| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide the portable telephone set whose voice signal level is changed so as to send a proper incoming voice signal at all times regardless of the quantity of a sound pressure picked up by a microphone at a speech. SOLUTION: An incoming voice signal picked up from a MIC 11 by the user is amplified by an AMP 12 and given to a CODEC 13, which digitally converts and encodes an analog voice signal from the AMP 12. A digital signal processing section DSP 17 monitors the incoming voice signal coded by the CODEC 13 to report its level sequentially to a CPU 16. The CPU 16 stores digital voice data from the DSP 17 to a memory section (MEM) 15 and averages the data in a prescribed timing from a timer section (TIM) 18, collates the resulting level with a set value of a voice level stored in advance in the MEM 15 and gives an instruction of it to an amplifier control section (GNC) 14 that the amplification factor of the AMP 12 or the CODEC 13 is changed thereby changing the level of the incoming voice signal to a proper level.</p> |
