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在最大多普勒频车达致十赫芝的高速衰落的数字调频陆地移动电台中,既不能忽视由于接收电波振幅变化引起的信号误码,也不可忽视由相位变化而产生的随机调频杂音引起无法降低的误码。本论文将以高速瑞利衰落下的鉴频和延迟检波数字调频为对象,分析采用检波后选择分集的改善效果。首先,着眼于把检波器输出变成便于分析误码率的式子,并导出对于高速瑞利衰落时的瞬时检波器输入振幅的误码率(带条件误码率)。求出分集接收时的平均误码率作为包含随机FM噪声影响的通解。其次,在陆地移动通信中为了有效地利用频率,研究了在不同地域反复采用同一频率的问题,求出了对于同频干扰的改善效果。最后,与检波后合成分集进行了比较,其改善效果是明显的。
In a digital FM land mobile station that achieves a high-speed fading of 10 Hertz at a maximum Doppler frequency car, neither signal error due to variation of the received radio wave amplitude nor random frequency modulation noise caused by the phase change can be neglected Unable to reduce the error code. In this dissertation, frequency discrimination and delay demodulation digital frequency modulation under the high-speed Rayleigh fading are taken as the object, and the improvement effect of the selective diversity after detection is analyzed. First of all, focusing on making the detector output an easy-to-analyze bit error rate and deriving the bit error rate (conditional error rate) for the instantaneous detector input amplitude at high speed Rayleigh fading. Find the average bit error rate during diversity reception as a general solution that includes the effects of random FM noise. Secondly, in order to make efficient use of frequency in land mobile communications, the problem of using the same frequency repeatedly in different regions is studied, and the improvement effect on co-channel interference is obtained. Finally, compared with the detection after the composite diversity, the improvement effect is obvious.