CN117202334A

CN117202334A - AGC method and system for low-power consumption Bluetooth receiver

Info

Publication number: CN117202334A
Application number: CN202311051885.3A
Authority: CN
Inventors: 戴加良; 陶可
Original assignee: Zhuhai Yingji Semiconductor Co ltd
Current assignee: Zhuhai Yingji Semiconductor Co ltd
Priority date: 2023-08-18
Filing date: 2023-08-18
Publication date: 2023-12-08

Abstract

The invention provides an AGC method and a system for a low-power consumption Bluetooth receiver, comprising the following steps: counting the number N of sampling points of the output data of the ADC module outside the saturation threshold interval range of the output data of the ADC module in t0 time, acquiring the maximum amplitude of the output data of the ADC module in t0 time, and judging the value of the N; if N is not equal to 0, selecting the corresponding AGC gain adjustment gear to modify the step length of gain adjustment according to the value of N; if n=0, selecting a corresponding AGC gain adjustment gear according to the maximum amplitude of the output data of the ADC module to perform gain adjustment; judging whether the gain of the front-end link module of the RF system reaches the maximum value or whether the adjusted gain value changes, and locking the existing gain if the gain reaches the maximum value or does not change. According to the invention, the number N of sampling points of the output data of the ADC module outside the saturation threshold range and the maximum amplitude of the output data of the ADC module are used as the judgment quantity of gain adjustment to carry out step-by-step adjustment, so that the gain adjustment under low power consumption is realized and the effect of improving the input stability of the ADC module is improved.

Description

AGC method and system for low-power consumption Bluetooth receiver

Technical Field

The invention relates to the technical field of wireless communication, in particular to an AGC (automatic gain control) method and system for a low-power Bluetooth receiver.

Background

Because the signal strength received by the receiver of the wireless communication system varies widely due to various factors such as the magnitude of the transmitting power, the distance between the transmitting and receiving, and the fading of the radio wave propagation, the receiver must have the capability of processing the input signal with a large dynamic range in the wireless communication system, and this requires an automatic gain control (AGC, automatic Gain Control) technique, which amplifies or attenuates the input signal to adjust the input analog signal to a proper level, so as to fully utilize the dynamic range of the ADC. The traditional AGC control method is to obtain the output signal of the ADC module in the radio frequency link, send the output signal into the power detection module, calculate the power of the input signal and transform the power into the logarithmic domain, and carry out gain adjustment after obtaining the power value in various ways, and the method is to choose to adjust the gain step by step in a feedback way, and also the method is to realize single-step adjustment by calculating the difference value between the target power and the actually measured power.

In the prior art, there are a plurality of methods for performing automatic gain control on a wireless communication receiver, and chinese patent publication No. CN115696543a discloses a receiver system with automatic gain control, which includes an FPGA chip, a detection voltage ADC, a first rf feed-forward AGC module, a second rf feed-forward AGC module, and an if feed-forward AGC module, and is controlled by a method that 2 rf feed-forward AGC modules and 1 if feed-forward AGC module work in parallel; the patent with publication number CN107086859B discloses a digital automatic gain control circuit for a wireless communication receiver, which comprises a digital amplifier, a module value calculating circuit, an average value filter, a power calculating circuit, a threshold comparing circuit and an error processing circuit, wherein the module value information of the module value calculating circuit is processed by adding the average value filter and then is sent to the power calculating circuit, so that the power value calculating part is optimized. The scheme can obtain higher adjustment precision, but has the problems of long AGC adjustment time, high power consumption, large hardware resource consumption and the like, and the modules such as filtering and the like also cause the increase of the AGC adjustment time, are not beneficial to Bluetooth reception, and increase the system cost.

