Ultra-wideband high-dynamic range automatic gain control receiver

Abstract

The invention provides an ultra-wideband high-dynamic-range automatic gain control receiver, which comprises a mode selection unit used for receiving a radio frequency signal which is output by an amplitude limiter and has a frequency range of 6-18GHz, and branching and inputting the radio frequency signal according to the input signal strength of the radio frequency signal to obtain input signals under different mode selections; the down-conversion link unit adopts three times of frequency mixing and is used for converting the received radio-frequency signal into a required intermediate-frequency signal, branching the input signal according to different frequencies of the input signal and carrying out the first time of frequency mixing to obtain a first intermediate-frequency signal, and then carrying out the second time of frequency mixing and the third time of frequency mixing on the first intermediate-frequency signal in sequence to obtain a third intermediate-frequency signal; frequency mixing is carried out on the received signal and a local oscillation signal provided by a frequency source in each time of frequency mixing; and the AGC unit comprises two stages of AGC loop units which are connected in series, and is used for receiving the third intermediate frequency signal, performing output gain control processing and outputting an intermediate frequency signal with stable power. According to the scheme, stable receiving performance can be kept under the condition of receiving of the signal strength and the ultra-wideband signal which change in a large range.

Description

Technical Field

[0001] The present invention relates to the fields of wireless communication and satellite communication, in particular to the field of superheterodyne receivers, and particularly to an automatic gain control receiver with ultra-wideband and high dynamic range. Background Art

[0002] With the increasingly complex electromagnetic environment, in a wireless communication system, the performance of a receiver directly affects the quality and reliability of communication. The industry has higher and higher requirements for the bandwidth and dynamics of receivers, and has increasingly higher requirements in aspects such as ultra-wideband, large instantaneous bandwidth, miniaturization, and low power consumption. Among them, a broadband frequency conversion component transforms a broadband frequency-domain signal to a lower frequency for sampling processing, which is a key component of wireless communication. Adopting a reasonable frequency conversion scheme is a key step to realize the performance of the frequency conversion component, and directly determines the performance of wireless communication equipment.

[0003] Since the signal will be affected by various factors during transmission, such as transmission distance, obstacles, multipath effects, etc., the intensity of the received signal will have large fluctuations. In order to keep the quality of the received signal stable, it is necessary to dynamically adjust the gain of the receiver. In order to make the amplitude of the output signal of the receiver constant, the conventional method is based on feedforward control, which has poor anti-interference ability and affects the signal processing rate.

[0004] Although traditional AGC systems can adjust the gain of the receiver to a certain extent, their performance is often limited when facing broadband signals and high dynamic range signals. Especially in a broadband receiver, due to the large signal bandwidth, higher requirements are put forward for the dynamic range and response time of the AGC system. Improper AGC will cause amplitude modulation, damage the signal envelope, and lead to demodulation error codes. Therefore, the receiver needs to have good AGC characteristics, meeting the requirements of large dynamic range, appropriate response time, fast settling time, small introduced signal distortion, and the output signal amplitude meeting the A / D input range and subsequent digital signal processing requirements. Summary of the Invention

[0005] An embodiment of the present invention provides an automatic gain control receiver with ultra-wideband and high dynamic range. This solution solves the deficiencies of the prior art in processing ultra-wideband and high dynamic range signals, and designs an automatic gain control receiver with a frequency range of 6 - 18 GHz and high dynamic range.

[0006] An embodiment of the present invention provides an automatic gain control receiver with ultra-wideband and high dynamic range, including: a limiter, a mode selection unit, a down-conversion link unit, an AGC unit, and a frequency source;

[0007] The mode selection unit is configured to receive the radio frequency signal with a frequency of 6-18 GHz output by the limiter, and split and input the radio frequency signal according to the input signal power of the radio frequency signal to obtain an input signal; wherein, different circuits are adopted for each path.

[0008] The down-conversion link unit adopts triple mixing, and is configured to receive the input signal, and split and perform the first mixing on the input signal according to the signal frequency of the input signal to obtain a first intermediate frequency signal, then perform the second mixing on the first intermediate frequency signal to obtain a second intermediate frequency signal, and perform the third mixing on the second intermediate frequency signal to obtain a third intermediate frequency signal; wherein, each mixing mixes the received signal with the local oscillator signal provided by the frequency source.

