发明名称 |
AUTOMATIC GAIN CONTROL FOR MOBILE MICROPHONE |
摘要 |
An automatic gain control unit controls the gain applied to an input signal produced by a microphone subject to ambient noise. The automatic gain control circuit continually monitors the signal level of said input signal. A first gain control circuit decreases the gain applied to the input signal in increments of a first size when the input signal exceeds a first predetermined level. A second gain control circuit increases the gain applied to said input signal in increments of a smaller size when the input signal falls below a second predetermined level and in response to the presence of a speech present signal. The second predetermined level is less than said first predetermined level. In one embodiment, the first gain control circuit controls the analog gain of a codec and the second gain control circuit controls the digital gain of the codec.
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申请公布号 |
US2007262819(A1) |
申请公布日期 |
2007.11.15 |
申请号 |
US20070740332 |
申请日期 |
2007.04.26 |
申请人 |
ZARLINK SEMICONDUCTOR INC. |
发明人 |
JIN GARY QU;HUANG YONGHONG |
分类号 |
H03G3/00 |
主分类号 |
H03G3/00 |
代理机构 |
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