CN119051662A

CN119051662A - Automatic gain control system and method based on ADC sampling data

Info

Publication number: CN119051662A
Application number: CN202411167147.XA
Authority: CN
Inventors: 曹晋; 杨小龙; 何兴; 谢明堂; 徐小强
Original assignee: Sichuan Jiuzhou Electric Group Co Ltd
Current assignee: Sichuan Jiuzhou Electric Group Co Ltd
Priority date: 2024-08-23
Filing date: 2024-08-23
Publication date: 2024-11-29

Abstract

The invention discloses an automatic gain control system and method based on ADC sampling data, wherein the automatic gain control system comprises an AGC controlled unit, an A/D converter and an FPGA controller, the AGC controlled unit is connected with the FPGA controller through the A/D converter, the FPGA controller judges the amplitude of an external signal according to the obtained A/D converter data, when the amplitude of the external signal exceeds a preset output threshold, the FPGA controller controls the AGC controlled unit, increases the attenuation of the AGC controlled unit, reduces the link gain, reduces the amplitude of an input signal of the A/D converter, otherwise, reduces the attenuation of the AGC controlled unit, increases the link gain, improves the amplitude of the input signal of the A/D converter, and enables the A/D converter data obtained by the FPGA controller to be in a required range, thereby realizing automatic gain control of the system. The method solves the technical problems of complex hardware, slow response speed, low control precision and the like of the traditional automatic gain control.

Description

Automatic gain control system and method based on ADC sampling data

Technical Field

The invention belongs to the technical field of automatic gain control, and particularly relates to an automatic gain control system and method based on ADC (analog to digital converter) sampling data.

Background

In practical engineering, in order to expand the dynamic range of radar and communication systems and give consideration to near-far targets, the gain of an amplifying link in the system is required to be automatically adjusted according to the intensity of external signals, and the working block diagram is shown in fig. 1. With the development of technology, the requirements of the system on an automatic gain control (Automatic Gain Control, abbreviated as AGC) circuit are increasing, including miniaturization, precision, rapidity and the like.

Conventional Automatic Gain Control (AGC) methods include analog AGC and digital AGC. The analog AGC consists of a detector, a comparator, a gain controller and the like, and has the defects of low response speed, low control precision and the like. The digital AGC consists of a detector, an A/D converter, an FPGA controller, a D/A converter, a voltage-controlled amplifier and the like, and has the defects of complex circuit, high cost and low expandability.

Disclosure of Invention

The invention aims to overcome the problems in the prior art, discloses an automatic gain control system and method based on ADC sampling data, and solves the technical problems of complex hardware, slow response speed, low control precision and the like of the traditional automatic gain control by the system and the method.

On the one hand, the aim of the invention is achieved by the following technical scheme:

An automatic gain control system based on ADC sampling data comprises an AGC controlled unit, an A/D converter and an FPGA controller, wherein external signals realize automatic gain control through the automatic gain control system;

the AGC controlled unit is connected with the FPGA controller through the A/D converter, and the FPGA controller judges the amplitude of the external signal according to the obtained data of the A/D converter;

when the amplitude of the external signal exceeds a preset output threshold, the FPGA controller controls the AGC controlled unit, increases the attenuation of the AGC controlled unit, reduces the link gain, reduces the amplitude of the input signal of the A/D converter, otherwise, reduces the attenuation of the AGC controlled unit, increases the link gain, improves the amplitude of the input signal of the A/D converter, and enables the data of the A/D converter obtained by the FPGA controller to be in a required range, thereby realizing automatic gain control of the system.

According to a preferred embodiment, the AGC controlled unit comprises several AGC controlled units 1 to n in series, where n is equal to or larger than 1.

According to a preferred embodiment, the AGC controlled unit n comprises a digitally controlled attenuator configured to perform amplitude attenuation control of the input signal, enabling control accuracy and depth control of the AGC controlled unit.

According to a preferred embodiment, the control accuracy of the control attenuator is 0.25dB, and the maximum control depth is 31.75dB.

According to a preferred embodiment, the AGC controlled unit n further comprises an amplifying and filtering module, wherein the amplifying and filtering module is composed of a linear amplifier and a filter and is used for amplifying and filtering the output signal of the numerical control attenuator.

According to a preferred embodiment, a limiter is further provided upstream of the AGC controlled unit, the limiter being configured to perform extraneous signal amplitude control to perform downstream circuit protection.

In another aspect, the invention also discloses:

An automatic gain control method based on ADC sampling data comprises the steps that an AGC controlled unit completes gain adjustment of external signal data based on an amplitude monitoring structure of the ADC sampling data and outputs signals meeting system requirements.