[0009] The AGC unit includes two cascaded AGC loop units, and is configured to receive the third intermediate frequency signal and perform output gain control processing to output an intermediate frequency signal with stable power.

[0010] Optionally, the mode selection unit includes a first switch, a low-noise amplification circuit and a direct-through circuit; one end of the first switch is connected to the limiter, and the other end of the first switch is respectively connected to the low-noise amplification circuit and the direct-through circuit; the mode selection unit is connected to the down-conversion link unit through a second switch.

[0011] Optionally, splitting and inputting the radio frequency signal according to the input signal power of the radio frequency signal includes:

[0012] Input the radio frequency signal with an input signal power of -70 to -40 dBm into the low-noise amplification circuit through the first switch, and adjust the radio frequency attenuator in the down-conversion link unit to the non-attenuation state through the second switch;

[0013] Input the radio frequency signal with an input signal power of -40 to -10 dBm into the low-noise amplification circuit through the first switch, and adjust the attenuation state of the radio frequency attenuator in the down-conversion link unit through the second switch;

[0014] Input the radio frequency signal with an input signal power of -10 to +10 dBm into the direct-through circuit through the first switch, and adjust the attenuation state of the radio frequency attenuator in the down-conversion link unit through the second switch.

[0015] Optionally, the mode selection unit is connected to the down-conversion link unit through a second switch;

[0016] The down-conversion link unit includes: three signal branches connected in parallel, a third switch, and a mixing link; the third switch is used to connect the signal branch and the mixing link.

[0017] The signal branch includes a first amplifier, a radio frequency attenuator, a first filter component, a second amplifier, a first mixer, a second filter component, and a third amplifier connected in sequence; among them, the first filter component or the second filter component in different signal branches has different frequency response characteristics;

[0018] The mixing link includes a second mixer, a third filter component, a fourth amplifier, a third mixer, and a fourth filter component connected in sequence.

[0019] Optionally, the signal branches are respectively a first signal branch, a second signal branch, and a third signal branch;

[0020] The splitting the input signal according to the signal frequency of the input signal for the first mixing includes:

[0021] Inputting an input signal with a signal frequency of 6 - 8 GHz to the first signal branch through the second switch for the first mixing;

[0022] Inputting an input signal with a signal frequency of 8 - 12 GHz to the second signal branch through the second switch for the first mixing;

[0023] Inputting an input signal with a signal frequency of 12 - 18 GHz to the third signal branch through the second switch for the first mixing.

[0024] Optionally, the first mixer mixes the signal transmitted by the second amplifier with the first local oscillator signal provided by the frequency source; among them, the frequencies of the first local oscillator signals adopted by different signal branches are different;

[0025] The second mixer mixes the signal transmitted by the signal branch with the second local oscillator signal provided by the frequency source;

[0026] The third mixer mixes the signal transmitted by the fourth amplifier with the third local oscillator signal provided by the frequency source.

[0027] Optionally, the third filter component includes two - stage low - pass filters and a band - pass filter; the fourth filter component includes two - stage LC band - pass filters.

[0028] Optionally, the input of the frequency source uses a 100 MHz crystal oscillator or an external clock.

[0029] Optionally, the AGC unit includes a first AGC loop unit, a fifth amplifier, a first filter, a second AGC loop unit, an intermediate - frequency attenuator, and a second filter connected in sequence;

[0030] The first AGC loop unit and the second AGC loop unit both include: a digital controlled attenuator, a sixth amplifier, a first power splitter, a logarithmic detector, and a voltage comparator;

[0031] The digital controlled attenuator is respectively connected to one end of the sixth amplifier and the voltage comparator; the other end of the sixth amplifier is connected to the first power splitter; the first power splitter is connected to the logarithmic detector; the logarithmic detector is connected to the voltage comparator.

[0032] Optionally, it further includes:

[0033] The logarithmic detector is used to obtain the output power from the first power splitter to extract the detection voltage;

[0034] The voltage comparator is used to compare the obtained reference voltage and the detection voltage sent by the logarithmic detector to obtain a control voltage, and send the control voltage to the digital controlled attenuator;

[0035] In the first AGC loop unit, the third intermediate frequency signal and the control voltage are input into the digital controlled attenuator, and then pass through the sixth amplifier and the first power splitter to obtain a first output signal;

[0036] The first output signal passes through a fifth amplifier and a first filter in sequence to obtain a second output signal;