In addition, the patent with the publication number of CN109788464A discloses a quick automatic power control method and system of a Bluetooth receiver, comprising the following steps: the AGC gain control module is respectively connected with the ADC module, the DFE module and the AGC module of the RF subsystem, and counts the amplitude information of IQ two paths in the input signal; the amplitude signalThe information is that the amplitude value of the nearest N1 points in the IQ two paths is continuously 2 ^WL-1 -number of 1 and 0, WL is ADC bit-width; calculating the moving average linear power of N2 points; converting the moving average linear power into a dB domain; based on the amplitude information, the dB domain and the frame synchronization signal sent by the DFE module, a gain control word is generated and sent to the RF subsystem for rapid automatic power control, and rapid response of overlarge or undersize signals is realized by utilizing the amplitude specificity of a Bluetooth modulation mode (GFSK), and the scheme is an automatic gain control method proposed by a Bluetooth receiver, but the scheme still needs a power detection module for carrying out module value operation and power calculation on I/Q two paths of data, and is accompanied by unavoidable hardware resource consumption.

Disclosure of Invention

The AGC method and system for the low-power consumption Bluetooth receiver are mainly used for solving the problems of long adjustment time, high power consumption, large hardware resource consumption and the like of the traditional gain adjustment method, so that the AGC control circuit is greatly simplified, the hardware resource consumption is reduced, meanwhile, the control logic is simplified to obtain better AGC adjustment effect, gain adjustment under low power consumption is realized, and the input stability of an ADC module is improved.

The invention realizes the above purpose through the following technical scheme:

an AGC method for a bluetooth low energy receiver, the AGC method being applied to an AGC control module, an input of the AGC control module being connected to an output of an ADC module, an output of the AGC control module being connected to an RF system front link module of the bluetooth low energy receiver, comprising:

s1: counting the number N of sampling points of the output data of the ADC module outside the saturation threshold interval range of the output data of the ADC module in t0 time, acquiring the maximum amplitude of the output data of the ADC module in t0 time, and judging the size of an N value, wherein the size of the N value reflects the overflow degree of the ADC module; s2: if N is not equal to 0, selecting a corresponding AGC gain adjustment gear to modify the gain adjustment step length according to the N value, acquiring the ADC module output data of a sampling point in the next t0 time after the adjustment time of t1, and repeating the step S1; s3: if n=0, selecting a corresponding AGC gain adjustment gear according to the maximum amplitude of the output data of the ADC module to perform gain adjustment; s4: and judging whether the gain of the front-end link module of the RF system reaches the maximum value or whether the adjusted gain value changes, and locking the existing gain if the gain reaches the maximum value or does not change.

Therefore, the invention samples the output data of the ADC module, counts the sampling point number N of the sampling value outside the saturation threshold interval range and obtains the maximum amplitude value, takes the sampling point number N and the maximum amplitude value as the judgment quantity of gain adjustment to carry out step-by-step adjustment, only needs to carry out simple threshold judgment on the sampling value, replaces the traditional control mode of carrying out the calculation of the module value and the power value on the I/Q two paths of signals and obtaining the signal power value in the dB domain as the judgment quantity of the AGC gain configuration module, saves various hardware resources required by the traditional control mode, greatly simplifies the AGC control circuit, reduces the consumption of hardware resources, provides a new idea for realizing miniaturization and light weight design of the Bluetooth receiver, simplifies the control logic to obtain better AGC adjustment effect, realizes gain adjustment under low power consumption, and improves the input stability of the ADC module.

According to the invention, the overflow degree of the ADC module is firstly judged through the sampling point number N of the sampling value outside the saturation threshold value interval range of the ADC module, gradual gain adjustment is carried out according to the corresponding AGC gain adjustment gear until the ADC module is not overflowed any more, and then the maximum sampling amplitude is used as a judgment value to carry out further gain adjustment according to the corresponding AGC gain adjustment gear.

The further scheme is that the ADC module output data of sampling points in t0 time is obtained from one optional path of the I/Q paths.

Further, the saturation threshold adc_sat of the output data of the ADC module is 95% of the maximum output thereof, and the interval range is [ -adc_sat, adc_sat ].

The further scheme is that the step value of gain adjustment is set to be 3dB, if N is not equal to 0, the AGC gain adjustment is divided into 2 gears according to the size of the sampling point number N outside the interval range, and the corresponding relation between the N value and the step length of the gain adjustment is as follows:

step is a step length of gain adjustment, n1=0.42×n2, n2=osxt0, OS is a sampling frequency value of the output data of the ADC module, and N2 is a total sampling point number in time t 0.

