| 摘要 |
PURPOSE:To adjust an output level without fluctuating an output impedance by connecting a circuit by which one of a ladder circuit connects with the 1st power supply and the other connects with a path connecting to the 2nd power supply via the 1st resistor with the 2nd power supply from a control input terminal via the 2nd resistor. CONSTITUTION:A connecting point of each ladder resistor weighted respectively by ladder resistors 3-9 is connected with a DA output 21 via a level selection analog switch. Further, the ladder resistor 9 is connected with the 1st power supply 10, the ladder resistor 3 is connected with the 2nd power supply 19 via a resistor 1 for deciding amplitude at no load and to the 2nd power supply 19 via a control input terminal 20 and a resistor 2 for deciding amplitude. A resistor is added between the ladder circuit and the power supply and other level adjusting resistor is changed in this way, and the analog output amplitude is adjusted easily without giving effect onto the input circuit of the next stage and remarkable increase in the externally mounted components and power consumption.
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