| 摘要 |
This invention includes a compression circuit for compress one of an audio signal and a mixture of the audio signal and an echo signal, a delay circuit for delaying an output signal of the compression circuit by a predetermined time and an expansion circuit having a conversion rate controlled by a DC voltage generated correspondingly to a regulation of the volume controller, for expanding the output signal of the delay circuit according to a reverse conversion function to the compression conversion function to generate the echo signal.
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