| 摘要 |
<p>PURPOSE:To prevent the fluctuation in the trace while eliminating a frequency error or a quantization error by applying sample/hold to a triangle wave formed based on a reference servo signal by means of a reproduction control signal at the special reproduction mode, comparing the output with the triangle wave, and using its comparison output as phase comparison information with respect to the reference servo signal. CONSTITUTION:A triangle wave is formed in a triangle wave generating means 16 based on the reference servo signal whose frequency is nearly 30Hz. Then the triangle wave is sampled and held by a sample-and-hold means 17 to obtain phase information. Moreover, a comparison means 18 compares the output of the sample-and-hold means 17 with the triangle wave in terms of level. In the special reproduction mode such as the 1/2 speed mode or the 1/4 speed mode, the phase of the output of the comparison means 18 is compared with that of the reference servo signal to apply phase servo. Thus, the frequency phase error and the quantization error are avoided and the fluctuation of trace is prevented.</p> |
