| 摘要 |
PURPOSE:To eliminate completely the noises out of the high frequency messes which are superposed which are superposed on each other in the form of the in-phase components, by using the noise component that cannot be deleted by a differential pair of transistors of the next stage among those high frequency messes superposed on each signal as the feedback signals and reducing the noises superposed on the 1st and 2nd signals with said feedback signals. CONSTITUTION:The 1st and 2nd video signals superposed with noise waveforms P1 and P2 are supplied to the 1st input terminal of the 1st and 2nd subtractors 18 and 19 respectively and subtracted by the feedback signal of the 2nd input terminal. This feedback signal is obtained by adding together the differential outputs amplified by a differential amplifier 20 and therefore used as an addition output of each in-phase noise component that could not be deleted by the amplifier 20. Therefore both subtractors 18 and 19 undergo the substantial differential amplification. The 1st and 2nd video signals perform the subtracting operations only to the noises. While the amplifier 20 lowers the noise level by an amount that cannot be deleted by the amplifier 20. |
