Agc implementation method, device and system based on multi-stage output signal strength detection

Abstract

The application provides an AGC implementation method, device and system based on multi-stage output signal strength detection, which comprises the following steps: detecting the output signal strength of multi-stage variable gain transmission modules in a communication main circuit respectively; judging the gain state of each variable gain transmission module based on the obtained output signal strength of each variable gain transmission module and at least one group of output signal strength threshold of the variable gain transmission module; and adjusting the variable gain transmission module with one or more stages of gain in saturation state or insufficient state to make the gain of each variable gain transmission module in normal amplification state. The application can be applied to short-distance wireless transmission systems such as Zig-Bee, Bluetooth, wireless broadband, ultra-wideband and near field communication, and can also be applied to long-distance wireless transmission systems such as mobile communication, data transmission radio communication, spread spectrum microwave communication, satellite communication and short wave communication system.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to an AGC implementation method, apparatus and system based on multi-level output signal strength detection. Background Technology

[0002] Auto Gain Control (AGC) is a signal processing circuit used in wireless communication. It adjusts the output signal using an effective combination of linear amplification and linear attenuation. When a weak signal is input, the linear amplification circuit operates to ensure the strength of the output signal; when the input signal reaches a certain strength, the gain attenuation circuit is activated, reducing the output amplitude. In other words, the AGC function can automatically control the gain amplitude by changing the input-output compression ratio. Normally, the radio frequency signal received by the antenna is very weak, but in certain special environments, such as when there is spatial interference, the signal can become very strong. In such cases, if the AGC loop cannot effectively detect the signal and adjust the system gain, the signal may block the communication link, causing the system to malfunction.

[0003] Currently, analog or digital AGC is mainly used to implement signal detection and automatic adjustment functions. Digital AGC only focuses on the gain control of the variable gain amplifier (VGA). When the input signal is large, the transmission module before the VGA already experiences compression, resulting in a significant deterioration in signal quality. In this case, even if the gain of the VGA is within its normal amplification range, the quality of the output signal cannot be guaranteed. Summary of the Invention

[0004] In order to overcome at least one deficiency of the prior art, the present invention provides an AGC implementation method, apparatus and system based on multi-level output signal strength detection.

[0005] To achieve the above objectives, the present invention provides an AGC implementation method based on multi-level output signal strength detection, comprising:

[0006] The output signal strength of the multi-stage variable gain transmission modules in the main communication circuit was detected respectively.

[0007] Based on the output signal strength of each stage of the variable gain transmission module obtained by detection and at least one set of preset output signal strength thresholds for that stage of the variable gain transmission module, the gain state of each stage of the variable gain transmission module is determined.

[0008] Adjust the gain of one or more variable gain transmission modules that are in a saturated or insufficient state so that the gain of each variable gain transmission module is in a normal amplification state.

[0009] According to one embodiment of the present invention, for a multi-stage variable gain transmission module, the threshold of each output signal strength level of the preceding stage variable gain transmission module is set to be less than the threshold of the corresponding output signal strength level of the following stage variable gain transmission module, and the gains of the multi-stage variable gain transmission modules are cascaded and superimposed sequentially along the signal transmission direction.

[0010] According to one embodiment of the present invention, when the gains of multiple variable gain transmission modules all enter a gain saturation state or a gain deficiency state, the gain of the previous stage variable gain transmission module is preferentially adjusted according to the signal transmission direction.

[0011] According to an embodiment of the present invention, when the variable gain transmission module has m sets of output signal strength level thresholds and m≥2, the m sets of output signal strength level thresholds form 2m+1 gain intervals; wherein, the gain interval in the middle is the gain interval in the normal amplification state, and the gain intervals on both sides are, in turn, the saturation gain intervals of multiple levels and the insufficient gain intervals of multiple levels.

[0012] According to one embodiment of the present invention, the output signal strength of all variable gain transmission modules in the main communication circuit is detected respectively.

[0013] According to one embodiment of the present invention, multiple RSSI envelope detection circuits are used to detect the output signal strength of the multi-stage variable gain transmission modules in the main communication circuit.

[0014] On the other hand, the present invention also provides an AGC implementation device based on multi-level output signal strength detection, which includes multiple output signal strength envelope detection circuits, at least one judgment unit, and an AGC adjustment unit. The multiple output signal strength envelope detection circuits respectively detect the output signal strength of multiple levels of variable gain transmission modules within the main communication circuit. Based on the detected output signal strength of each level of variable gain transmission module and at least one preset set of output signal strength thresholds for that level, each judgment unit determines the gain state of each level of variable gain transmission module. Based on the judgments of the multiple judgment units, the AGC adjustment unit adjusts the gain of one or more levels of variable gain transmission modules that are in a saturated or insufficient gain state so that the gain of each level of variable gain transmission module is in a normally amplified state.

