| 摘要 |
PROBLEM TO BE SOLVED: To improve the SNR of a reception signal without the need of a large scale device by applying spread spectrum processing to a noise component of a sampled reception signal and applying low pass filtering to the resulting signal. SOLUTION: A sum ai +ni of a transmission signal with a hand width W and additional noise signal ni with a mean power N are received, a sampling means 1 samples them at a very small sampling interval and a permutation means 2 is used to convert the ai into a discrete signal ai . Then the sampling value of the ai is permutated so as to be the same as before conversion to convert a discrete noise ni with the band width W and the man power N into a discrete noise ni with the band width W' and the mean power N. Since there are many discontinuous adjacent points in the ni ', the relation of W'>>W is established, but the relation of the ai is unchanged. Thus, the ai +ni is given to a low pass filter 3, the ai passes through the filter but the energy of the ni ' is lost because of the relation of W'>>W, then the SNR is improved. |
