| 摘要 |
<p>PURPOSE:To use s single discriminating circuit for discrimination of desired detecting cycles by using the division output obtained by divising the revolution detecting pulse of a capstan motor to sample a tracking error signal. CONSTITUTION:A revolution detecting pulse FG of 300Hz is delivered from a capstan motor in a standard mode and undergoes 1/9 division through a dividing circuit 2. This dividing output S is set at 33.3Hz, i.e., a frequency little higher than the double frequency of 15Hz. Therefore a sample and hold circuit 3 which uses a tracking error signal E as a reference input and the dividing output S as a sampling output performing a sampling action with a slight shift of position to the waveform of the signal E. Thus the amplitude of the holding output is gradually changed. A waveform shaping circuit 4 using the output H as an input performs the shaping of waveforms based on the threshold level and forms a square waveform of 33.3Hz when the amplitude of the output H is increased.</p> |