[0015] According to one embodiment of the present invention, each judgment unit provides at least one set of output signal strength level thresholds for the corresponding variable gain transmission module. Each output signal strength level threshold of the preceding variable gain transmission module is smaller than the output signal strength level threshold of the following variable gain transmission module. The gains of the multi-level variable gain transmission modules are cascaded and superimposed sequentially along the signal transmission direction.

[0016] According to an embodiment of the present invention, when the gains of multiple variable gain transmission modules all enter a gain saturation state or a gain deficiency state, the AGC adjustment unit preferentially adjusts the gain of the previous stage variable gain transmission module according to the signal transmission direction.

[0017] According to one embodiment of the present invention, the output signal strength detection circuit is an RSSI envelope detection circuit.

[0018] On the other hand, the present invention also provides a communication system, which includes a main communication circuit and the above-described AGC implementation device based on multi-level output signal strength detection. The main communication circuit includes at least two variable gain transmission modules connected in sequence.

[0019] According to an embodiment of the present invention, the main communication circuit includes a low-noise amplifier, an off-chip RF filter, an on-chip RF preamplifier, a downconverter, an intermediate frequency filter, an adjustable gain amplifier, and an analog-to-digital converter connected in sequence; the main communication circuit includes a three-stage variable gain transmission module, namely a low-noise amplifier, an on-chip RF preamplifier, and an adjustable gain amplifier.

[0020] In summary, the AGC implementation method based on multi-level output signal strength detection provided by this invention determines the current gain state of each variable gain transmission module by detecting the output signal strength of multiple variable gain transmission modules within the main communication circuit. The gain of one or more variable gain transmission modules that are in an abnormal amplification state is adjusted, thereby ensuring that the gain of all multiple variable gain transmission modules is in a normal amplification state, preventing signal compression at each stage and guaranteeing optimal signal output quality. Furthermore, by controlling the threshold of each variable gain transmission module, a gain superposition cascade effect is created between multiple variable gain transmission modules. When multiple variable gain transmission modules are in a saturated or under-saturated state, only one or a partially saturated or under-saturated variable gain transmission module needs to be adjusted according to priority to ensure that the gain of all transmission modules is in a normal amplification state; that is, while ensuring output signal quality, the AGC adjustment speed is rapidly increased, achieving high-quality and fast AGC. The AGC implementation method, device, and system based on multi-level output signal strength detection provided by this invention can be applied to various types of communication, including common short-range wireless transmission systems such as Zig-Bee, Bluetooth, Wi-Fi, UWB, and NFC, as well as long-range wireless transmission systems such as mobile communication, data radio communication, spread spectrum microwave communication, satellite communication, and shortwave communication systems.

[0021] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 The diagram shown is a flowchart of an AGC implementation method based on multi-level output signal strength detection provided in an embodiment of the present invention.

[0023] Figure 2 The diagram shown is a schematic block diagram of an AGC implementation device based on multi-level output signal strength detection according to an embodiment of the present invention.

[0024] Figure 3 The diagram shown is a schematic block diagram of a communication system provided in an embodiment of the present invention. Detailed Implementation

[0025] In existing wireless communication systems, VGA implementation only targets the variable gain amplifier located at the signal output end. However, for wireless communication systems that include multiple variable gain transmission modules, when signal compression occurs in the upstream variable gain transmission module, even if the gain of the output variable gain amplifier is in its normal amplification range, high-quality signal output cannot be achieved.

[0026] In view of this, this embodiment provides an AGC implementation method based on multi-level output signal strength detection, such as... Figure 1 As shown, it includes: detecting the output signal strength of multiple variable gain transmission modules in the main communication circuit (step S10). Based on the detected output signal strength of each variable gain transmission module and at least one preset output signal strength threshold for that module, determining the gain state of each module (step S20). Adjusting the gain of one or more modules that are in a saturated or insufficient state to ensure that the gain of each module is in a normal amplification state (step S30).

