| 摘要 |
PURPOSE:To always recover a signal whose duty ratio is 50% by providing a feedback circuit feeding back a gain of an amplifier or a threshold voltage of a comparator so as to make smooth signals outputted respectively from integration devices equal thereby making the duty ratio by waveform shaping output signals in phase and in opposite phase equal to each other. CONSTITUTION:An input signal A is amplified by an amplifier 1 to be an amplified signal B. The amplified signal B is compared with a threshold voltage VTH at a comparator 2 and waveform-shaped and the result is outputted as a waveform shaped output signal CA in phase with the input signal A and a waveform shaping output signal CB in opposite phase to the input signal A. Then the waveform shape output signals CA, CB are integrated by an integration device 3 respectively and become smoothed signals DA, DB. A difference between the smoothed signals DA, DB is amplified by a differential amplifier 4 and the result is fed to a gain control circuit 5. Thus, even if there is a difference between the smoothed signals DA, DB, the gain of the amplifier 1 is fed back so as to decrease the difference, then the actual waveform shaping output signals CA, CB are pulses whose duty ratio is both 50% as show in an alternate long and to short dashes line in figure. |
