A voltage - controlled oscillator resistant to variations of the process, voltage and temperature is presented. The proposed method allows to detect and compensate the control voltage value deviations due to the process variations. The system stabilizes the voltage val¬u¬e during the Voltage-Controlled Oscillator (VCO) operation and therefore improves the circu¬it reliability and reduces the parameter variability. The mixed-signal circuit is dete¬ct¬i¬n¬g the changes in input reference voltage values, and based on the deviation direction, reduces its impact. The compensation system is adjusting the reference signal value at the VCO operati¬on start. The proposed system is compatible for most high-speed data links and is implemented with a standard VCO block.