[0027] The AGC implementation method based on multi-level output signal strength detection provided in this embodiment uses a hierarchical detection approach to detect the output signal strength of each variable gain transmission module in the main communication circuit. Based on at least one preset set of output signal strength thresholds, it realizes the judgment and feedback adjustment of the current gain state of each variable gain transmission module, thereby ensuring that each variable gain transmission module is within the normal gain amplification range. This effectively solves the problem of signal quality degradation caused by compression of the front-end variable gain transmission module in existing VGA implementations, and achieves optimal signal quality output.

[0028] This embodiment uses the RF receiver main circuit with integrated RF filter as an example to explain in detail the control principle of the AGC implementation method based on multi-level output signal strength detection provided in this embodiment. For example... Figure 3As shown, the main RF receiver circuit with integrated RF filters includes a low-noise amplifier (LNA) 1, an off-chip RF filter (RF Filter) 2, an on-chip RF preamplifier (RFA) 3, a downconverter (MIXER) 4, an intermediate frequency filter (IF Filter) 5, an adjustable gain amplifier (VGA) 6, and an analog-to-digital converter (ADC) 7 connected in sequence. The RF modulated signal is received into the signal channel through an antenna (not shown) via the RF input port (LNA_IN). The received RF signal is amplified by the front-end low-noise amplifier (LNA) 1. Then, it passes through the off-chip RF filter (RF Filter) 2 and is connected back to the on-chip RF preamplifier (RFA) 3 for further amplification. Afterward, it is connected to the downconverter 4 (MIXER). The intermediate frequency filter 5 (IF Filter) filters out the intermediate frequency signal that needs to be demodulated within the bandwidth through channel selection. The selected intermediate frequency (IF) signal is amplified by the adjustable gain amplifier 6 (VGA) to provide an appropriate signal strength to the analog-to-digital converter 7 (ADC), thereby converting the IF analog signal into a digital signal; finally, these digital signals are processed in the digital baseband.

[0029] The integrated RF filter's RF receiving main circuit includes a three-stage variable gain transmission module: a low-noise amplifier (LNA) 1, an on-chip RF preamplifier (RFA) 3, and an adjustable gain amplifier (VGA) 6. However, this invention does not limit the specific composition of the communication main circuit. In other embodiments, the AGC implementation method based on multi-stage output signal strength detection provided by this invention is also applicable to communication main circuits consisting of multi-stage variable gain transmission modules and fixed gain transmission modules. For communication circuits containing fixed gain transmission modules, since the gain of the fixed gain transmission module cannot be adjusted, the AGC implementation method based on multi-stage output signal strength detection provided in this embodiment only adjusts the gain of the multi-stage variable gain transmission module. In this case, as long as the gain of the multi-stage variable gain transmission module meets the set target, the normal operation of the fixed gain transmission module can be ensured.

[0030] Similarly, this invention does not limit the number of stages of the variable gain transmission module within the main communication circuit. In other embodiments, the main communication circuit may also have two or more stages of variable gain transmission modules.

[0031] In the main circuit, the output of the preceding stage circuit module becomes the input of the following stage circuit module; that is, the output signal strength of the variable gain transmission module is the received signal strength (Received Signal Strength Indication) of the immediately following circuit module. Therefore, in this embodiment, a Received Signal Strength Envelope Detection Circuit (i.e., an RSSI envelope detection circuit) is used to detect the output signal strength of the variable gain transmission module. However, this invention does not limit this in any way. In other embodiments, circuits with other structures can also be used to detect the output signal strength of the variable gain transmission module.

[0032] based on Figure 3 The RF receiver main circuit of the integrated RF filter shown employs three high-precision RSSI envelope detection circuits in step S10 to detect the output signal amplitude energy of the three variable gain transmission modules: the low-noise amplifier (LNA) 1, the on-chip RF preamplifier (RFA) 3, and the adjustable gain amplifier 6 (VGA), to obtain the RSSI of each variable gain transmission module. In this embodiment, the detection result of the RSSI envelope detection circuit is the DC output corresponding to the amplitude energy of the output signal of the variable gain transmission module, and the RSSI envelope detection circuit is a DC output detection circuit based on an envelope detector. However, the present invention does not limit this in any way. In other embodiments, the voltage signal or power signal corresponding to the amplitude energy of the output signal can also be used to characterize the output signal strength of the variable gain transmission module.

[0033] In this embodiment, the three RSSI envelope detection circuits are independently configured in three variable gain transmission modules. However, this invention does not impose any limitations on this. In other embodiments, multiple RSSI envelope detection circuits may also be integrated into one unit.

