Wideband FM detection using an adaptive second order TDTL

In this work a time delay tanlock loop (TDTL) with an adaptive loop mechanism for faster acquisition and more reliable locking is proposed. The adaptive loop is designed to preserve the high SNR properties of the second order TDTL and overcomes its frequency locking limitation. This achieved by adjusting the loop digital filter coefficients and the digital controlled oscillator frequency when the system is subjected to large frequency disturbances that cause the loop to go out of lock. The sensing of the frequency disturbances and the adaptation process is automatically controlled by a finite state machine (FSM).