OSCILLATOR PHASE NOISE AND SAMPLING CLOCK JITTER RETHNAKARAN PULIKKOONATTU

ABSTRACT. This technical note presents and overview of oscillator phase noise and its characteristics, which are paramount to the understanding of digital receiver and modems. Oscillators used in practical systems deviate from ideal spectral characteristics. Due to this, there arise unpleasant performance issues. A/D and D/A converters used in digital receivers use sampling clocks (for sampling or sample and hold) which are derived from sinusoidal oscillators. Phase noise present in the source oscillator could translate to jitter in clock waveform. There is an established relationship between the mean square jitter and phase noise spectrum. The mathematical formula to compute the rms phase jitter from a given oscillator phase noise spectrum is derived and furnished with examples. The result obtained thus matches with those obtained using a web based tool [1