| 摘要 |
<p>The effect of non-linear distortion on a received signal point is reduced by the use of a circular limiter. In particular, the circular limiter computes the distance (rA') of the received signal point (A') from the center of the signal point constellation. If this distance exceeds a desired limit (r), then both dimensions of the received signal point are reduced by the same factor to maintain the original phase. This reduction in the dimensions of the received signal point decreases the corresponding error signal that is calculated by a Viterbi decoder. As a result, this further reduces the value of the accumulated path metrics of the Viterbi decoder which results in an improvement in system performance. In addition, the circular limiter also realizes a slight improvement in system performance against additive white Gaussian noise. The value of the limiting distance (r) can either be predefined, or determined adaptively to match channel conditions of the communications system. <IMAGE></p> |
