关 键 词：

毕业设计论文

资源描述：

0129、串行通信的电子密码锁论文资料,毕业设计论文

内容简介：

单工无线发射接收系统 摘 要 : 利用无线通信信道的远距离语音传输业务，是近年来发展很快的一门技术。由于语音业务对误码不敏感，可以采用调频方式发送信息 。 设计中采用了分立元件构成音频无线发射电路 。接收机采用第三代立体声放收音机电路 CXA1238 组成的单片收音机，外围元件极少。它在片内完成了混频、中放、鉴频及立体声解码等功能，接收机采用电容分压式滤波器，即可提高镜像抑制比，又可使天线达到最佳匹配，具有动态范围大，调整方便的特点。本设计使用模拟调频技术，在 32MHz 的频段上，实现了线路输入语音信号的小功率远距离单 工发送和接收。系统发射功率大约 20mW，发射距离大于 5m，本系统可实现无明显失真的语音传输。 关键词 ：单工无线 调频 语音传输 CXA1238 Simplex wireless emissive and Receiving system Abstract： The remote audio transmission service code through wireless communication channels is a fast developing technology in recent years. As the audio service code is not sensitive to the mistaken code, the frequency modulation can be used to send information. The separate components was adopted to consist audio-frequency wireless emissive circuit in the design. The third generation stereo radio circuit CXA1238 which constitutes the single chip radio was used in the receiver, so the peripheral components are very few. The function such as frequency mixing, supersonic amplification, frequency discrimination and stereo decoding can be achieved in the chip. The electric filter which was based on the capacitance potentiometer was adopted in the receiver . This kind of filter can both raise the mirror-image repression ratio and make the antenna attain its best match. The two characteristics of it are large dynamic and convenient adjustment. The simulating frequency modulation technique was adopted in the design .In the frequency interval of 32MHz,the audio signals can be sent out and received with the small power in a long distance .The emissive power of the system is about 20mW and the emissive distance is more than 5m.There is no obvious distortion in the audio tran