[0034] Although this embodiment uses the output signal strength detection of all variable gain transmission modules in the main communication circuit as an example, the present invention does not limit this in any way. In practical circuit applications, some variable gain transmission modules may maintain their gain within the normal amplification range even when the input signal amplitude changes significantly; or some variable gain transmission modules may have very little impact on signal quality. In this case, to improve the response speed of AGC adjustment, the output signal strength detection of these individual variable gain transmission modules may not be performed; that is, in step S10, only some (at least two) of the variable gain transmission modules in the main communication circuit may be subjected to output signal strength detection and gain adjustment.

[0035] After obtaining the output signal strength of each variable gain transmission module in step S10, step S20 is executed. Based on the detected output signal strength of each stage of the variable gain transmission module and at least one preset output signal strength threshold for that stage of the transmission module, the gain state of each stage of the variable gain transmission module is determined. The variable gain transmission module has three states: normal amplification state, saturation state, and under-amplification state. Of course, each state can also be divided into levels according to its degree.

[0036] This embodiment illustrates the example where each stage of the variable gain transmission module has a preset set of output signal strength thresholds. Each set of output signal strength thresholds includes two threshold values. For the nth stage of the variable gain transmission module, these two threshold values ​​are denoted by Hn and Ln, where n = 1…N, and N is the total number of variable gain transmission modules performing output signal strength detection. In this embodiment, as… Figure 3 As shown, N equals 3. For the nth variable gain transmission module, the two output signal strength threshold values ​​form three gain intervals. The interval between Hn and Ln is the gain interval under normal amplification, while the interval greater than Hn is the saturation gain interval, and the interval less than Ln is the insufficient gain interval. However, this invention does not impose any limitations on this.

[0037] In other embodiments, two or more sets of output signal strength level thresholds can be preset for each stage of the variable gain transmission module. For example, when the variable gain transmission module has m sets of output signal strength level thresholds and m≥2, the m sets of output signal strength level thresholds form 2m+1 gain intervals; wherein, the gain interval in the middle is the gain interval in the normal amplification state, and the gain intervals on both sides are, in turn, multiple levels of saturated gain intervals and multiple levels of insufficient gain intervals. Specifically, for the two sets of level thresholds, there are four output signal strength level threshold values, namely Hn2, Hn1, Ln1, and Ln2; forming five gain intervals, namely: a high saturated gain interval greater than Hn2; a low saturated gain interval between Hn2 and Hn1; a normal amplification gain interval between Hn1 and Ln1; a low insufficient gain interval between Ln1 and Ln2; and a high insufficient gain interval greater than Ln2. Setting multiple output signal strength thresholds enables precise division of the current gain state of each variable gain transmission module, which not only improves the accuracy of AGC implementation but also increases the speed of AGC implementation.

[0038] In this embodiment, after obtaining the RSSI (denoted as RSSIn) of the nth variable gain transmission module, RSSIn is compared with the two output signal strength threshold values ​​Hn and Ln of the nth variable gain module. The comparison outputs are represented by RSSI_n_H and RSSI_n_L, respectively. When RSSIn is greater than Ln (RSSI_n_L = 1) and RSSIn is less than Hn (RSSI_n_H = 0), it indicates that the gain of the nth variable gain transmission module is within the gain range of the normal amplification state. When RSSIn is greater than Hn (RSSI_n_H = 1), it indicates that the signal energy is too large and the gain has entered the saturation gain range; conversely, when RSSIn is less than Ln (RSSI_n_L = 0), it indicates that the signal energy is too small and the gain has entered the insufficient gain range.

[0039] Based on the above principle, the current gain state of each variable gain transmission module is judged. In step S30, the gain of one or more variable gain transmission modules is adjusted based on the judgment result so that the output of all variable gain transmission modules is within the gain range of the normal amplification state (i.e., satisfying the condition RSSI_n_L=1 and RSSI_n_H=0), thereby ensuring that the communication main circuit outputs the optimal signal.

[0040] Specifically, for the variable gain transmission module determined to be in a saturated state in step S20, the AGC adjustment unit will output a signal to the variable gain transmission module to reduce its gain; conversely, for the variable gain transmission module determined to be in an insufficient state in step S20, the AGC adjustment unit will output a signal to the variable gain transmission module to increase its gain. In the adjustment of step S30, the AGC adjustment unit can perform independent gain adjustment for each variable gain transmission module with abnormal gain to meet the energy requirements of the communication main circuit output signal. However, within the communication link, the output of the subsequent variable gain transmission module is closely related to the adjustment of the preceding variable gain transmission module, and the independent adjustment of multiple variable gain modules will affect the implementation speed of AGC to some extent. Therefore, it is necessary to consider how to improve the implementation speed of AGC during adjustment.

