| 摘要 |
PURPOSE:To complete initializing in a short time by sending different signal pints with phase difference of 90 deg. from each other from a transmitting side in a data communication MODEM adopting the pre-emphasis system, receiving them at a reception side and applying initializing when a difference between signal points and those at two preceding points of time is not 0. CONSTITUTION:A signal at a point A and a point B is transmitted alternately at first and then a signal at a point C and a point B is transmitted alternately. The converting point from the pattern of alternate transmission of the signals at points A and B into the pattern of sending the signals at the points C and B is obtained and the various kinds of initializing processings are applied at the converting point. That is, a signal is inputted to taps T22-T34 of the equalizer, and the reciprocal of the mean value is obtained by a reciprocal arithmetic circuit 30 from the output of the taps T22-T29 and the center tap of the automatic equalizer is initialized by substituting the reciprocal of the mean value to the center tap of the automatic equalizer. Moreover, a multiplier 34 multiplies the reciprocal of the mean value with the output of the tap T29 (signal point C) to apply normalization and its complex number conjugation is taken and substituted to a delay element to apply initializing to the phase. |
