| 摘要 |
PURPOSE:To enable more accurate readout for analog information, by inputting the slice reference voltage of a window pulse generating circuit as digital information externally, at an A/D conversion circuit of a magnetic disc device. CONSTITUTION:An analog signal read out from a head is amplified and a digital zero cross pulse is produced at a differentiation circuit 21 and a zero cross point detection circuit 22. Further, an amplified analog signal is also inputted to a window pulse generating circuit 23. This generating circuit 23 consists of A/D conversion circuits in high speed, and a positive/negative reference voltage for waveform slice is applied from a reference voltage generating circuit 24. This reference voltage generating circuit 24 receives one or more digital information given from the outside of a magnetic disc device and produces reference voltages +VT, -VT of both polarities corresponding to the bit information. Thus produced logical product between window and digital zero cross pulses is taken and the result is outputted as digital information. |
