一种Eureka-147数字声音广播系统频率捕获算法

A Novel Frequency Acquisition Algorithm in Eureka-147 Digital Audio Broadcasting (DAB) System

提出了一种新的Eureka-147数字声音广播(DAB)系统的频率捕获算法.该算法采用了基于相邻子载波之间差分检测的频率估计,消除了符号定时误差引起的相移影响,根据频率估计测度的最高值与其左右邻近值关系将粗频率估计分辨率提高到0.5,频率捕获残留的载波频率偏移减少到-0.25～0.25,避免了通常的精频率偏差估计算法在±0.5左右时性能严重恶化的问题.

The proposed algorithm is based on the differential detection technique between adjacent subcarriers to eliminate the phase shift effects of symbol timing offset. The maximum value among the frequency estimation metric and the two adjacent values of the maximum is used to reduce the offset estimation resolution. The frequency offset estimation resolution can be 0.5 and then the remaining carrier frequency offset is reduced to between -0.25 and +0.25. For conventional fine frequency synchronization, the problem of a severe performance degradation when the carrier frequency offset is near +0.5 or -0.5 would be avoided.