阅读说明：本技术 一种基于fpga的应答机数字aoc处理方法和装置 (Responder digital AOC processing method and device based on FPGA ) 是由 夏喜龙 郝精一 于 2019-10-16 设计创作，主要内容包括：本发明公开了一种基于FPGA的应答机数字AOC处理方法和装置,将数字AOC装置作为应答机数字解调调制单元的一部分,用于生成门限控制信号,控制视频处理单元的灵敏度。通过数字AOC功能,降低应答速率,从而保护了发射机；抑制了应答机对较弱信号的应答,保证了对强信号的响应,提升了监视性能。本发明的效果是：(1)性能参数稳定：采用了数字电路实现,设计时采用同步逻辑设计,可靠稳定；(2)调试简单：采用数字电路后,参数固化在程序中,无需调试；(3)便于系统集成：由于采用数字逻辑实现,便于与其他数字处理逻辑集成,减少设备尺寸、重量、功耗,提升设备经济性；(4)该模块上升速率为0.1dB/ms,下降速率为0.083dB/ms,满足DoD AIMS 03-1000A的要求。(The invention discloses a transponder digital AOC processing method and device based on FPGA, wherein a digital AOC device is used as a part of a transponder digital demodulation and modulation unit and is used for generating a threshold control signal and controlling the sensitivity of a video processing unit. The response rate is reduced through the digital AOC function, so that the transmitter is protected; the response of the responder to a weaker signal is inhibited, the response to a strong signal is ensured, and the monitoring performance is improved. The invention has the following effects: (1) the performance parameters are stable: the digital circuit is adopted for realization, and a synchronous logic design is adopted during design, so that the method is reliable and stable; (2) the debugging is simple: after the digital circuit is adopted, the parameters are solidified in the program without debugging; (3) the system integration is facilitated: due to the adoption of digital logic, the digital logic is convenient to integrate with other digital processing logics, the size, the weight and the power consumption of the equipment are reduced, and the economy of the equipment is improved; (4) the module has a rising rate of 0.1dB/ms and a falling rate of 0.083dB/ms, and meets the requirements of DoD AIMS 03-1000A.)

1. An FPGA-based responder digital AOC processing method is characterized in that: the digital AOC device is used as a part of a digital demodulation and modulation unit of the responder and is used for generating a threshold control signal and controlling the sensitivity of the video processing unit.

2. The digital AOC processing method for the FPGA-based responder according to claim 1, wherein the AOC device works as follows:

a) the digital AOC device detects a response indicating signal from the coding and decoding unit;

b) when the overload is found, generating a threshold control signal to the video processing unit;

c) when there is no overload, the video processing unit is controlled to quickly recover the sensitivity.

3. The FPGA-based transponder digital AOC processing method according to claim 1, characterized in that: the digital AOC device consists of part 1: overload detection unit and component 2: the threshold control unit comprises the following functions:

component 1: detecting whether the response signal is overloaded or not, and generating an overload control signal after the overload is detected;

component 2: when receiving the overload control signal, the sensitivity is reduced, and when the overload control signal is not available, the sensitivity is recovered.

4. The FPGA-based transponder digital AOC processing method according to claim 3, wherein the overload detection unit:

the overload detection unit sets a detection reporting period to be 5ms and sets a response pulse within 100 ms;

the overload detection unit comprises components 1-1: 10ms counting unit, part 1-2: FIFO, parts 1-3: overload judgment, the functions of each part are as follows:

component 1-1: calculating response numbers within 10ms, and generating 1 count value every 10 ms;

component 1-2: caching the 10ms count value;

parts 1-3: and counting the number of answers within 100ms, and generating an overload indication every 10 ms.

5. The FPGA-based transponder digital AOC processing method according to claim 3, wherein the threshold control unit: when an overload signal is found, the threshold is quickly raised, so that the sensitivity is reduced, small signals are filtered, large signals are reserved, and the system is prevented from being overloaded; when not overloaded, the sensitivity is rapidly reduced to MTL.

6. The FPGA-based transponder digital AOC processing method according to claim 3,

the threshold control unit is designed by adopting a state machine, and has five states:

state 0: the initial state, the default state is the sensitivity of the answering machine, after detecting the overload, turn to the state 1;

state 1: a threshold is raised, and the state is switched to a state 2 after the threshold is raised;

state 2: a 12ms timing-rising state, starting 12ms timing, detecting overload in the period, turning to a state 1, or turning to a state 3 after 12 ms;

state 3: a threshold reducing state, and after the threshold is reduced, the state is switched to a state 4;

and 4: 12ms time _ down state: starting 12ms timing, detecting overload in the period, and turning to a state 1; otherwise, after 12ms, if the threshold is greater than MTL, the state is switched to 3, and if the threshold is less than or equal to MTL, the state is switched to 0.

