| 摘要 |
PURPOSE:To perform speech with sufficient articulation by eliminating a noise component from a transmission acoustic signal when a noise level exceeds a certain value, and reducing the low-pass spectrum level of a reception acoustic signal when the noise level further exceeds certain limitation. CONSTITUTION:At a transmission part, an analog acoustic signal A1 outputted from a microphone 112 is amplified by an amplifier 113, and moreover, it is converted to a digital acoustic signal D1 by an A/D converter 114. A noise elimination circuit 115 judges the noise level by using the signal D1, and further eliminates the noise component from the signal D1. A digital acoustic signal D4 from which the noise component is eliminated is encoded by a speech coder 116, and further by a channel coder 117, respectively, and is transmitted via an antenna 101. While, at a reception part 102, a low-pass spectrum component D3 is reduced from the reception acoustic signal D8 when the noise level exceeds the certain limitation, and output with superior articulation can be obtained by applying D/A conversion 108 and sound control 109 to the signal, etc. |
