Title :
Nonlinearity compensation circuit for voltage-controlled oscillator operating in linear frequency sweep mode
Author :
Kang, B.K. ; Kwon, H.J. ; Mheen, B.K. ; Yoo, H.-J. ; Kim, Y.H.
Author_Institution :
Dept. of Electr. Eng., Pohang Inst. of Sci. & Technol., South Korea
fDate :
12/1/2000 12:00:00 AM
Abstract :
A circuit that can compensate for nonlinearity in frequency modulation of a voltage-controlled oscillator (VCO) is proposed. The circuit uses a fixed-length delay line and an analog phase-locked loop (PLL). It sweeps the frequency of VCO output linearly in time and easily adjusts the rate of frequency sweep. For a VCO operating in a frequency range of 5.3-5.4 GHz, the nonlinearity in frequency modulation was measured by observing the beat frequency fB(t) between the VCO and delayed VCO outputs. The deviations of fB (t) of ~28 % from its average values (2, 5, and 10 kHz) were reduced to <2% after compensation, indicating that the linearity in frequency modulation was improved significantly independent of the rate of frequency sweep
Keywords :
compensation; frequency modulation; microwave oscillators; phase locked loops; voltage-controlled oscillators; 5.3 to 5.4 GHz; FM nonlinearity; FMCW radar; SHF; VCO nonlinearity compensation circuit; analog PLL; analog phase-locked loop; fixed-length delay line; frequency modulation nonlinearity; linear frequency sweep mode; radar altimeter; voltage-controlled oscillator; Antenna measurements; Chirp modulation; Circuits; Delay lines; Frequency measurement; Frequency modulation; Linearity; Phase locked loops; Radar measurements; Voltage-controlled oscillators;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
