| 摘要 |
PURPOSE:To shorten the delay time of a control loop by selecting a control signal from an output when the control signal obtained from the input signal of a transversal equalizer is not equal to the control signal obtained from an output signal, and feeding back it through an error integrating low pass filter to a local carrier oscillator. CONSTITUTION:A comparing means 6 compares an output C1 of a control circuit 51 with an output C2 of a control circuit 52, when they consistent, that is when the input signal is stationary, the output C1 of the control circuit 41 is selected, when they are inconsistent, namely when it is unstationary, a switching signal SEL to select the output C2 of the control circuit 52 is generated, and it is outputted to a selecting means 7. The selecting means 7 selects the output C1 of the control circuit 51 at the stationary time, it selects the output C2 of the control circuit 52 at the unstationary time, and it is outputted to a low pass filter 8. The low pass filter 8 makes pass through the low frequency range part of the control signal C1 or C2, integrates it for a constant time, generates direct current voltages Vc1 and Vc2, and impresses them to a local carrier oscillator 2. Thus, the delay time of a control loop L to reproduce the carrier can be prevented from increasing. |
