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在数字电路中,常用单稳电路进行脉冲宽度变换。适当选取单稳电路的时间常数,可获得宽度远大于输入脉冲宽度的输出脉冲。但用这种电路所获得的展宽脉冲,其幅度与输入脉冲幅度无关。若要使输出幅度与输入幅度成比例,一般采用图1所示的由二极管和电容器构成的脉冲展宽电路。图1(a)适用于输入脉冲为正极性情形,图1(b)适用于输入脉冲为负极性情形。当输入脉冲到来时,二极管D导通,输入电流经二极管正向电阻R对电容C充电;输人消失后,二极管D成反向偏置。由于
In digital circuits, commonly used monostable circuit for pulse width conversion. Appropriate selection of the time constant of the monostable circuit provides an output pulse that is much wider than the input pulse width. However, the width of the pulse obtained by this circuit is not related to the amplitude of the input pulse. To make the output amplitude proportional to the input amplitude, generally used in Figure 1 by the diode and capacitor pulse width expansion circuit. Figure 1 (a) applies to the input pulse is positive, Figure 1 (b) applies to the input pulse is negative. When the input pulse arrives, the diode D turns on, the input current through the diode forward resistor R to charge the capacitor C; input disappears, the diode D reverse bias. due to