[0041] To address this issue, this embodiment provides an AGC implementation method based on multi-level output signal strength detection, which further includes: adjusting the two output signal strength threshold values ​​Hn and Ln of each stage of the variable gain transmission module in step S20, so that the gains of the multi-level variable gain transmission modules are cascaded and superimposed sequentially along the signal transmission direction. To satisfy this condition, each output signal strength threshold value of the preceding stage variable gain transmission module is set to be less than the corresponding output signal strength threshold value of the following stage variable gain transmission module, i.e., H(n-1)≤Hn≤H(n+1) and L(n-1)≤Ln≤L(n+1). Figure 3For example, H1≤H2≤H3 and L1≤L2≤L3. Here, H1 and L1 are the two output signal strength thresholds for the low-noise amplifier (LNA); H2 and L2 are the two output signal strength thresholds for the on-chip radio frequency preamplifier (RFA); and H3 and L3 are the two output signal strength thresholds for the adjustable gain amplifier (VGA). In practical applications, the specific parameters of Hn and Ln need to be set according to the requirements of the main communication circuit, the normal gain range of each transmission module, and the compression point.

[0042] The aforementioned threshold setting creates a cascading effect between multiple variable gain transmission modules. Increasing the gain of a preceding variable gain transmission module will synchronously increase the output signal energy amplitude of a subsequent variable gain transmission module; similarly, decreasing the gain of a preceding variable gain transmission module will synchronously decrease the output signal energy amplitude of a subsequent variable gain transmission module. Therefore, based on this setting, a priority-based adjustment method can be used to quickly implement AGC. The following will combine... Figure 3 The implementation of fast AGC under different input signal conditions will be explained in detail.

[0043] As the signal energy at the input gradually increases:

[0044] In the first scenario, when the input signal energy is low, all stages of the variable gain transmission module are in maximum gain mode to meet the input signal requirements of the analog-to-digital converter 7 (ADC). In this case, if step S20 determines that each stage of the variable gain transmission module satisfies RSSI_n_H = 0 and RSSI_n_L = 1, meaning each stage is within the normal amplification gain range, the signal is not compressed, and no AGC adjustment is needed.

[0045] In the second scenario, as the input signal energy increases, the gain of each stage of the cascaded variable gain transmission module accumulates, requiring the later stage to process a larger signal. Therefore, the last stage (Nth stage) of the variable gain transmission module enters saturation first. At this point, the comparison output of the last stage in step S20 changes from RSSI_N_H = 0 and RSSI_N_L = 1 to RSSI_N_H = 1 and RSSI_N_L = 1. Meanwhile, the outputs of the first to N-1 stages of the variable gain transmission module remain RSSI_(1~N-1)_H = 0 and RSSI_(1~N-1)_L = 1. The AGC adjustment unit then only needs to reduce the gain of the Nth stage to satisfy RSSI_N_H = 0 and RSSI_N_L = 1. After AGC adjustment, the input signal amplitude of the analog-to-digital converter 7 (ADC) remains unchanged, neither the preceding nor following stages are compressed, and the system operates at its optimal signal-to-noise ratio.

[0046] The third scenario: As the energy of the input signal continues to increase, the variable gain transmission modules before the last stage gradually begin to partially enter a compression state, meaning that multiple consecutive variable gain transmission modules all enter gain saturation. Based on the superposition and cascading effect of the main communication circuit, the gain of the previous stage transmission module is adjusted preferentially according to the signal transmission direction. Specifically, when the variable gain transmission modules from the nth stage to the last stage (Nth stage) all enter saturation, the gain of the nth stage variable gain transmission module is preferentially reduced to satisfy RSSI_n_H = 0 and RSSI_n_L = 1. At this time, two situations will occur from the (n+1)th stage to the Nth stage: ① The variable gain transmission modules after the (n+1)th stage also quickly enter: RSSI_(n+1~N)_H = 0 and RSSI_(n+1~N)_L = 1; AGC adjustment is completed, and the output signal meets the input signal energy requirements of the analog-to-digital converter 7 (ADC). ② Stages n to k satisfy RSSI_(n~k)_H=0 and RSSI_(n~k)_L=1; while stages (k+1) to N are still in saturation, RSSI_(k+1~N)_H=1 and RSSI_(k+1~N)_L=1, where k is a natural number greater than n and less than N. At this point, based on priority, the gain of the (k+1)th stage variable gain transmission module is reduced first. This process is repeated until all variable gain transmission modules satisfy RSSI_n_H=0 and RSSI_n_L=1, at which point the output signal meets the input signal energy requirements of the analog-to-digital converter 7 (ADC).