[0037] In the second AGC loop unit, the second output signal and the control voltage are input into the digital controlled attenuator, and then pass through the sixth amplifier and the first power splitter to obtain the intermediate frequency signal.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention provides an ultra-wideband high-dynamic range automatic gain control receiver. The receiver performs a series of processes such as limiting, amplifying, filtering, and frequency conversion on the received radio frequency signal in the range of 6 - 18 GHz, and through frequency conversion, it is processed into the intermediate frequency signal required for the baseband, realizing an ultra-wideband of 6 - 18 GHz. At the same time, in the radio frequency front end, the radio frequency signal is split according to the input signal power through the mode selection unit, and the high dynamic range is jointly realized through the radio frequency attenuator.

[0040] In the present invention, a logarithmic detector and a voltage comparator are introduced into the receiver frequency converter. The error signal is obtained through the voltage comparator, the automatic gain error value is calculated and output, the error value is processed by the error calibrator to generate a gain control signal, and after the variable gain amplifier unit detects the gain control signal, internal processing is performed to control the gain change.

[0041] The receiver of the present invention can maintain stable reception performance under a wide range of signal strength variations and is suitable for various complex communication environments. At the same time, through reasonable circuit design, it can achieve the reception of ultra-wideband signals in the range of 6 - 18 GHz. On the basis of ensuring the device performance, the present invention selects integrated and miniaturized components, improving the reliability and high integration of the module, making it have the characteristics of low noise, high dynamic range, small spurious, low power consumption, light weight, and small size. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 It is a schematic diagram of the architecture of an ultra-wideband high-dynamic range automatic gain control receiver provided by an embodiment of the present invention;

[0044] Figure 2 It is a schematic diagram of the architecture of another ultra-wideband high-dynamic range automatic gain control receiver provided by an embodiment of the present invention;

[0045] Figure 3 It is a circuit diagram of an AGC loop unit provided by an embodiment of the present invention;

[0046] Reference numerals: 10 - limiter; 20 - mode selection unit; 30 - down-conversion link unit; 40 - AGC unit; 50 - frequency source;

[0047] S1 - first switch; 201 - low-noise amplifier circuit; 202 - direct-through circuit; S2 - second switch;

[0048] 301 - first amplifier; 302 - RF attenuator; 303 - first filter assembly; 304 - second amplifier; 305 - first mixer; 306 - second filter assembly; 307 - third amplifier; S3 - third switch; 308 - second mixer; 309 - third filter assembly; 310 - fourth amplifier; 311 - third mixer; 312 - fourth filter assembly;

[0049] 401 - first AGC loop unit; 402 - fifth amplifier; 403 - first filter; 404 - second AGC loop unit; 405 - intermediate frequency attenuator; 406 - second filter. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] The following is the concept of the present invention. As Figure 1 shown, the embodiments of the present invention provide an ultra-wideband high-dynamic range automatic gain control receiver, including: a limiter 10, a mode selection unit 20, a down-conversion link unit 30, an AGC unit 40, and a frequency source 50;

[0052] The mode selection unit 20 is configured to receive a radio frequency signal with a frequency of 6 - 18 GHz output by the limiter 10, and split the radio frequency signal for input according to the input signal power of the radio frequency signal to obtain an input signal; wherein, different circuits are adopted for each path;

[0053] The down-conversion link unit 30 adopts triple mixing, and is configured to receive the input signal, and split the input signal for the first mixing according to the signal frequency of the input signal to obtain a first intermediate frequency signal, then perform a second mixing on the first intermediate frequency signal to obtain a second intermediate frequency signal, and perform a third mixing on the second intermediate frequency signal to obtain a third intermediate frequency signal; wherein, each mixing mixes the received signal with the local oscillator signal provided by the frequency source 50;

[0054] The AGC unit 40 includes two cascaded AGC loop units, and is configured to receive the third intermediate frequency signal and perform output gain control processing to output an intermediate frequency signal with stable power.

[0055] In the embodiments of the present invention, the receiver performs a series of processes such as limiting, amplifying, filtering, and frequency conversion on the received radio frequency signal in the 6 - 18 GHz frequency range, and after frequency conversion, it becomes the intermediate frequency signal required for the baseband, realizing an ultra-wideband of 6 - 18 GHz. At the same time, at the radio frequency front end, the radio frequency signal is split according to the input signal power through the mode selection unit, and the high dynamic range is jointly realized through the radio frequency attenuator.

