Digital audio interaction system and method based on non-real-time operating system
By using the combination of SOC, FPGA and RS422 interface chips in aeronautical communication devices, the window buffer area of the FPGA is dynamically maintained, solving the intermittent and interruption of digital audio transmission caused by Linux non-real-time operating systems, and achieving accurate timed transmission and improving voice quality.
Patent Information
- Application Number
- CN202510250388.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2025-05-30
AI Technical Summary
The Linux non-real-time operating system causes intermittent and interruption of digital audio transmission between different devices due to system timing errors, which cannot meet the high-standard timing transmission requirements of aviation communication equipment.
Using the combination of SOC, FPGA and RS422 interface chips, the cache area is dynamically maintained to ensure the stability and accuracy of data transmission by setting up a 1024-byte window buffer in the FPGA and setting two thresholds N1=256 bytes and N2=768 bytes.
It realizes accurate and timed transmission of digital audio, avoids the problems of intermittent and interruption of transmission, and improves the voice quality of aviation communication equipment.
Smart Images
Figure CN120075361A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electronic communications, and particularly to a digital audio interaction system and method based on a non-real-time operating system. Background Art
[0002] With the rapid development of avionics technology, airborne electronic equipment is developing towards high integration and miniaturization. Radio equipment in various frequency bands such as shortwave, ultra-shortwave, satellite communication, and electronic countermeasure are integrated in the limited space inside the airframe, and the electromagnetic interference signals generated by their common operation are relatively complex. In order to improve the voice quality of aviation communication equipment, it has become the current mainstream solution to change the voice output signals of communication equipment such as shortwave and ultra-shortwave to digital audio signals from the traditional analog.
[0003] In order to improve the voice quality, the current audio output of airborne shortwave communication equipment generally adopts a digital audio design solution, separating the audio AD / DA conversion from the shortwave communication equipment side and placing it in front of the digital aircraft communication module of the airborne aircraft communication system. The two communicate with each other through an RS422 serial port strictly in accordance with the agreed audio coding transmission protocol for data interaction.
[0004] With the increasing requirement of domestic localization substitution, more and more products use domestic Linux operating systems to replace foreign Vxworks operating systems. Since the Linux operating system is a non-real-time operating system with poor system timing accuracy and cannot meet the high-standard timing transmission requirements of digital audio with a packet size of 5 ms, and using the Linux non-real-time operating system will cause system timing errors, resulting in intermittent and interrupted digital audio transmission between different devices. Therefore, there is an urgent need to invent a digital audio interaction system for use with the Linux non-real-time operating system to achieve precise timing transmission of digital audio. Summary of the Invention
[0005] The purpose of the present invention is to provide a digital audio interaction system and method based on a non-real-time operating system, which can solve the problems of intermittent and interrupted digital audio transmission between different devices caused by system timing errors in the Linux non-real-time operating system of the integrated service processing module of airborne shortwave equipment, achieve precise timing transmission of digital audio, and improve the voice quality of aviation communication equipment.
[0006] The technical solution for achieving the purpose of the present invention is: A digital audio interaction system based on a non-real-time operating system, including an SOC, an FPGA, and an RS422 interface chip;
[0007] The SOC is used to implement shortwave waveform processing and various services and functions of the radio station;
[0008] The FPGA is used to implement radio frequency digitization processing of shortwave and serial port data transceiver;
[0009] The RS422 interface chip is used for data interaction according to the agreed audio coding transmission protocol.
[0010] Furthermore, the SOC uses the LC1881 chip of Spreadtrum Communications, and the operating system adopted is the Linux operating system.
[0011] Furthermore, a data transmission window mechanism is established between the FGPA and the SOC. The FGPA sets up a 1024-byte window buffer, and sets two thresholds N1 = 256 bytes and N2 = 768 bytes. The FGPA maintains this buffer.
[0012] Furthermore, when the system initially runs, the method for the FGPA to maintain the buffer is as follows:
[0013] When the data in the buffer is less than N1, the SOC sends data at a rate with inaccurate timing of one packet per 5 ms until the data in the buffer is greater than N1. At this time, the FGPA starts to send data at a rate with a standard timing of one packet per 5 ms according to the requirements of the communication protocol.
