Wireless Voice Transmission System Based On Stm32

With the high speed development of mobile communication technology, the application of the wireless communication technology is more and more widely, which become one of the most important transmission mode of voice communications. For the wireless communication technology, communication quality and communication capacity are two most important factors, and these are the entry point for the wireless communication research. In this thesis, the compressing decoding technology compresses bit rate from the view of information source. Increasing the number of channels in certain information channel and increasing the utilization rate of information rate in order to save frequency sources have significant importance to wireless communication.The main purpose of this thesis is to design a wireless transmission system, including transmitting subsystem and receiving subsystem. Main chips used in the system are:main control chip STM32series microprocessor, SI4432transceiver chip which is designed especially for the work in the frequency range of433MHz ISM frequency (industry, research and medical treatment) and speech acquisition and playing chip.The major work of this thesis is as follows:Firstly, we use C language to achieve the Speex voice encoding/decoding algorithm, including the implementation of encoder and decoder, which can be used to complete corresponding function.Secondly, the hardware of wireless voice transmission system is designed. The main control chip is responsible for collecting data and logical processing including the realization of Speex speech coding/decoding and analog to digital conversion of collected data and RF module driving. SI4432transceiver chip is used to realize wireless delivery and automatic packing and receiving/transmitting of data. Then, the schematic diagram and PCB diagram are designed.Thirdly, the software of wireless voice transmission system is designed, which consists of sending and receiving subsystem. The transmit subsystem includes an analog to digital conversion process, the timer interrupt program, Speex encoder and RF module driver. Receiving subsystem includes SI4432receiver programming, timer interrupt program, the Speex decoder and audio output program. Finally, the system testing has been completed, including the error rate and packet loss rate. The testing process is divided into four scenes: indoor close range, indoor obstacle, outdoor30meters and60meters outdoors. Discovered through testing, the design can achieve the transmission of wireless voice very well, the voice quality is excellent, the system is very stable. Furthermore, the system power consumption is low and the product can support more function expansion.