| 摘要 |
PURPOSE:To ensuer an assured lead-in of the regenerated carrier wave to the prescribed phase by controlling the control voltage of the voltage control oscillator which has the phase synchronization with the input signal of the orthogonal partial response modulated wave via the switch which selects phase detection output. CONSTITUTION:The orthogonal partial response modulated wave sent from input terminal IN is applied to phase detector PD1 and PD2, and the phase detection is given by the output carrier wave of voltage control oscillator VCO. In this case, the carrier waves featuring the 90 deg.-phase difference is applied to PD1 and PD2 through 90 deg.-phase shifter PHS. This output is then applied to logic circuit LG plus delay circuit DL1 and DL2. The output of DL1 is branched off into two: one is sent to adder ADD via inverter INV1 and switch SW1, and the other is sent also to ADD via SW2. In the same way, one of the output of DL2 is applied to ADD via SW3 and the other is applied to ADD via inverter INV2 respectively. The output of ADD is fed back to oscillator VCO via low pass filter LPF. |
