To provide a waveform equalizer by which the high speed and the stabilization of the optimization of a factor are made compatible.
An update circuit 68 performs an update processing operation in an update amount which is instructed from an update-amount selection circuit 67. At this time, a counting circuit 69 counts the number of times of a factor update operation. Then, when the number of times of the updata operation reaches the prescribed number of times of N, a control signal is sent to an averaging circuit 65 and to the update-amount selection circuit 67. Then, according to the signal, the averaging circuit 65 changes the number of times of an averaging operation (number of data) in an averaging processing operation, and it changes the frequency of the averaging processing operation, i.e., the frequency of the update operation. Actually, the frequency is made high at the initial stage of an optimization processing operation, and the frequency is made low after the update operation is performed the number of times of N. On the other hand, the update-amount selection circuit 67 changes over the decision method of the update amount from a proportional control system to a constant increment system.
MIYAZAWA SHOICHI
HOTTA RYUTARO
HIROOKA TSUGUYOSHI
NARA TAKASHI