In a further scheme, the relation between the maximum amplitude ADC_Max of the output data of the ADC module and the maximum amplitude Xin of the input analog quantity of the ADC module in the t0 time is as follows:

20log ₁₀ ADC_Max＝20log ₁₀ (Xin)-20log ₁₀ (LSB)

wherein the full-scale range is 20log ₁₀ (LSB) is a constant.

In a further scheme, the step value of gain adjustment is set to be 3dB, if n=0, the AGC gain adjustment is divided into 9 steps according to the ratio b of the maximum amplitude adc_max to the full-scale output amplitude of the ADC module, and the correspondence between the ratio b and the adjustment gain Φ is:

further, if the bit width of the ADC module is W, the full-scale output amplitude of the ADC module is: am=2 ^W ^-1 -1, the correspondence between the maximum amplitude adc_max and the adjustment gain Φ is:

the output end of the ADC module is connected with the input end of the modem, after the AGC control module is started to perform gain adjustment, if the packet synchronization signal MDM_SYNC sent by the modem is detected, the existing gain is locked until the next data packet is received, the AGC control module is started again to perform gain adjustment, and if the packet synchronization signal MDM_SYNC is not received, the gain adjustment is continued.

The AGC system for the low-power Bluetooth receiver comprises an AGC control module, wherein the AGC method of the low-power Bluetooth receiver is applied to the AGC control module, the input end of the AGC control module is connected with the output I path or the output Q path of an ADC module of the low-power Bluetooth receiver and used for collecting output data of the ADC module, the output end of the ADC module is connected with the input end of a modem, the output end of the AGC control module is connected with the front-end link module of an RF system of the low-power Bluetooth receiver, and the AGC control module is used for selecting a corresponding AGC gain adjustment gear according to the number N of sampling points of output data of the ADC module outside a saturation threshold range of the ADC module and the maximum amplitude of the output data of the ADC module so as to carry out gain adjustment on the front-end link module of the RF system.

The RF system front-end link module comprises an LNA module, a Mixer module and a filter module, wherein the output end of the AGC control module is respectively connected with the LNA module and the filter module and is used for performing gain adjustment on the LNA module and the filter module according to the AGC gain adjustment gear.

Therefore, the AGC system of the invention adopts a feedback control mechanism, and the gain of the radio frequency front end is controlled by acquiring the output data of the ADC module, thereby realizing the automatic adjustment of the signal power gain, ensuring that the input signal of the ADC module is in a proper size and improving the stability of the system.

The invention is described in further detail below with reference to the drawings and the detailed description.

Drawings

Fig. 1 is a flow chart of an AGC method for a bluetooth low energy receiver in accordance with the present invention.

FIG. 2 is a schematic diagram of the output code and saturation threshold of the ADC module in the unsaturated state according to the present invention.

Fig. 3 is a schematic diagram of the output code and saturation threshold of the ADC module in the saturated state according to the present invention.

FIG. 4 is a schematic diagram of the maximum amplitude of the output code of the ADC module according to the present invention.

Fig. 5 is a block diagram of a system for applying the present invention to a bluetooth low energy receiver.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without creative efforts, based on the described embodiments of the present invention fall within the protection scope of the present invention.

AGC method embodiment for low-power consumption Bluetooth receiver

Referring to fig. 1, the AGC method for a bluetooth low energy receiver according to the present invention is applied to an AGC control module, wherein an input end of the AGC control module is connected to an output end of an ADC module, and an output end of the AGC control module is connected to an RF system front-end link module of the bluetooth low energy receiver, and the AGC method includes:

s1: counting the number N of sampling points of the output data of the ADC module outside the saturation threshold interval range of the output data of the ADC module in t0 time, acquiring the maximum amplitude ADC_Max of the output data of the ADC module in t0 time, and judging the size of the N value, wherein the size of the N value reflects the overflow degree of the ADC module.

Specifically, after the AGC module of this embodiment is started, each flag bit of the AGC is cleared, and the gain initial value of each module of the radio frequency link is set to be the maximum value.

