| 摘要 |
PURPOSE: To provide an analog signal level adjustment device capable of performing multi-stage level changeover with less number of parts, an analog signal adder capable of changing the ratio of two signals in multiple stages and a facsimile equipment using them. CONSTITUTION: This device is composed of a pulse width modulation PWM generation circuit 11, an analog switch 13 for switching analog signals and ground or switching the analog signal A and the analog signal B by PWM signals, a filter 14 for smoothing the output of the switch 13 and a control part 16 for controlling the pulse width of the PWM signals. Also, the facsimile equipment uses channel monitoring signals for the analog signals or the facsimile equipment uses the opposite phase signals of reception signals and transmission signals for the analog signals A and B. |
