| 摘要 |
PURPOSE:To enhance the stereophonic effect without lowering the noise properties even at reception of the weak electric field by increasing the stereophonic feeling with addition of the sound image magnifying device in case the antenna input signal level is low. CONSTITUTION:The output of stereo demodulator 7, which delivers the stereo signals supplied to antenna 1 as demodulation signals Lout and Rout, is distributed into three parts to be applied to space transmission properties additional circuits 20 and 21 forming variable sound image magnifying circuit 18 and 19 as well as to linear switches 22 and 23. At the same time, the output signals magnified the stereo feeling of signals Vout and Rout are applied to switches 22 and 23 via circuits 20 and 21. Then switches 22 and 23 are controlled by the output of level detector 8 which detects the level of IF amplifier 5, and the output of the two different types of signals systems supplied to switches 22 and 23 with different frequency properties are controlled. The frequency properties are changed continuously to increase the magnifying effect of the sound image. Switches 22 and 23 of circuits 18 and 19 are formed with the differential amplifiers. |
