| 摘要 |
A compatible AM stereo system employing a modified quadrature modulation scheme where the gain in the quadrature-phased channel, and thus the phase angle between the L and R modulated phase components of the composits modulated signal, is dynamically varied with changing modulations conditions. In the transmitter, a matrix cct.(40) adds and substracts L and R audio signals to produce sum (L+R) and different (L-R) signals. An analog divider(54) adjusts the gain of the (L-R) signal in accordance with a gain control signal(AQ). The (L+R) and gain adjuster (L-R) signals are transmitted on two quadrature-phased carriers by a quadrature AM(QAM) transmitter(50).
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