Specifically, in this embodiment, as shown in fig. 2, if n=0, it indicates that the ADC module outputs unsaturated, and the digital signal output by the ADC module is accurate at this time; as shown in fig. 3, if n+.0, the ADC module is in saturation state, and the larger the N value, the larger the overflow degree.

S2: if N is not equal to 0, selecting a corresponding AGC gain adjustment gear to modify the gain adjustment step length according to the N value, obtaining the ADC module output data of a sampling point in the next t0 time after the adjustment time of t1, and repeating the step S1.

Specifically, if the AGC gain has reached a minimum value of 0, the gain is kept unchanged until the next packet is received.

Specifically, in this embodiment, since a certain adjustment time is required when the gain of the front-end link module of the RF system is adjusted from one gear to another gear, a new ADC sampling point is obtained after a time of (t0+t1) μs is required for adjusting the AGC gain once, and the I/Q output data of the ADC module is compared with the saturation threshold again.

S3: and if n=0, selecting a corresponding AGC gain adjustment gear according to the maximum amplitude ADC_Max of the output data of the ADC module to perform gain adjustment.

Specifically, in this embodiment, the step value of gain adjustment is generally set to 3dB, the whole output range of the ADC module is divided into 9 segments, the range to which the maximum amplitude adc_max belongs is determined, and the gain of AGC is adjusted according to the gain adjustment amount Φ corresponding to the table, so that the output value of the ADC module can be adjusted to be within the range of 0.637-0.9 of the full scale range of the ADC.

S4: and judging whether the gain of the front-end link module of the RF system reaches the maximum value or whether the adjusted gain value changes, and locking the existing gain if the gain reaches the maximum value or does not change.

In this embodiment, the output data of the ADC module at the sampling point in the time t0 is obtained from an optional one of the I/Q paths.

Specifically, in this embodiment, only one path of ADC signal output by the ADC module needs to be processed, which greatly simplifies the AGC control circuit.

In this embodiment, the saturation threshold adc_sat of the output data of the ADC module is 95% of the maximum output thereof, and the interval range is [ -adc_sat, adc_sat ].

Specifically, in this embodiment, after the AGC control module is enabled, the I/Q ADC data output by the ADC module in the time t0 μs is compared, and the number of sampling points with the size outside the [ -adc_sat, adc_sat ] interval is counted, to obtain the number N of ADC data exceeding the threshold value in the time t0 μs, and at the same time, obtain the maximum amplitude adc_max of the codeword output by the ADC module in the time t0 μs, where the maximum amplitude adc_max is the absolute value.

If the input signal range of the ADC module is-VFSR to +vfsr, the relationship between the input signal of the ADC module and the output binary code word is shown in the following table 1:

table 1ADC block encoding table

ADC input signal amplitude	ADC output code word
		+VFSR	1111…1111
+0.75VFSR	1110…0000
		+0.5VFSR	1100…0000
+0.25VFSR	1010…0000
		0	1000…0000
-0.25VFSR	0110…0000
		-0.5VFSR	0100…0000
-0.75VFSR	0010…0000
		-VFSR+1LSB	0000…0001
-VFSR	0000…0000

Specifically, the input signal of the ADC module in this embodiment is a sine wave signal, and the decimal output codeword of the ADC module is obtained from the binary codeword, and when the amplitude of the input signal does not exceed the input range of the ADC, the full-scale output codeword of the ADC module cannot be output by the ADC module; when the amplitude of the input signal exceeds the input range of the ADC, the output of the ADC module is saturated, the output of the ADC module reaches the full-scale maximum codeword, the larger the amplitude of the input signal of the ADC module is, the more sampling data exceeding the saturation threshold of the ADC is obtained within the period of t0 mu s, the larger the N value obtained by statistics is, and the larger the overflow degree of the ADC module is reflected.

In this embodiment, the step value of gain adjustment is set to 3dB, if N is not equal to 0, the AGC gain adjustment is divided into 2 steps according to the size of the sampling point number N outside the interval range, and the correspondence between the N value and the step size of the gain adjustment is:

In this embodiment, the relationship between the maximum amplitude adc_max of the output data of the ADC module and the maximum amplitude Xin of the input analog quantity of the ADC module in the time t0 is:

20log ₁₀ ADC_Max＝20log ₁₀ (Xin)-20log ₁₀ (LSB)

wherein the full-scale range is 20log ₁₀ (LSB) is a constant.

