| 摘要 |
PURPOSE:To prevent the occurrence of an abnormal signal output at the changing point of a code signal of a 12-bit code inspecting system, by adding a memory circuit and a control circuit after a decoding circuit. CONSTITUTION:A decoding circuit 2 supplies a signal train which is serial in terms of time and demodulated by a demodulating circuit 1, inspects the code with the latest 12-bit signal train with every input of a 1-bit signal and at that moment and delivers either one of the signals S0, S1 and S2 corresponding to the input codes. This output signal is held temporarily at a memory circuit 5. On the other hand, an abnormal signal SX is delivered in case the signal excepting the code signal is supplied. With input of the signal SX, a control circuit 6 delivers a preceding value holding command signal 6a to the circuit 5 to hold the output at the preceding value. The signal SX is not delivered to outside via an abnormal signal output circuit 4 until the signal SX is continuous for 12 bits. The signal SX is not continuous for >=11 bits at the changing point of the code signal and accordingly never outputted to outside. |
