| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device that can generate a side-tone without increasing a load of a CPU and the need for an externally mounted circuit component. SOLUTION: A microprocessor 1 comprises a DSP (Digital Signal Processing circuit) 10, a CPU (11) for controlling the DSP 10 and an interface circuit 12. The interface circuit 12 comprises an input circuit 20 that inputs a digital signal synchronously with a first clock signal (CLK 1) and outputs the digital signal to the DSP 10, a gain adjustment circuit 21 capable of adjusting the gain of the digital signal supplied to the input circuit 20, and an output circuit (22) that adds a digital signal received from the DSP 10 to the digital signal with the adjusted gain and provides an output synchronously with the first clock signal. The signal path from the input circuit to the output circuit via the gain adjustment circuit is formed as hardware and so-called side-tone processing is implemented by a transmission digital signal passing through the signal path.
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