| 摘要 |
PURPOSE:To detect a changing point with high accuracy despite a large distortion of a line by obtaining a vector difference between two signals having a distance of two sample periods and then detecting the changing point in the training sequence of a modulating/demodulating device. CONSTITUTION:The in-phase component 130I of a received signal is applied to a vector difference arithmetic function 200I at one side and also to the function 200I with a delay 202I at the other side. In the same way, the orthogonal component 130Q is applied to a vector difference arithmetic function 200Q at one side and also to the function 200Q with a delay 202Q at the other side. Both delays 202I and 202Q adds a time delay equivalent to two samples, i.e., two symbol periods to the received signal, respectively. A comparison function 212 sets outputs 218 and 220 in a significant state respectively when the input 210 exceeds the threshold value. Thus it is informed that the changing point from the alternate code series to the pseudo random code series is detected. |
