Reproducing unit for recording disc

Abstract

Abstract PURPOSE: To make constant the pressure relation between the disc surface and the stylus and to lower the mechanical impedance of the reproducing pickup stylus substantially, by picking up the change in the stylus pressure as a signal and operating the driving unit with the signal. CONSTITUTION: The uneven signal recorded on the disc 2 is traced with the reproducing stylus 7, the pressure change of the stylus produced with the uneven signal is converted into electric signal with the mechanical-electro conversion element, and amplification is made so that desired output can be obtained with the head amplifier 11. The reproduced output signal is obtained at the output terminal of the signal processing circuit 12. A part of the signal 20 amplified at the amplifier 11 picks up the envelope of the signal at the envelope detector 14. In this case, when the stylus 7 keeps the desired stylus pressure, the output signal 19 of the detector 14 is a given voltage value, but if the stylys pressure is subjected to change due to the surface oscillation of the disc 2, the signal 19 changes with the period of the change in the stylus pressure. Further, the current corresponding to the change in the stylus pressure flows to the coil 8, allowing to operate the permanent magnet 6 and control the stylus pressure to a constant value through the set of the stylus pressure to a desired value. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Masayoshi Abe

Bibliographic Details