[0056] In a preferred embodiment, as Figure 2 shown, the mode selection unit 20 includes a first switch S1, a low-noise amplification circuit 201, and a direct-through circuit 202; one end of the first switch S1 is connected to the limiter 10, and the other end of the first switch S1 is respectively connected to the low-noise amplification circuit 201 and the direct-through circuit 202; the mode selection unit 20 is connected to the down-conversion link unit 30 through a second switch S2.

[0057] In a preferred embodiment, the RF signal is split and input according to the input signal power of the RF signal, including:

[0058] Through the first switch S1, the RF signal with an input signal power of -70 to -40 dBm is input into the low-noise amplifier circuit 201, and through the second switch S2, the RF attenuator 302 in the down-conversion link unit 30 is adjusted to the non-attenuation state;

[0059] Through the first switch S1, the RF signal with an input signal power of -40 to -10 dBm is input into the low-noise amplifier circuit 201, and through the second switch S2, the attenuation state of the RF attenuator 302 in the down-conversion link unit 30 is adjusted;

[0060] Through the first switch S1, the RF signal with an input signal power of -10 to +10 dBm is input into the direct-through circuit 202, and through the second switch S2, the attenuation state of the RF attenuator 302 in the down-conversion link unit 30 is adjusted.

[0061] It should be noted that a low-noise amplifier is provided on the low-noise amplifier circuit.

[0062] In the present invention, in order to ensure the realization of a high dynamic range for receiving RF signals, the RF front-end is designed with a mode selection unit, which has two modes, namely the normal mode and the low-distortion mode, corresponding to RF signals with input intensities in different amplitude ranges. When a small signal enters, the system is set to the normal mode, and the signal is switched to the low-noise amplifier circuit; when a large signal enters, the system is set to the low-distortion mode, and the signal is switched to the direct-through circuit. The high dynamic range of the receiver is jointly realized by the mode selection circuit and the RF digital control attenuator circuit.

[0063] Specifically, in the present invention, the amplitude dynamic range of the input signal of the receiver is not less than 80 dB, that is, the intercepted signal level is -70 to +10 dBm. Generally, limited by the characteristics of the amplifier, the achievable instantaneous dynamic range is generally 40 to 50 dBm. When a large signal enters the front-end amplifier, it is easy to cause saturation. To meet the design of a dynamic range not less than 80 dB, a mode selection unit is introduced. After the RF signal passes through the limiter, it enters the mode selection unit, which is divided into two branches, as Figure 2As shown in the figure. When the input signal power is -70 to -40 dBm, the RF signal goes through the low-noise amplifier circuit (i.e., the normal mode), and the RF attenuator is in the non-attenuation state; when the input signal power is -40 to -10 dBm, the RF signal goes through the low-noise amplifier circuit (i.e., the normal mode), and the RF attenuator is set to an appropriate attenuation state as needed; when the input signal power is -10 to +10 dBm, the RF signal goes through the direct path (i.e., the low-distortion mode), and the RF digital controlled attenuator is set to an appropriate attenuation state as needed. Therefore, by controlling the first switch to switch different modes and then controlling the attenuation state of the RF digital controlled attenuator, the present invention can achieve a high dynamic reception of not less than 80 dB.

[0064] In a preferred embodiment, as Figure 2 shown, the mode selection unit 20 is connected to the down-conversion link unit 30 through the second switch S2;

[0065] The down-conversion link unit 30 includes: three signal branches connected in parallel, a third switch S3, and a mixing link; the third switch S3 is used to connect the signal branch and the mixing link;

[0066] The signal branch includes a first amplifier 301, an RF attenuator 302, a first filter component 303, a second amplifier 304, a first mixer 305, a second filter component 306, and a third amplifier 307 connected in sequence; among them, the first filter component 303 or the second filter component 306 in different signal branches has different frequency response characteristics;

[0067] The mixing link includes a second mixer 308, a third filter component 309, a fourth amplifier 310, a third mixer 311, and a fourth filter component 312 connected in sequence.

[0068] In a preferred embodiment, the signal branches are the first signal branch, the second signal branch, and the third signal branch respectively;

[0069] The input signal is split according to the signal frequency of the input signal for the first mixing, including:

[0070] The input signal with a signal frequency of 6 to 8 GHz is input to the first signal branch through the second switch S2 for the first mixing;

[0071] The input signal with a signal frequency of 8 to 12 GHz is input to the second signal branch through the second switch S2 for the first mixing;

[0072] The input signal with a signal frequency of 12 to 18 GHz is input to the third signal branch through the second switch S2 for the first mixing.

