| 摘要 |
PURPOSE:To attain the temperature compensation, by using a signal via differential logical circuit and a filter having the same temperature characteristics as the signal circuit as a bias input of a balancing mixer, in a balancing digital linear polyphase modulator. CONSTITUTION:A digital signal applied to input terminals 1, 2 is read in flip- flops (FFs) 4, 5 with a timing signal from an input terminal 3, each signal is amplified at differential logical circuits 16, 17, the frequency band is limited at low pass filters 18A, 19A, and phase modulation is done with a carrier signal having an orthogonal relation with a local oscillator 22 at balancing mixers 20, 21. The other bias input of the mixers 20, 21 is obtained by stepping down a signal of a rectangular wave oscillator 31 into 1/2 with FFs 32, 33 having the same temperature characteristics as the FFs 4, 5, and after the result is amplified into a specified level at differential logical circuits 34, 35 having the same characteristics as the circuits 16, 17 and the AC component is eliminated at low pass filters 36, 37, and the DC fluctuation of the signal rate of the mixers 20, 21 is compensated complementarily. |