[0014] Furthermore, when the system runs normally, the method for the FGPA to maintain the buffer is as follows:
[0015] When the data value in the buffer is greater than N1 and less than N2, both the SOC with inaccurate timing and the FGPA send data at a rate of one packet per 5 ms according to the requirements of the communication protocol;
[0016] When the data value in the buffer is lower than N1, the FGPA sends a LOW signal to the SOC, and the SOC increases the rate on the basis of the current data sending rate until the data value in the buffer is greater than N2;
[0017] When the data value in the buffer is higher than N2, the FGPA sends a HI signal to the SOC, and the SOC decreases the rate on the basis of the current data sending rate until the data value in the buffer is less than N1.
[0018] A digital audio interaction method based on a non-real-time operating system is provided with an SOC, an FGPA, and an RS422 interface chip. The specific process is as follows:
[0019] The SOC performs shortwave waveform processing and executes various services and functions of the radio station;
[0020] The FGPA performs radio frequency digitization processing of the shortwave and executes serial port data transceiver;
[0021] The RS422 interface chip conducts data interaction according to the agreed audio coding transmission protocol.
[0022] Further, the SOC uses the LC1881 chip of Spreadtrum Communications, and the operating system used is the Linux operating system.
[0023] Further, a data transmission window mechanism is established between the FGPA and the SOC. The FPGA sets up a 1024-byte window buffer, and sets two thresholds N1 = 256 bytes and N2 = 768 bytes. The FGPA maintains this buffer.
[0024] Further, when the system initially runs, the method for the FGPA to maintain the buffer is as follows:
[0025] When the data in the buffer is less than N1, the SOC sends data at a rate with inaccurate timing of one packet every 5 ms until the data in the buffer is greater than N1. At this time, the FPGA starts to send data at a rate with a standard timing of one packet every 5 ms according to the requirements of the communication protocol.
[0026] Further, when the system runs normally, the method for the FGPA to maintain the buffer is as follows:
[0027] When the data value in the buffer is greater than N1 and less than N2, both the SOC with inaccurate timing and the FPGA send data at a rate of one packet every 5 ms according to the requirements of the communication protocol;
[0028] When the data value in the buffer is lower than N1, the FPGA sends a LOW signal to the SOC, and the SOC increases the rate on the basis of the current data sending rate until the data value in the buffer is greater than N2;
[0029] When the data value in the buffer is higher than N2, the FPGA sends a HI signal to the SOC, and the SOC decreases the rate on the basis of the current data sending rate until the data value in the buffer is less than N1.
[0030] Compared with the prior art, the significant advantages of the present invention are: (1) It solves the problem that the digital audio transmission between different devices is intermittent and interrupted due to the system timing error of the Linux non-real-time operating system in the integrated service processing module of the airborne short-wave equipment, and improves the voice quality of the aviation communication equipment; (2) It uses the domestic Linux operating system to replace the foreign Vxworks operating system, meets the domestic localization replacement requirements, and improves the autonomy and security of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 is a schematic structural diagram of a digital audio interaction system based on a non-real-time operating system of the present invention.
[0032] Figure 2 is a schematic structural diagram of the window buffer established by the FPGA in the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0033] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.
[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.
[0035] The present invention provides a digital audio interaction system based on a non-real-time operating system, including an SOC, an FPGA, and an RS422 interface chip;
[0036] The SOC is used to implement shortwave waveform processing and various services and functions of the radio station;
[0037] The FPGA is used to implement radio frequency digitization processing of shortwave and serial port data transceiver;
[0038] The RS422 interface chip is used to perform data interaction according to the agreed audio coding transmission protocol.
[0039] As a specific example, the SOC uses the Lianxin Technology LC1881 chip, and the operating system used is the Linux operating system.
[0040] As a specific example, a data transmission window mechanism is established between the FGPA and the SOC. The FPGA sets up a 1024-byte window buffer, and sets two thresholds of N1 = 256 bytes and N2 = 768 bytes. The FGPA maintains this buffer.
[0041] As a specific example, when the system initially runs, the method for the FGPA to maintain the buffer is:
[0042] When the data in the buffer is less than N1, the SOC sends data at a rate with an inaccurate timing of one packet every 5 ms until the data in the buffer is greater than N1. At this time, the FPGA starts to send data at a rate with a standard timing of one packet every 5 ms according to the requirements of the communication protocol.