According to a preferred embodiment, the automatic gain control method specifically includes:

When the ADC data amplitude exceeds the maximum output threshold required by the system, judging the control state of a digital attenuator in the current AGC controlled unit;

if the numerical control attenuator reaches the maximum control attenuation, ending the flow;

If the numerical control attenuator does not reach the maximum attenuation, the attenuation amount is increased until the data amplitude of the ADC meets the system requirement.

when the ADC data amplitude does not exceed the maximum output threshold required by the system, judging whether the ADC data amplitude is lower than the minimum output threshold required by the system;

if the data amplitude is not lower than the minimum threshold of the system, the output signal amplitude is indicated to be in the interval required by the system at the moment, and the control flow is ended at the moment;

If the data amplitude is lower than the minimum threshold of the system, judging the control state of the numerical control attenuator in the current AGC controlled unit, if the attenuation of the numerical control attenuator is zero, ending the flow, and if the attenuation of the numerical control attenuator is not zero, reducing the attenuation of the numerical control attenuator until the data amplitude of the ADC meets the system requirement.

According to a preferred embodiment, the automatic gain control method further comprises performing an external signal amplitude control by a limiter to complete downstream circuit protection before performing the external signal data gain adjustment.

The foregoing inventive concepts and various further alternatives thereof may be freely combined to form multiple concepts, all of which are contemplated and claimed herein. Various combinations will be apparent to those skilled in the art from a review of the present disclosure, and are not intended to be exhaustive or all of the present disclosure.

The invention has the beneficial effects that:

The invention uses the automatic gain control link based on ADC sampling data, which originally has the A/D converter and FPGA chip to realize the automatic gain control function, optimizes the chips such as the common detector, comparator and the like, saves the hardware cost and improves the reliability of the system. Meanwhile, the number of the AGC controlled units can be flexibly increased or decreased according to the system requirement, so that the universality of the AGC controlled units is ensured.

Drawings

FIG. 1 is a schematic block diagram of automatic gain control;

FIG. 2 is a schematic diagram of an automatic gain control system according to the present invention;

fig. 3 is a schematic diagram of the internal structure of an AGC controlled unit in the automatic gain control system according to the present invention;

Fig. 4 is a flow chart of the automatic gain control method of the present invention.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. In addition, in the present invention, if a specific structure, connection relationship, position relationship, power source relationship, etc. are not specifically written, the structure, connection relationship, position relationship, power source relationship, etc. related to the present invention can be known by those skilled in the art without any creative effort.

Example 1

Referring to fig. 2 to 4, the embodiment discloses an automatic gain control system based on ADC sampling data, which includes a limiter, an AGC controlled unit, an a/D converter, and an FPGA controller, through which an external signal realizes automatic gain control.

Preferably, the limiter is connected with the AGC controlled unit, the AGC controlled unit is connected with the FPGA controller through the A/D converter, and the FPGA controller judges the amplitude of the external signal according to the obtained A/D converter data.

Preferably, the limiter is used for controlling the intensity of the external signal amplitude entering the subsequent circuit, and protecting the subsequent circuit from being burnt.

Preferably, the AGC controlled unit includes a plurality of AGC controlled units 1 to AGC controlled units n in series, where n.gtoreq.1.

The AGC controlled unit n consists of a numerical control attenuator, a linear amplifier and a filter, wherein the numerical control attenuator controls the control precision and depth of the AGC unit, and the amplifier ensures the maximum gain of the AGC unit.

The control precision of the single numerical control attenuator is 0.25dB, the maximum control depth is 31.75dB, and the linear amplifier and the filter are flexibly selected according to the system requirements.

Compared with the traditional method, the novel method has higher control precision and shorter adjustment time.

Preferably, the a/D converter is configured to convert an analog signal to a digital signal, providing an input to an FPGA controlled gain control algorithm.

Preferably, the FPGA controller is configured to control the gain of the AGC controlled unit according to the size of data input by the a/D converter, so that the output signal meets the system requirement.

The method comprises the steps of firstly enabling an external signal to pass through a limiter, enabling the limiter to protect a subsequent circuit from being burnt by a large signal, then enabling the external signal to enter an AGC controlled unit, amplifying and filtering the external signal in the AGC controlled unit, outputting an analog signal meeting the sampling requirement of an A/D converter, enabling the analog signal to finish digital-to-analog conversion in the A/D converter, outputting a digital signal to an FPGA controller, enabling the FPGA controller to compare the digital signal with an output threshold required by a system after receiving the digital signal, adjusting the gain of the AGC controlled unit, and outputting a signal meeting the system requirement.