Specifically, in this embodiment lsb=2 VFSR/2 ^N The input voltage corresponding to the output codeword of the ADC module when changing by 1 is represented, VFSR represents the maximum value of the input voltage acceptable by the ADC module, -VFSR represents the minimum value of the input voltage acceptable by the ADC module, and N represents the conversion bit number of the ADC module.

Specifically, in this embodiment, the LSB is a constant, that is, after the conversion between the input and output results of the ADC module is switched to the logarithmic domain, the conversion between the input and output results of the ADC module may be implemented by adding or subtracting the constant, so that the change in the size of the input signal of the ADC module may be directly reflected in the change in the adc_max value.

In this embodiment, the step value of gain adjustment is set to 3dB, if n=0, the AGC gain adjustment is divided into 9 steps according to the ratio b of the maximum amplitude adc_max to the full-scale output amplitude of the ADC module, and the correspondence between the ratio b and the adjustment gain Φ is as shown in the following table 2:

table 2 correspondence table of ratio b and adjustment gain amount Φ

Level	ADC_Max/ADC maximum output code	AGC gain adjustment value phi (dB)
			Level0	[0.900,1.000]	-3
Level1	[0.637,0.900]	0
			Level2	[0.451,0.637]	3
Level3	[0.319,0.451]	6
			Level4	[0.226,0.319]	9
Level5	[0.160,0.226]	12
			Level6	[0.113,0.160]	15
Level7	[0.080,0.113]	18
			Level8	[0,0.080]	18

Specifically, in this embodiment, the AGC gain adjustment gear is selected according to the ratio of the maximum amplitude adc_max and the full-scale output amplitude of the ADC module in the table, and the gain adjustment amount Φ of the corresponding gear is adjusted.

In this embodiment, if the bit width of the ADC module is W, the full-scale output amplitude of the ADC module is am=2 ^W-1 -1, the correspondence between the maximum amplitude adc_max and the adjustment gain Φ is shown in table 3:

table 3 correspondence table of maximum amplitude adc_max and adjustment gain Φ

Level	ADC_Max	AGC adjusting gain value phi (dB)
			Level0	[0.9AM,AM]	-3
Level1	[0.637AM,0.9AM]	0
			Level2	[0.451AM,0.637AM]	3
Level3	[0.319AM,0.451AM]	6
			Level4	[0.226AM,0.319AM]	9
Level5	[0.160AM,0.226AM]	12
			Level6	[0.113AM,0.160AM]	15
Level7	[0.08AM,0.113AM]	18
			Level8	[0,0.08AM]	21

Specifically, in this embodiment, the AGC gain adjustment gear is selected according to the maximum amplitude adc_max in the table, and is adjusted according to the gain adjustment amount Φ of the corresponding gear.

In this embodiment, the output end of the ADC module is connected to the input end of the modem, and further includes step S11: after the AGC control module is started to perform gain adjustment, if the packet synchronization signal MDM_SYNC sent by the modem is detected, the existing gain is locked until the next data packet is received, the AGC control module is started again to perform gain adjustment, and if the packet synchronization signal MDM_SYNC is not detected, the gain adjustment is continued.

Specifically, in this embodiment, for example, in the low-power bluetooth 1M mode, an ADC module with 10 bits and a sampling frequency of 24Mhz is selected, the gain adjustment range of the AGC control module is set to be [0,66] db, the range of the output codeword of the ADC module is calculated to be [ -512,511], and the maximum amplitude value of the output codeword is selected to be 511. The saturation threshold adc_sat is 95% of the full range value output by the ADC module, and in practical application, the threshold is an integer, i.e. adc_sat=485. From this, it is easy to know that the oversampling rate of the ADC module is 24, and since the receiver processes a bluetooth receiving packet of 1Mbps, output data of an optional one of the two I/Q paths of the ADC module in the period of t0=1 μs is taken for comparison.