[0043] As a specific example, when the system runs normally, the method for the FGPA to maintain the buffer is:
[0044] When the data value in the buffer is greater than N1 and less than N2, both the SOC with inaccurate timing and the FPGA send data at a rate of one packet every 5 ms according to the requirements of the communication protocol;
[0045] When the data value in the buffer is lower than N1, the FPGA sends a LOW signal to the SOC, and the SOC increases the rate on the basis of the current data sending rate until the data value in the buffer is greater than N2;
[0046] When the data value in the buffer is higher than N2, the FPGA sends a HI signal to the SOC, and the SOC decreases the rate on the basis of the current data sending rate until the data value in the buffer is less than N1.
[0047] The present invention also provides a digital audio interaction method based on a non-real-time operating system, which is provided with an SOC, an FPGA, and an RS422 interface chip. The specific process is as follows:
[0048] The SOC performs short-wave waveform processing and executes various services and functions of the radio station;
[0049] The FPGA performs radio frequency digitization processing of short waves and executes serial port data sending and receiving;
[0050] The RS422 interface chip performs data interaction according to the agreed audio coding transmission protocol.
[0051] As a specific example, the SOC uses the Spreadtrum LC1881 chip, and the operating system used is the Linux operating system.
[0052] As a specific example, a data transmission window mechanism is established between the FGPA and the SOC. The FPGA sets up a 1024-byte window buffer, and sets two thresholds of N1 = 256 bytes and N2 = 768 bytes. The FGPA maintains this buffer.
[0053] As a specific example, when the system initially runs, the method for the FGPA to maintain the buffer is:
[0054] When the data in the buffer is less than N1, the SOC sends data at a rate of one packet every 5 ms with inaccurate timing until the data in the buffer is greater than N1. At this time, the FPGA starts to send data at a rate of one packet every 5 ms with a standard timing according to the requirements of the communication protocol.
[0055] As a specific example, when the system runs normally, the method for the FGPA to maintain the buffer is:
[0056] When the data value in the buffer is greater than N1 and less than N2, both the SOC with inaccurate timing and the FPGA send data at a rate of one packet every 5 ms according to the requirements of the communication protocol;
[0057] When the data value in the buffer is lower than N1, the FPGA sends a LOW signal to the SOC, and the SOC increases the rate based on the current data transmission rate until the data value in the buffer is greater than N2;
[0058] When the data value in the buffer is higher than N2, the FPGA sends a HI signal to the SOC, and the SOC decreases the rate based on the current data transmission rate until the data value in the buffer is less than N1.
[0059] The following further describes the present invention in detail with reference to the accompanying drawings and specific embodiments.
[0060] Embodiment
[0061] Combined with Figure 1 , a digital audio interaction system based on a non-real-time operating system, includes a SOC, an FPGA, and an RS422 interface chip;
[0062] The SOC is used to implement shortwave waveform processing and various services and functions of the radio station;
[0063] The FPGA is used to implement radio frequency digitization processing of shortwave and serial port data transceiver;
[0064] The RS422 interface chip is used to perform data interaction according to the agreed audio coding transmission protocol.
[0065] As a specific example, the SOC uses the Lianxintec LC1881 chip, and the operating system used is the Linux operating system.
[0066] In the Linux operating system kernel, the kernel code is non-preemptible during execution. Once a task starts to execute, other tasks must wait for the task to complete before they can execute. Especially under the condition of high kernel load, it will cause a large delay in the execution of new tasks and inaccurate system timing. In practical applications, the timing of the SOC digital audio serial port to send data is less than one packet per 5 ms, while the FPGA sends one packet per 5 ms according to the standard timing, resulting in the problem of the buffer being emptied and the sound being intermittent.
[0067] As a specific example, a data transmission window mechanism is established between the FGPA and the SOC. The FPGA sets up a 1024-byte window buffer, and sets two thresholds N1 = 256 bytes and N2 = 768 bytes. The FGPA maintains this buffer, as Figure 2 shown.
[0068] As a specific example, when the system initially runs, the method for the FGPA to maintain the buffer is:
[0069] When the data in the buffer is less than N1, the SOC sends data at a rate with inaccurate timing of one packet every 5 ms until the data in the buffer is greater than N1. At this time, the FPGA starts to send data at a rate with a standard timing of one packet every 5 ms according to the requirements of the communication protocol.