[0073] It should be noted that the second switch is used to implement the dynamic path selection of input signals with different signal frequencies, and each signal branch only allows signals in the current processing frequency band to pass through.

[0074] Specifically, after the radio frequency signal enters, the down-conversion link unit selects different modes according to the signal strength. After passing through the second switch, it is divided into three paths of signals, and the corresponding frequency band ranges are 6 - 8 GHz, 8 - 12 GHz, and 12 - 18 GHz respectively. After passing through three different band-pass filters for out-of-band spurious and interference suppression, components such as its harmonics and image frequencies are filtered out. Then, before the signal is processed in the signal branch and enters the mixer, the signal needs to be power-adjusted through a radio frequency attenuator and an amplifier; then it enters the first mixer to obtain three paths of first intermediate frequency signals, which are 10.94 GHz, 6.75 GHz, and 4.63 GHz respectively. Subsequently, they are combined into one path (actually a single-path selection mechanism) through a radio frequency switch (i.e., the third switch). Before the second mixing, the radio frequency signal needs to pass through a MEMS filter bank (as the second filter component) to filter out local oscillator leakage and high-order intermodulation components to suppress out-of-band spurious after the first mixing; at the same time, the signal needs to pass through the amplifier again for power compensation, and then enters the second-stage mixer. After the second mixing, a second intermediate frequency signal of 1.06 GHz is obtained. Then, after filtering and amplification, it enters the third mixer to obtain the required third intermediate frequency signal. The down-conversion link unit has the characteristics of high sensitivity, low noise, and ultra-wide bandwidth, and can ensure that the radio frequency signal maintains high quality during transmission.

[0075] It should be noted that regarding the radio frequency image frequency signal, it can be suppressed by adding a filter in front of the mixer. According to the required bandwidth requirements, different surface acoustic wave or ceramic dielectric filters, etc. are selected to achieve image frequency suppression. According to the filter specifications, generally, the image frequency suppression requirement of not less than 40 dB can be met.

[0076] In a preferred embodiment, as Figure 2 shown, the first mixer 305 mixes the signal transmitted by the second amplifier 304 with the first local oscillator signal provided by the frequency source 50; among them, the frequencies of the first local oscillator signals used in different signal branches are different;

[0077] The second mixer 308 mixes the signal transmitted by the signal branch with the second local oscillator signal provided by the frequency source 50;

[0078] The third mixer 311 mixes the signal transmitted by the fourth amplifier 310 with the third local oscillator signal provided by the frequency source 50.

[0079] In a preferred embodiment, the input of the frequency source 50 uses a 100 MHz crystal oscillator or an external clock. Specifically, when using an external clock, it can adapt to a 10 MHz / 100 MHz reference signal.

[0080] Specifically, the first local oscillator signal uses a broadband local oscillator, which can generate point frequency and stepped frequency local oscillator signals; the second local oscillator signal and the third local oscillator signal both use point frequency local oscillators, and are directly generated by the frequency synthesis module (i.e., the frequency source) and output to the frequency conversion component.

[0081] In a more preferred embodiment, the input of the frequency source is divided by a power splitter to obtain a first signal. The signal after passing through a phase-locked loop (PLL) and a voltage-controlled oscillator (VCO) is mixed with the first signal passing through a direct digital frequency synthesizer (DDS), and then successively passes through frequency multiplication, a power splitter, an amplifier, and an attenuator to generate three first local oscillator signals (LO1) required for the RF link. Finally, one of the first local oscillator signals corresponding to the signal branch is selected through a switch;

[0082] The input of the frequency source is divided by a power splitter to obtain a second signal. The second signal passes through a phase-locked loop (PLL) and a voltage-controlled oscillator (VCO), and then successively passes through a power splitter, an amplifier, and an attenuator to generate the second local oscillator signal (LO2) required for the RF link;

[0083] The input of the frequency source is divided by a power splitter to obtain a third signal. The third signal passes through a phase-locked loop (PLL) and a voltage-controlled oscillator (VCO), and then successively passes through a power splitter, an amplifier, and an attenuator to generate the third local oscillator signal (LO3) required for the RF link.

