CN115514393A

CN115514393A - Automatic gain control method and device based on configurable event trigger

Info

Publication number: CN115514393A
Application number: CN202211165143.9A
Authority: CN
Inventors: 张婷; 程晨; 房爱兵; 汤颢
Original assignee: Jiangsu Xinyun Electronic Technology Co ltd
Current assignee: Jiangsu Xinyun Electronic Technology Co ltd
Priority date: 2022-09-23
Filing date: 2022-09-23
Publication date: 2022-12-23

Abstract

The invention discloses an automatic gain control method and device based on configurable event triggering, relates to the technical field of signal processing, and solves the technical problem that control and adjustment of circuit gain are not accurate enough in a complex channel environment. The automatic gain control device can identify impulse noise and adjust the gain according to the signal energy of the non-impulse noise part; the single-tone noise and the out-of-band interference can be detected and filtered, and the target adjustment energy is improved according to the corresponding scene; the progress of gain control can be adjusted according to the number of times of adjustment and the communication state.

Description

Automatic gain control method and device based on configurable event trigger

Technical Field

The present application relates to the field of signal processing technologies, and in particular, to an automatic gain control method and apparatus based on configurable event triggering.

Background

The goal of the agc circuit is to quickly and stably control the input energy within the desired energy range of the receiver under any condition, so that the next stage circuit can operate under normal conditions. Without the agc circuit, the receiver may saturate or drown the signal in noise when receiving a very strong or very weak signal, thereby causing the receiver to malfunction.

In Power Line Carrier Communication (PLC), the transmission environment of a Power Line channel is complex and variable, and the largest interference comes from periodic pulse interference, narrow-band interference (near-single-tone noise) and strong in-band and out-band gaussian noise interference of electrical appliances such as transformers and switching Power supplies. In addition, the signal characteristics and preamble length also determine that the available gain control time is short, and the energy needs to be stabilized within 200 us. Based on the above factors, the automatic gain control circuit of the PLC needs to have multiple special gain control capabilities, and therefore, according to the complex application scenario of the power line communication environment, the automatic gain control circuit capable of being triggered by a configurable event is designed to achieve accurate and rapid regulation and control.

Disclosure of Invention

The application provides an automatic gain control method and device based on configurable event triggering, and the technical purpose is to flexibly adjust an event list and state control according to different scenes, fully adjust and optimize in various complex and changeable channel environments to obtain optimal gain control performance, and accurately and quickly finish adjustment and control.

The technical purpose of the application is realized by the following technical scheme:

a configurable event trigger-based automatic gain control method comprises a data path and a control path, wherein the data path comprises an energy calculation module, a gain calculation module and an event detection module, and the control path comprises an event summary module, an event hit module, a state machine and a feedback regulation module;

the energy calculation module carries out energy detection on input ADC data to obtain an energy standard value;

the gain calculation module calculates the gain adjustment quantity according to the energy standard value and the current gain from the feedback adjustment module;

the event detection module calculates an energy-related flag according to the energy standard value and a corresponding threshold, calculates a gain-related flag according to the gain adjustment quantity and a corresponding threshold, and then outputs the energy-related flag and the gain-related flag to a control path;

the event summarizing module summarizes the energy-related flag and the gain-related flag, and takes each flag as an event to form an event list;

the event hit module generates hit events according to the event list and the software configuration signals;

the state machine determines whether an event in the event list is hit according to the energy correlation flag and the gain correlation flag of the event detection module, and if the event is hit and the jump condition is met, the state machine jumps;

the feedback adjusting module outputs a feedback control signal to adjust the gain according to the current state of the state machine and the updating action of the hit event, and outputs the current gain to the gain calculating module.

An automatic gain control device based on configurable event triggering comprises a data path and a control path, wherein the data path comprises an energy calculation module, a gain calculation module and an event detection module, and the control path comprises an event summary module, an event hit module, a state machine and a feedback regulation module;

the output of the energy calculation module is input to the gain calculation module and the event detection module, and the output of the gain calculation module is input to the event detection module; the output of the event detection module is input to the event summarizing module, the output of the event summarizing module is input to the event hit module, the output of the event hit module is input to the state machine, and the output of the state machine is input to the feedback adjusting module; the feedback adjusting module outputs a feedback control signal to adjust the gain and outputs the current gain to the gain calculating module.

The beneficial effect of this application lies in: according to the automatic gain control method and device based on configurable event triggering, an event list is firstly established through data of a data path, and then corresponding adjustment is triggered through various 'events' detected by an event detection module. The automatic gain control device can identify impulse noise and adjust the gain according to the signal energy of the non-impulse noise part; the single-tone noise and the out-of-band interference can be detected and filtered, and the target adjustment energy is improved according to the corresponding scene; the progress of gain control can be adjusted according to the number of times of adjustment and the communication state.

