My name is Lutz and I am from Bremen/Germany. I am not a physicist but an electronic engineer - mostly interested in analog electronics. I have worked for 10 years in electronic industries and for more than 20 years as a lecturer at a university. Now I am retired and, therefore, I have enough time to concentrate on my favorite subject "Analog Signal Processing" - in particular, active filters and harmonic oscillators. I am looking forward having nice discussions with some of you.