[0084] It should be noted that the specifications of the phase-locked loop (PLL), voltage-controlled oscillator (VCO), power splitter, amplifier, and attenuator used when generating different local oscillator signals are not the same.

[0085] In a preferred embodiment, the third filter assembly 309 includes two-stage low-pass filters and a band-pass filter; the fourth filter assembly 312 includes two-stage LC band-pass filters.

[0086] Specifically, before the signal enters the third mixer, the signal needs to pass through two-stage low-pass filters and a band-pass filter to filter out spurious signals, and then the signal is power-compensated by an amplifier. After that, after the signal enters the third mixer, two-stage LC band-pass filters are used to suppress out-of-band spurious signals, and then the output power is automatically adjusted by the AGC unit, and finally the signal is input to the input port of the ADC for signal conversion and processing.

[0087] In a preferred embodiment, as Figure 2 shown, the AGC unit 40 includes a first AGC loop unit 401, a fifth amplifier 402, a first filter 403, a second AGC loop unit 404, an intermediate frequency attenuator 405, and a second filter 406 connected in sequence;

[0088] AsFigure 3 As shown in the figure, the first AGC loop unit 401 and the second AGC loop unit 404 both include: a digital controlled attenuator, a sixth amplifier, a first power splitter, a logarithmic detector, and a voltage comparator;

[0089] The digital controlled attenuator is respectively connected to one end of the sixth amplifier and the voltage comparator; the other end of the sixth amplifier is connected to the first power splitter; the first power splitter is connected to the logarithmic detector; the logarithmic detector is connected to the voltage comparator.

[0090] In a preferred embodiment, it further includes:

[0091] The logarithmic detector is used to obtain the output power from the first power splitter to extract the detection voltage;

[0092] The voltage comparator is used to compare the obtained reference voltage and the detection voltage sent by the logarithmic detector to obtain the control voltage, and send the control voltage to the digital controlled attenuator;

[0093] In the first AGC loop unit 401, the third intermediate frequency signal and the control voltage are input into the digital controlled attenuator, and then pass through the sixth amplifier and the first power splitter to obtain the first output signal;

[0094] The first output signal passes through the fifth amplifier 402 and the first filter 403 in sequence to obtain the second output signal;

[0095] In the second AGC loop unit 404, the second output signal and the control voltage are input into the digital controlled attenuator, and then pass through the sixth amplifier and the first power splitter to obtain the intermediate frequency signal.

[0096] In the present invention, since a single-stage AGC circuit cannot provide a large enough gain control range, a multi-stage structure is adopted in the present invention. The AGC loop unit in the AGC unit generally consists of a VGA (Variable Gain Amplifier) circuit, a logarithmic detector, and a voltage comparator. Among them, the control voltage Vc of the VGA has a linear relationship with the power (unit: dBm), and the detection voltage Vd has a linear relationship with the output power (unit: dBm); the difference between the detection voltage Vd and the reference voltage Vr is used to control the VGA through the control voltage Vc of the VGA obtained after error voltage amplification and low-pass filtering. In this way, by introducing a logarithmic detector and a voltage comparator, an error signal is obtained through the voltage comparator, the automatic gain error value is calculated and output, the error value is processed by an error calibrator to generate a gain control signal, and the variable gain amplifier (VGA) unit performs internal processing after detecting the gain control signal to control the gain change.

[0097] In the present invention, in order to achieve precise gain controllability, the VGA unit in the AGC loop unit adopts a high-precision and small-step digital-controlled attenuator + fixed-gain amplifier method. For the detailed link, see the appendix Figure 3 . By using the digital-controlled attenuator, the gain is adjusted by controlling its attenuation state. In a specific embodiment, the selected fixed-gain amplifier can provide a gain of approximately 28.5 dB within the required intermediate frequency range, and the attenuation controllable range of the selected digital-controlled attenuator is not less than 31 dB, with a control accuracy of 0.5 dB. Therefore, the VGA unit composed of these two devices can achieve a VGA of -2.5 to +28.5 dB. In order to compensate for the signal attenuation introduced by the filter component, an amplifier is connected in series between the two-stage AGC loop units.

[0098] In the present invention, the actual gain control range of the AGC loop unit reaches nearly 62 dB, and the gain control accuracy is less than 0.5 dB. When the input signal gradually decreases from the upper end of the control range to the lower end of the control range, the detection voltage gradually increases in an approximately linear trend.