Drawings

Fig. 1 is a block diagram of an automatic gain control apparatus according to the present application;

FIG. 2 is a functional block diagram of a data path;

FIG. 3 is a flow chart of data path gain adjustment;

FIG. 4 is a functional block diagram of a control path;

FIG. 5 is a circuit diagram of a control path event hit module;

FIG. 6 is a schematic diagram of control path state hopping;

fig. 7 is a schematic diagram of a simulation result of automatic gain control in a scenario of an input burst signal.

Detailed Description

The technical solution of the present application will be described in detail below with reference to the accompanying drawings.

The configurable event trigger-based automatic gain control device comprises a data path and a control path, wherein the data path comprises an energy calculation module, a gain calculation module and an event detection module, and the control path comprises an event summary module, an event hit module, a state machine and a feedback regulation module. The output of the energy calculation module is input to the gain calculation module and the event detection module, and the output of the gain calculation module is input to the event detection module; the output of the event detection module is input to the event summarizing module, the output of the event summarizing module is input to the event hit module, and the output of the event hit module is input to the state machine; the feedback adjusting module outputs a feedback control signal to adjust the gain and outputs the current gain to the gain calculating module.

As shown in fig. 2, in the data path, the energy calculation module performs energy detection on the input ADC data to obtain an energy standard value. Specifically, the energy calculation module divides input ADC data into N small sections, calculates the sum of squares of the ADC data of the N small sections to obtain energy, converts the energy into dB representation by adopting a dichotomy table look-up mode, and finally takes a second-order small value in the N small sections as an energy standard value. The detection length and the number of the segments can be configured, and the detection length participates in subsequent feedback adjustment so as to be more adaptive to the channel environment.

And the gain calculation module calculates the gain adjustment quantity according to the energy standard value and the current gain from the control channel. As shown in fig. 3, the configurable target energy is first subtracted from the current energy standard value to obtain the target gain adjustment amount, and then the upper and lower limits of the gain adjustment amount are controlled according to the current gain and the threshold. Wherein the target energy and the current gain are both from the control path, and the adjustment of both variables is triggered by a configurable event. The output current gain adjustment is also sent to the control path for changing the current gain after an event is triggered. Thus, the gain calculation module and the control path form a closed loop, thereby exerting better feedback regulation effect.

And the event detection module calculates an energy-related flag according to the energy standard value and the corresponding threshold, and calculates a gain-related flag according to the gain adjustment quantity and the corresponding threshold. The energy related flag comprises an energy saturation flag, an impulse noise flag and the like, the gain related flag comprises an energy stable flag, an adjustment frequency exceeding threshold flag and the like, and each flag is an event.

As shown in fig. 4, the control path summarizes all the flags from the data path to form an event list, activates the corresponding event according to software configuration, "activation", and the data path detects that the corresponding flag is pulled up or down, determines whether the event is hit, and then triggers the state machine to jump and corresponding feedback adjustment actions.

Specifically, the event summarizing module aligns all events to the last output event, uses pulse event _ vld as an event list effective marker, and the event list is represented by event _ list, and the bit width is determined by the number of events output by the data path. Each event is updated after a new energy detection is started, but all events are updated only at event _ vld. The event hit module activates events according to the software configuration signals cfg _ mask and cfg _ invert, and bit widths of the events are consistent with the event list event _ list, for example, if there are 20 events in the event list, the bit widths of the event list, cfg _ mask and cfg _ invert are all 20. The software configures the bit corresponding to the event to be activated by the cfg _ mask as 1, and the rest bits are masks of 0. If the activation event is pulled high indicating a hit, the cfg _ invert corresponding bit is configured to 0, otherwise to 1. As shown in FIG. 5, at the event _ vld time, after the cfg _ invert and the cfg _ mask of the event list are subjected to AND-OR with the cfg _ invert, if the result is consistent with the cfg _ mask, the event is hit, and the flag _ match is pulled high. The flag _ match is used as a jump condition of the state machine, so that a plurality of corresponding flag _ matches exist in each state, and the jump state is configured by cfg _ jmp _ state, thereby ensuring that the jump condition and the jump state of each state are both configurable. And the feedback adjusting module is used for adjusting the gain according to the current state of the state machine and the hit event updating action.

The state machine designs 6 jump states according to the communication flow of one frame, which are an IDLE state (IDLE), a detected signal state (SIG _ DET), a WAIT frame synchronization state (WAIT _ SYNC), an energy LOCK state (LOCK), a frame end state (WAIT _ DROP), and a forced LOCK energy state (FORCE _ LOCK), respectively, and the state jumps are shown in fig. 6. In fig. 6, a solid black line indicates a fixed state jump, a dashed black line indicates that a jump condition is available, and Fx indicates an event. The current state of the state machine and the hit event jointly determine the update of the feedback regulation action, the most important feedback regulation quantity, namely gain regulation, generally passes 3 to 5 times of gain regulation, and the automatic gain control circuit can stabilize the energy to complete the regulation. Besides gain adjustment, other feedback adjustment actions such as target energy adjustment, calculated energy length adjustment and the like are added, so that energy detection and adjustment are performed more accurately, and energy stabilization is expected to be achieved rapidly.

