| 摘要 |
PURPOSE:To simplify the circuit configuration of an amplitude limiter, by using reproduced FM video signals as the 1st input and output signals passed through an LPF as the 2nd input and providing the 1st amplitude limiting amplifier which fetches the differential amplification output between both the inputs, and then, inputting the differential amplification output in the 2nd amplitude limiting amplifier. CONSTITUTION:When reproduced FM video signals are inputted in a negative feedback amplifier 21 from a terminal 20, low-frequency components of the inputted signal components are reduced in gain because of feedback by an LPF22. On the other hand, the gain against the high-frequency components becomes larger and the high-frequency components are outputted after amplitude limitation. On account of this action, the output of the negative feedback ampli fier 21 becomes that the output of high-frequency carrier components becomes sufficiently larger in amplification ratio than the low side band components of the low-frequency. Therefore, only one LPF is sufficient in such a circuit. |
