| 摘要 |
PROBLEM TO BE SOLVED: To remove noise generated in a level conversion circuit completely. SOLUTION: An in-phase detection circuit 41 outputs a reverse phase output signal s4 when input signals s1, s2 and s3 are entirely L or H. The signals s1, s2 and s3 are subjected to level conversion, respectively, in level conversion circuits 1 (31), 2 (32) and 3 (33). Output signal s4 from the in-phase detection circuit 41 is subjected to level conversion in a level conversion circuit 42 for noise decision. A noise decision circuit 43 receives output signals s5, s6, s7 and s8 from the level conversion circuits and makes a decision whether a normal signal is received or noise is received. When the signals s5, s6, s7 and s8 are entirely H or L, a decision is made that noise is received and a noise detection signal s9 is delivered to a transmission circuit 44. Upon receiving the noise detection signal s9, the transmission circuit 44 decides that the signals s5, s6 and s7 are noise and does not transmit them as signals s10, s11 and s12. Consequently, noise generated in the level conversion circuit is removed. |