Firstly, acquiring output data of an ADC module of 24 sampling points in 1us, obtaining the relation between the output data of the ADC module and a saturation threshold as shown in fig. 2, obtaining a result when the ADC module is saturated as shown in fig. 3, obtaining the maximum amplitude ADC_Max of an output codeword of the ADC module as shown in fig. 4, counting the number N of sampling points, the size of which is outside a section, in the output data of the ADC in 1 mu s, and obtaining the maximum amplitude ADC_Max of the output codeword of the ADC module in 1 mu s.

Then, when N is not equal to 0, the output of the ADC module is in saturated state, the gain of the AGC is gradually reduced by adopting a step mode, a step value is set to step, and the step length of the AGC gain adjustment is set according to the overflow degree of the ADC module, that is, according to the magnitude of the N value, the step length of the AGC gain adjustment is compared with table 4, so as to reduce the gain of the AGC, after t1=2μs, the gain adjustment is completed, the steps of N value statistics and gain down adjustment are repeated until n=0, that is, the ADC is not saturated and overflowed any more, and if the gain of the AGC has reached the minimum value of 0, the gain is kept unchanged until the next packet is received.

Table 4N value and AGC gain adjustment gear position correspondence table

1us internal interval [ -485,485 []Number of sample points N	AGC gain adjusting gear step (dB)
		0	0
[1,10]	-3
		[11,24]	-6

Then, when n=0, the ADC module is in a normal working state, and the output value of the ADC module is adjusted to be within a range of 0.637-0.9 of the full range by adopting a fast gain adjustment manner, so as to ensure that the ADC module is in an optimal working state, specifically, the maximum amplitude adc_max is compared with the threshold value of the Level in table 5, the Level to which the maximum amplitude adc_max belongs is determined, and then further AGC gain adjustment is performed according to the corresponding Φ (dB) value in table 5 on the basis of the original gain.

And in the process of the up-regulation of the gain, if the gain reaches the maximum value, stopping up-regulation, and locking the existing gain in the process of receiving the Bluetooth packet.

Specifically, for example, when the ratio of the maximum amplitude adc_max to the full-scale output amplitude of the ADC module is 0.6, reading table 5 shows that the AGC control module needs to be increased by 3dB based on the current Gain, and considering that the Gain range of the AGC control module is [0, g_max ], the Gain is stopped from being adjusted when the Gain of the AGC control module reaches g_max, i.e. if the AGC Gain before being adjusted is gain_now, the actual Gain adjustment amount is Δ=min { Φ, gmax-gain_now }.

And judging whether the gain value after adjustment is changed, if not, indicating that the signal gain before non-adjustment is in a desired range, and skipping the gain adjustment time t1 at the moment to directly lock the gain.

Table 5 maximum amplitude adc_max and AGC adjustment gain Φ correspondence table

AGC system embodiment for low-power consumption Bluetooth receiver

Referring to fig. 5, the AGC system for a bluetooth low energy receiver according to the present invention includes an AGC control module 10, wherein the AGC method of the bluetooth low energy receiver is applied to the AGC control module 10, an input end of the AGC control module 10 is connected to an output I or Q of the ADC module 30, and is used for collecting output data of the ADC module 30, an output end of the ADC module 30 is connected to an input end of the modem 40, an output end of the AGC control module 10 is connected to the RF system front-end link module 20, and the AGC control module 10 is used for selecting a corresponding AGC gain adjustment gear according to a maximum amplitude of output data of the sampling point N, ADC module 30 of the output data of the ADC module 30 outside a saturation threshold range thereof, and performing gain adjustment on the RF system front-end link module 20.

In this embodiment, the RF system front-end link 20 module includes an LNA module 21, a Mixer module 22, and a filter module 23, where output ends of the AGC control module are respectively connected to the LNA module 21 and the filter module 23, and are used for performing gain adjustment on the LNA module 21 and the filter module 23 according to the AGC gain adjustment gear.

The above embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, but any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention are intended to be within the scope of the present invention as claimed.

