发明名称 |
Multiplex stereo demodulator |
摘要 |
A stereo demodulator capable of demodulating a composite signal without performing a switching operation is disclosed. A subcarrier generating circuit generates a square wave subcarrier signal V1 of 38 KHz which is in turn converted into a triangular wave subcarrier signal V4 of 38 KHz synchronized with the square wave subcarrier signal V1. The composite signal is converted into a current signal i which is then amplified by a voltage-controlled amplifier whose gain varies in accordance with the triangular wave subcarrier signal V4 applied thereto as a control voltage. Since the voltage-controlled amplifier is of such a type that the gain thereof logarithmically varies in accordance with the control voltage, the composite signal is amplified by a gain which varies substantially sinusoidally in accordance with the triangular wave subcarrier signal V4. As an output of the voltage-controlled amplifier is in the form of a pair of currents iR and iL which vary complementarily to each other, the signals represent right and left channel signals.
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申请公布号 |
US4651106(A) |
申请公布日期 |
1987.03.17 |
申请号 |
US19860824061 |
申请日期 |
1986.01.30 |
申请人 |
NIPPON GAKKI SEIZO KABUSHIKI KAISHA |
发明人 |
YOKOYAMA, KENJI |
分类号 |
H03D1/22;H04H40/45;H04H40/72;(IPC1-7):H03D1/02;H04H5/00 |
主分类号 |
H03D1/22 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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