7. The FPGA-based transponder digital AOC processing method according to claim 3, characterized in that:

threshold rise rate calculation:

when overload is detected, the threshold is lifted once every 10ms, the lifting value is 1dB, and the rising rate is about 0.1 dB/ms;

threshold descent rate calculation:

when the overload is not caused, the threshold is reduced every 12ms, the lifting value is 1dB, and the reduction rate is 1/12 dB/ms;

the requirements of the DoD AIMS03-1000A on the ascending/descending rate are met through the calculated ascending rate and the descending rate:

rising rate: (0.075-0.1) dB/ms;

the descending rate: (0.075-0.1) dB/ms.

8. A transponder digital AOC device based on FPGA is characterized in that the digital AOC device is used as a part of a transponder digital demodulation and modulation unit and is used for generating a threshold control signal and controlling the sensitivity of a video processing unit;

the AOC device works as follows:

a) the digital AOC device detects a response indicating signal from the coding and decoding unit;

b) when the overload is found, generating a threshold control signal to the video processing unit;

c) when no overload exists, the video processing unit is controlled to quickly recover the sensitivity;

the device comprises:

the overload detection unit detects whether the response signal is overloaded or not, and generates an overload control signal after the overload is detected;

and the threshold control unit is used for reducing the sensitivity after receiving the overload control signal and recovering the sensitivity when the overload control signal does not exist.

9. The FPGA-based transponder digital AOC device of claim 8, wherein: the overload detection unit sets a detection reporting period to be 5ms and sets a response pulse within 100 ms;

the overload detection unit comprises components 1-1: 10ms counting unit, part 1-2: FIFO, parts 1-3: overload judgment, the functions of each part are as follows:

component 1-1: calculating response numbers within 10ms, and generating 1 count value every 10 ms;

component 1-2: caching the 10ms count value;

parts 1-3: and counting the number of answers within 100ms, and generating an overload indication every 10 ms.

Technical Field

The invention relates to a transponder digital AOC processing method and device based on FPGA.

Background

Response Rate Control, also known as Automatic Rate Control (AOC), is one of the important functions and capabilities of an answering machine. According to the requirements of the civil aviation accessory 10: "to protect the system from the effects of transponder overload, the device must have reduced sensitivity response limit control to prevent response to weaker signals when a predetermined response rate has been reached". By means of the AOC function, the following effects can be achieved:

(1) when the preset response rate is reached, the response to a weak signal is prevented, and the response to a strong signal is ensured, so that the response to a short-distance radar is improved, and the monitoring performance is improved.

(2) By reducing the response rate, the transmitter is protected from overloading and operates at a nominal value.

Disclosure of Invention

Aiming at the technical defects of the background technology, in order to adapt to the development trend of the current and future comprehensive avionics, a digital AOC method and a digital AOC device are designed based on an FPGA.

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

a digital AOC device is used as a part of a digital demodulation and modulation unit of the responder and is used for generating a threshold control signal and controlling the sensitivity of a video processing unit.

Preferably, the AOC device operates as follows:

a) the digital AOC device detects a response indicating signal from the coding and decoding unit;

b) when the overload is found, generating a threshold control signal to the video processing unit;

c) when there is no overload, the video processing unit is controlled to quickly recover the sensitivity.

Preferably, the digital AOC device is composed of a part 1: overload detection unit and component 2: the threshold control unit comprises the following functions:

component 1: detecting whether the response signal is overloaded or not, and generating an overload control signal after the overload is detected;

component 2: when the overload control signal is received, the sensitivity is reduced (the threshold control signal is increased), and when the overload control signal is not received, the sensitivity is recovered (the threshold control signal is reduced to the sensitivity).

Preferably, the overload detection unit:

the overload detection unit is used for outputting an overload indication signal timely and accurately, setting a detection reporting period to be 5ms for enabling a system to respond quickly, and setting response pulses within 100ms for enabling the system to detect accurately;

the overload detection unit comprises components 1-1: 10ms counting unit, part 1-2: FIFO, parts 1-3: overload judgment, the functions of each part are as follows:

component 1-1: calculating response numbers within 10ms, and generating 1 count value every 10 ms;

component 1-2: buffering the 10ms count value (adopting a 10-level FIFIFIO structure);

parts 1-3: counting the number of answers within 100ms, and generating an overload indication every 10ms (when the answer is overloaded, an overload indication pulse is generated, otherwise, no pulse is output).

