| 摘要 |
PURPOSE:To obtain a natural presence by sharing output levels of left and right rear channels depending on the ratio of the level of left and right front channel input signals. CONSTITUTION:The above processor is provided with a divider 6, a logarithmic amplifier 7, a voltage controlled attenuator(VCA) circuits 8,9, an inverse amplifier 10, a variable resistor 11 and averaging circuits 12,13 in addition to differential amplifiers 1,4,5, a phase shifter 2 and an inverse amplifier 3. Then the divider 6 calculates an amplitude ratio of an original signal of both channels, the logarithmic amplifier 7 applies logarithmic transformation to the amplitude ratio to output a logarithmic amplitude ratio signal. Then the variable resistor 11 adjusts the amplitude of the logarithmic amplitude ratio to output a reference voltage signal, the VCA circuits 8,9 receive an indirect signal and uses the reference voltage signal to adjust the amplitude of the indirect signal thereby outputting a rear channel signal. Thus, a natural presence is realized. |
