| 摘要 |
PURPOSE:To evade erroneous detection due to noises on a transmission circuit by obtaining original information by receiving and judging a frequency-deviation modulated signal transmitted from a transmission part by a frequency/voltage converting circuit, level detecting circuit and deciding circuit. CONSTITUTION:When transmitted from a transmission part onto a transmission circuit, a signal of frequency fH, part of frequency-deviation modulated signal, is converted by frequency/voltage converting circuit 51 into a voltage (in a range between V3 and V4) that corresponds to frequency FH and its output is applied to both level detecting circuits 52 and 53. Only level detecting cir cuit 52 having a set level that corresponds to the voltage in the range between V3 and V4 detects it to generate output S1 of a high level and output S2 of level detect ing circuit 53 becomes low in level. At deciding part 35, the inverted signal of output S2 and the direct signal of output S1 are AND-ed and its output S3 is held high to obtain original information. |
