| 摘要 |
PURPOSE:To effectively reduce the shock noise of a switching signal, by supplying the output of a differential amplifier consisting of two transistors biased by a constant current source to a floor circuit consisting of four transistors. CONSTITUTION:Assuming a voltage at the base of the transistor TR2 as Vd and the current of the constant current source 8 as I0, the collector current of the TR3, that is, the current value Ic of the current source of a voltage floor circuit is shown in equation I. In such a case, (q) represents the charge of electron, and K a Boltzmann's constant, and T an absolute temperature. Also, the open circuit voltage gain Av of the differential amplifier by TRs 4, 5-7 is expressed as Av=alphaIc assuming (alpha) as a proportional constant. The differential amplifier is used as a voltage floor, and a transmission amplification degree Ad to terminals 51-54 is expressed as Ad=Av/(1+Av). And the collector current of the TR3 changes moderately since a differential circuit is used, and the delivery fluctuation of bias at the terminal 54 is reduced at a low level, and also, the shock noise at the time of switching is small.
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