A digital approach for automatic tuning of continuous-time high-Q filters

A digital scheme for automatic tuning of continuous-time high-Q filters is proposed. The tuning scheme uses the phase information for both frequency and Q-factor tuning, therefore, the relationship between the filter´s passband magnitude and Q is immaterial. Due to the digital control of the tuning loops, only one loop is active at a given time interval, which eliminates the need for a slow Q tuning loop, improves stability and reduces tuning time. Experimental breadboard tests verify the operation where approximately 1% tuning error is accomplished using the offline tuning algorithm.