2 . reseach different methods and steps carried out including discrete cosine translation , run - length enconding and haffman encoding about signals coding and decoding . the signal - coding structure diagrams and programmable flow charts are not only established but also the applide program about signal coding and decoding is complied on vc developable flat 研究了信源编解码的各种方法(包括dct 、游程编码和哈夫曼编码等)以及实现的步骤,建立了信源编码实现的结构图和程序流程图,并在vc的开发平台下,编制了信源编解码实现过程的应用程序。
Secondly , we apply tk operator to the cross - correlation of received signal code and pn code to separate the multi - paths . it comes to a conclusion that tk operator can separate the multi - paths within less than the chip period accurately of spread - spectrum system with space - modulation by simulation . at last , we apply this algorithm to the practical signal collected by gps tap , and from the result we can drop a conclusion the tk algorithm is practical 本文首先阐述了时空调制扩频信号原理以及在多径干扰下时空调制接收机的性能和teager - kaiser接收机的原理;接着对时空调制扩频系统的解调信号与伪码的互相关函数采用tk接收机进行多径分离,仿真结果表明, tk接收机对时延在一个码片内的时空调制扩频通信多径信号有很好的分离效果;最后用数据采集器对一个gps信号进行接收和多径的估计,验证了该算法在实际的运用中对多径的扩频信号有很好的分离效果。
When the speech signal coding is at 8kb / s and 9 . 6kb / s , its understanding and definition are quite satisfaction . completely achieve the common telephone effect . only in the shade of naturalness . when the speech signal coding is at 4kb / s and 4 . 8kb / s the voice transmission result is as good as that of the ordinary telephones 本文所设计的q4401应用电路,在语音压缩速率为8kb s和9 . 6kb s时,其语音质量在可懂度和清晰度方面均十分满意,完全达到了普通电话的通话效果,仅在自然度方面略显逊色。