The voltage controlled digital analog oscillator and the frequency synthesizer using the same

The present invention is an invention relating to an oscillator and a frequency synthesizer. In particular to a voltage controlled oscillator analog and digital frequency synthesizer using the same. The present invention is an oscillator that the frequency of the output signal varies with the digital value input to the voltage and the digital input that is input to the analog input terminal, and the intermittent voltage to the first threshold voltage and second threshold voltage magnitude input to the analog input the comparison, and provides a voltage controlled oscillator including a digital-to-analog digital tuning device for changing the digital value input to the digital input terminal depending on the result. It also provides a frequency synthesizer using the same. Oscillator according to the invention and a frequency synthesizer noise is ever eumyeonseodo has the advantage that can obtain the frequency of the output bandwidth. Oscillator (oscillator), a frequency synthesizer (frequency synthesizer), VCO (voltage controlled oscillator).