[0099] Considering the influence of the AGC loop delay, in this embodiment, since the AGC loop response time is related to the delays of the VGA amplifier circuit, the power detection circuit, and the AGC voltage generation circuit. Excessive delay will cause the AGC loop to fail to respond to the change in the received signal amplitude in a timely manner, resulting in signal envelope distortion, too long discharge time, and longer AGC stabilization time. Therefore, in this solution, crystal filters or surface acoustic wave filters with relatively large delays are not considered for use between the VGA amplifier circuit and the power detection circuit. In addition, the function of the power detection voltage output filter capacitor is to filter out the carrier signal, and its capacitance value cannot be too large to ensure a small AGC loop delay.

[0100] In a specific embodiment, the screening of devices in the present invention is relatively strict. Specifically, since the noise figure is crucial for the performance of the receiver, according to the noise formula of multi-stage cascaded devices, the noise figure of the system mainly depends on the noise figure of the pre-stage amplifier. Before the pre-stage amplification, all losses in the link are included in the noise. Therefore, low-loss devices such as limiters and switches should be selected as much as possible. At the same time, the high gain of the low-noise amplifier on the low-noise amplifier circuit can weaken the influence of the subsequent stage on the noise figure. Therefore, when selecting devices, the low-noise amplifier is selected according to the minimum noise figure and high gain, and secondly, it is necessary to ensure that the third-order intermodulation products are as small as possible. The amplifier on the link after this amplifier, while providing sufficient gain, takes into account the 1 dB compression point power and selects an amplifier with high P -1 . The amplifier can provide a relatively large linear range for the front stage of the RF link.

[0101] In a specific embodiment, a double-balanced mixer circuit is selected for the mixer. It has a working bandwidth that can reach several octaves and good isolation between the RF signal and the local oscillator ports. If harmonic components are considered, the output of the mixer only contains the sum and difference components of odd harmonics, and the even harmonic components are all cancelled out, and its output spectrum is relatively ideal. Since the ports of the mixer are in a mismatched state, a certain amount of attenuation is generally required at the input and output ports to improve signal reflection. The filter component is an indispensable device in the RF system. It plays the role of filtering out clutter and extracting useful signals. Commonly selected filters include LC filters, cavity filters, dielectric filters, surface acoustic wave filters, MEMS filters, etc. Judging from the filter characteristics alone, the cavity filter is undoubtedly relatively good, but its volume is relatively large. In this design, due to the consideration of miniaturization requirements, cavity filters with relatively large volumes should be used as little as possible. Considering comprehensively, the filter bank is designed in the way of LC + MEMS filters. The LC method is used for low frequencies, and the MEMS filter is used for high frequencies.

[0102] It can be understood that the structure schematically shown in the embodiments of the present invention does not constitute a specific limitation on an ultra-wideband high-dynamic-range automatic gain control receiver. In other embodiments of the present invention, an ultra-wideband high-dynamic-range automatic gain control receiver may include more or fewer components than those shown in the figure, or combine certain components, or split certain components, or have different component arrangements. The components shown in the figure can be implemented in hardware, software, or a combination of software and hardware.

[0103] Regarding the information interaction, execution process, etc. between the various modules in the above device, since it is based on the same concept as the method embodiment of the present invention, the specific content can be referred to the description in the method embodiment of the present invention, and will not be elaborated here.

[0104] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An ultra-wideband high-dynamic-range automatic gain control receiver, characterized in that, Comprising: A limiter, a mode selection unit, a down-conversion link unit, an AGC unit, and a frequency source; The mode selection unit is configured to receive a radio frequency signal with a frequency of 6 - 18 GHz output from the limiter, and split and input the radio frequency signal according to the input signal power of the radio frequency signal to obtain an input signal; wherein, different circuits are adopted for each path; The down-conversion link unit adopts triple mixing, and is configured to receive the input signal, and split and perform the first mixing on the input signal according to the signal frequency of the input signal to obtain a first intermediate frequency signal, then perform the second mixing on the first intermediate frequency signal to obtain a second intermediate frequency signal, and perform the third mixing on the second intermediate frequency signal to obtain a third intermediate frequency signal; wherein, each mixing mixes the received signal with the local oscillator signal provided by the frequency source; The AGC unit includes two-stage AGC loop units connected in series, and is configured to receive the third intermediate frequency signal and perform output gain control processing to output an intermediate frequency signal with stable power.