As a specific embodiment, when the present application is applied in a power line carrier communication environment, input signals are sufficiently collected and detected in a data path, and 20 events are adopted as an event list to be activated for controlling the state of the path. In the configuration item cfg _ mask of 20 bits, a bit configured as 1 corresponds to an activated event. 4, 5 and 4 configurable jump conditions are reserved in the states of IDLE, SIG _ DET and WAIT _ SYNC respectively.

Events within a jump condition are in an AND relationship, and jump conditions are in an OR relationship. Taking the IDLE state as an example, when an event 1 (block energy is saturated, event _ list corresponds to bit 1) occurs, or when an event 4 (energy is stable, event _ list corresponds to bit 4) and an event 5 (energy exceeds the noise floor, event _ list corresponds to bit 5) are simultaneously pulled high, the IDLE jumps to SIG _ DET. Then the two hop conditions are 20'h1 and event folder = =20' h1 and 20'h30 and event _list = =20' h30, respectively.

During debugging of the automatic gain control circuit, corresponding event selection and configuration are carried out on the SIG _ DET state and the WAIT _ SYNC state by software. In other states, the jumping process basically has no emergency, and the situation is single, so the jumping condition is fixed without additional configuration.

Fig. 7 shows a case where a large signal is suddenly generated after a background noise is inputted, and as shown in fig. 7, after a small signal is detected for about 5us, the circuit increases the gain once, and thereafter, the energy is stabilized in the SIG _ DET state, and no effective signal is generated. After a large signal appears in about 40us, the circuit continuously performs coarse adjustment twice, the gain is greatly reduced step by step, then the energy is gradually adjusted to be close to the target gain through fine adjustment twice, the flag _ pwr _ agc _ stable is pulled up, the state machine also enters a WAIT _ SYNC state to WAIT for frame synchronization, and the effective signal adjustment takes 12us in total.

The application designs an automatic gain control circuit based on configurable event triggering, and by utilizing an event configuration mechanism combining software and hardware, the behavior of the automatic gain control circuit can be adjusted on line, so that the adaptability of the circuit to a complex electromagnetic environment is effectively improved.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and all equivalent structures or flow transformations made by the present specification and drawings, or applied directly or indirectly to other related arts, are included in the scope of the present invention.

Claims

1. A configurable event trigger-based automatic gain control method is characterized in that the method is realized through a data path and a control path, the data path comprises an energy calculation module, a gain calculation module and an event detection module, the control path comprises an event summary module, an event hit module, a state machine and a feedback regulation module, and the method comprises the following steps:

the energy calculation module performs energy detection on input ADC data to obtain an energy standard value;

the gain calculation module calculates gain adjustment quantity according to the energy standard value and the current gain from the feedback adjustment module;

the state machine determines whether the events in the event list are hit according to the energy correlation flag and the gain correlation flag of the event detection module, and if the events are hit and the jump condition is met, the state machine jumps;

the feedback adjusting module outputs a feedback control signal to adjust the gain according to the current state of the state machine and the hit event updating action, and outputs the current gain to the gain calculating module.

2. The method of claim 1, wherein the states of the state machine comprise an idle state, a detected signal state, a wait for frame synchronization state, an energy lock state, an end of frame state, and a force lock energy state.

3. The method of claim 1, wherein the feedback adjustment module adjusts the target energy and the calculated energy length based on a current state of the state machine and a hit event update action.

4. The method of claim 1, wherein the energy computation module performs energy detection on the input ADC data, comprising: dividing input ADC data into N sections, respectively calculating the square sum of the ADC data of the N sections to obtain energy, then converting the energy into dB to represent, and finally taking the second minimum value of the N sections as an energy standard value.

5. The method of claim 1, wherein the jump conditions for the state machine to jump the state include at least one, and a relation of or between different jump conditions; each of said jump conditions comprises at least one hit, the respective hit being in an and relationship.

6. The method of claim 1, wherein the calculating the gain adjustment amount comprises: subtracting the energy standard value from the configurable target energy to obtain a target gain adjustment quantity, and then controlling the upper limit and the lower limit of the gain adjustment quantity according to the current gain and a corresponding threshold; wherein the target energy is from a control path.

7. The method of claim 1, wherein the energy-dependent flag includes an energy saturation flag and an impulse noise flag; the gain-related flag includes an energy-stable flag and an adjustment number exceeding a threshold flag.

8. The method of claim 1, wherein a bit width of the event list is the same as a bit width of the software configuration signal.

9. The method of claim 1, wherein the software configuration signals include cfg _ mask and cfg _ invert, the cfg _ mask corresponding to events to be activated in the list of events, the cfg _ invert corresponding to the positive and negative polarity of the activated events.

10. The automatic gain control device based on configurable event triggering is characterized by comprising a data path and a control path, wherein the data path comprises an energy calculation module, a gain calculation module and an event detection module, and the control path comprises an event summary module, an event hit module, a state machine and a feedback regulation module;