linearity, and the test value of IM3 is about 10dB higher than that of the same type of products, which will make the whole system more stable.

[0094] When the low noise amplifier is equipped with a compatible amplifier module, due to the interference between the two circuits, the measured IM3 value is slightly lower than that of the single channel on the basis of other indicators remaining unchanged, see Figure 7 , Figure 7 The FM signal waveform diagram when the low noise amplifier compatible with the amplification module 300 is used in the utility model is provided. Figure 7 It can be seen that the IM3 value of the FM circuit is 54dBM. Figure 8 , Figure 8 The DAB signal waveform diagram when the low noise amplifier compatible with the amplifier module 300 is used in the utility model is composed of: Figure 8It can be seen that the IM3 value of the DAB part circuit is 44dBM. When the two modulation modes are combined, the IM3 value of the FM part circuit of the utility model is still about 4dB higher than that of similar products, and the IM3 value of the DAB part circuit can also be stabilized at around 50dBM, thereby improving the stability and linearity of the entire system.

[0095] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or system including the element. The serial numbers of the above-mentioned embodiments of the utility model are for description only and do not represent the advantages and disadvantages of the embodiments.

[0096] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A low noise amplifier circuit, characterized in that: The low-noise amplifier circuit comprises a low-noise amplifier module and an automatic gain adjustment module, the input end of the low-noise amplifier module is connected to the input end of the low-noise amplifier circuit, and the output end of the low-noise amplifier module serves as the output end of the low-noise amplifier circuit; the input end of the automatic gain adjustment module is connected to the output end of the low-noise amplifier module, and the output end of the automatic gain adjustment module is connected to the input end of the low-noise amplifier module; wherein: The low-noise amplifier module is used to amplify the input signal to obtain an output signal; The automatic gain adjustment module is used to generate a gain adjustment signal according to the difference between the parameter information corresponding to the output signal and the preset power parameter, and feed the gain adjustment signal back to the low-noise amplifier module to adjust the amplification gain of the low-noise amplifier module; The automatic gain adjustment module includes an automatic gain adjustment unit and a sensitivity setting unit; the input end of the automatic gain adjustment unit is connected to the output end of the low noise amplification module through the sensitivity setting unit, and the output end of the automatic gain adjustment unit is connected to the input end of the low noise amplification module; The automatic gain adjustment unit includes an error integration subunit, a reference power supply subunit and a peak detection subunit; wherein the peak detection subunit includes a first peak detection subunit and a second peak detection subunit, the reference power supply subunit is connected to the first input end of the error integration subunit through the first peak detection subunit, the reference power supply subunit is connected to the second input end of the error integration subunit through the sensitivity setting unit and the second peak detection subunit in sequence, and the output end of the error integration subunit serves as the output end of the automatic gain adjustment unit; The error integrator unit includes a first amplifier, a first resistor, a first capacitor and a first inductor; wherein: The inverting input terminal of the first amplifier serves as the first input terminal of the error integrator unit, the non-inverting input terminal of the first amplifier serves as the second input terminal of the error integrator unit, the output terminal of the first amplifier is connected to the inverting input terminal of the first amplifier through the first resistor and the first capacitor respectively, the output terminal of the first amplifier is also connected to the first terminal of the first inductor, and the second terminal of the first inductor serves as the output terminal of the error integrator unit.

2. The low noise amplifier circuit according to claim 1, characterized in that The peak detection subunit includes a first diode, a second capacitor, a second resistor and a third resistor; wherein: The anode of the first diode is connected to the reference power supply subunit or the sensitivity setting unit, the cathode of the first diode is grounded through the second resistor and the second capacitor respectively, and the cathode of the first diode is also connected to the error integrator subunit through the third resistor.

3. The low noise amplifier circuit according to claim 1, wherein: The sensitivity setting unit includes a third capacitor, a sensitivity adjustment subunit, and a fourth resistor; wherein: The first end of the sensitivity adjustment subunit is connected to the output end of the low noise amplifier module, the second end of the sensitivity adjustment subunit is connected to the second peak detection subunit through the third capacitor, and the fourth resistor is connected between the reference power supply subunit and the second peak detection subunit.

4. The low noise amplifier circuit according to claim 3, characterized in that: The sensitivity adjustment subunit is a variable resistor.

5. The low noise amplifier circuit according to claim 1, wherein: The automatic gain adjustment unit further comprises a voltage stabilizing subunit, and the voltage stabilizing subunit is connected between the reference supply subunit and the first peak detection subunit.

6. The low noise amplifier circuit according to claim 1, wherein: The low noise amplifier circuit further includes a compatible amplification module; the input end of the compatible amplification module is connected to the input end of the low noise amplification module, and the output end of the compatible amplification module is connected to the output end of the low noise amplification module; wherein: The compatible amplifying module and the low-noise amplifying module have different modulation modes.

7. A low noise amplifier, characterized in that: The low noise amplifier comprises a housing and the low noise amplifier circuit according to any one of claims 1 to 6, wherein the low noise amplifier circuit is arranged in the housing.

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