2. The receiver according to claim 1, wherein The mode selection unit includes a first switch, a low-noise amplification circuit, and a direct-through circuit; one end of the first switch is connected to the limiter, and the other end of the first switch is respectively connected to the low-noise amplification circuit and the direct-through circuit; the mode selection unit is connected to the down-conversion link unit through a second switch.

3. The receiver according to claim 2, wherein, The splitting and inputting the radio frequency signal according to the input signal power of the radio frequency signal includes: Inputting a radio frequency signal with an input signal power of -70 to -40 dBm into the low-noise amplification circuit through the first switch, and adjusting the radio frequency attenuator in the down-conversion link unit to be in a non-attenuation state through the second switch; Inputting a radio frequency signal with an input signal power of -40 to -10 dBm into the low-noise amplification circuit through the first switch, and adjusting the attenuation state of the radio frequency attenuator in the down-conversion link unit through the second switch; Inputting a radio frequency signal with an input signal power of -10 to +10 dBm into the direct-through circuit through the first switch, and adjusting the attenuation state of the radio frequency attenuator in the down-conversion link unit through the second switch.

4. The receiver according to claim 1, wherein The mode selection unit is connected to the down-conversion link unit through a second switch; The down-conversion link unit includes: three signal branches connected in parallel, a third switch, and a mixing link; the third switch is used to connect the signal branch and the mixing link; The signal branch includes a first amplifier, a radio frequency attenuator, a first filter component, a second amplifier, a first mixer, a second filter component, and a third amplifier connected in sequence; wherein, the first filter component or the second filter component in different signal branches has different frequency response characteristics; The mixing link includes a second mixer, a third filter component, a fourth amplifier, a third mixer, and a fourth filter component connected in sequence.

5. The receiver according to claim 4, wherein The signal branches are respectively a first signal branch, a second signal branch, and a third signal branch; The splitting and performing the first mixing on the input signal according to the signal frequency of the input signal includes: An input signal with a signal frequency of 6 - 8 GHz is input to the first signal branch through the second switch for the first mixing; An input signal with a signal frequency of 8 - 12 GHz is input to the second signal branch through the second switch for the first mixing; An input signal with a signal frequency of 12 - 18 GHz is input to the third signal branch through the second switch for the first mixing.

6. The receiver according to claim 4, wherein The first mixer mixes the signal transmitted by the second amplifier with the first local oscillator signal provided by the frequency source; among them, the frequencies of the first local oscillator signals adopted by different signal branches are different; The second mixer mixes the signal transmitted by the signal branch with the second local oscillator signal provided by the frequency source; The third mixer mixes the signal transmitted by the fourth amplifier with the third local oscillator signal provided by the frequency source.

7. The receiver according to claim 4, characterized in that, The third filter component includes two - stage low - pass filters and a band - pass filter; the fourth filter component includes two - stage LC band - pass filters.

8. The receiver according to claim 1, wherein, The input of the frequency source adopts a 100 MHz crystal oscillator or an external clock.

9. The receiver according to any one of claims 1 to 8, characterized in that, The AGC unit includes a first AGC loop unit, a fifth amplifier, a first filter, a second AGC loop unit, an intermediate - frequency attenuator, and a second filter connected in sequence; Both the first AGC loop unit and the second AGC loop unit include: a digital - controlled attenuator, a sixth amplifier, a first power splitter, a logarithmic detector, and a voltage comparator; The digital - controlled attenuator is respectively connected to one end of the sixth amplifier and the voltage comparator; the other end of the sixth amplifier is connected to the first power splitter; the first power splitter is connected to the logarithmic detector; the logarithmic detector is connected to the voltage comparator.

10. The receiver according to claim 9, wherein, It further includes: The logarithmic detector is used to obtain the output power from the first power splitter to extract the detection voltage; The voltage comparator is used to compare the obtained reference voltage and the detection voltage sent by the logarithmic detector to obtain a control voltage, and send the control voltage to the digital - controlled attenuator; In the first AGC loop unit, the third intermediate - frequency signal and the control voltage are input to the digital - controlled attenuator, and then pass through the sixth amplifier and the first power splitter to obtain a first output signal; The first output signal passes through the fifth amplifier and the first filter in sequence to obtain a second output signal; In the second AGC loop unit, the second output signal and the control voltage are input to the digital - controlled attenuator, and then pass through the sixth amplifier and the first power splitter to obtain the intermediate - frequency signal.

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