Preferably, the threshold control unit: when an overload signal is found, the threshold is quickly raised, so that the sensitivity is reduced, small signals are filtered, large signals are reserved, and the system is prevented from being overloaded; when not overloaded, the sensitivity is rapidly reduced to MTL.

As a preferred mode of execution,

the threshold control unit is designed by adopting a state machine, and has five states:

state 0: the initial state, the default state is the sensitivity of the answering machine, after detecting the overload, turn to the state 1;

state 1: a threshold is raised, and the state is switched to a state 2 after the threshold is raised;

state 2: a 12ms timing-rising state, starting 12ms timing, detecting overload in the period, turning to a state 1, or turning to a state 3 after 12 ms;

state 3: a threshold reducing state, and after the threshold is reduced, the state is switched to a state 4;

and 4: 12ms time _ down state: starting 12ms timing, detecting overload in the period, and turning to a state 1; otherwise, after 12ms, if the threshold is greater than MTL, the state is switched to 3, and if the threshold is less than or equal to MTL, the state is switched to 0.

As a preferred mode of execution,

threshold rise rate calculation:

when overload is detected, the threshold is lifted once every 10ms, the lifting value is 1dB, and the rising rate is about 0.1 dB/ms;

threshold descent rate calculation:

when the overload is not caused, the threshold is reduced once every 12ms, the lifting value is 1dB, and the reduction rate is 1/12dB/ms (about 0.083 dB/ms);

the requirements of the DoD AIMS03-1000A on the ascending/descending rate are met through the calculated ascending rate and the descending rate:

rising rate: (0.075-0.1) dB/ms;

the descending rate: (0.075-0.1) dB/ms.

A digital AOC device of a transponder based on FPGA, the digital AOC device is regarded as a part of the digital demodulation modulating unit of the transponder, used for producing the control signal of the threshold, control the degree of sensitivity of the video processing unit;

the AOC device works as follows:

a) the digital AOC device detects a response indicating signal from the coding and decoding unit;

b) when the overload is found, generating a threshold control signal to the video processing unit;

c) when no overload exists, the video processing unit is controlled to quickly recover the sensitivity;

the FPGA-based transponder digital AOC device comprises:

the overload detection unit detects whether the response signal is overloaded or not, and generates an overload control signal after the overload is detected;

the threshold control unit is configured to decrease the sensitivity (increase the threshold control signal) when receiving the overload control signal and to restore the sensitivity (decrease the threshold control signal to the sensitivity) when there is no overload control signal.

As an optimal mode, the overload detection unit should output an overload indication signal timely and accurately, in order to make the system response quick, the detection reporting period is set to be 5ms, and in order to make the system detection accurate, a response pulse within 100ms is set for detection;

the overload detection unit comprises components 1-1: 10ms counting unit, part 1-2: FIFO, parts 1-3: overload judgment, the functions of each part are as follows:

component 1-1: calculating response numbers within 10ms, and generating 1 count value every 10 ms;

component 1-2: buffering the 10ms count value (adopting a 10-level FIFIFIO structure);

parts 1-3: counting the number of answers within 100ms, and generating an overload indication every 10ms (when the answer is overloaded, an overload indication pulse is generated, otherwise, no pulse is output).

Preferably, the threshold control unit is designed by a state machine, and has five states:

state 0: the initial state, the default state is the sensitivity of the answering machine, after detecting the overload, turn to the state 1;

state 1: a threshold is raised, and the state is switched to a state 2 after the threshold is raised;

state 2: a 12ms timing-rising state, starting 12ms timing, detecting overload in the period, turning to a state 1, or turning to a state 3 after 12 ms;

state 3: a threshold reducing state, and after the threshold is reduced, the state is switched to a state 4;

and 4: 12ms time _ down state: starting 12ms timing, detecting overload in the period, and turning to a state 1; otherwise, after 12ms, if the threshold is greater than MTL, the state is switched to 3, and if the threshold is less than or equal to MTL, the state is switched to 0.

The invention has the beneficial effects that:

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is an analog circuit employed in the prior art;

FIG. 2 is a diagram of an external interface relationship of a digital AOC device;

FIG. 3 is a digital AOC device composition;

FIG. 4 is a functional block diagram of overload detection;

fig. 5 is a state transition diagram of a threshold control unit.

Detailed Description

The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.