| 摘要 |
PURPOSE:To detect a bit of information in which the influence of a peak shift is suppressed with a simple circuit constitution without adding a differentiation circuit by duplicating a signal modulated so as to carry the bit of information by the interval or the position of a pulse, and detecting the bit of information at its trailing edge. CONSTITUTION:Reflected light from a magnetic disc in a system is detected with an optical detector 1, and the reflected light is converted to an electrical signal, then being amplified at a pre-amplifier 2. The output of the pre-amplifier 2 is added on a zero cross detector 3, and the output is binary-coded at a zero cross point. Assuming that the bit of information stored at the disc is as (a) and a signal to be recorded as (b), a reproducing signal outputted from the pre-amplifier 2 becomes (c). In the reproducing signal (c), it is recognized that the peak shift is observed at the leading edge X of the bit of information 1 generated after the continuance of the bits of information 0 and the peak shift is reduced at its trailing edge. And a binarization is performed directly at the trailing edge point at the detector 3, and the differentiation circuit is made unnecessary, and the influence of the peak shift is suppressed.
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