Research on Embedded Multichannel Audio Conversion Module

The synchro is a kind of micromotor used for angle measurement. It can output analog signals containing angle information, which is widely used in the fire control system. In order to facilitate the processing, it is necessary to digitize these analog signals. In this paper,8255A is used as the main control chip, and high-speed, high-precision digital to analog and analog to digital converters are used for real-time analog acquisition or mathematical conversion of selsyn signals to realize real-time data communication between fire control equipment and external equipment, and selsyn signals are used for real-time data communication, The technology has the characteristics of flexible control, simple circuit, strong real-time, high reliability, and it has been widely used in the fire control system of naval gun, and achieved good results

This paper explores the integration of Li-Fi technology for transmitting high-fidelity audio signals in modern communication systems. Li-Fi, a wireless communication technology utilizing light signals, offers numerous advantages over traditional radio frequency-based methods, including higher data rates, reduced electromagnetic interference, and enhanced security. Leveraging the unique properties of Li-Fi, such as its ability to transmit data through light waves, this study investigates its potential application in audio signal transmission. Through experimental analysis and theoretical considerations, we demonstrate the feasibility and efficacy of Li-Fi for delivering high-quality audio signals in various scenarios. Our findings contribute to advancing the understanding of Li-Fi technology and its potential role in shaping the future of wireless audio communication.

this paper studies a kind of hearing aid device based on Bluetooth technology and single chip microcomputer. According to the degree of hearing loss of hearing-impaired children, appropriate gain is selected to realize sound amplification, so that children with hearing impairment can hear the outside sound clearly and provide convenience for their life. This design adopts the design idea of the host and slave, the audio amplification parameters in the host are wireless transmitted to the slave through Bluetooth technology, and the audio code coding chip is given instructions. By selecting the appropriate audio signal amplification gain, the audio signal is amplified and processed, so that the hearing-impaired children can hear the external sound clearly. In this design scheme, the system hardware module design mainly includes the system control module, audio module, power module, Bluetooth communication module, etc., among which the audio module also includes the microphone input signal conditioning circuit, audio codec circuit, audio interface circuit, etc. The software platform uses the STM32F103xx firmware library provided by STMicroelectronics Company, and uses the library function provided by it and the corresponding instance to modify and debug.

The subject matter of the article is аudio signal transmission method in network-based audio analytics system. The creation of a network-based audio analytics system leads to the emergence of new classes of load sources that transmit packetized sound data. Therefore, without constructing adequate mathematical models, it is impossible to build a well-functioning network-based audio analytics system. A fundamental question in traffic theory is the question of load source models. The development of an method for transmitting audio signals in a network-based audio analytics system becomes necessary. Based on this, the goal of the work is to create methods an method for transmitting audio signals in a network-based audio analytics system to ensure efficiency and accuracy in audio analytics. The following tasks were solved in the article: the formation of a model for the system's load sources, investigation of connection and traffic management, implementation of control and traffic monitoring functions in the network, research of methods to ensure the quality of audio signal transmission and the development of a method of transmitting an audio signal by virtual routes switching. To achieve these goals, the following methods are used: mathematical signal processing, data compression algorithms, optimization of network protocols, and the use of high-speed network connections. The obtained results include modeling of the system's load sources, examination of connection and traffic management, investigation of methods to ensure the quality of audio signal transmission and a method of transmitting an audio signal by virtual routes switching was proposed. In conclusion, the possibilities of using simulation modeling of nodes in the network-based audio analytics system are highly limited. This is explained by the fact that the acceptable level of information loss in data centers is very low. The use of the developed method enables effective control and processing of sound information in real-time. This method can find broad applications in various fields, including security, healthcare, management systems, and other industries where the analysis of audio signals is a crucial element.

A design of soil detection device based on STM32 single chip microcomputer is proposed The concept of “controller + function module” is adopted as a whole. STM32F103ZET6 single-chip microcomputer as the main control chip, integrated servo motor, HMI serial display, pressure sensor, ball screw and other devices. It can accurately detect the soil strength and display it in real time. With the traditional PID algorithm real-time adjustment of speed can be realized After testing, the detector has high practicability and reliability.

