| 摘要 |
PURPOSE:To always output most trust worthy address even when an address- demodulation is failed by outputting a set address or an abnormal signal in accordance with the coincidence/disagreement between a demodulated address and a set address. CONSTITUTION:An FF 7 is reset in the initialization, and a selector 4 selects the output of the first latch 1 under the control of a logic circuit 11, and a demodulated address is taken in the third latch 5. As far as a correct address of a disk is demodulated and read, the address number is outputted from the latch 5. If the demodulated addresses and their order completely coincide with the addresses and their order stored in the second latch 2 beforehand, the output of the latch 2 is used as a demodulated address. On the other hand, in case the outputs of the latches 1 and 2 comes dessident with each other for a few times consecutively, the FF 7 is cleared, the auto increment mode is released, and an abnormal signal is transmitted to a CPU.
|
