| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate a noise signal that is mixed from a high frequency signal processing circuit, etc., and to improve the quality a transmitted voice in a digital small portable telephone. SOLUTION: A transmitting microphone 101 outputs a voice signal based on a non-linear output characteristic whose output voice signal level falls in accordance with the rise of a sound pressure level of a transmitting sound source. A DSP 105 performs restoration processing of an output voice signal based on the non-linear output characteristic of the microphone 101 into alignment, based on non-linear processing characteristic which is symmetrical to the non-linear output characteristic of the microphone 101 whose level rises in accordance with the rise of an output voice signal level, and a noise signal at a low level which is mixed into an output voice signal through the processing is suppressed to slightly increase (gradually decrease) against the rise of the entire signal level. The output voice signal is inputted to a radio part 106, and the voice signal is performed modulation here, also converted into a prescribed frequency and transmitted by radio from an antenna.</p> |
