| 摘要 |
PURPOSE:To vary the mixing degree in response to the difference signal level between L and R signals and to reduce noise to prevent the deterioration of separation, by providing a subtractor, a waiting circuit, an envelope detector, etc. to a noise filter connected to an FM receiver. CONSTITUTION:A filter B is connected to an FM stereo receiver A, and a subtractor 12 is provided to the filter B to deliver the difference signal between L and R channel signal from the receiver A. This difference signal is applied to a waiting circuit 13, and this signal 13 increases the frequency level which is audible to human ears. The L and R signals delivered from the circuit 13 are fed to an envelope detecting circuit 14 to deliver the DC voltage corresponding to the levels of L and R signals. This DC voltage controls the resistance value of a voltage variable element 18, and the output of the element 18 controls a switch 9 which supplies the output of a level detector 7. Then the mixing degree is increased when the difference signal is small to reduce noises. This prevents the deterioration of separation. |
