| 摘要 |
PURPOSE:To attain the miniaturization by forming the modulator with two time-division multiplex means, a multiplier means multiplying both outputs and a D/A converter D/A-converting its output. CONSTITUTION:I (t), Q (t) being biphase digital signals 1, 2 are subjected to time-division by using a selector 8a. Similarly, the output of an oscillator 7 and biphase local signals IL (t), QL (t) passing through a phase shifter 5 are subjected to time-division by using a selector 8b. Then the signals subjected to time-division by the selectors 8a, 8b respectively are multiplied by a multiplier 9, and I (t)XIL (t) and Q (t)XQL (t) being outputs of the multiplier 9 subjected to time division are synthesized by using an adder 10 and a latch 11 and resetting the latch 11 at each other period with respect to the transmission speed. The output is converted into an analog signal at a D/A converter 3 and it is outputted, or other components than the D/A converter 3 are formed by one ROM. Thus, only one D/A converter requiring a large circuit scale is enough for the purpose. |