[0047] Similarly, as the signal energy at the input gradually decreases, the comparison results of the N variable gain transmission modules are all: RSSI_(1~N)_H=0, RSSI_(1~N)_L=0, indicating that the system gain needs to be increased. Likewise, based on the signal transmission direction, the gain of the preceding transmission module is adjusted first, i.e., the gain of the first-stage variable gain transmission module is increased first, so that it satisfies RSSI_1_H=0, RSSI_1_L=1. By increasing the gain of the first-stage variable gain transmission module, the signal energy of the subsequent stage will increase simultaneously; at this time, two situations will occur in the subsequent stage: ① The subsequent stage variable gain transmission module also quickly enters RSSI_(2~N)_H=0, RSSI_(2~N)_L=1, the AGC adjustment is completed, and the output signal meets the input signal energy requirements of the analog-to-digital converter 7 (ADC). ② Levels 2 through j satisfy RSSI_(2~j)_H=0 and RSSI_(2~j)_L=1; while levels j+1 through the last level (level N) are still in a state of insufficient gain, RSSI_(j+1~N)_H=0 and RSSI_(j+1~N)_L=0, where j is a natural number greater than 2 and less than N. At this point, based on priority, the gain of the variable gain transmission module in level j+1 is increased first, and this process is repeated until all variable gain transmission modules satisfy RSSI_n_H=0 and RSSI_n_L=1. At this point, the output signal meets the ADC input signal energy requirements.

[0048] The AGC implementation method based on multi-level output signal strength detection provided in this embodiment adjusts AGC by prioritizing the cascading effect between multi-level variable gain transmission modules. This means AGC only needs to adjust the variable gain transmission modules that are in a saturated or insufficient state according to their priority, thus significantly improving the AGC implementation speed. Compared to existing AGC implementation methods, the AGC implementation method based on multi-level output signal strength detection provided by this invention ensures both optimal output signal quality and meets the required AGC implementation speed.

[0049] Corresponding to the above-described AGC implementation method based on multi-level output signal strength detection, this embodiment also provides an AGC implementation device 200 based on multi-level output signal strength detection, which includes multiple output signal strength detection circuits 10, multiple judgment units 20, and an AGC adjustment unit 30. The multiple output signal strength detection circuits 10 respectively detect the output signal strength of multiple variable gain transmission modules within the communication main circuit 100. Based on the detected output signal strength of each variable gain transmission module and at least one preset set of output signal strength thresholds for that module, each judgment unit 20 determines whether the gain of each variable gain transmission module is saturated or insufficient. Based on the judgments of the multiple judgment units, the AGC adjustment unit 30 adjusts the gain of one or more variable gain transmission modules that are saturated or insufficient to ensure that the gain of each variable gain transmission module is in a normally amplified state.

[0050] Since the output of the preceding stage circuit module in the main circuit is the input of the following stage circuit module, the output signal strength of the variable gain transmission module is the received signal strength (Received Signal Strength Indication) of the immediately following circuit module. Therefore, in this embodiment, a Received Signal Strength Envelope Detection Circuit (RSSI Envelope Detection Circuit) is used to detect the output signal strength of the variable gain transmission module; that is, the output signal strength detection circuit 10 is an RSSI envelope detection circuit. However, the present invention does not limit this in any way. In other embodiments, circuits with other structures can also be used to detect the output signal strength of the variable gain transmission module.

[0051] In this embodiment, three RSSI envelope detection circuits are used to detect the RSSI of three variable gain transmission modules on the main communication circuit 100. These three modules are the low-noise amplifier (LNA) 1, the on-chip radio frequency preamplifier (RFA) 3, and the adjustable gain amplifier (VGA) 6, with corresponding detection results of RSSI1, RSSI2, and RSSI3. However, this invention does not limit the number of RSSI envelope detection circuits. The number can be determined based on the number of variable gain transmission modules on the main communication circuit that require RSSI detection; alternatively, in other embodiments, the three RSSI envelope detection circuits can be integrated into one unit. Similarly, in this embodiment, three judgment units 20 are used to determine the current gain state of the three variable gain transmission modules. The AGC adjustment unit 30 adjusts the gain of the three variable gain transmission modules based on the judgment results of the three judgment units 20.

