| 摘要 |
PURPOSE:To obtain a squelch effect by a digital processing, by monitoring the error rate of a frame synchronizing bit, and suppressing the output of a decoding signal when the error rate exceeds a constant value. CONSTITUTION:The output of an encoder 14, that is, the output of a demodulator 20 includes the frame synchronizing bit at every frame in case of transmitting sound by encoding it to a constant length of frame. The frame synchronizing bit is, for example, a datum having a constant pattern like an alternating pattern of n-bits. A frame bit monitoring part 24 monitors the pattern of the frame synchronizing bit, and when the error rate of the bit exceeds the constant value, it stops the operation of a decoder 21, and suppresses the output of the decoding signal. Thus, it is possible to suppress the output of the decoding signal by detecting the increase of the error rate of a reception data, by the frame bit monitoring part 24, and to obtain the squelch effect by the digital processing. |
