| 摘要 |
PROBLEM TO BE SOLVED: To improve noise suppression effect by de-emphasis. SOLUTION: A transmitter compresses a transmitting signal and transmits it after pre-emphasis is performed. A receiver 20 is equipped with an expanding circuit 22, including a variable gain amplifier 221 for expanding a receiving signal, a first de-emphasis circuit 23 for de-emphasizing the receiving signal before expansion, and a second de-emphasis circuit 24 for de-emphasizing the receiving signal, expanded by the expanding circuit 22. By controlling the gain of the amplifier 221 with the output of the first de-emphasis circuit 23, the receiving signal is expanded in the pre-emphasized state, as it is, by the expanding circuit 22. After that, de-emphasis is performed by the second de- emphasis circuit 24.
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