Based on the introduction of the acoustic and seismic detection technology for the networked ammunitions, a data acquisition system with an input of eight channels for the acoustic and seismic signals is designed for the distributed acoustic and seismic sensor arrays. Programs are made for the spectrum analysis, design of the filter, time delay estimation of the multichannel signals. The acquisition of acoustic and seismic signals of the moving target is carried out in the field. Several sets of experiment data are obtained, and one set of acoustic signal and seismic signal are analyzed in this paper. The spectrum of the signal is analyzed and a filter is designed according to the spectrum. The signals are filtered and cross-correlation is made for the acquired multichannel signals. Then the time delay of the multichannel signals is obtained. At last, the cross-correlation result and the time delay estimation result are analyzed in this paper.

Under the laser tracker measurement of angle subsystem environment,signal acquisition system of laser tracker incremental encoder based on FPGA was designed in this paper. The FPGA in this system was mainly responsible for the encoder signal acquisition, processing, and generating timing signals, data caching mechanism and asynchronous output of the data. This paper detailedly introduced quadrupler frequency, phase discrimination, counting, latches, and UART asynchronous serial port output sub-modules in the process of signal acquisition of FPGA, which was implemented by Verilog HDL language. Online logic analyzer of the Quartus software acquired the value of encoder signal in real time, and the rationality of the design was verified ultimately.

This paper describes a new digital NTSC TV and audio signal transmission system in which circuit configurations are simplified and made more inexpensive than MPEG 2 on the basis of the subjective evaluation of the picture quality. An NTSC TV signal and an audio signal can easily be transmitted to the receiver at the same time, since the transmission rate is kept unchanged due to the insertion of the digital audio signal into the horizontal sync pulse of the digital NTSC TV signal. The proposed system has three features. Firstly, the system could give a satisfactory picture quality for consumer-use visual appliances even though the quality of the reproduced pictures is lower than that of the normal digital NTSC TV picture codes obtained at a sampling frequency of 4.00/spl times/fsc with a quantisation level of 8 bits. Secondly, the system can satisfactorily transmit NTSC TV picture codes at a low transmission rate of 50 Mbps even if such an advanced compression technique as MPEG 2 has not been used. Thirdly, the system is used for transmission of the digital audio signals which are inserted into the horizontal sync pulse of the digital NTSC TV signal. A combination of edge-emitting LEDs (ELEDs) and single-mode (SM) optical fibers enables the system to easily transmit a digital NTSC TV picture signal together with digital audio signals over a distance of 10 km through the SM optical fibers.

Compact disk (CD) players have strengthened what was formerly one of the weakest links of audio systems-the mechanical conversion of recorded sound into electric signals. They have almost none of the distortion produced by turntables and vinyl records. Digital information, in the form of small pits, is inscribed onto plastic disks and detected by laser. However, another weak link in audio systems-the conversion of electric signals to sound-remains weak, as advances in speaker technology have been slow, and even the best speakers are highly sensitive to placement. The objections that have been raised to the sound produced by CD players are discussed. It is pointed out that in view of the wide selection of available recordings for turntables, and the large capital investment that many consumers have made in record collections over the years, turntables seem destined to remain in many homes for some time. Some of the electronic synthesizers that are now available for home use are described.

Force plates have commonly been used to measure ground reaction forces. The acquired signals can be used to calculate several parameters for different motor tasks performed by human beings. Therefore, the goal of this tutorial is to present general information regarding the most common force plates, as well as their descriptions in terms of their structures, setup procedures, and signal acquisition, conversion, and export functions. This tutorial primarily provides information for those interested in using force plates to investigate human performances in the fields of motor behavior and biomechanics.

In this paper, we are interested in localizing acoustic sources such as gunfire of Automatic Pistol (AP) and Kalashnikov AK-47 via the Imote2 wireless sensor node platform, using an array of four synchronized microphones connected to ITS400 sensor board of Imote2. More particularly, this work concerns the implementation of a localization algorithm based on the TDOA (Time Difference of Arrival) between the acquired signals by the microphones. This work can be divided into two parts. The first part is dedicated to the realization of an Imote2-based platform, which allows the acquisition of acoustic signals. In the second part, we have evaluated the performance of relative TOA (Time of Arrival) estimation algorithms, where CA-CFAR (Cell Averaging Constant False Alarm Rate) algorithm gave the best results.

