A DCO Gain Estimation Algorithm for Digital Phase Locked Loops

An adaptive DCO (Digital Controlled Oscillator) gain tracking algorithm for an ADPLL (All Digital Phase Locked Loops), which is working as a frequency synthesizer, is presented in this paper. By using this DCO gain real-time tracking method, the requirement of DCO linearity and the complexity of the circuits can be highly decreased. The result shows that with introducing a small amount of training signal the actual DCO gain can be accurately estimated in short time with a fine resolution and the EVM (Error Vector Magnitude) performance is improved significantly.