[0052] In this embodiment, each judgment unit provides a set of output signal strength thresholds for the corresponding variable gain transmission module. Each output signal strength threshold of the preceding variable gain transmission module is smaller than the corresponding output signal strength threshold of the following variable gain transmission module, i.e., H1≤H2≤H3 and L1≤L2≤L3. The gains of the multiple variable gain transmission modules are cascaded and superimposed sequentially along the signal transmission direction. Specifically, H1 and L1 are two output signal strength threshold values ​​provided by the judgment unit 20 connected to the low-noise amplifier (LNA) 1; H2 and L2 are two output signal strength threshold values ​​provided by the judgment unit 20 connected to the on-chip radio frequency preamplifier (RFA) 3; and H3 and L3 are two output signal strength threshold values ​​provided by the judgment unit 20 connected to the adjustable gain amplifier (VGA) 6. This configuration allows the low-noise amplifier (LNA) 1, the on-chip radio frequency preamplifier (RFA) 3, and the adjustable gain amplifier (VGA) 6 to form a cascaded superposition.

[0053] When only the adjustable gain amplifier (VGA) 6 in the third stage enters the saturation or under-saturation state, the AGC adjustment unit only needs to adjust the gain of the adjustable gain amplifier (VGA) 6 to make it meet RSSI_3_H=0 and RSSI_3_L=1, and the AGC will complete the adjustment.

[0054] When both the on-chip RF preamplifier (RFA) 3 and the adjustable gain amplifier (VGA) 6 are in saturation (or both are in under-saturation), the on-chip RF preamplifier (RFA) 3, located in the second stage, is adjusted first to satisfy RSSI_2_H = 0 and RSSI_2_L = 1. At this time, if the adjustable gain amplifier (VGA) 6 also satisfies RSSI_3_H = 0 and RSSI_3_L = 1, the AGC adjustment unit 30 completes the adjustment. If the adjustable gain amplifier (VGA) 6 is still in saturation or under-saturation, the AGC adjustment unit 30 adjusts the gain of the adjustable gain amplifier (VGA) 6 again.

[0055] Similarly, when the low-noise amplifier (LNA) 1, the on-chip radio frequency preamplifier (RFA) 3, and the variable gain amplifier (VGA) 6 all enter saturation (or are all under-saturated), the AGC adjustment unit 30, according to priority, first adjusts the LNA 1, which is located in the first stage, to ensure that RSSI_1_H = 0 and RSSI_1_L = 1. At this time, if all three variable gain transmission modules satisfy RSSI_n_H = 0 and RSSI_n_L = 1, the AGC adjustment unit 30 completes the adjustment. If there are still variable gain transmission modules in an abnormal amplification state, they are adjusted sequentially according to priority.

[0056] On the other hand, this embodiment also provides a communication system including a main communication circuit 100 and the aforementioned AGC implementation device 200 based on multi-level output signal strength detection. The main communication circuit 100 includes a low-noise amplifier (LNA) 1, an off-chip RF filter 2, an on-chip RF preamplifier (RFA) 3, a downconverter (MIXER) 4, an intermediate frequency filter (IF filter) 5, an adjustable gain amplifier (VGA) 6, and an analog-to-digital converter (ADC) 7 connected in sequence. The low-noise amplifier (LNA) 1, the on-chip RF preamplifier (RFA) 3, and the adjustable gain amplifier 6 (VGA) are a three-stage variable gain transmission module connected in sequence. However, this invention does not limit the structure of the main communication circuit.

[0057] In summary, the AGC implementation method based on multi-level output signal strength detection provided by this invention determines the current gain state of each variable gain transmission module by detecting the output signal strength of multiple variable gain transmission modules within the main communication circuit. The gain of one or more variable gain transmission modules that are in an abnormal amplification state is adjusted, thereby ensuring that the gain of all multiple variable gain transmission modules is in a normal amplification state, preventing signal compression at each stage and guaranteeing optimal signal output quality. Furthermore, by controlling the threshold of each variable gain transmission module, a gain superposition cascade effect is created between multiple variable gain transmission modules. When multiple variable gain transmission modules are in a saturated or under-saturated state, only one or a partially saturated or under-saturated variable gain transmission module needs to be adjusted according to priority to ensure that the gain of all transmission modules is in a normal amplification state; that is, while ensuring output signal quality, the AGC adjustment speed is rapidly increased, achieving high-quality and fast AGC. The AGC implementation method, device, and system based on multi-level output signal strength detection provided by this invention can be applied to various types of communication, including common short-range wireless transmission systems such as Zig-Bee, Bluetooth, Wi-Fi, UWB, and NFC, as well as long-range wireless transmission systems such as mobile communication, data radio communication, spread spectrum microwave communication, satellite communication, and shortwave communication systems.