Claims

1. An AGC method for a bluetooth low energy receiver, the AGC method being applied to an AGC control module, an input of the AGC control module being connected to an output of an ADC module, an output of the AGC control module being connected to an RF system front link module of the bluetooth low energy receiver, the AGC method comprising:

s1: counting the number N of sampling points of the output data of the ADC module outside the saturation threshold interval range of the output data of the ADC module in t0 time, acquiring the maximum amplitude of the output data of the ADC module in t0 time, and judging the size of an N value, wherein the size of the N value reflects the overflow degree of the ADC module;

s2: if N is not equal to 0, selecting a corresponding AGC gain adjustment gear to modify the gain adjustment step length according to the N value, acquiring the ADC module output data of a sampling point in the next t0 time after the adjustment time of t1, and repeating the step S1;

s3: if n=0, selecting a corresponding AGC gain adjustment gear according to the maximum amplitude of the output data of the ADC module to perform gain adjustment;

2. The AGC method for a bluetooth low energy receiver according to claim 1, wherein:

and obtaining the ADC module output data of the sampling point in the t0 time from the optional one of the I/Q paths.

3. The AGC method for a bluetooth low energy receiver according to claim 2, wherein:

the saturation threshold ADC_SAT of the output data of the ADC module is 95% of the maximum output of the ADC module, and the interval range is [ -ADC_SAT, ADC_SAT ].

4. The AGC method for a bluetooth low energy receiver according to claim 3, wherein:

setting the step value of gain adjustment to be 3dB, if N is not equal to 0, dividing AGC gain adjustment into 2 gears according to the size of sampling points N outside a range, wherein the corresponding relation between the N value and the step length of gain adjustment is as follows:

5. The AGC method for a bluetooth low energy receiver according to claim 1, wherein:

and in the t0 time, the relation between the maximum amplitude ADC_Max of the output data of the ADC module and the maximum amplitude Xin of the input analog quantity of the ADC module is as follows:

20log ₁₀ ADC_Max＝20log ₁₀ (Xin)-20log ₁₀ (LSB)

wherein the full-scale range is 20log ₁₀ (LSB) is a constant.

6. The AGC method for a bluetooth low energy receiver of claim 5 wherein:

setting the step value of gain adjustment to be 3dB, if N=0, dividing AGC gain adjustment into 9 gears according to the ratio b of the maximum amplitude ADC_Max to the full range output amplitude of the ADC module, wherein the corresponding relation between the ratio b and the adjustment gain value phi is as follows:

7. the AGC method for a bluetooth low energy receiver of claim 6 wherein:

let the bit width of the ADC module be W, the full scale output amplitude of the ADC module is: am=2 ^W-1 -1, the correspondence between the maximum amplitude adc_max and the adjustment gain Φ is:

8. AGC method for a bluetooth low energy receiver according to any of the claims 1-7, characterized in that:

the output end of the ADC module is connected with the input end of the modem, after the AGC control module is started to perform gain adjustment, if a packet synchronization signal MDM_SYNC sent by the modem is detected, the existing gain is locked until the next data packet is received, the AGC control module is started again to perform gain adjustment, and if the packet synchronization signal MDM_SYNC is not received, the gain adjustment is continued.

9. An AGC system for a bluetooth low energy receiver, comprising:

the AGC control module, according to any one of claims 1 to 8, wherein an input end of the AGC control module is connected to an output I or Q of an ADC module of the bluetooth low energy receiver, and is configured to collect output data of the ADC module, an output end of the ADC module is connected to an input end of a modem, an output end of the AGC control module is connected to a front-end link module of the RF system of the bluetooth low energy receiver, and the AGC control module is configured to select a corresponding AGC gain adjustment gear according to a number N of sampling points of the output data of the ADC module outside a saturation threshold range thereof, and a maximum amplitude of the output data of the ADC module, so as to perform gain adjustment on a front-end link module of the RF system.

10. The AGC system for a bluetooth low energy receiver of claim 9 wherein:

the RF system front-end link module comprises an LNA module, a Mixer module and a filter module, wherein the output end of the AGC control module is respectively connected with the LNA module and the filter module and used for performing gain adjustment on the LNA module and the filter module according to the AGC gain adjustment gear.