Design And Realization Of Industrial Broadcast Alarm System

The industrial broadcast alarm system is mainly used in production sites with harsh environment and high risk factor.In the event of an emergency,the system can send out a broadcast alarm signal in time to ensure the safe evacuation of the staff as required,and greatly reduce the economic loss of the enterprise.At present,the industrial broadcast alarm system is mainly divided into two types: digital and analog.The digital broadcast alarm system overcomes the defects of poor compatibility,low scalability,complicated installation and high failure rate of the analog system,and has a wider application in the industry.However,the digital broadcasting system is easily interfered by various noises during the operation process,so that the played voice signal contains a lot of noise,which reduces the recognizability of the voice signal.How to analyze the noisy speech signal,remove the noise in the signal,and improve the signal-to-noise ratio of the signal is the focus of this paper.This paper improves the LMS algorithm,designs the industrial broadcast alarm A+B dual redundancy system scheme,and implements it in the embedded system,The main research contents are described as follows:(1)In view of the defect that the Least Mean Squared Error(LMS)algorithm cannot take into account the steady-state error when it converges rapidly in speech noise reduction,this paper introduces the Wavelet Threshold algorithm based on the LMS algorithm to denoise the speech signal.Firstly,the time-frequency analysis of the speech signal is carried out by using the Wavelet Soft Threshold algorithm to realize the preliminary removal of noise;then,a new variable-step-size LMS algorithm is proposed by establishing the nonlinear functional relationship between the step-size factor and the error signal.Further noise reduction processing is performed on the speech signal.The experimental results show that the variable-step LMS speech noise reduction algorithm based on wavelet threshold has great improvement in Signal-to-Noise Ratio(SNR),Mean Square Error(MSE),and Perceptual Evaluation of Speech Quality(PESQ),improves the quality of calls between stations in this system.(2)Design a digital industrial broadcast alarm A+B dual-redundancy system.When the main system fails,it can automatically switch to the backup system.While improving the system stability,it can also ensure the continuity of system business.The hardware design of the system takes ARM as the core,and uses optical fiber to connect the two systems.The systems establish synchronization and communication connections through multicast.The backup system monitors the node information of the main system.When receiving information about the failure of the main system,it automatically switches to the backup system and restores the file directory by using logs and mirrors.The failover test results verify that the design of the digital A+B dual-redundancy system can improve the reliability of the system.(3)Build the hardware platform of the industrial broadcast alarm A+B dual-redundancy system,and implement the proposed voice noise reduction algorithm on the platform.System test for the station,loudspeaker,SIP call and voice signal denoising algorithm of the industrial broadcast alarm system.The test results show that the system can realize the functions of broadcasting,alarming and two-way communication;the algorithm proposed in this paper can effectively improve the accuracy of the voice signal of the industrial broadcasting alarm system and improve the anti-noise interference of the system.The problems that occurred in the testing process were revised and improved in time,and the system ran stably and met the expected design requirements.