| 摘要 |
PURPOSE:To prevent the output of an undesired signal at the changeover of a signal subjected to time division by controlling the changeover of a signal changeover circuit before a signal sent in succession to a non-modulation block is received by a switching latch circuit based on a detection signal of the non- modulation block included in a transmission signal. CONSTITUTION:A non-modulation block detection circuit 8 of a receiver side detects a non-modulation block included in a transmission signal from a sender side and a changeover latch circuit 9 based on the detection signal applies changeover control to a signal changeover circuit before a signal sent in succession to the non-modulation block is received. That is, even when an outputted mute signal S3 is stopped after a prescribed time, while a data signal S2 is received, since a mute signal S4 is outputted from a data reception circuit 7, an output of an OR circuit 10 is kept to an H level during that time and a changeover switch 4 keeps the OFF state (voice mute state). Thus, since the data signal S2 is not entirely outputted from an earpiece 6, an event of giving a sense of displeasure to the user on the receiver side is prevented. |
