| 摘要 |
PURPOSE:To secure a high-accuracy phase decision by having the synchronous detection with use of the input signal received the 8-phase modulation and the reference phase signal and then giving the phase decision to the phase detection signal through the decision circuit which uses the pi/4 phase of MOD (pi/4) as the threshold level. CONSTITUTION:The 8-phase modulated signal is supplied from input terminal 400 to undergo the synchronous detection through synchronous detection circuit 410 based on the reference phase signal, i.e., the output of conversion circuit 407. The synchronous detection output is supplied to decision circuit 402, and decision code is delivered to terminal 403. This decision code and the synchronous detection output signal are supplied to phase difference detection circuit 420, and the phase difference of both input is detected to be supplied to circuit 407 via low band pass circuit 406. Synchronous detection circuit 410 consists of sine wave read-only memory 404 into which the sine wave signal is written and phase comparison circuit 401. And circuit 420 comprises memory 404 and phase error arithmetic circuit 405. |