Further, when the amplitude of the external signal exceeds a preset output threshold, the FPGA controller controls the AGC controlled unit, increases the attenuation amount of the AGC controlled unit, reduces the link gain, reduces the amplitude of the input signal of the A/D converter, otherwise, reduces the attenuation amount of the AGC controlled unit, increases the link gain, improves the amplitude of the input signal of the A/D converter, and enables the data of the A/D converter obtained by the FPGA controller to be in a required range, thereby realizing automatic gain control of the system.

The automatic gain control method based on ADC sampling data optimizes a hardware circuit based on digital AGC, realizes an automatic gain control time adjustable and controllable function, and improves the accuracy and depth of automatic gain control. The hardware circuits such as a common detector and a common comparator are abandoned, the hardware circuits of the system are used for realizing the automatic gain control function, the system cost is reduced, and the miniaturization of equipment is realized. The number of the AGC controlled units can be dynamically configured, the depth of gain control can be designed independently, and the AGC controlled unit has universality.

Example 2

On the basis of embodiment 1, the invention also discloses an automatic gain control method based on ADC sampling data, and the method is shown with reference to FIG. 4. The automatic gain control method comprises the steps that an AGC controlled unit completes gain adjustment of external signal data based on an amplitude monitoring structure of ADC sampling data, and signals meeting system requirements are output.

Preferably, the automatic gain control method specifically includes:

Further, the automatic gain control method further comprises the step of completing external signal amplitude control through a limiter before external signal data gain adjustment is performed so as to complete downstream circuit protection.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims

1. An automatic gain control system based on ADC sampling data, characterized in that the automatic gain control system comprises: an AGC controlled unit, an A/D converter and an FPGA controller, and an external signal is automatically controlled by the automatic gain control system;

The AGC controlled unit is connected to the FPGA controller via the A/D converter, and the FPGA controller determines the amplitude of the external signal according to the A/D converter data obtained;

When the amplitude of the external signal exceeds the preset output threshold, the FPGA controller controls the AGC controlled unit to increase its attenuation, reduce the link gain, and reduce the amplitude of the A/D converter input signal; conversely, the attenuation of the AGC controlled unit is reduced, the link gain is increased, and the amplitude of the A/D converter input signal is increased; so that the A/D converter data obtained by the FPGA controller is within the required range, thereby realizing automatic gain control of the system.

2. The automatic gain control system according to claim 1, characterized in that the AGC controlled unit comprises a plurality of AGC controlled units 1 to AGC controlled units n connected in series, wherein n≥1.

3. The automatic gain control system as claimed in claim 2, characterized in that the AGC controlled unit n includes a digitally controlled attenuator, which is configured to complete the amplitude attenuation control of the input signal to achieve control accuracy and depth control of the AGC controlled unit.

4. The automatic gain control system as claimed in claim 3, characterized in that the control accuracy of the attenuator is 0.25dB and the maximum control depth is 31.75dB.

5. The automatic gain control system as claimed in claim 2, characterized in that the AGC controlled unit n also includes an amplification and filtering module; the amplification and filtering module is composed of a linear amplifier and a filter, and is used to realize amplification and filtering of the output signal of the digital controlled attenuator.

6. The automatic gain control system as claimed in claim 1, characterized in that a limiter is also provided upstream of the AGC controlled unit, and the limiter is configured to complete the external signal amplitude control to achieve downstream circuit protection.

7. An automatic gain control method based on ADC sampling data, characterized in that the automatic gain control method includes: an amplitude monitoring structure based on the ADC sampling data uses an AGC controlled unit to complete gain adjustment of external signal data and output a signal that meets system requirements.

8. The automatic gain control method according to claim 7, characterized in that the automatic gain control method specifically comprises:

When the ADC data amplitude exceeds the maximum output threshold required by the system, the control state of the digital controlled attenuator in the current AGC controlled unit is determined;

If the digital controlled attenuator has reached the maximum controlled attenuation, the process ends;

If the digitally controlled attenuator does not reach the maximum attenuation, increase the attenuation until the ADC data amplitude meets the system requirement.

9. The automatic gain control method according to claim 7, characterized in that the automatic gain control method specifically comprises:

When the ADC data amplitude does not exceed the maximum output threshold required by the system, determine whether the ADC data amplitude is lower than the minimum output threshold required by the system;

If the data amplitude is not lower than the minimum threshold of the system, it means that the output signal amplitude is within the range required by the system, and the control process ends;

If the data amplitude is lower than the system minimum threshold, the control state of the digital controlled attenuator in the current AGC controlled unit is judged. If the attenuation of the digital controlled attenuator is zero, the process ends; if the attenuation of the digital controlled attenuator is not zero, its attenuation is reduced until the ADC data amplitude meets the system requirements.

10. The automatic gain control method according to claim 7, characterized in that the automatic gain control method further comprises completing external signal amplitude control by a limiter before performing external signal data gain adjustment to complete downstream circuit protection.