00261nam a2200109Ia 4500008004100000041001200041082001100053100001600064245005900080260000600139650000600145221030s9999    xx            000 0 und d  aEnglish  a105.23  aL. W. Couch 0aDigital & Analog Communication Systemscby L. W. Couch  c0  aB