| 摘要 |
PURPOSE: To realize a carrier reproducing device which removes unnecessary frequency components generated from a digital signal subjected to N-phase phase modulation at the time of hooking or acquisition. CONSTITUTION: This carrier reproducing device is provided with a demodulation means, a voltage controlled oscillator, a phase shifter 3 which shifts the phase by 90 deg., a PLL consisting of a filtering means which subjects base band signals X1(t) and Y1(t) to low pass filtering, a loop filter, and a sampling means which samples signals X1(t) and Y1(t) by a sampling frequency Fe (Fe>(2p+1)|n|/T where T is a reciprocal of the modulation speed), a signal generation means which is inserted to this PLL and sets the code of the output signal of the filtering means to SIN(2pΦk) and COS(2pΦk) in accordance with the phase error, a phase/frequency comparator, a means which detects synchronization and the hooking loss, and a prescribed filtering means. |
