| 摘要 |
PURPOSE:To eliminate a tap coefficient setting error in an abnormal transient state, by controlling a setting operation of a tap coefficient, in the event of a steplike error variation which occurs after an output of an automatic equalizer becomes a steady state. CONSTITUTION:An equalizing error of an automatic equalizer, which is the difference between an output of a tolerance deciding device 11 and an output in a signal output point 9 is converted to an absolute value by an absolute value circuit 13, and in a level comparator 14, the output of the absolute value circuit 13 and a constant L generated from a constant generator 15 are compared in terms of levels, and the quantity of an equalizing error exceeding the constant L is detected. Subsequently, as a result of this detection, in case when the equalizing error quantity exceeds the constant L, an integrator of each stage is reset, and its output is set to zero. That is to say, in a tap coefficient setting expression, the integral term is set to zero consequently, and Cn=Cn<-1>, therefore, each tap coefficient of tap coefficient registers 31-3n holds its previous state, and the automatic equalizer becomes an equalization stop state. |
