【摘要】 本文采用时频分析方法推导了理想信道条件下单码片成形直扩信号及其解扩信号的短时频谱特性,并给出了基于匹配滤波和最大比合并解扩解调算法的信噪比和误码率计算公式。分析计算结果表明,直扩系统的误码性能与码片波形的选择密切相关,并且与扩频码片的最大比合并有效性是相一致的。最大比合并有效性可以作为衡量码片波形性能的尺度,通过比较各种扩频码片波形的最大比合并有效性来对其误码性能进行定性分析。更多还原

【Abstract】 The short-term spectra of single-chip waveform coded DSSS (Direct Sequence Spread Spectrum) signals and their de-spread signals are analyzed using time-frequency analysis. BER-vs-SNR expression of a de-spread/demodulation is also deduced based on matched filter and MRC (Maximum Ratio Combining). The results suggest that the BER performance of DSSS communication system has close relationship with the chip wave-shaping and is consistent with MRCE (Maximal Ratio Combining Efficiency). MRCE can be used as a performance measure for chip waveforms. For this reason, the BER performance of different chip waveforms can be qualitatively analyzed through comparing their MRCE.更多还原