[0070] As a specific example, when the system is running normally, the method for the FGPA to maintain the buffer is as follows:
[0071] When the data value in the buffer is greater than N1 and less than N2, both the SOC with inaccurate timing and the FPGA send data at a rate of one packet every 5 ms according to the requirements of the communication protocol;
[0072] When the data value in the buffer is lower than N1, the FPGA sends a LOW signal to the SOC, and the SOC increases the rate on the basis of the current data sending rate until the data value in the buffer is greater than N2;
[0073] When the data value in the buffer is higher than N2, the FPGA sends a HI signal to the SOC, and the SOC decreases the rate on the basis of the current data sending rate until the data value in the buffer is less than N1;
[0074] Through this dynamic window coordination method, the FGPA data buffer is dynamically maintained to ensure that the FGPA does not empty or overflow the data in the FPGA buffer, thereby ensuring the continuous and stable output of audio data.
[0075] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A digital audio interactive system based on a non-real-time operating system, characterized in that: Including SOC, FPGA and RS422 interface chip; The SOC is used to implement shortwave waveform processing and various services and functions of the radio station; The FPGA is used to realize shortwave radio frequency digital processing and serial port data transmission and reception; The RS422 interface chip is used for data exchange according to the agreed audio coding transmission protocol.
2. The digital audio interactive system based on a non-real-time operating system according to claim 1, characterized in that: The SOC adopts the LC1881 chip of Leadcore Technology and the operating system adopted is the Linux operating system.
3. The digital audio interactive system based on a non-real-time operating system according to claim 1, characterized in that: A data transmission window mechanism is established between the FGPA and the SOC. The FPGA establishes a 1024-byte window buffer area and sets two thresholds of N1=256 bytes and N2=768 bytes. The FGPA maintains the buffer area.
4. The digital audio interactive system based on a non-real-time operating system according to claim 3, characterized in that: When the system is initially running, the FGPA maintains the cache area as follows: When the data in the buffer area is less than N1, the SOC sends data at an inaccurate rate of 5 ms per packet until the data in the buffer area is greater than N1. At this time, the FPGA starts to send data at a standard rate of 5 ms per packet according to the communication protocol requirements.
5. The digital audio interactive system based on a non-real-time operating system according to claim 3, characterized in that: When the system is running normally, FGPA maintains the cache area as follows: When the data value in the buffer is greater than N1 and less than N2, the SOC timing is inaccurate and the FPGA sends data at a rate of 5ms per packet according to the communication protocol requirements; When the data value in the buffer area is lower than N1, the FPGA sends a LOW signal to the SOC, and the SOC increases the rate based on the current data transmission rate until the data value in the buffer area is greater than N2; When the data value in the buffer area is higher than N2, the FPGA sends a HI signal to the SOC, and the SOC reduces the rate based on the current data transmission rate until the data value in the buffer area is less than N1.
6. A digital audio interaction method based on a non-real-time operating system, characterized in that: Equipped with SOC, FPGA and RS422 interface chip, the specific process is as follows: The SOC performs shortwave waveform processing and executes the various services and functions of the radio station; FPGA performs shortwave radio frequency digital processing and executes serial port data transmission and reception; The RS422 interface chip performs data exchange according to the agreed audio coding transmission protocol.
7. The digital audio interaction method based on a non-real-time operating system according to claim 6, characterized in that: The SOC adopts the LC1881 chip of Leadcore Technology and the operating system adopted is the Linux operating system.
8. The digital audio interaction method based on a non-real-time operating system according to claim 6, characterized in that: A data transmission window mechanism is established between the FGPA and the SOC. The FPGA establishes a 1024-byte window buffer area and sets two thresholds of N1=256 bytes and N2=768 bytes. The FGPA maintains the buffer area.
9. The digital audio interaction method based on a non-real-time operating system according to claim 8, characterized in that: When the system is initially running, the FGPA maintains the cache area as follows: When the data in the buffer area is less than N1, the SOC sends data at an inaccurate rate of 5 ms per packet until the data in the buffer area is greater than N1. At this time, the FPGA starts to send data at a standard rate of 5 ms per packet according to the communication protocol requirements.
10. The digital audio interaction method based on a non-real-time operating system according to claim 8, characterized in that: When the system is running normally, FGPA maintains the cache area as follows: When the data value in the buffer is greater than N1 and less than N2, the SOC timing is inaccurate and the FPGA sends data at a rate of 5ms per packet according to the communication protocol requirements; When the data value in the buffer area is lower than N1, the FPGA sends a LOW signal to the SOC, and the SOC increases the rate based on the current data transmission rate until the data value in the buffer area is greater than N2; When the data value in the buffer area is higher than N2, the FPGA sends a HI signal to the SOC, and the SOC reduces the rate based on the current data transmission rate until the data value in the buffer area is less than N1.