An accurate noise prediction is important in order to reduce noise emission significantly and to prevent expensive after-design treatments. This study aims to examine the aerodynamics and aeroacoustics performance of an open system consisting of an axial fan and a heat exchanger where hybrid method incorporating CFD (Computational Fluid Dynamics) and CAA (Computational Aeroacoustics) is used to predict the noise behavior. The hybrid model method used consists of three steps. Firstly, the flow is computed by means of flow-computed fluids and the pressure fluctuations are obtained. This is followed by the acquisition of acoustic signals from these fluctuations and the attainment of a sound pressure level approach with the FW-H (Ffowcs Williams & Hawkings) model.  Unsteady flow field of the air channel case was obtained by using different turbulence models. The SAS model is capable of resolving largescale turbulent structures without the time and grid-scale resolution restrictions of LES (Large Eddy Simulations), often allowing the use of existing grids created for URANS simulations. For this reason, two different turbulence models, namely URANS (Unsteady Reynolds Averaged Navier Stokes) model, SAS (Scale Adaptive Simulations) model have been applied. Acoustic sources were computed based on the pressure fluctuations and sound pressure level and frequency dependent graphics were plotted with Fast Fourier Transform. On the other hand, acoustic measurements were performed in a semi-anechoic chamber for both of them. When the experimental and numerical results were compared with the previously determined receiver points, the accuracy rate was obtained as SAS, URANS respectively.

In this paper, a novel tricolor dot matrix display system in which all the LEDs are modulated and encoded with audio information is presented. The novelty is on the concurrent use of the tricolor LEDs for simultaneous visual message display and audio signal transmission in a free space optical link. The system is comprised of a tricolor LED dot matrix display panel with an interface circuit to a computer, an audio signal transmitter and a receiver. The system further comprises an executive program that runs on the computer for the display control of characters, decorative pattern or messages on the display panel. The receiver, combined with a speaker, is located at some distance from the display system. The receiver is designed to demodulate the optically transmitted audio information and reproduce the messages with the speaker. For modulating emission of tricolor LEDs, an oscillator is used to vary the frequency of on/off periods of the LEDs. The frequency of flicker is high enough to be indistinguishable by human eye and hence display appears to be constantly illuminated. This is a new generation of tricolor LED dot matrix display where in addition to the usual function of LED display, they concurrently provide audio broadcasting through the visible light rays transmitted by the display panel or assembly.

Described is an addressed audio and video signal transmission system in which audio and video signals together with their address consisting of 8 frequencies can simultaneously be sent from the sender to the designated receivers through the optical fibers. The received audio signal covered the frequency range of 10 Hz to 20 kHz with a distortion factor of less than 0.5% and with an SNR of 60 dB (62 dB without addresses). The received video signal covered the frequency range of 100 Hz to 4.2 MHz with a DG of less than 5% and with a DP of less than 5 degrees.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In recent years, deep learning-based audio signal processing is a popular way to extract features from audio signals and make the system learnt about those extracted features and patterns. These features are used for speech recognition, tracking vehicles and different types of audio processing. In many cases, to extract salient features and make the system learnt about those features, conversion of audio signal to spectrogram is a vital step. Spectrograms exhibiting minimum noise and interference, contribute significantly to feature extraction, thereby optimizing the efficiency of the learning system. In this paper, a novel adjustable window function, based on Cosine Hyperbolic Function, is proposed to design Finite Impulse Response (FIR) low-pass filter which can be utilized for reducing noise and interference from the spectrograms. The spectral characteristics of the proposed window function are compared with the state-of-the-art window functions. The performance of the Proposed window-based FIR low-pass filter is assessed with state-of-the-art FIR low-pass filters in terms of reducing noise and interference from spectrograms. Experimental result show that the proposed window-based FIR lowpass filter outperforms the existing methods to eliminate noise and interference from audio to spectrogram conversion.