| 摘要 |
PURPOSE:To eliminate impulse noise and Gauss distribution noise due to out of synchronism by making a loop gain of phase locked loop variable. CONSTITUTION:An input signal 40 becomes a signal 41 with a prescribed amplitude level by an AGC circuit 20. The signal 41 becomes a signal 48 having an amplitude level changed by using a gain control circuit 31 controlled by a voltage 49 set by an external variable resistor 32. Thus, the loop gain, i.e., a phase locking holding range is controlled by changing the amplitude level of the input signal 48 fed to a phase locked loop 10. Thus, in setting the loop gain larger by adjusting the variable resistor 32, the impulse noise is eliminated. Further, in decreasing the loop gain, the Gauss distribution noise is eliminated.
|