[0058] Although the present invention has been disclosed above by way of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of protection claimed in the claims.

Claims

1. An AGC implementation method based on multi-level output signal strength detection, characterized in that, include: The output signal strength of the multi-stage variable gain transmission modules in the main communication circuit was detected respectively. Based on the output signal strength of each stage of the variable gain transmission module obtained by detection and at least one set of preset output signal strength thresholds for that stage of the variable gain transmission module, the gain state of each stage of the variable gain transmission module is determined. Adjust the gain of one or more variable gain transmission modules that are in a saturated or insufficient state so that the gain of each variable gain transmission module is in a normal amplification state. Specifically, for multi-stage variable gain transmission modules, the threshold for each output signal strength level of the preceding stage variable gain transmission module is set to be lower than the corresponding output signal strength level threshold of the following stage variable gain transmission module. The gains of the multi-stage variable gain transmission modules are cascaded and superimposed sequentially along the signal transmission direction. When the gains of the multi-stage variable gain transmission modules all enter the gain saturation state or the gain insufficiency state, the gain of the variable gain transmission module with the abnormal state in the preceding stage is adjusted first according to the signal transmission direction.

2. The AGC implementation method based on multi-level output signal strength detection according to claim 1, characterized in that, When the variable gain transmission module has m preset output signal strength level thresholds and m≥2, the m output signal strength level thresholds form 2m+1 gain intervals; among them, the gain interval in the middle is the gain interval in the normal amplification state, and the gain intervals on both sides are the saturation gain intervals of multiple levels and the insufficient gain intervals of multiple levels, respectively.

3. The AGC implementation method based on multi-level output signal strength detection according to claim 1, characterized in that, The output signal strength of all variable gain transmission modules in the main communication circuit is detected separately.

4. The AGC implementation method based on multi-level output signal strength detection according to claim 1, characterized in that, Multiple RSSI envelope detection circuits are used to detect the output signal strength of the multi-stage variable gain transmission modules in the main communication circuit.

5. An AGC implementation device based on multi-level output signal strength detection, characterized in that, include: Multiple output signal strength detection circuits are used to detect the output signal strength of the multi-stage variable gain transmission module in the main communication circuit. Multiple judgment units determine the gain state of each stage of variable gain transmission module based on the output signal strength of each stage of variable gain transmission module obtained by detection and at least one set of preset output signal strength level thresholds of the stage of variable gain transmission module. The AGC adjustment unit, based on the judgments of multiple judgment units, adjusts the gain of one or more variable gain transmission modules that are in a saturated or insufficient state so that the gain of each variable gain transmission module is in a normal amplification state. Each judgment unit provides at least one set of output signal strength level thresholds for the corresponding variable gain transmission module. Each output signal strength level threshold of the preceding variable gain transmission module is smaller than the output signal strength level threshold of the following variable gain transmission module. The gains of the multiple variable gain transmission modules are cascaded and superimposed along the signal transmission direction. When the gains of the multiple variable gain transmission modules all enter the gain saturation state or the gain is insufficient, the AGC adjustment unit adjusts the gain of the preceding variable gain transmission module with the abnormal state according to the signal transmission direction.

6. The AGC implementation device based on multi-level output signal strength detection according to claim 5, characterized in that, The output signal strength detection circuit is an RSSI envelope detection circuit.

7. A communication system, characterized in that, include: The main communication circuit includes at least two variable gain transmission modules connected in sequence. as well as The AGC implementation device based on multi-level output signal strength detection as described in any one of claims 5 to 6.

8. The communication system according to claim 7, characterized in that, The main communication circuit includes a low-noise amplifier, an off-chip RF filter, an on-chip RF preamplifier, a downconverter, an intermediate frequency filter, an adjustable gain amplifier, and an analog-to-digital converter connected in sequence; the main communication circuit includes a three-stage variable gain transmission module, namely a low-noise amplifier, an on-chip RF preamplifier, and an adjustable gain amplifier.

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