Automatic tuning of frequency and Q-factor of bandpass filters based on envelope detection

The paper discusses an approach using very simple tuning circuitry based on the envelope detection method. A second-order bandpass filter is used as a demonstration vehicle. The complete tuning circuit consists of frequency and Q-factor tuning blocks, and operates on a 3 V power supply. Due to its simplicity, this method can be used for automatic tuning of high-Q bandpass filters at very high frequencies with very little circuit overhead.