THE DIGITAL PREDISTORTION OF NONLINEAR FREQUENCY-MODULATION OF VOLTAGE-CONTROLLING-OSCILLATOR IN MM-BAND

The reason and rectificatian method of the non-linear frequency modula tion of voltage-controlling-oscillator in millimeter-wave band have be en presented in this paper. The digital predistortion for the controll ing signal of the varactor in VCO possesses high rectification sensiti vity, simple circuit and convenient adjustment. The method can be used in mm-wave and Microwave VCOs that are fabricated by all kinds' trans mission lines, and can eliminate the dispersion of FM characteristic i n VCOs that are usually caused by the machining deviation and the inco nsistent parameters of semiconductors. The digital predistortion techn ique has been applied in NRD-guide VCO in Ka-band, which main performa nces are: 10 = 36.30648GHz, the frequency-stability reaches 2.26 x 10( -5), the maximum frequency-deviation is ISOMHz, the linear-FM error is less than 5%.