| 摘要 |
PURPOSE:To attain EFM demodulation in a simple constitution with use of an ROM of small capacity by applying group division, conversion, etc. to an EFM (eight-to-fourteen modulation) signal to produce a 10-bit signal and accessing to a memory. CONSTITUTION:For the EFM signal of 1 word and 14 bits which is latched by a latch circuit 4, 12 bits are grouped every 3 bits with remaining 2 bits left as they are by an EFM demodulating circuit 5. These grouped bits are converted into signals of 2 bits respectively by NOR gates 50 and 51, 52 and 53.... Then an ROM58 storing the demodulation signal is accessed by a signal of 10 bits. Thus the EFM demodulation is made possible in a simple constitution with use of an ROM of small capacity. |
