| 摘要 |
PURPOSE: To attain frame synchronization of a receiving modem after 'training on data' by correcting a previously determined phase value in accordance with a calculated error and reducing an error generated by the correction to a minimum value suited to the operation of the modem. CONSTITUTION: In the receiving modem, an analog signal is processed by a demodulation/filtering/conversion block 20, so that a point is obtained on a complex plane defined by an amplitude and a phase at each Baud time. A phase rotation signal outputted form a multiplier 22 is decoded by a data decoding device 26 and a constellation estimation point corresponding to a transmitted original constellation point is determined. A estimation value (a) and the phase rotation signal are inputted to an error circuit 28 and a square means error is calculated. At the time of certifying that the receiving modem is in an asynchronous mode due to the change in delay time, a phase sequence generated from a phase sequence block 24 is delayed/advanced so as to minimize the error. |
